| 00:00 | So the multiple, multiple choice is gives me a good opportunity to expand |
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| 00:07 | them. Share the the exam on , I don't know where this |
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| 00:24 | That's on canvas. OK? That's . We can do the other |
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| 00:59 | We're gonna do this anyway. Right. Yeah. Since nobody did |
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| 01:08 | , I can do what I So we on canvas isn't where, |
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| 01:41 | on canvas is the that exam? . What? There's an exam in |
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| 01:49 | if you go to the files tab There is a final exam that's uploaded |
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| 02:15 | and we waste a lot of this . So I think this is all |
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| 02:21 | by to somebody else. OK? Brown from previous question. So here |
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| 02:27 | 12. So I didn't share this you. No, I did get |
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| 02:35 | . Yeah, because I put it somewhere else. Yeah, you |
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| 02:51 | All right, we can just do here. OK. Chris be |
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| 02:58 | They, they have mhm All As long as there's interest in doing |
|
| 03:08 | . All right. Uh So the multiple multiples, what are the |
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| 03:12 | about this? These are basically for and false. So the top gives |
|
| 03:17 | a heading for it, right. these four questions are first for |
|
| 03:21 | are related to the gamma ray OK. So first one true or |
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| 03:27 | is a measurement of gamma ray intensity to the disintegration of plutonium potassium and |
|
| 03:35 | . True or false. What three false? Why is it false? |
|
| 03:45 | uh uranium and thorium. This is difference than the one you printed. |
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| 03:51 | is on canvas. Yeah, it's not glutton like those three elements that |
|
| 03:59 | part of the uh uh basically the ray, one of the gamma ray |
|
| 04:05 | actually distinguished between those with spectral gamma distinguished between those three elements, |
|
| 04:13 | Uh which of the three was related organics, which of the 22 of |
|
| 04:17 | are related to claves, which two those which were related to organic. |
|
| 04:28 | have a lot of studying to do . You remember we went, we |
|
| 04:35 | through a uh subsurface example where we at that uh and uranium is related |
|
| 04:44 | organic tai thorium clays. So typically are grouped the pats thorium together some |
|
| 04:51 | those because that's clay indicator and then uh uranium uh looks separately particularly that's |
|
| 05:02 | and unconventional pick sweet spots, things that. People look at the uranium |
|
| 05:08 | , we looked at an example of gamma ray log has a depth of |
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| 05:16 | of 3 ft and a resolution of inches to repulse. Yeah, |
|
| 05:28 | it's not, it would be much if that were true, it has |
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| 05:31 | depth of investigation for the tool of inches and a uh vertical resolution of |
|
| 05:39 | ft. The opposite of that works in hard rocks as the SP |
|
| 05:50 | So the SP is often substituted, example of this. Again. Remember |
|
| 05:58 | looked at that, we talked about the field lines are pulled into the |
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| 06:02 | resistivity formations. Uh Remember how you how do you pick, right? |
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| 06:09 | do you pick be boundaries? Where you pick them when you want? |
|
| 06:18 | were three rules we had for picking zoning squaring logs. If you remember |
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| 06:24 | were the three roles, the inflection , the be boundaries that inflection |
|
| 06:41 | your memory specifically went through, that through the reasoning as to why as |
|
| 06:47 | pull it, pull a tool up a borehole, you approach a pet |
|
| 06:52 | , right? The signal is going be increasing, it's could be increasing |
|
| 06:56 | an increasing rate. Second derivative when straddles the bed boundary, what's gonna |
|
| 07:03 | is now it's still gonna increase. we pull the tool into the |
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| 07:07 | it's gonna be increasing at a smaller . And therefore the bed boundary on |
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| 07:13 | tools is picked at the inflection OK. Which is what that |
|
| 07:18 | That's basically when the sign of the derivative changes uh or the other tool |
|
| 07:29 | . And the reason this comes up , if your number in very resistive |
|
| 07:34 | , you literally can't use the but it's all smeared out. |
|
| 07:38 | And you can't tell where the PF are. You had a specific slide |
|
| 07:43 | it's not a slide but a powerpoint where we looked at that. And |
|
| 07:49 | , uh it's even if you have high resistivity contrast, it's hard to |
|
| 07:54 | up that boundary still at the inflection , it just doesn't really look like |
|
| 07:58 | . Uh So that was one of big rules, right? That inflection |
|
| 08:05 | over the other 21 was mentioned already the maximum development of the log that |
|
| 08:12 | either direction where you pick it because the closest to the true answer. |
|
| 08:19 | , in thinner beds where you have bed, right? You're never gonna |
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| 08:23 | the maximum development of the law because averaging to adjacent beds, but your |
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| 08:29 | value will be the maximum development of law, right? Therefore, you |
|
| 08:37 | pick that, that's the point where would make shoulder back corrections from that |
|
| 08:43 | development. What was the third Yeah, you, you, you |
|
| 08:54 | only where it affects your calculation, it is. So again, for |
|
| 09:00 | gamma ray, why did they introduce exception to the gamma ray as long |
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| 09:05 | we're on this project? The gamma ? Yeah, absolutely because there's statistical |
|
| 09:17 | in it and therefore the peaks really what you want because that's reflected with |
|
| 09:23 | . So you go through the average of gamma ray at the peak, |
|
| 09:27 | ? You try to average that high . Notice it, it's um whenever |
|
| 09:34 | showed you the logs, the gaming noisier than the speed of the brain |
|
| 09:39 | because of that reason. All Uh And so works poorly in the |
|
| 09:46 | rock of the sp. So the , so that one's true uh is |
|
| 09:52 | useful for determining the degree of shass a formation. Yeah, it's |
|
| 10:01 | It's useful for it. Can you quantitative with it? That's pretty |
|
| 10:06 | Just beware of generating four significant figures this is how j something that's based |
|
| 10:14 | the game, I think, particularly you're normalizing based on, on uh |
|
| 10:19 | either the overburden or the under burden that formation, if you're going to |
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| 10:25 | the under burden or overburden, which should you be using? Mentioned that |
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| 10:32 | the course too. I know which one is more of, of |
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| 10:39 | sort of depositional setting, which one more to that depositional setting, an |
|
| 10:45 | burden or an overburden, the one of you had to get it |
|
| 10:53 | ? Uh It's not necessarily closer, it's the end member of, |
|
| 10:56 | So usually you have a high energy and then the energy gets lower and |
|
| 11:01 | as you, as you approach the turbo die or whatever it is, |
|
| 11:06 | ? So the overburden would be the of choice. It's probably gonna be |
|
| 11:10 | one that's more related to the clays are deposited. Uh in that |
|
| 11:16 | Whereas the under burden is a basically different whole different sequence. So it'd |
|
| 11:22 | less likely to be related to Uh OK, the gamma ray have |
|
| 11:30 | come up with their places too. so it is often useful. |
|
| 11:34 | but so at least a qualitative Again, all of these, the |
|
| 11:40 | and, and the gamway are about reservoir versus non res rock. And |
|
| 11:46 | you remember we went through several instances high gamma ray would be your reservoir |
|
| 11:53 | opposed to low gamma ray, which true in classic typically. Yeah. |
|
| 12:00 | radioactive Dolomites, for example, um if you had something related to a |
|
| 12:07 | , granite wash or something like that your reservoir, that would probably be |
|
| 12:12 | higher rating of activity than adjacent possibly higher. Fair enough. Number |
|
| 12:20 | , which are true for dual induction work well in high salinity muds. |
|
| 12:28 | false because you're supposed to be thinking with the dual induction log. And |
|
| 12:37 | what happens then again, if you at the focal current, it's induced |
|
| 12:42 | the borehole, what will happen if have a high salinity mud basically will |
|
| 12:47 | out the tool most of your current interior in the borehole as opposed to |
|
| 12:54 | the Bodin nation. Yeah, we'll about later life in a second. |
|
| 13:00 | , they do not work well. high salinity funds, you won't get |
|
| 13:05 | . The medium induction is close to deep induction when there is little |
|
| 13:18 | And that's true because your act that, that is true. That's |
|
| 13:24 | about right. The shallow tool the usually read is dominated by RXO. |
|
| 13:32 | medium gets close to. That means invaded to that point. And if |
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| 13:37 | not, it means that it's closer RT. So your invasion shallow, |
|
| 13:42 | ? That led to you being able use those three logs in combination with |
|
| 13:48 | , what kind of block liking the that it was called, it's called |
|
| 14:00 | tornado plot. So you use the deep and shallow with a tornado plot |
|
| 14:08 | infer what the diameter of invasion what RXO was and what RT |
|
| 14:16 | you had basically three logs and three you were gonna solve for in that |
|
| 14:21 | . You get a little bit of , I think in one of the |
|
| 14:23 | , right? Ok. Uh may used with the medium induction and spherical |
|
| 14:31 | logs to estimate depth of invasion. and R zero. That's the one |
|
| 14:39 | just talked about. So obviously true corrected for invasion effects with the use |
|
| 14:49 | spine and rib clots. No, just talked about it being a tornado |
|
| 15:00 | . We use the spine and rib for what remember the density log, |
|
| 15:10 | we use the spinal ribs plot along the density log or or for correcting |
|
| 15:24 | mud cake, right. So it us up to right with the correction |
|
| 15:30 | about 0.15 g per CCS right density us to correct back to the |
|
| 15:38 | which was the answer you wanted. you have too big a mud |
|
| 15:41 | you're basically just gonna make a mud density, right? So all of |
|
| 15:46 | ribs actually curl over. So why that limit, the amount of fraction |
|
| 15:51 | can make? Because all of those basically coalesced before they curl back, |
|
| 15:57 | ? Everything's measured dominated by mud. you can't find out which rib you |
|
| 16:03 | on. Yeah. Right. He talking about that later. Uh So |
|
| 16:11 | , they are not corrected. That be the tornado chart. Yeah, |
|
| 16:17 | like these because it tests your conceptual of things. Uh The other thing |
|
| 16:25 | will tell you is every time I've exams like this, that uh your |
|
| 16:30 | , the student's grade on the true false questions, correlates high, very |
|
| 16:36 | with the rest of the test. they, they, uh, they're |
|
| 16:41 | try to convince me that they aren't of anything. The, the evidence |
|
| 16:46 | that it is, can't do the unless you understand the terminology. Understand |
|
| 16:53 | concepts which statements are true for lateral . Remember the difference between an induction |
|
| 16:58 | and a lateral log. Yeah, of them, one, you've got |
|
| 17:07 | on one, you've got series. already told you that induction logs were |
|
| 17:15 | . So must be the right. what we're left with. So the |
|
| 17:20 | hole, the invaded zone and deep and the layers, different layers are |
|
| 17:28 | in series for this tool, everything in series. It's because it injects |
|
| 17:35 | rather than inducing a current around the , it injects the current through the |
|
| 17:41 | and that it has to curl back the tool. That's why the layers |
|
| 17:45 | more or less in series or li this one works best in well based |
|
| 17:53 | to answer this question for you. false because the mud is in |
|
| 18:02 | So if I can't get the current the mud, right? Oil based |
|
| 18:06 | , in particular, I if I get current through the mud, I |
|
| 18:11 | not get a reading from the So oil based muds uh actually the |
|
| 18:16 | log is preferred. This is why they switched in the deep water oil |
|
| 18:20 | muds, they all run almost exclusively logs. What was the downside of |
|
| 18:27 | that we talked about then that and to thin beds again, why is |
|
| 18:36 | a problem for the induction log is your shales are more conductive than your |
|
| 18:42 | , particularly if they are oil So you will just be dominated. |
|
| 18:47 | , your resistivity measure will be dominated the sands will be done. Sorry |
|
| 18:55 | this tool, they will be dominated the shales because they're more conductive. |
|
| 19:00 | . And that's not what we it's not what we wanna diagnose we |
|
| 19:04 | . We wanna know how much oil in our sin. So how did |
|
| 19:09 | respond to this? The industry respond this. There's a tool available now |
|
| 19:17 | the Tri Ayal tool, right, it actually induced the current, not |
|
| 19:23 | around the below, we have a borehole here perpendicular to that. So |
|
| 19:28 | beds were in series now. So got more responsive to the sands, |
|
| 19:34 | ? For a series combination. OK. Great. So may be |
|
| 19:42 | to indicate depths in which there are oil saturation. This one ought to |
|
| 19:49 | obvious because we did the uh quick exercise. The second part of that |
|
| 19:56 | , he was looking for movable So, absolutely, that's true. |
|
| 20:01 | actually had an example where you worked . People haven't done the homework yet |
|
| 20:07 | . Got a lot of work. come out before Wednesday. If you |
|
| 20:12 | not turn those in, you will getting a zero on those homeworks. |
|
| 20:17 | need to get them in a quick exercise with the homework that we started |
|
| 20:25 | class, right? But most of got almost all the way through |
|
| 20:30 | but we didn't get started on the oil. That was pretty straightforward. |
|
| 20:36 | gotta do is look at those three that actually had hydrocarbons in it and |
|
| 20:41 | see the repo changed in those three . So you could calculate, you |
|
| 20:46 | calculate how much movable oil and what saturation difference was. That was the |
|
| 20:52 | part of that exercise. Pretty Something like what was going on, |
|
| 20:58 | is where you were asked to do . You could also do that on |
|
| 21:02 | line if you want some sense, , making the body more obvious. |
|
| 21:13 | ? C measures a series combination of flush zone resistivity and the true |
|
| 21:24 | It was like three days. obviously, it's true because I just |
|
| 21:29 | it was true, you know, the measurement by inducing a poco current |
|
| 21:37 | the borehole. Then obviously both because just told you it didn't do |
|
| 21:42 | right. Like a few minutes it injects currents through added guard |
|
| 21:48 | What are termed guard electrodes to the keeps it from returning through the mud |
|
| 21:54 | by those guard electrodes. So the has to directly enter. So that's |
|
| 21:59 | puts everything in series problem. Street four, which statements are true for |
|
| 22:09 | law has a bad resolution of about inches. No, even the more |
|
| 22:20 | density logs run slowly, you can down to about a foot or so |
|
| 22:25 | conventional density is more like 3 ft everything else. So you have |
|
| 22:29 | to get that higher illusion, you to run it slowly, do a |
|
| 22:33 | more signal averaging, et cetera and use the latest generation of tools. |
|
| 22:39 | that is false, heavy minerals cause porosity read too high. Yeah, |
|
| 22:53 | can, you can uh we're gonna about uh the other neutron log in |
|
| 23:00 | . But uh what's the way to your way through this density log measures |
|
| 23:05 | the amount of rock or the pore measures the rock. So if we |
|
| 23:11 | pr for example, we're gonna read little rock or too much rock. |
|
| 23:19 | , we're gonna eat too much. . So therefore the broth is gonna |
|
| 23:25 | out too low. OK. The other way to think about that |
|
| 23:31 | the neutron log, right? That a little dumb because the new travel |
|
| 23:37 | doesn't care about fire, right? right measures the electron density of the |
|
| 23:43 | by the scattering of gamma rays off proton. What is the density log |
|
| 23:52 | ? Remember each tool I went through told you the fundamental physics that the |
|
| 23:57 | measured right, gamma rays measuring natural . The SP I guess we haven't |
|
| 24:07 | an SP question but I can ask that. Now the SP measured it |
|
| 24:18 | a resistivity contrast between the mud filtrate the formation water. OK. The |
|
| 24:25 | log measured. These are things you have to know to understand how the |
|
| 24:31 | is gonna respond. For example, I were to ask you, can |
|
| 24:37 | quantitatively measure permeability from the SP No, obviously it's measuring a resistivity |
|
| 24:48 | between the mud filtrate, right? , and and the formation of |
|
| 24:53 | Is there a permeability anywhere in the equipment for the SP No, not |
|
| 25:01 | the saturation. It's not measuring the . It's measuring the resistivity contrast. |
|
| 25:08 | is the density log measure the electron , right? It measures the electron |
|
| 25:20 | via compton scattering. OK. So electron density is that gonna care about |
|
| 25:29 | ? No. Is that gonna care permeability? No. So it basically |
|
| 25:37 | it measures the amount of rock. does it measure the amount of rock |
|
| 25:42 | be a fair essay question. What's density of typically density of the |
|
| 25:56 | The intermediate one? What's the what's the grain density of limestone? |
|
| 26:05 | figures is enough dolemite. Another thing told you to remember 2.8 put a |
|
| 26:15 | there if you want 285 and then 265, right? So what's the |
|
| 26:24 | of water? One nominally? But already have a factor, let's say |
|
| 26:31 | or rock. What's a typical Maybe 25% give or take? So |
|
| 26:40 | already have a factor of four times rock with 2.5 times the density, |
|
| 26:46 | is a factor of 10. So 10 times more sensitive to the rock |
|
| 26:51 | it is the fluid. So you , you're measuring the amount of rock |
|
| 26:57 | the density line I could ask you exactly that question. Why do we |
|
| 27:03 | that as opposed to the neutron law long as we're here, what's it |
|
| 27:13 | ? It's measuring the hydrogen density? , actually protons, why does it |
|
| 27:23 | that they're scattering neutrons off of Those have approximately the same mass? |
|
| 27:34 | the mass of an electron which is small. So again, you get |
|
| 27:39 | momentum transfer when you have something colliding something of equal mass. OK. |
|
| 27:46 | , it's far more sensitive to a density than it is the rock |
|
| 27:52 | So the neutron log is measuring hydrogen . Therefore, it's measuring the pore |
|
| 28:00 | . So it measures right, the of poor fluids, right, which |
|
| 28:04 | why it's so nice to run In combination with the density law, |
|
| 28:08 | is measuring the rock, they have responses that makes the combination of them |
|
| 28:15 | lithology dependent that in in that uh cross clotting exercise. What was one |
|
| 28:23 | the major plots you always used? had density on one axis, you |
|
| 28:28 | neutron ferocity of the other and therefore got a nice lithology contrast between those |
|
| 28:36 | and they basically have very different effects here quicker than I thought you would |
|
| 28:44 | late. Actually, I predicted that well, but we're not even close |
|
| 28:50 | being done. Uh So we're still density log. I got heavy |
|
| 29:00 | We did measures the electron density of formation by scattering gamma rays off of |
|
| 29:13 | . No, it gammas off of . We just went through this, |
|
| 29:18 | . Yeah, constant scattering, measuring electron density. Yes, it's not |
|
| 29:25 | it pop of protons. OK. depth of investigation increases with increasing process |
|
| 29:43 | be able to reason your way through right. It's measuring the amount of |
|
| 29:49 | increase in porosity is less rock. uh with the gamma rays get more |
|
| 29:55 | or deeper clearly, going hold them , not clearly, but they're gonna |
|
| 30:02 | deeper because they are less rock, ? Yeah. And this is why |
|
| 30:07 | actually try to summarize the tools for . Just remember a few basic facts |
|
| 30:13 | the tools. You can think your through all of these questions, maybe |
|
| 30:20 | didn't believe. all right litho density . What was that tool? Is |
|
| 30:25 | a separate tool or did we just the data from the density log in |
|
| 30:37 | different way? Answer to the second is true. Remember the density log |
|
| 30:46 | scattering versus absorption which is more sensitive lev absorption is always more sensitive than |
|
| 31:06 | . OK. Scattering just has to with right. It's an interaction which |
|
| 31:10 | not very lithology dependent for the density right? Density log. The only |
|
| 31:16 | it cares about is the density of electrons, right? That does vary |
|
| 31:22 | the bulk density or grain density of material, right? But it's not |
|
| 31:28 | as sensitive as the litho density which is actually measuring right, you |
|
| 31:34 | captured gamma rays, right? You kick out a case shell you're absorbing |
|
| 31:39 | gamma rays, right. So you you, you basically measure it's related |
|
| 31:44 | that absorption of those gamma rays. the CNL well, that's a neutron |
|
| 31:50 | . But remember we studied two density we we study the studied the standard |
|
| 31:58 | and we studied the the basically the density lit the density was about |
|
| 32:04 | the standard density is about scattering. which one is more lithology dependent lit |
|
| 32:12 | density? And that was actually quite . But remember you did this was |
|
| 32:17 | plot you had when you did basically that lithology dependent exercises. And |
|
| 32:24 | remember that it was almost with the response, it's almost independent of |
|
| 32:33 | therefore almost independent of gas. And it gave you a lithology almost |
|
| 32:40 | right? Where, where is the log at a significant lithology depends the |
|
| 32:47 | density, all right, which we're the lift of density. So provides |
|
| 32:57 | photoelectric absorption curve in addition to the density measurement just answered that it's |
|
| 33:05 | it's basically, it's it's you're analyzing same data, you're analyzing it at |
|
| 33:10 | energy, right? Uh these gamma scatter about lose energy ultimately get |
|
| 33:17 | And you're looking at a low energy of your gamma rays. OK. |
|
| 33:27 | nice for getting lithology as you found the exercise. I hope one of |
|
| 33:33 | reasons we did that was hopefully to kind of a lot of these concepts |
|
| 33:37 | obvious measures the photoelectric absorption by energy of gamma ray. It's like a |
|
| 33:47 | to me. What we just described a photoelectric measurement which is relatively independent |
|
| 33:55 | porosity. Sounds like another truth to . According to what I just described |
|
| 34:03 | developed to provide a higher resolution than conventional density. No, it's pasted |
|
| 34:10 | same tool. You're just looking at spectra and you're looking at the low |
|
| 34:15 | spectra of the gamma ray. So gonna have pretty much the same |
|
| 34:20 | The standard density fair enough should be through. Should we give kind of |
|
| 34:29 | ? Uh First thing six, which the following are true for the compensate |
|
| 34:46 | neutron law. The tool measures the density. Well, we already know |
|
| 34:51 | got problems there in a formation by scattering of gamma rays. No, |
|
| 34:57 | called the neutron log for a It's looking at scattering of neutrons off |
|
| 35:02 | proton, right. So G A would have been true if it was |
|
| 35:07 | density log, not the neutron. enough pathology has very little effect on |
|
| 35:14 | tool. No, it has a effect on the tool, right. |
|
| 35:24 | you can the the interpretation of the lo is not nearly right. Uh |
|
| 35:32 | simple as for the density log, have basically have to do Monte Carlo |
|
| 35:36 | of scattering absorption cross sections and things that. Uh Pretty much everybody used |
|
| 35:43 | be that companies did this for themselves did. Uh But nowadays, they |
|
| 35:48 | on the vendor for the tools. lithology does have remember CNL had a |
|
| 35:55 | more, much larger lithology dependence than epidermal neutron to. All right. |
|
| 36:01 | was that? What was the difference the epidermal and the compensated neutron. |
|
| 36:09 | we're here, we might as What's the compensated mean? People have |
|
| 36:18 | lot of studying to do, I tell compensate a neutron meant there was |
|
| 36:24 | any tool meant there was multiple So for example, you were measuring |
|
| 36:30 | ratio of the two detectors for the log, right? What the |
|
| 36:38 | So because the epidermal is higher so it's more scattering phenomena than the |
|
| 36:47 | or compensated tool. It is actually less lithology dependence than the standard |
|
| 36:56 | And remember you can go back and through the notes and the lithology dependence |
|
| 37:01 | that slide is significantly less for the neutron than it was the standard neutron |
|
| 37:07 | them. OK. Right. Gas the tool to read a porosity that |
|
| 37:17 | too hot. What what is this measuring the amount of poor fluid? |
|
| 37:28 | would happen if we had gas? expecting the poor space to be |
|
| 37:37 | So if we were displacing that with , we had a way too few |
|
| 37:43 | hydrogen in the hydrogen density of oil water is approximately the same. This |
|
| 37:48 | why it can't tell oil from So if we replace that with |
|
| 37:55 | which has a much lower hydrogen we would read not as much |
|
| 38:02 | It's basically measuring the amount of fluid throw, you throw a a you |
|
| 38:10 | at a wall. What happens? comes back with essentially the same energy |
|
| 38:14 | you that it hit the wall So the matrix really does not slow |
|
| 38:19 | neutrons. However, hydrogen does, measuring the amount of poor fluid fair |
|
| 38:30 | . Uh Part D plays cause the to read a porosity that is too |
|
| 38:40 | , false, it reads too high there are oh groups associated with clay |
|
| 38:47 | . But you will still measure so will measure too high a porosity. |
|
| 38:51 | the way, the neutron log is reason we had to rethink what our |
|
| 38:56 | of porosity was. Why was Because it's measuring basically the amount of |
|
| 39:05 | or fluids in the formation. And it cannot tell bound water from free |
|
| 39:11 | , bound water does not contribute to capacity. And therefore, right, |
|
| 39:17 | tool, right, we now call , the total amount of water |
|
| 39:23 | both bound and free water. I talk about that freely. Now that |
|
| 39:29 | all experts as we talked about shaley , right? We talked about found |
|
| 39:34 | free water, what that is? probably will be a question coming up |
|
| 39:40 | to that. But by the professor Professor Ha's lecture, there will |
|
| 39:45 | questions on the final on her So you cannot sleep during it, |
|
| 39:53 | ? But you can, but I suggest, you know, all |
|
| 40:01 | compensated Sonic law. This one we mean is compensated. We actually uh |
|
| 40:08 | tool, we actually send an acoustic in both directions, both up the |
|
| 40:13 | and down why did we do Does this tool is a centered |
|
| 40:24 | It can be centered, it could off that basically not in the middle |
|
| 40:27 | the borehole. Exactly. It could tilted, there can be washouts, |
|
| 40:32 | like that into first order. Combining two measurements allows us to first order |
|
| 40:39 | for that by measuring in both right? We always have a mud |
|
| 40:45 | time that we need to correct for that tool. And it allows us |
|
| 40:50 | least the first door to be able do that. Ok. So what |
|
| 40:54 | it measure? We talked about We didn't talk about what is the |
|
| 40:59 | sonic? What are we measuring? it's measuring a travel time, |
|
| 41:12 | But literally a travel time, the in travel time for two receiving coils |
|
| 41:19 | in it, it's not a coil a receiving transducer is the electrics, |
|
| 41:26 | ? So a measures the travel time the sheer acoustic energy in a |
|
| 41:32 | This is the standard compensated sign. That really is not true for |
|
| 41:39 | It's it's measuring again the standard or if you remember what it did, |
|
| 41:44 | just measured an arrival time, For the burst acoustic wave arriving, |
|
| 41:50 | gonna be the compressional wave arrives before sheer wave. So you would be |
|
| 41:57 | a compressional wave is sensitive to the of buggy porosity. One of my |
|
| 42:12 | actually being a Professor Hampton and I this question measure is sensitive to the |
|
| 42:23 | of buggy fo That's true. Uh not what was asked. I think |
|
| 42:39 | great language. Thank you. I know. I'm not sure. |
|
| 43:03 | agree with all of that. it is sensitive to the presence of |
|
| 43:07 | porosity. Again, the common thing uh I typically state is that the |
|
| 43:15 | is nonlinear in the matrix Boity linear the buggy. So, is it |
|
| 43:21 | to a yes professor hat it Is it more sensitive to the matrix |
|
| 43:27 | ? It's also right? And that's it measured it, it it measures |
|
| 43:33 | matrix ferocity because more sensitive to one with them than the other a lot |
|
| 43:42 | times. Uh And good question if had two rocks both with 20% |
|
| 43:49 | one was 10% matrix 10% bug and was 20% matrix porosity. Which one |
|
| 43:56 | be bath 10% 10% because the lower ferocity would speed up the would shorten |
|
| 44:09 | travel time more than the buggy ferocity it. So again, there's a |
|
| 44:17 | in the in the notes that Dean that acoustic logs quote unquote, don't |
|
| 44:24 | buggy porosity. That's what that It's not sensitive as sensitive to buggy |
|
| 44:30 | as it is. Matrix Nero we that directly with uh with the rock |
|
| 44:39 | data in fact, published in a uh is not sensitive to gas cycle |
|
| 44:52 | attenuation. It's the most sensitive to of any of the tools we study |
|
| 44:59 | to the point where you can't get from it cycle skipping was what um |
|
| 45:09 | attenuates so much that you actually miss first arrival and you actually sense the |
|
| 45:15 | of a later arrival. So it the travel time too large or too |
|
| 45:23 | . Yeah, too large. Whereas which also happens with attenuation, |
|
| 45:29 | So what will noise do you will it trigger early and therefore make your |
|
| 45:36 | time too short. What's it based is the fact that almost all these |
|
| 45:42 | will occur on the bar receiver? the near one because the effects are |
|
| 45:47 | for the bar receiver than would be near receiver. Case you a |
|
| 46:02 | Yeah, a long travel time is slower run. Sure. That's exactly |
|
| 46:09 | went slower and the travel time is . All right. Uh it's not |
|
| 46:22 | to gas. I just answered that is useful in conjunction with the density |
|
| 46:28 | neutron los for lithology determination. Find story right now. General what you |
|
| 46:41 | have been able to see with the of bugs by comparing mythology there |
|
| 46:48 | it's not nearly as good because all of things are going on with |
|
| 46:52 | right? What kind of things affected the uh travel time? One's |
|
| 47:00 | That's why it's called a ferocity But beyond that, what else entered |
|
| 47:04 | the things like the lithology brain contact modulus? Remember Gasman equation? |
|
| 47:16 | what a mess. That was actually a pretty equation actually. But uh |
|
| 47:21 | was barely complicated. That's the best we had for what a determines an |
|
| 47:29 | velocity. So there's all kinds of in it. The fluid modulus is |
|
| 47:33 | it, the frost in it. then the hardest thing to get was |
|
| 47:37 | frame modulus. Do you remember? , in the brain modulus, we |
|
| 47:42 | all these lithology uh and all these things that make, that almost make |
|
| 47:47 | difficult to calculate. Oh What's going if I wanna go look back through |
|
| 47:57 | that calculation right gas equation? All . So again, in terms of |
|
| 48:05 | interpretation, et cetera, we went the density to the neutron, the |
|
| 48:09 | log where interpretation got more and more . Now we get on to your |
|
| 48:15 | scan exercise, what these two are . They can't follow the progression. |
|
| 48:22 | course, here at night, a plot is useful for determining what did |
|
| 48:26 | get from your picket plot? What the slope of the line? That |
|
| 48:36 | the M, what was the intercept from the picket fly? So you're |
|
| 48:48 | a pick a plot to a ferocity one. All you have left is |
|
| 48:52 | water. Get RW. So uh one, Archie X phone and |
|
| 49:00 | that's false. Wow. I'm That's true. In fact, I'm |
|
| 49:05 | you it's true from the slope. , remember how to get the |
|
| 49:09 | You don't go take the anti lod reading numbers off the ax actions, |
|
| 49:13 | have to use a ruler of some . And that working depends on the |
|
| 49:19 | , vertical and horizontal being the same matrix travel time. Can I take |
|
| 49:27 | pick the plot and extrapolate it to porosity? That's zero. No. |
|
| 49:36 | many cycles do I have to go get the zero on a log log |
|
| 49:41 | ? And the infinite number you cannot there. However, on a Hingle |
|
| 49:46 | , you can, this is exactly what you did. You extrapolated Archie |
|
| 49:53 | zero pros on the Hingle plot, cation exchange capacity of a formation. |
|
| 50:02 | . Uh that will mean that your plot doesn't work because you're gonna |
|
| 50:07 | you have another source of conductivity. equation doesn't hold and therefore it's not |
|
| 50:13 | apply, right? And as if any of you plotted the shales |
|
| 50:17 | that pickup plot, you found that came way off, right? The |
|
| 50:22 | of the plots didn't believe me. Archie's equation does not hold in a |
|
| 50:31 | . OK. Uh formation porosity rarely that. Actually. What, what |
|
| 50:42 | you plotting on a picket plot was the X? What was on the |
|
| 50:53 | ? You had RT on the you had ferocity on the X, |
|
| 50:57 | ? It's an input, you don't it from it. You use it |
|
| 51:00 | the block. It's like you wouldn't if I ask you uh it's useful |
|
| 51:07 | RT. You would say no, you get saturation from a picket |
|
| 51:14 | A lot of, you asked me to do it. And so, |
|
| 51:20 | , particularly if you're willing to assume equals and just a sequence of parallel |
|
| 51:25 | and just interpolate. Do you remember three zones that had oil in |
|
| 51:32 | Right. Um They fell off the . You got to get your |
|
| 51:43 | Next, the Hingle plot is plotted log, log paper but common |
|
| 51:50 | No, it's plotted on Hingle paper it's plotted on Hingle paper for the |
|
| 51:57 | M value. But what, what the order? I thought? At |
|
| 52:02 | you should solve these in. What you do? First? You had |
|
| 52:06 | guess M use Hingle paper. They you a matrix, right? A |
|
| 52:12 | uh density which allowed you to take bulk density to porosity, which allowed |
|
| 52:18 | to make a picket plot, which you to get a guess for RW |
|
| 52:23 | M estimate from it, which allowed to actually the M allowed you to |
|
| 52:29 | a RW a calculation. Then as went through these in principle, you |
|
| 52:35 | refine that to get them all to to using the same properties on each |
|
| 52:41 | the plots. You have to make initial guesses. Uh and BRW may |
|
| 52:54 | determined from a Hingle pla No, doing that on a picket fly, |
|
| 53:04 | extensity or velocities may be determined by the voc of one just answered |
|
| 53:14 | No, you on a Hingle you would strap to a pros of |
|
| 53:18 | . And again, I'm still quite , I don't think any of you |
|
| 53:23 | , but still quite impressed, maybe a better word. You can take |
|
| 53:28 | equation, you can extrapolate it to fros one, you can extrapolate it |
|
| 53:33 | aros of zero and still gives reasonable for that velocity measurements. By the |
|
| 53:38 | , do not do that. That's you have a critical ferocity where |
|
| 53:44 | where the uh properties of the mixture dramatically at the percolation threshold for the |
|
| 53:54 | . OK. D may be used determine movable oil saturations if a micro |
|
| 54:00 | log or a micro SFL is Are you talking about this that you |
|
| 54:11 | have done this for that quick scan ? Right? It's exactly what you |
|
| 54:18 | . Now we move on to the Shirley sand question. The cation exchange |
|
| 54:24 | is an important parameter for shaley sand . First of all, what is |
|
| 54:30 | C ad ion exchange capacity? Nobody's to help that iron exchange facy. |
|
| 54:46 | . So we have a clay and actually have uh that have undergone gone |
|
| 54:52 | substitution of one iron typically aluminum. another example, that's usually quite nice |
|
| 54:59 | occurs fairly domin is potassium for Aluminum is plus three. Potassium is |
|
| 55:07 | one. What condition does that leave clay in? You play matrix? |
|
| 55:15 | are negative? We replaced plus three was electrically neutral with plus one. |
|
| 55:26 | does that mean about our minus charges the play, they are no longer |
|
| 55:35 | . So we end up with this of negative charges just because aluminum plus |
|
| 55:40 | is pretty high trouble when I say . But iron, if it's in |
|
| 55:46 | plus three state won't change the It's also plus three against the change |
|
| 55:56 | probably right. Yeah. So iron clay, they could if they can |
|
| 56:07 | have a fairly low and change capacity of that anyway. So everybody knows |
|
| 56:15 | end up this to me is one the reasons I can still make a |
|
| 56:20 | doing formation analysis is rocks are right? Why are they fun? |
|
| 56:27 | have a poor system that poor system multiple length scale in it and time |
|
| 56:34 | if you have some kind dependent, lot of them fractals, right? |
|
| 56:38 | about what a fractal was. That's origin of the fractal nature of a |
|
| 56:42 | . It's the four system. Then do we do? We sometimes in |
|
| 56:47 | rocks we have clays which have a negative charge to them. Well, |
|
| 56:53 | makes things more interesting. Now we a polar fluid in this rock |
|
| 56:59 | Yeah. So water because of that interact with those negative charges. This |
|
| 57:05 | found water versus free water also generates cat ions, right? Uh mobile |
|
| 57:13 | ions, right? These are called ions, right? These cause all |
|
| 57:18 | of fun electrical properties, the excess and wax and Smiths, for |
|
| 57:23 | right? And then what do we ? We make this even more |
|
| 57:27 | we dissolve a salt in this this stuff dissociates as I should have |
|
| 57:34 | this first as these negative and positive uh molecules in them which interact with |
|
| 57:42 | negative charges which generate right. Can the the exchange ions generate a double |
|
| 57:49 | , generate bound and free water. kinds of really fun stuff that's going |
|
| 57:54 | which we need to understand because we understand how much of that water has |
|
| 58:00 | replaced by oil or gas. So all of that physic going on that |
|
| 58:07 | have to interpret. You should be about it too that there are still |
|
| 58:12 | left to understand, may maybe have applications for the. But that's the |
|
| 58:19 | news. There's a lot more physics than one. Yes. All |
|
| 58:25 | That was a nice game uh as important parameter for shaley sand analysis. |
|
| 58:31 | I just answer that question. It is the origin of the excess |
|
| 58:38 | which we have to account for. is that important? Because if we |
|
| 58:42 | account for it, we will attribute excess connectivity to a lower oil |
|
| 58:49 | So we will get our economics If we use the Archie's equation for |
|
| 58:56 | , we talked about this particularly for oil saturation, we will be making |
|
| 59:02 | mistakes. We looked at why we Wax and Smith to the point where |
|
| 59:08 | we could figure that out. You reason your way does the saturation entered |
|
| 59:14 | VQB over SL when we put oil , we are replacing free water, |
|
| 59:22 | B water bottom. Uh Reason for , all right, linear really related |
|
| 59:29 | the specific surface area. That's actually tough one. We did talk about |
|
| 59:34 | . Uh the clays, right, amount of clay you have is more |
|
| 59:39 | less related to the C exchange right? And it related to the |
|
| 59:45 | of surface area which is dominated by amount of clay plays are more fine |
|
| 59:51 | material. You remember I showed you pictures where you have this big huge |
|
| 59:56 | and you have these dispersed plays in poor space. So lots of surface |
|
| 60:00 | associated with clays and so they destroy . Uh The other thing I didn't |
|
| 60:08 | mention that all right, rocks are because the distribution of all of these |
|
| 60:13 | phases actually significantly impacts the rock Uh also true. So is linear |
|
| 60:21 | this is actually true is linear related the specific surface area. Clay, |
|
| 60:26 | dominate surface area and they're so Great, great. It's a number |
|
| 60:33 | papers that have looked at that measured areas compared that to the mountain ways |
|
| 60:39 | related to the volume of bound water a sample answer. This one |
|
| 60:45 | Absolutely bound water is the water that's associated with clay surfaces. How does |
|
| 60:54 | end up bound? If water is . Why would it end up electrostatic |
|
| 61:00 | ? Because it is surrounding the sodium . You get six waters for sodium |
|
| 61:06 | , that sodium iron is attracted to negative. And therefore that water is |
|
| 61:13 | found via the sodium ion, the . OK. And the amount of |
|
| 61:21 | water right? That uh is is to the salinity, right? Because |
|
| 61:29 | see it's true may be measured using potential techniques. Well, sure I |
|
| 61:36 | about that miss glass or not. the answer is yes. So what |
|
| 61:42 | the membrane potential? I will tell now, if it comes up |
|
| 61:46 | what you do is you in the , you'll take a plug, you'll |
|
| 61:49 | grid, one salinity grind past one , you'll flow another salinity grind past |
|
| 61:54 | other end. And you will measure that salinity grading difference, you would |
|
| 62:00 | to generate a potential just like the . However, that will be less |
|
| 62:09 | the lab because you have clays which inhibit the motion of a chlorine |
|
| 62:15 | the lb because the clays are negatively . Therefore, the activity of those |
|
| 62:21 | is less. Your potential will be . We did talk about that related |
|
| 62:26 | the sp. What happens to the as you add clays? No, |
|
| 62:33 | in your nose, professor, I'll somebody answer. Go ahead. |
|
| 62:39 | Very good. Yes. As I explained, the the EMF generated the |
|
| 62:59 | is basically generated by how mobile the are. So how much EMF you |
|
| 63:04 | generate is related to that. This why it's an activity, not just |
|
| 63:09 | salinity, right? So, like Professor Ha just talked about why |
|
| 63:15 | have to go through that chart. how you calculated from the sp |
|
| 63:21 | what the salinity was? How did do that? That was a |
|
| 63:30 | But by the way, II, have asked the T A, if |
|
| 63:33 | don't hand these homeworks and you will a zero on those homeworks, please |
|
| 63:38 | them just to reinforce that. it's basically you, have you done |
|
| 63:58 | ? I would like for you, cannot do the final. If you |
|
| 64:02 | done the hormone, maybe you've noticed by now, but this is purely |
|
| 64:07 | your own good. I would, the way, I would love to |
|
| 64:11 | with the entire class A that actually in one of my classes once it's |
|
| 64:17 | a while now. Uh you're not with each other. You all get |
|
| 64:22 | , you all get a lovely fell that we all learn the material and |
|
| 64:29 | didn't. Great. So this is I like this. See how much |
|
| 64:34 | is involved in the multiple who right? Basically, we cover almost |
|
| 64:40 | the material in the course. So , I find that the grades on |
|
| 64:46 | , I have even been tempted to purely multiple choice, but students seem |
|
| 64:50 | not like that for some reason I completely understand. But uh it's because |
|
| 64:57 | covers the material so well. Gives a depth that she is hard |
|
| 65:03 | do otherwise, then you get to questions. So a little bit more |
|
| 65:09 | uh it's a little bit more rigorous the true or false. So |
|
| 65:13 | 50% is the expected value or answers the true and false. If you |
|
| 65:20 | them randomly, you should get 50% can think of this as a |
|
| 65:26 | right? Is the other way to at this, right? You get |
|
| 65:30 | credit for these independent, whether you nothing. So uh one way to |
|
| 65:35 | , although I have found significant amount time, students get roughly 50% of |
|
| 65:41 | , right? So that's a little for me. So uh is what |
|
| 65:48 | is though, right? Why do run Sonic Law talked about this? |
|
| 65:56 | would we run those things? Anybody answer? I'm sorry, what? |
|
| 66:09 | se calibration? Absolutely. That's a one. Ferocity is another good |
|
| 66:14 | Rock strength is another good one. often correlated with rock strength, perfect |
|
| 66:22 | ferocity, another good one. So of those are just explain why. |
|
| 66:27 | a little bit more why about why is de describes how it measures |
|
| 66:33 | How does it measure it? You a transmitter to receivers that looks at |
|
| 66:40 | arrival time at the two, at two receivers, right? Yes. |
|
| 66:44 | know how far apart they are, know, the time difference. So |
|
| 66:47 | can get, you can get a velocity out of it, right? |
|
| 66:51 | does the compensation work? And how that improve the measure? I talked |
|
| 66:56 | a lot of this already. How the compensation work? If you remember |
|
| 67:03 | , you remember the slide, you two transmitters, you transmit in both |
|
| 67:08 | you received and going both directions. this two first order corrects for sizes |
|
| 67:14 | bore hole and bore hole entered tools tilt from that, right. So |
|
| 67:21 | how it improves it. The, problem with the other tools is they |
|
| 67:25 | pad tools, right? And this is actually centered in the port. |
|
| 67:30 | there is a mud travel time associated this that you have to correct |
|
| 67:35 | It's not insignificant, everybody. With this one, what would be |
|
| 67:44 | ? Yeah. Right. What is difference between an absolute effective and relative |
|
| 67:52 | ? Talk about this. It's an permeability. All right, Professor |
|
| 68:03 | star student. Oh, that's The only one fluid in the porch |
|
| 68:13 | . So why would we do this as well ask that, you |
|
| 68:19 | it was to have the, the . You often do it with 100% |
|
| 68:27 | and 100% oil. You often do with both in theory, should those |
|
| 68:33 | out the same? If Darcy's equation , they would. So the fact |
|
| 68:42 | they don't like the example you've got , they were not, they were |
|
| 68:47 | different in this course. And yeah, this is one of the |
|
| 68:52 | I don't call it Darcy's law. too many exceptions to it. It's |
|
| 68:57 | . It's a useful model, but have to understand kind of what the |
|
| 69:01 | , like any model. If you what the exceptions are, this is |
|
| 69:05 | slippage, oil typically will come will come out with a higher firm |
|
| 69:11 | water and in a water wet which is because this non slip pound |
|
| 69:18 | , right, or rigorously held or in a water wet rock than for |
|
| 69:24 | . So oftentimes, in fact, the majority of the time they end |
|
| 69:28 | normalizing to the oil firm, To get relative burn. So what's |
|
| 69:33 | effective peril? Remember her answer or confirms what changed? You have a |
|
| 69:48 | fluid present. So why is Because we almost always have two fluids |
|
| 69:54 | , right? We were flowing oil the presence of water. So your |
|
| 69:59 | permeability is the permeability measure, for , to oil and the presence of |
|
| 70:05 | amount of water still has units of . It's just reduced because we're only |
|
| 70:12 | a partial saturation. Is that OK everybody? Ok. So 100% water |
|
| 70:27 | took, we took, we took sample, we cleaned and dried |
|
| 70:31 | saturated it with water, we measured occur. Yeah, they yeah, |
|
| 70:36 | oil firm. He cleaned all the out, dried and saturated with |
|
| 70:41 | We only have one bait. what we do is we will |
|
| 70:48 | right. We, we will take rock sample to a partial saturation. |
|
| 70:53 | measure an oil permeability. So we oil through it. At this partial |
|
| 70:59 | , we measure the pressure drop in oil G. What we will get |
|
| 71:03 | a lower permeability than absolute perm. as units of permeability still measured basically |
|
| 71:10 | same way pressure top in the flow . In dark equation, we still |
|
| 71:15 | Darcy's equation still works right? And do that at several, we can |
|
| 71:20 | that at any saturation we would like do with that. And how about |
|
| 71:26 | terms that what have we done We took these effective firms and we |
|
| 71:38 | them to our largest absolute firm. for example, the example that you |
|
| 71:44 | in the notes, we are normalizing the oil for but those numbers are |
|
| 71:49 | less than one, the relative Why do we care about these |
|
| 71:56 | Which would be the other thing you add to this? Why do we |
|
| 72:02 | ? This is about pro this is how much oil do we make for |
|
| 72:07 | in a time? So this is about money rather than valuing money. |
|
| 72:14 | OK. With these, you were stressed good maybe I mean real study |
|
| 72:26 | the difference between the litho density and law. I already did this in |
|
| 72:32 | . What was the difference only about minutes ago? What was the litho |
|
| 72:39 | tool? Litho is a huge That means you're getting lithology from |
|
| 72:54 | Yeah, you looked at lower you looked at absorption and not just |
|
| 73:01 | . And so you were, you a much, in fact, this |
|
| 73:05 | pretty dramatic. You get a very lithology determination, almost independent of property |
|
| 73:12 | of gas, accurate, et I mean, so it was about |
|
| 73:17 | energy discrimination on a gamma X ray on our gamma. Why was the |
|
| 73:26 | density law developed? Who get improved determination? Wasn't about resolution, wasn't |
|
| 73:38 | anything like that. It was about nice vertical plots. You remember they |
|
| 73:43 | almost independent across. Remember we had E curve versus porosity. That was |
|
| 73:50 | of your cross plots. Remember what cross plot looked like the lines were |
|
| 73:55 | vertical. So it really didn't depend the density, right, just on |
|
| 74:01 | lithology. It's almost all you would that or how I told you |
|
| 74:06 | it. Don't try to get a from this cross because it is so |
|
| 74:12 | that minor changes in the pe, ? The joint f what's the difference |
|
| 74:20 | volumetric absorption and the pe value? was volumetric absorption? We looked at |
|
| 74:35 | much of our gamma rays be lost that was volumetric absorption. So that |
|
| 74:43 | basically an amount of gamma rays that absorbed when we accounted for that through |
|
| 74:48 | correlation, we got to a pe which was, which is basically an |
|
| 74:55 | proper property just related to the So we don't want to use both |
|
| 75:02 | we want to use the key. . Yeah. How is it |
|
| 75:09 | Get with All right, Archie's My favorite. I probably go up |
|
| 75:15 | get this right. Uh What do mean by write down Archie's equation? |
|
| 75:21 | mean, you write down everything. F is equal to what I is |
|
| 75:27 | to what? Right ro is what is what you need to know all |
|
| 75:35 | terminology. Why do I say this because people talk about Cocw plots, |
|
| 75:42 | should know exactly what that means. is AC OCW plot? They just |
|
| 75:50 | this in shale sans. I'll let best they have I done. |
|
| 76:09 | no oil. So you should know automatically what that is but you should |
|
| 76:16 | what Ro is. You should know RT is. You should know what |
|
| 76:21 | doing. You should know what That's the oil industry. It's incredibly |
|
| 76:28 | uh fishing and usage, right? uses these definitions. I have not |
|
| 76:34 | people vary away from this. So all the time will talk about. |
|
| 76:40 | my RT was this? What's RT example, what is the T stand |
|
| 76:50 | ? True Relativity. Thank you. is the R zero? What is |
|
| 76:54 | zero stand for? No oil? , right? R zero. |
|
| 77:06 | RW resistivity of the water. Hopefully one's obvious, right? What is |
|
| 77:12 | stand for? What does F stand again? Universally these terms are |
|
| 77:21 | And what's the formation factor you really to be able to find what |
|
| 77:33 | It is RO divided by RW. a measure of the tortuosity in the |
|
| 77:41 | . OK. So it is this parameter, right? Remember how RO |
|
| 77:47 | equal to F times RW to write down. It's the definition of |
|
| 77:54 | So it's this scaling factor that relate to RO. So that equation itself |
|
| 78:02 | itself, it's pretty remarkable because gee resistivity varies, directly, directly proportional |
|
| 78:09 | the resistivity of the flo that breaks when you have plays. RO is |
|
| 78:17 | longer F is no longer a constant of RW. The resistivity index is |
|
| 78:25 | to what F is also equal to over B to the M. That's |
|
| 78:30 | Hardee's equation right there. It's the Law part of it. It's part |
|
| 78:34 | time. What's the resistivity index? is equal to one over SW to |
|
| 78:48 | N with that term that analogous uh we add this was important to me |
|
| 78:57 | it was a major clue as to to model rocks and activity of rocks |
|
| 79:04 | was the beginning of staged differential effect . I, by the way, |
|
| 79:12 | got credit for that. Just the . OK. I only claim the |
|
| 79:22 | . Are we OK with this? we mean by that? Explain the |
|
| 79:26 | to wax and Smiths. What happened we added the wax and Smiths? |
|
| 79:32 | did we do? He just gave like we actually changed the, the |
|
| 79:44 | of ions in the brine, we to CWCW plus BQV. We changed |
|
| 79:52 | concentration of the prime all the due due to the pre the play counter |
|
| 80:00 | the other to get a Smith is , we added the cap. So |
|
| 80:07 | substituted right for the connectivity of the with this new VIV and RG and |
|
| 80:16 | gave those to the two, the clay counter ions and the ions |
|
| 80:21 | the brine gave them the same This was the origin of their claiming |
|
| 80:27 | were in parallel, they would have virtuosity if they were in parallel. |
|
| 80:35 | right. What are the assumptions implicit excuse? I think I've talked about |
|
| 80:39 | right? Then the last thing and I'll let her have them, give |
|
| 80:48 | class. Do I need to go this or not? How do you |
|
| 80:52 | these models? What was the first you did not do it? |
|
| 80:56 | sir. OK. What about Can I explain the answer? |
|
| 81:10 | Wax and Smith, you look at board, I guess you can see |
|
| 81:13 | Wax and Smiths Wing down here, ? So what did we do Archie's |
|
| 81:19 | ? All we do is we set , equal to zero, right? |
|
| 81:24 | then this term goes away, we're to Archie's point. OK. So |
|
| 81:28 | would then be CO is equal to . So all we've done is |
|
| 81:35 | we've said we've gone from CW uh this is the connectivity right of the |
|
| 81:41 | absent place to we increase that by and CW times RW is what this |
|
| 81:51 | probably call capital R wine. So we've gone from CW from that, |
|
| 81:59 | this connectivity to we increased the Remember what QV was, that was |
|
| 82:04 | concentration of the, of the cat , right? Of the, of |
|
| 82:12 | clay counter ions. It was the of those in the four space. |
|
| 82:18 | we have an additional source of right? So what determines CW is |
|
| 82:23 | concentration of the ions of the sodium chlorine in the floor space? So |
|
| 82:29 | increased that right from just CW to now to to by BQV, the |
|
| 82:40 | source QV is the concentration just like we determine what this salinity is, |
|
| 82:45 | salinity of A R is directly related proportional to the amount of sodium and |
|
| 82:53 | . The concentration of the salt in brine, I double that concentration of |
|
| 82:58 | , I double the connectivity. So absolutely true. Go look at |
|
| 83:02 | chart, you find that's absolutely true you get near a salt saturate |
|
| 83:08 | Then what happens is they're interacting with other, interfering with each other that |
|
| 83:12 | down. So we've increased the, increased the number of ions due to |
|
| 83:17 | QV, which is the concentration of of the clay counter ions per unit |
|
| 83:22 | volume just like salinity is it's the of irons in the water. So |
|
| 83:29 | this case, in a rock, pretty horrible if we assume that's full |
|
| 83:33 | water, right? This doesn't include saturation effects by the way. And |
|
| 83:39 | because these ions, because they are , electrostatic, attracted to the |
|
| 83:47 | they don't have uh the same mobility the ions in the free water, |
|
| 83:52 | sodium and chlorine and the free water . So this b accounts for that |
|
| 83:57 | them less, right, basically So that's added. And then the |
|
| 84:05 | other thing we had to add was speed to the M which is the |
|
| 84:09 | related to the tortuosity of the ions the poor state. It was just |
|
| 84:17 | paper at SPW A which had had . So that's rolling over in their |
|
| 84:26 | quite clearly. But there is in my humble opinion, the nonsense |
|
| 84:31 | the literature, uh it's fairly straightforward this thing does and the first order |
|
| 84:37 | it correctly? There is some nuance I, that I get first order |
|
| 84:45 | . But I have been, this a lot of physical sense is that |
|
| 84:55 | ? Then M controls what? So , the, the other thing I |
|
| 85:04 | mention when you write down Archie's equation M and N, what are |
|
| 85:15 | They're the exponents and what they are they tell you the rate of change |
|
| 85:19 | tortuosity with velocity or saturation. So quickly is the tortuosity changing as the |
|
| 85:28 | change like bugs is one because remember bugs, the tortuosity was independent of |
|
| 85:37 | . That's what an exponent one means of two means that as I change |
|
| 85:43 | porosity, my tortuosity increases and less one means that my tortuosity is actually |
|
| 85:55 | as I increase, actually my tortuosity , decreases as I increase, decrease |
|
| 86:03 | that you find the place. What you OK with wax and Smiths, |
|
| 86:13 | understand where QV comes from this form this equation. We went through DC |
|
| 86:22 | the number of exchange sites per unit of material, either gram or milligrams |
|
| 86:31 | 100 g or gram is the two use. And all we're doing is |
|
| 86:37 | changing it from those units, the of exchange sites for unit 41. |
|
| 86:43 | to get from a weight to a , we need the density and then |
|
| 86:48 | get from a brain volume to a volume, you need to one line |
|
| 86:53 | over when minus speech, the grain and pretty good school block polar volume |
|
| 87:01 | unit bulk volume. So the bulk go away. And all I'm doing |
|
| 87:04 | changing from brain volume, poor volume . And we need that because it's |
|
| 87:15 | or a conductivity me, we need concentration charges in the bright. So |
|
| 87:24 | does this change with saturation? All do is divide this thing put an |
|
| 87:28 | to the end out in front because changing the tortuosity. And then we |
|
| 87:35 | by sw here because the, the of these guys gets bigger. The |
|
| 87:41 | of the pre water does not We, when we put oil in |
|
| 87:45 | rock said this multiple times. We not replacing bound water, we are |
|
| 87:51 | free water, we cannot replace bound . It is bound to tightly. |
|
| 87:57 | even went through. How do you ? A Catholic pressure, sir? |
|
| 88:04 | , we're back to this then. how do we do these models? |
|
| 88:09 | willing to help? Very common? , for me to give you |
|
| 88:16 | this problem. I usually don't do like give you different free water |
|
| 88:24 | I won't do that to this It's something quite similar to the exercise |
|
| 88:29 | did in class. How did you that exercise? What are the basic |
|
| 88:32 | in the exercise? What's your workload people? You're always worried about work |
|
| 88:39 | , right? What did you First thing was we had this equation |
|
| 88:50 | here? Sure, I can do . Yeah, you could see my |
|
| 89:00 | . You plugged in all the numbers and you got h was proportional to |
|
| 89:04 | mercury pressure. Yeah. Remember that guys got 1.1 for your specific |
|
| 89:13 | right? Then what did you do ? We had a relationship then between |
|
| 89:21 | cap pressure and height above free water , which was this guy, |
|
| 89:25 | All we did was re label that times zero was 01.1 times 100 was |
|
| 89:32 | and 10 et cetera. So we height above free water level. What |
|
| 89:35 | we do next? He needed a tie point of some sort. |
|
| 89:44 | This one actually has multiple layers in . So we had a depth tie |
|
| 89:48 | . We had three things we could as a depth tie point. We |
|
| 89:51 | the critical water saturation, right? was where water began to flow. |
|
| 89:56 | the tangents go up vertically to get critical water saturation. We had the |
|
| 90:02 | pressure 100% water level so that we the PD displacement pressure of the cap |
|
| 90:08 | . That was another one. And the third one we had was free |
|
| 90:15 | level which we actually saw where we take pressures. We have given |
|
| 90:20 | look for where they intercept and that you zero cap pressure. So there |
|
| 90:25 | zero cap pressure, there was 100% level. The PD of the cap |
|
| 90:30 | displace the pressure of the cap And we had the critical water s |
|
| 90:34 | . All of those three, you determine in a bore is the point |
|
| 90:38 | can go in with a spinner survey find out, for example, where |
|
| 90:41 | start producing oil, you could go and use our cheese equation to find |
|
| 90:46 | where we start to have oil, . You can go in and measure |
|
| 90:51 | right. Uh with a down hole of some sort and measure pressures in |
|
| 90:56 | oil phase, measure pressures in the phase where they cross gives me zero |
|
| 91:01 | pressure. So I could give you problem any of those three and ask |
|
| 91:08 | next thing you do. Once you this depth tide point is you calculate |
|
| 91:12 | depth of the free water level, free water level is at zero kepler |
|
| 91:21 | . Ok. So from there, depth, that's it, my next |
|
| 91:28 | mark would be 100 and 10 ft it, 220 ft above it, |
|
| 91:32 | cetera rlabel, all the ticks in of a depth. What did you |
|
| 91:37 | next? After that? You now depths. You uh have a geologist |
|
| 91:45 | you ask about your depositional model. are my sands? What depths are |
|
| 91:50 | sands at? You could draw that model on your cap curve. You |
|
| 91:55 | knew what cap curve you were on what depth. And so you could |
|
| 92:00 | your saturation profile in. Yeah, was basically the end of it. |
|
| 92:08 | would probably be the end of the here. You also could calculate |
|
| 92:13 | How do you do that is from ? This is Tamir's relationship for |
|
| 92:19 | I think you gotta ask that on bottle, right? Yeah, you |
|
| 92:24 | have to be aware that uh uh you should be, should be doing |
|
| 92:32 | in terms of um this is log pen, for example, then you |
|
| 92:42 | to use saturations, not fractional for , things like that. They used |
|
| 92:50 | to get the firm ability. So example, typically these are miliar micro |
|
| 92:59 | . If you do that wrong, the way, you're off by a |
|
| 93:02 | 10 to the fourth. If you fractional instead of percent you off by |
|
| 93:07 | batch of 100 square basically here But that's not a trivial thing to |
|
| 93:14 | wrong. Every time somebody gets that without you, they use, they |
|
| 93:21 | the step for step, they use . OK? We're done, I |
|
| 93:29 | . Not so bad, right? got through it and two hours you |
|
| 93:37 | three hours for the test. So recommend understand what I said here, |
|
| 93:46 | ? That's your first priority, If you go through any lecture, |
|
| 93:50 | should be going through what we just through next, the homeworks, |
|
| 93:58 | How do you do the homeworks? ? So how do you do these |
|
| 94:01 | things? I can ask you simplified of that. And then finally, |
|
| 94:07 | if you have time you go through individual lectures again, go through all |
|
| 94:12 | lectures you're gonna be going through 30 hours a lecture? I doubt |
|
| 94:17 | gonna do that. So if I studying, I would basically go through |
|
| 94:21 | lecture, go through the homeworks, through the practice exam and make sure |
|
| 94:26 | know how I would study. I know how to give you better hints |
|
| 94:30 | that or succeeding. Your success is success. By the way, you |
|
| 94:36 | not believe that if it's true, rooting for you. All right. |
|
| 94:44 | I think I'm done. This is last time I'm gonna talk to |
|
| 94:48 | Professor Haley's gonna spend, she's got hours so she's gonna talk to you |
|
| 94:54 | . So, to me, I'll you an introduction. This is actually |
|
| 94:58 | nice contrast to everything we've talked about the course because she just used these |
|
| 95:05 | her seminar this morning and you go unconventional, you are stepping through the |
|
| 95:10 | glass and a lot of things that talked about are no longer true. |
|
| 95:16 | do you step through the looking Because the pores are so gosh, |
|
| 95:21 | small, right? I could use more definitive expletive than that, |
|
| 95:27 | They're on the order of a few , 10 molecules in size give or |
|
| 95:32 | . So surface effects dominate. So of cool things go on. You |
|
| 95:37 | do saturation height model. These things work. They're not, they are |
|
| 95:42 | a capillary equilibrium. If they they'd be full of water and full |
|
| 95:47 | oil, right? And so there'd nothing to calculate. So again, |
|
| 95:54 | in T gas Kepler modeling doesn't So the basic things I used to |
|
| 96:00 | that resistivity modeling doesn't work. I'm so quite sure about that anymore based |
|
| 96:05 | something we just saw. So resistivity an open question in these things I |
|
| 96:13 | say and if it does work, parameters in Archie equation are very different |
|
| 96:20 | what we see in conventional locks. they would have to be calibrated |
|
| 96:26 | That does explain to me a Everybody does Archie's equation, but sometimes |
|
| 96:31 | much success. But uh they at try it, at least worth a |
|
| 96:37 | . So all of these things we about, I think she's gonna touch |
|
| 96:41 | will not be quite so simple. she will tell you how they think |
|
| 96:44 | gonna talk about how to evaluate right? How to evaluate the logs |
|
| 96:49 | unconventional. So, application of logs unconventional. And then I think it's |
|
| 96:55 | to point out how it's different from . Not sure how much of that |
|
| 96:59 | gonna do, but I'll try if can. All right. So I |
|
| 97:05 | it's time for a 10 minute So we'll take a 10 minute break |
|
| 97:09 | then uh we'll wrap up the corks for me. OK. Better. |
|
| 97:35 | . All right. We're gonna start a little bit about formation evaluation in |
|
| 97:39 | reservoirs after we do a little brief . So I don't know how many |
|
| 97:45 | you are working in unconventional or have in unconventional. The OK. So |
|
| 97:57 | is sort of a summary of the between the required elements in the conventional |
|
| 98:03 | an unconventional play. All right. basically an image of a thin section |
|
| 98:12 | mm showing the pore space in very large grain size and pore size |
|
| 98:19 | . Um In general, these tend have high permeability because of that, |
|
| 98:24 | don't need to do a lot of like fracking. Um But there are |
|
| 98:29 | , many elements that we have to that have to occur at the right |
|
| 98:35 | . So I have to have a . So in this case, you |
|
| 98:40 | here, I have an Antal Essentially, I have to have a |
|
| 98:44 | . This is the ceiling lithology on of the reservoir, I have to |
|
| 98:48 | a source rock that source rock has be heated enough so that it generates |
|
| 98:55 | . And then those hydrocarbons have to into the reservoir. Uh And so |
|
| 99:01 | of those risks are principally geologic, ? So we have to know the |
|
| 99:07 | of the basin. We have to a basin model. We have to |
|
| 99:10 | able to show that all of the works out that the thermal maturity is |
|
| 99:15 | . Um And typically because these are permeable, we tend to access these |
|
| 99:20 | vertical wells most of the time. is an image of a shale reservoir |
|
| 99:26 | the sem. Um It's hard to from at this magnification. Uh |
|
| 99:33 | these dark regions are either organic material pores. It's hard to tell from |
|
| 99:38 | image, all right. Uh But , if that's the pore size here |
|
| 99:43 | this is the core size over This is much, much tighter, |
|
| 99:48 | less permeable than the conventional formation. that reason, I'm gonna have to |
|
| 99:53 | a large hydraulic frack if I'm going get these hydrocarbons to flow into the |
|
| 99:58 | bore. In this case, I'm to evaluate um organic matter content. |
|
| 100:06 | people call this heroin content. Uh talk a little bit about that a |
|
| 100:11 | bit about the difference between thin and material in a minute. I have |
|
| 100:16 | know the thermal maturity because I have have heated this thing enough that it |
|
| 100:20 | generated significant volumes of either oil or . And that's what I wanna |
|
| 100:26 | I need to know something about the of the formation. Uh And we |
|
| 100:31 | tend to use the clay content as proxy for that. Since clays are |
|
| 100:36 | ductal in terms of their behavior, fluid pressure can be important. I |
|
| 100:42 | because these things are so tight if have a high fluid overpressure that helps |
|
| 100:46 | produce the fluids. And then of , just a total saturation or a |
|
| 100:51 | volume of hydrocarbons. In this the primary risk is economic. And |
|
| 100:58 | all of these, we tend to those via horizontal wells rather than vertical |
|
| 101:06 | . So again, this is another of this where we have our anti |
|
| 101:12 | , possibly a migration fairway along this . Uh everything that we're doing |
|
| 101:18 | And we just talked about this in terms of buoyant pressure and capillary |
|
| 101:23 | . All of these. Everything that worried about here is really about hydrodynamic |
|
| 101:29 | placement and trapping, which is again by the local structure and this photography |
|
| 101:35 | really well defined limits, right? The highest oil accumulation I could have |
|
| 101:42 | be if this fault was ceiling and had this filled to spill, |
|
| 101:47 | Um And then I could have anything than that, depending on again, |
|
| 101:56 | ceiling capability of this fault and, other parameters. Right. So |
|
| 102:01 | I don't have to produce this one I don't have to stimulate this one |
|
| 102:06 | . Um This is actually a coal , methane example. So here I |
|
| 102:10 | a coal bed at the base of uh section. I don't care about |
|
| 102:17 | structure here because if it's thermally mature to have generated gas, it will |
|
| 102:23 | gas everywhere along its extent. So long as I have coal present and |
|
| 102:32 | at the right thermo maturity, I have gas. So I could have |
|
| 102:37 | anywhere along the extent of this coal . Um And it could be discontinued |
|
| 102:44 | continuous or locally isolated accumulations. And , it requires stimulation to produce |
|
| 102:55 | So with an unconventional, I may the extent the lateral extent of a |
|
| 103:03 | , but not every part of the is going to be appropriate for me |
|
| 103:08 | drill a well into. Um I'm we've all heard of what a source |
|
| 103:16 | is, all right. Um Most the reservoirs that are what we would |
|
| 103:22 | a shale reservoir is basically a source that has generated a substantial volume of |
|
| 103:30 | has expelled what it can expel. remainder is retained in the source |
|
| 103:35 | And now we are drilling into that rock like a reservoir to produce |
|
| 103:41 | So it was is whatever residual saturation in that source rock is the size |
|
| 103:47 | the prize that we are looking for unconventional or shale reservoir. Yeah, |
|
| 103:54 | also have things like the Bakken where parts of the Bakken, there are |
|
| 103:59 | silts, then those silts have been charged with oil that has since cracked |
|
| 104:06 | pyro bitumen and natural gas. So are all kinds of variations in this |
|
| 104:13 | . Not every unconventional or quote shale is a source rock, but most |
|
| 104:20 | the ones that I have worked with their lives as source rocks and now |
|
| 104:26 | are producing them as reservoirs. And basically, the defining characteristic of that |
|
| 104:33 | rock is that it has sufficient organic that has survived deposition, biodegradation, |
|
| 104:42 | kind of oxidation in the water column below, you know, uh just |
|
| 104:48 | the sediment, water interface, burial and whatever Tchin is usually, we're |
|
| 104:55 | , we have to have at least 8% 22 total organic carbon in a |
|
| 105:01 | for us to even remotely consider it source rock. Usually it takes more |
|
| 105:07 | that, but we, we draw absolute minimum at. So this is |
|
| 105:14 | just a global map of where. this was, I think this was |
|
| 105:20 | 2017, 2018. So probably needs be updated but the extent of unconventional |
|
| 105:29 | formations and where they're productive on a scale. So this is just around |
|
| 105:34 | globe. You can see that North as quite a number of accumulations uh |
|
| 105:41 | potential reservoirs. We're gonna zoom in North America. Um Before we do |
|
| 105:49 | though, just in general countries with unconventional and this is just gas |
|
| 105:56 | not gas and oil, but just . Uh North America has 29% of |
|
| 106:03 | global estimates, Asia, 21% South , 18% Africa, 16% and Europe |
|
| 106:11 | 10% with Australia coming in at So this is basically just showing where |
|
| 106:18 | gas or shale gas resources um based the number of technically recoverable resources where |
|
| 106:27 | are located on a global scale. if we zoom in to the US |
|
| 106:33 | North America, um we're gonna start at each of these individual regions. |
|
| 106:41 | this is the Bakken Three Forks Uh You can see it is probably |
|
| 106:46 | Dakota, lots of drilling activity in Bakken here. Um This continues up |
|
| 106:53 | and is equivalent to the Montan and clegg formation in Canada. Um We |
|
| 107:00 | have an estimate of how many billions barrels of oil are in place. |
|
| 107:05 | is actually, so this whole extent the extent of the known formation. |
|
| 107:13 | is the extent of where we think could be producible. So you can |
|
| 107:18 | that there is the formation itself is quite widely, but where it is |
|
| 107:26 | is a much smaller region. At up to this point, we don't |
|
| 107:30 | how far it extends yet because we evaluated everything yet. There could be |
|
| 107:35 | resources associated with the Bakken. But right now, this is our estimate |
|
| 107:41 | the limits of that. And with uh recoverable with current technology, the |
|
| 107:47 | is um five billion barrels of So 6000 right. So this is |
|
| 107:56 | million, so 5000 million 5 billion of oil equivalent. All right. |
|
| 108:02 | And the source of this is the Information Agency in the US. Here's |
|
| 108:10 | Monterey formation in Canada, Canada in , all could be almost like |
|
| 108:18 | Um The Monterey doctor Myers can talk that. He worked on it. |
|
| 108:24 | When he first started in the they estimate 13.7 billion barrels in |
|
| 108:32 | but recoverable with current technology, only million barrels. And that's because in |
|
| 108:41 | and reasonably so some active faults, know, fracking is not allowed. |
|
| 108:48 | we cannot track this formation in the of California. Therefore, these billions |
|
| 108:55 | barrels of resource will remain untapped because we have to crack it if we're |
|
| 109:00 | to produce it all bunch of other here. The NIRA shown here, |
|
| 109:10 | accumulations of the Nyerere and where the has been most extensively drilled. Let |
|
| 109:16 | see here and here, the total estimate there is 500 billion barrels and |
|
| 109:23 | with current technology. Depends who you . All right. Um 460 million |
|
| 109:29 | according to the Energy Information Agency and billion barrels acco according to the Oil |
|
| 109:35 | Gas Journal. So big difference, is the problem that we have, |
|
| 109:40 | ? The formation actually extends all the here, right? Uh And also |
|
| 109:45 | some Nyra uh where we are drilling it here and here and here. |
|
| 109:51 | the Niara itself is very extensive. do we estimate recoverable reserves is a |
|
| 109:58 | because we don't know how far these called sweet spots, sweet spots might |
|
| 110:04 | . And then I just put in , the top 10 landholders at the |
|
| 110:09 | uh in the NAAB Brera, of , Anadarko was purchased by Oxy |
|
| 110:17 | So uh OXY should appear here instead Anadarko. But uh I think many |
|
| 110:23 | these same players are still very active the ny rare, the Woodford uh |
|
| 110:31 | here, Texas, Louisiana area uh then into the Midcontinent, Cal uh |
|
| 110:39 | and Kansas, Oklahoma. Uh Woodford into the Permian Basin as well. |
|
| 110:47 | resource. We're not clear. Um recoverable with current technology. This is |
|
| 110:51 | gas reservoir. So about almost 19 cubic feet of gas. Fayetteville also |
|
| 111:02 | reservoir, no estimate of total resource recoverable gas with current technology 7.1 |
|
| 111:13 | Now we're getting into our neck of woods. Uh We've got the |
|
| 111:18 | the Hainesville, Bossier, the Wolf and Bone Springs out here, the |
|
| 111:23 | Ford and the Barnett. So the camp and Bone Springs in the, |
|
| 111:29 | , Permian basin. So we're looking this region right here. Again, |
|
| 111:34 | no estimate of the total barrels in but recoverable with current technology, about |
|
| 111:40 | million barrels. The Barnett here and was really where much of this effort |
|
| 111:48 | . This was the first really widely quote shale gas play. Although a |
|
| 111:54 | of the production is coming out of stones um that are highly quart |
|
| 112:01 | So, but we're oil and we'll call anything a shale. All |
|
| 112:06 | . So here we are. And Barnett recoverable with current technology about only |
|
| 112:12 | million barrels of oil and 17 TCF gas. And again, most of |
|
| 112:17 | was for gas production when this whole revolution started the Hainesville Bossier over here |
|
| 112:28 | uh Louisiana. Uh Mississippi and Again, no estimate of total reserves |
|
| 112:35 | place. But recoverable with current again, highly variable. Uh If |
|
| 112:43 | conservative, like the Energy Information Agency TCF, if you are wildly |
|
| 112:49 | like the Oil and gas Journal, 70 TCF, so big difference in |
|
| 112:54 | two estimates. And then finally, the Eagle Bird here, um |
|
| 113:00 | no estimate of the total reserve in but recoverable with current technology on the |
|
| 113:07 | of 4.3 billion barrels of oil and 22 CF of gas. So a |
|
| 113:14 | , very prominent oil shale oil play in Texas. And then we move |
|
| 113:21 | to the east coast, the Marcellus Utica, very big shale gas plays |
|
| 113:26 | , although not in New York. again, you can see that the |
|
| 113:34 | pretty much end right at the boundary New York and not sure what state |
|
| 113:41 | is maybe Pennsylvania. Um again, estimate of resource in place and wildly |
|
| 113:52 | estimates of recoverable reserves with current Um 143 million barrels of oil in |
|
| 114:00 | where we're not in the gas 87.1 TCF uh potentially. Uh And |
|
| 114:09 | again is the Energy Information Agency, the Oil and Gas Journal estimates 100 |
|
| 114:16 | 41 TCF of gas and they clearly not do any work to estimate what |
|
| 114:22 | oil reserves would be in the Marcellus the Utica, New Albany is down |
|
| 114:29 | . Antrim was another early play uh Michigan but not nearly as prolific as |
|
| 114:35 | of these others. So if we at estimates just in general of global |
|
| 114:41 | for shale reservoirs, uh in terms shale oil, you see that Russia |
|
| 114:48 | the highest estimated resource, United States too far behind. And second with |
|
| 114:55 | third, Argentina Libya, you can that as well as I can. |
|
| 114:59 | the total estimated worldwide reserves in billion of shale oil is 345 billion. |
|
| 115:06 | contrast to that, you can see China is far and away, estimated |
|
| 115:11 | have the highest uh shale gas uh with the world total being 7300 trillion |
|
| 115:22 | feet of gas from shale red All right. So we've looked |
|
| 115:30 | we've seen where these things are um actually did the source rocks form and |
|
| 115:37 | can look at world source rock distribution deposition through geologic time. And it's |
|
| 115:43 | a function of several intersecting parameters. in general need to have a restricted |
|
| 115:51 | , meaning I don't have connectivity to open marine setting. Uh And that |
|
| 115:58 | would mean that in that case, don't get a lot of mixing vertically |
|
| 116:01 | the water column. And that would that I would tend to have an |
|
| 116:06 | minimum zone developed with an invasive uh level is also important, high nutrient |
|
| 116:13 | . So, off the west coast the US and other continents, we |
|
| 116:17 | nutrient upwelling that organic material causes local blooms, things like that, the |
|
| 116:24 | take oxygen out of the water column then as they decay, there's nothing |
|
| 116:28 | oxidize them, they fall to the floor, they generate this oxygen minimum |
|
| 116:34 | um and are preserved in the sea . Sediment sedimentation rate is also |
|
| 116:43 | We don't want a lot of terrestrial in these regions because that's just gonna |
|
| 116:48 | in a bunch of organic material from and land plants that don't generate anything |
|
| 116:53 | a little bit of gas. And finally, if we have sea level |
|
| 116:57 | superimposed on this, this kind of all of these other, the |
|
| 117:03 | the nutrient levels um and reduces the rate into the deeper parts of |
|
| 117:12 | So if we look at time when things have coincided in general, we |
|
| 117:17 | that there are certain regions of the time scale where we have most of |
|
| 117:23 | known formations. And a lot of are North American. I do have |
|
| 117:28 | little bit of diversity here in terms Europe, the North Sea and South |
|
| 117:34 | . But even in when I look Chinese uh formations, they tend to |
|
| 117:39 | in the same time zones if you . So the upper Devonian to lower |
|
| 117:46 | there, in terms of us, or formations, we have the |
|
| 117:50 | the Barnett and the Marcellus, of , in the Pennsylvanian, we have |
|
| 117:55 | wolf camp in the Jurassic. Uh upper Jurassic is the North Sea Krage |
|
| 118:02 | . The source pretty much of all the hydrocarbons in the North Sea, |
|
| 118:07 | not all but a lot of them , very, extremely rich uh source |
|
| 118:13 | . The Hainesville is also in the Jurassic in terms of the upper |
|
| 118:19 | Here, we have the Vaca Muerta Argentina, uh the Eagle Ford and |
|
| 118:24 | Narea and then in the late Uh an example, there would be |
|
| 118:28 | Monterey, all right. So basically deposition of a source rock and the |
|
| 118:36 | of the organic material, as we said is a complex function of basin |
|
| 118:42 | . So usually we're looking at some of either a an extensional margin, |
|
| 118:47 | could have a convergent margin setting where have a barred basin um that generates |
|
| 118:54 | restriction. So we need restriction is thing that we need. Um if |
|
| 118:59 | superpose a sea level rise on that we are located in a position such |
|
| 119:08 | we're in the rain shadow of whatever system. Um In other words, |
|
| 119:14 | don't want a lot of terrestrial input line. So low sedimentation rate um |
|
| 119:21 | combined with nutrient availability um will give the conditions that we need. And |
|
| 119:28 | lot of these, the nutrient availability been shown to be related to what |
|
| 119:32 | call super plume events, which are anybody know what those are basically rapid |
|
| 119:38 | four split sea floor spreading episodes um the world ocean. Ah and look |
|
| 119:47 | it is. So when sea sea floor spreading rates are high, |
|
| 119:56 | tend to have enhanced production of organic in the water column. Uh |
|
| 120:02 | because so much CO2 is actually being essentially belched into the water column with |
|
| 120:10 | oceanic lava. Um These tend to oceanic anoxic events or O AES uh |
|
| 120:20 | or super greenhouse events as happened in Mesozoic and then organic matter is then |
|
| 120:27 | by that anoxia on the sea And then we get accumulation of organic |
|
| 120:33 | sediment. So I like to show to engineers because they much less of |
|
| 120:43 | familiarity with geologic time than geologists So I always like to point |
|
| 120:48 | OK, here's earth history, here's that we're not talking about. And |
|
| 120:55 | little essentially blip right here is the AO Zoic and this is where we're |
|
| 121:00 | be looking for our source rocks. you can see here the number of |
|
| 121:04 | flu super plume events that have happened the last 500,000 years. All |
|
| 121:12 | So anybody ever heard about a model a deposition of organic rich sediments? |
|
| 121:22 | one very prominent basin that figures quite . It's the Black Sea. The |
|
| 121:31 | Sea is a permanently stratified deep incoming sediment from surrounding areas. Freshwater |
|
| 121:42 | density stays on top of a much density, high salinity and fairly |
|
| 121:50 | So, therefore more dense, deeper of water. So they don't |
|
| 121:54 | So there's no oxygen going from shallow deep. There's no set bottom seeking |
|
| 122:00 | going from shallow to deep. And what happens is all of the organisms |
|
| 122:06 | live in that water column when they , they settle to the bottom of |
|
| 122:10 | black seed and are preserved as sedimentary material. I had a friend who |
|
| 122:17 | on a like an ocean drilling trip they went to the Black Sea. |
|
| 122:23 | she said that the sediment at the water interfaith, you could pick it |
|
| 122:28 | and it was like anybody ever let rot in their vegetable drawer at |
|
| 122:34 | And then you get kind of this gooey stuff. That's kind of what |
|
| 122:40 | bottom sediment in the Black Sea is . It is this slimy gooey decaying |
|
| 122:46 | debris, basically, mostly comprised of material. But how many black seeds |
|
| 122:55 | there in the entire planet today? , thank you, Doctor Myers. |
|
| 123:01 | that cannot be the only place where make these things. So where else |
|
| 123:06 | we make them? Um This is example, as I mentioned previously about |
|
| 123:12 | that's more like the um uh this is the, I don't know |
|
| 123:17 | my western continental shelf and I don't that one here, but here we |
|
| 123:22 | a restricted shelf. So I've got carbonate reef system here. I've got |
|
| 123:27 | , a back reef system. I've , I do have some terrestrial |
|
| 123:32 | but it gets trapped very close to . And so I have this shallow |
|
| 123:37 | shelf on a carbonate margin where I a lagoon set up and those lagoons |
|
| 123:44 | to be, there's high productivity that material sucks all the oxygen out of |
|
| 123:49 | water column. And so we get matter preservation here. You can also |
|
| 123:57 | restricted deeper water rifted basins. Um again, like I mentioned previously, |
|
| 124:04 | upwelling western continental margins. All of tend to have the occurrence of organic |
|
| 124:13 | shales. It's because I've got it deep rifted basin. That means I'm |
|
| 124:21 | getting open communication with the marine environment sets up a local stratified water column |
|
| 124:30 | just like we had discussed previously. that is what allows us to get |
|
| 124:36 | in the water column, which is we have to have if we want |
|
| 124:39 | preserve the organic material during deposition. . So if I want to have |
|
| 124:49 | successful source rock or mud rock there are a number of parameters that |
|
| 124:54 | have to consider. Ok. Um first one of these is depth. |
|
| 125:00 | , there's a couple of reasons why would be important. And you think |
|
| 125:04 | one. Well, I've got to it hot enough to have generated hydrocarbons |
|
| 125:20 | one. So it has to be other thing is is that the deeper |
|
| 125:23 | go, the more expensive my well are so and that economic risk is |
|
| 125:31 | the biggest one. So I'm kind balancing. So in a lot of |
|
| 125:35 | basins, right? Those things have buried more deeply and now they're |
|
| 125:39 | for example. So that would enhance pressure. That would take something that |
|
| 125:45 | at a higher thermal maturity, bring shallower so that I don't have to |
|
| 125:49 | as much money drilling it. Um those, those two components are pretty |
|
| 125:55 | , the depth and the fluid the thickness I'm gonna be drilling along |
|
| 126:02 | . I need to stay in the . I would like to have it |
|
| 126:05 | thick, an accumulation of organic rich as possible because I'm not only gonna |
|
| 126:11 | a long lateral, I'm gonna frack , right. So I would like |
|
| 126:14 | to be thick and have nice organic rich properties through that whole thickness. |
|
| 126:21 | then of course, I need the . Where is that saturation occurring? |
|
| 126:28 | saturation is actually when we're producing from unconventional reservoir, we are producing from |
|
| 126:35 | in the organic material itself. So saturation is going to be directly tied |
|
| 126:42 | how much organic matter I have. I have to have a high toc |
|
| 126:48 | organic content. That toc has to the right type. Obviously, if |
|
| 126:53 | have a terrestrial coal, if gas what I'm looking for, I could |
|
| 126:58 | some gas in a terrestrial coal. I want oil or lighter hydrocarbons, |
|
| 127:03 | going to have to have a marine uh of organic material and it has |
|
| 127:11 | also be thermally mature. And then course, I need to have |
|
| 127:17 | Uh Obviously, we know we don't very much permeability. Anybody have an |
|
| 127:22 | about the range of permeability in shale . I know you. All |
|
| 127:28 | So sandstones, you guys were just at some sandstones, did they calculate |
|
| 127:32 | perm on those on their saturation? function right? An anybody got a |
|
| 127:39 | for permeability of sandstone in Miller I know it. Ok, Doctor |
|
| 127:47 | . Give me affirm your ability, ? You called on me? |
|
| 127:52 | I'm calling on you. I I just said that work. |
|
| 128:04 | Yeah. So Miller Darcy to Darcy perme ail in these reservoirs typically on |
|
| 128:11 | nano Darcy range. Although there is argument about that. Some people when |
|
| 128:15 | measure it, say at Darcy, what, 10 to the minus 12 |
|
| 128:24 | and the is 18. OK. really, really, really impermeable. |
|
| 128:30 | that's why we got to frack All right. So we're really mostly |
|
| 128:33 | in what's the porosity, the porosity on all of our work is associated |
|
| 128:40 | the organic material. So we need have toc if we have toc and |
|
| 128:44 | right ma maturity, we will have , right? We also are interested |
|
| 128:50 | the mineralogy uh for two reasons. , if I have the right |
|
| 128:56 | I might have early cement precipitation that's to inhibit the mechanical compaction of this |
|
| 129:05 | as I bury it. All So, since anybody have a |
|
| 129:11 | how much uh ferocity do we tend lose in a sandstone from compaction, |
|
| 129:17 | say we started at 40%. how well you can get pretty damn |
|
| 129:27 | just due to compaction though this mechanical . If we start at 40% maybe |
|
| 129:33 | get down to 25 20 to 25% porosity depending on. Obviously, we |
|
| 129:42 | in a well sorted SAN, Um And then cementation of some sort |
|
| 129:50 | other would reduce further. Now, can have actually inter granular pressure solution |
|
| 129:57 | chemical compaction. Those sands are really, really low prostate. All |
|
| 130:02 | . Um However, if we have cementation, not too much of |
|
| 130:08 | just a little bit, it stops sand from compacting in a similar |
|
| 130:14 | it stops the shales from compacting. we lose an average 50% of our |
|
| 130:21 | just due to mechanical compaction. If can stop that, we will preserve |
|
| 130:26 | porosity for our our desired uh shale . So, early cementation is good |
|
| 130:36 | that. Also what's more uh brittle frable? Something that's cemented or something |
|
| 130:44 | not cemented. Yeah, cemented. that early cementation also enhances my |
|
| 130:53 | So I get a bonus from that two reasons in it inhibits compaction, |
|
| 131:01 | my formation more frable. And then course, we have to be aware |
|
| 131:06 | the structure of the basin. Present . Has there been faulting? What's |
|
| 131:11 | present and past stress regime? Because , if I'm gonna frack something, |
|
| 131:16 | need to open that frack against the horizontal stress in the basin. So |
|
| 131:22 | need to know what the stress orientations . All right. So anybody got |
|
| 131:30 | idea what this is. I know do, you just saw this |
|
| 131:35 | This is actually anybody ever heard of focused imb messy ma fib. So |
|
| 131:43 | what that instrument does is it you mill the surface. You take a |
|
| 131:49 | of the surface, the ion mill on the order of 5 to 8 |
|
| 131:56 | of material. You take another picture , ion mill off another 8 to |
|
| 132:01 | nanometers. You take another picture, do that thousands of times you put |
|
| 132:05 | stack together and you get a pseudo volume of the poor system, the |
|
| 132:12 | material and the rock frame of your . Very cool, very expensive. |
|
| 132:19 | problem is that this is 20 microns 20 microns, by six microns in |
|
| 132:25 | costs about $15,000 to generate. And got no idea how representative it |
|
| 132:31 | but it's cool. This was very early on. People still do pay |
|
| 132:36 | do it. Um I, I'm sure if it's still as popular as |
|
| 132:41 | used to be. I shall I responsible for trying to build a model |
|
| 132:49 | how ferocity and shale reservoirs uh varies a function of burial history and thermo |
|
| 132:57 | . And basically, and we, were looking at this to potentially model |
|
| 133:03 | in these things. It's just not representative elementary volume of the material. |
|
| 133:10 | we stopped generating them. I don't . Can anybody see that? It's |
|
| 133:14 | dark, if you could see you would see that there are two |
|
| 133:17 | squares, one here and one a little square here, a little |
|
| 133:26 | here and then there's two little rectangles stick out of those little squares, |
|
| 133:32 | two little rectangles are actually where two volumes were generated. So two of |
|
| 133:38 | 3d stacks in a shale reservoir. cool is I get about five nanometers |
|
| 133:45 | pixel resolution. The problem is they're next to each other, their organic |
|
| 133:51 | content, their porosity, the relative , everything was so different. We |
|
| 133:57 | , how the heck do you upscale ? So if someone tries to sell |
|
| 134:01 | this, that is a very valid that you should ask them. Um |
|
| 134:06 | sure they'll tell you that they But we at shell, we went |
|
| 134:11 | from this technique because we did not how we could upscale. All |
|
| 134:19 | then we have here, I've got some two D images uh from each |
|
| 134:25 | these regions. Well, from one these regions, this is what it |
|
| 134:29 | like in thin section. So in standard sem imaging, I've got about |
|
| 134:34 | nanometers per pixel resolution in a transmitted image. I've got about 0.11 microns |
|
| 134:41 | pixel. So all of these are for MS, they're very large as |
|
| 134:46 | as for MS go. That tells I had a lot of oxygen in |
|
| 134:50 | water column at this time. I have these ploys here. This is |
|
| 134:56 | all the porosity is in this This is the eagle bird, by |
|
| 135:00 | way. And um these very large plods also tell me that there was |
|
| 135:06 | in the water column having said that are still some strands of primary marine |
|
| 135:15 | that survive uh deposition and burial. And we're gonna look at those, |
|
| 135:20 | think, I don't know, I know if we're gonna look at any |
|
| 135:23 | images of those or not. before we generated this suite of |
|
| 135:32 | we had AC T scan of a plug. So you can see how |
|
| 135:36 | variable. So these are, these dark and light regions are a function |
|
| 135:40 | density. So the density of the is changing quite frequently across here. |
|
| 135:47 | is a a fracture that we generated we acquired the core plug, um |
|
| 135:55 | dark regions, the dark lamination other this fracture are rich in organic |
|
| 136:03 | The brighter the region is it's either porous or it has more carbonate content |
|
| 136:09 | both. So that's what we're looking here in the SCM. Here we |
|
| 136:14 | looking at a transmitted light image of end trim from this core plug. |
|
| 136:19 | here we're looking at a reflected light of a wafer that we ion |
|
| 136:25 | So we ion milled the whole surface a one inch core plug so that |
|
| 136:29 | could go in and do sem What we did further was we identified |
|
| 136:35 | lamination types. And then we generated area two D image mosaics in each |
|
| 136:41 | those lamination types to characterize them in of mineralogy, toc uh porosity, |
|
| 136:48 | cetera. And so this green circle is in this lamina. And this |
|
| 136:56 | section is also taken from this one . So you can see that if |
|
| 137:01 | get one picture of this thing, really got no idea what the heck |
|
| 137:05 | going on because this lamination is extremely . So one of the things we |
|
| 137:12 | is we took large area image mosaic each lamination type, we estimated the |
|
| 137:20 | percent of each lamination type in the . And we upscaled those properties to |
|
| 137:26 | core plug scale. So we were to say, OK, this core |
|
| 137:33 | that has this average gray scale so we could tie it to the whole |
|
| 137:38 | CT scan has this much toc and much porosity since those are two of |
|
| 137:44 | principal things that we're interested in, course, that three, that 3 |
|
| 137:51 | or 1 m of core is from base of a formation that's 100 m |
|
| 137:56 | and the map of the occurrence of Eagle Ford. Uh this the extent |
|
| 138:02 | that is on the order of 100 . So how do we take this |
|
| 138:08 | of observation and make it relevant at scale? And we're not gonna do |
|
| 138:14 | here. This is from a different , but we do need ultimately to |
|
| 138:21 | able to take all of these scales observation and understand how these properties are |
|
| 138:26 | on a basin scale. So we're our, well, we're going to |
|
| 138:36 | our, well, so where does data come from? I actually really |
|
| 138:41 | this because it puts a lot of logging tools into context. This is |
|
| 138:47 | of the society of Petro physicists and , log analysts. So let's |
|
| 138:52 | let's start ladder log tool and my induction tool they see 8 to 10 |
|
| 139:01 | into the formation from the borehole. I do an RFT or an |
|
| 139:07 | I'm also getting fluids from around 9 into the borehole most of the |
|
| 139:14 | What am I actually running? I'm a borehole sens acoustic lock which sees |
|
| 139:21 | four inches into the formation. Maybe running uh a compensated neutron log and |
|
| 139:29 | gamma ray that he may be almost foot into the formation. I'm running |
|
| 139:34 | litho density tool. I see maybe or six inches into the formation and |
|
| 139:43 | I am, here's my microspheres So that sees, you know, |
|
| 139:50 | , maybe an inch into the So, logging tool measurements that you're |
|
| 139:58 | into a little bit of context. you've got Rugose on the borehole, |
|
| 140:02 | you've got the borehole wash out for reason, many of the most important |
|
| 140:09 | tools that, that we need to for these formations aren't gonna give us |
|
| 140:15 | good data. So you just have keep that in. All right. |
|
| 140:20 | what do we want to do in unconventional reservoir? We need to assess |
|
| 140:26 | or not we have. I don't the term Carrigan. Anybody know what |
|
| 140:29 | definition of Carrigan is, we can the lights back on. It's |
|
| 140:33 | I don't want people to sleep through entire thing. The definition of |
|
| 140:43 | Huh? No, it's in Insoluble, insoluble, yes. Insoluble |
|
| 140:49 | material that is of detrital origin is we call carid. Most of what |
|
| 140:55 | organic material that is left by the we are producing from these things is |
|
| 141:00 | Kogen. But because that's the term is embedded in oil and gas uh |
|
| 141:09 | , I prefer to say just toc organic carbon rather than Carro. |
|
| 141:16 | if the source rock has just been , it needs to have Carro in |
|
| 141:20 | . But by the time I'm drilling , I hope it has very little |
|
| 141:24 | and mostly generated hydrocarbons. So, right. So, but I still |
|
| 141:30 | to know I have to get the and the TOC is gonna be very |
|
| 141:35 | correlated to the hydrocarbon saturated porosity. that's an important thing. Uh In |
|
| 141:43 | to that I need to know or able to assess the brittleness of the |
|
| 141:49 | because I have to rack it. . And so basically, we're gonna |
|
| 141:53 | looking at keratin, we're gonna talk little bit about how we might assess |
|
| 141:57 | maturity. And when we do that should be related to the porosity |
|
| 142:03 | in the organic material. Talk a bit about the brittleness of the |
|
| 142:08 | et cetera. Uh And you can here, we've got a category all |
|
| 142:12 | own for pyrite. Now, Doctor and I are coming back to around |
|
| 142:21 | circle that maybe some of this could be applied in unconventional reservoirs. At |
|
| 142:29 | we did not think so. All . So you all know these |
|
| 142:33 | these are Archie's equations. All And the fundamental assumption that I have |
|
| 142:40 | what I know. So I figured ask it again. So basically, |
|
| 142:53 | rock frame and any hydrocarbons are perfect . And the only thing that could |
|
| 143:01 | electricity, therefore, in the formation aqueous fluid. And then we've already |
|
| 143:09 | that with shaley Satan, right? And obviously, there's a lot more |
|
| 143:16 | shale in a shale reservoir than there in a sandstone. Um But based |
|
| 143:23 | like you said, some pre some work, we think that it's possible |
|
| 143:29 | the exchange sites and those have been by heavy organic molecules that water won't |
|
| 143:39 | no matter what ion it has in . All right. So, logging |
|
| 143:47 | in shale reservoirs are highly influenced by material. All right. So the |
|
| 143:56 | ray, typically, we think that high response in the gamma ray is |
|
| 144:00 | with clay minerals. However, in depositional settings, anybody here do any |
|
| 144:11 | uh sequence photography? No. All . So basically deep marine settings where |
|
| 144:22 | have very low terrestrial input and we also a sea level rise associated with |
|
| 144:31 | we define something called a maximum flooding . And that would be developed at |
|
| 144:36 | top of what we call a transgressive track. Basically, that's where uranium |
|
| 144:46 | to be concentrated and associated with organic . So in that depositional setting, |
|
| 144:54 | gamma ray could be completely dominated by associated with the organics and not have |
|
| 145:04 | whole heck of a lot to do the potassium and thorium in clay |
|
| 145:09 | We need to untangle that. All . What next? OK. So |
|
| 145:16 | we have a spectral, sometimes they run a spectral gamma ray. So |
|
| 145:20 | that case, they measure individually the to uranium thorium and potassium. If |
|
| 145:26 | do that, our work is done us. However, spectral gamma ray |
|
| 145:30 | expensive and of course, economic margins these formations are tight. So we |
|
| 145:37 | not run a uh a spectral or we're evaluating historical wells, we probably |
|
| 145:45 | have a spectral gambler. But in , marine Carrigan can be associated if |
|
| 145:52 | in the right setting with a high content. And again, thorium and |
|
| 145:58 | are typically tied to the amount of input and to clay minerals, bulk |
|
| 146:05 | organic material has a density if it's dense on the order of maybe 1.2 |
|
| 146:11 | per CC, which is about half of quartz, right uh or even |
|
| 146:16 | little less than half that of So, bulk density is going to |
|
| 146:22 | very sensitive too the presence of organic . On the other hand, when |
|
| 146:30 | have high toc, I can frequently high pyrite concentration associated with that because |
|
| 146:37 | waters are so anoxic, they are we call euin, which means that |
|
| 146:43 | have H two s actually free H S in the water column, almost |
|
| 146:49 | oxygen. And we actually precipitate pyrite of seawater associated with these highly anoxic |
|
| 146:58 | . So, yeah, I got low density organics, but damn |
|
| 147:02 | I've got really high density pyrite associated it. So those two effects could |
|
| 147:08 | each other out potentially. All Now, the neutron tool, the |
|
| 147:13 | sees organics. It sees the hydrogen with organic material just like it sees |
|
| 147:20 | structural hydrogens in clay minerals. So neutron tool may see high toc as |
|
| 147:27 | higher porosity. Of course, if have gas in the pores gas is |
|
| 147:32 | impact both the neutron and the density . And I already mentioned that clay |
|
| 147:38 | also increased. The apparent neutron ferocity acoustic logs, organics and over pressures |
|
| 147:47 | are potentially associated with generated hydrocarbons can transit time. And then finally, |
|
| 147:54 | resistivity logs, there tends to be increase in resistivity with increasing toc, |
|
| 148:02 | that only happens up to a And then at very high thermal |
|
| 148:07 | the organic material itself can also become as it becomes more graphite like. |
|
| 148:14 | as a function of thermo maturity, influence on resistivity could also change. |
|
| 148:21 | right. So we're talking about gamma here. So this is just uh |
|
| 148:25 | is actually a really nice chart to . And again, this is from |
|
| 148:28 | S Lumber J chart book. It's the log density of common silicate and |
|
| 148:35 | phases. It's got the for two of the neutron tool. What the |
|
| 148:43 | neutron porosity is for each of those . Uh Here is the transit |
|
| 148:48 | sheer oh no compressional and sheer transit , the pe and the volumetric absorption |
|
| 148:57 | . Um And then we have gamma here which you'll notice all of none |
|
| 149:03 | these phases have a gamma ray signal with them. And then the capture |
|
| 149:09 | section for those gamma rays. All . Now we get to the clay |
|
| 149:17 | . So you can see the various mineral families over here, the |
|
| 149:21 | the bulk density of that material, the uh SNP or CNL ferocity |
|
| 149:31 | So two generations of the neutron So you can see for example that |
|
| 149:37 | on the newer uh generations of the tool that if we have chlorite, |
|
| 149:41 | got 50% ferocity seen by the neutron . Um Mo maronite can have on |
|
| 149:47 | order of 60% ferocity. This is inner layer water and expand ability as |
|
| 149:53 | as the structural water. Uh Here's pe for those various phases again. |
|
| 149:59 | then the gamma ray associated with each those and the gamma ray captured cross |
|
| 150:04 | . So just kind of a nice too old to have to know what |
|
| 150:09 | might expect your log responses to Ok. So here we're just what |
|
| 150:16 | got. This is actually a well the Woodford, we've got our caliber |
|
| 150:22 | here in purple, pinkish. So on the caliber, what's the condition |
|
| 150:28 | the well bore? See, these the things I always ask. So |
|
| 150:37 | here. So this is right This is probably the bit diameter. |
|
| 150:42 | where everything is straight up and we're in good shape down here. |
|
| 150:47 | got a little bit of a wash . We'd have to be careful |
|
| 150:50 | Uh Up here, we, we're out a little bit. So we're |
|
| 150:54 | have to be careful there with interpreting really shallow penetrating logs. OK. |
|
| 151:02 | , if I can't read it, don't know if you can. |
|
| 151:04 | So now I've got a spectral lucky me. So I've got uranium |
|
| 151:10 | green and I've got thorium in blue potassium in pink. So what is |
|
| 151:15 | thing that you notice as you go here? What's really changing as we |
|
| 151:20 | down the section in this particular What the green one is the |
|
| 151:32 | this is the total gamma over here blue. So you can see this |
|
| 151:38 | scaled from 0 to 300 what we API units. OK. So the |
|
| 151:44 | ray went so high that it had come back and now it's wrapped around |
|
| 151:48 | it's in light blue. So now light blue is going from 300 to |
|
| 151:54 | API E. All right, that's you read it when the signal |
|
| 152:00 | OK. And here is the the uranium signal is in P |
|
| 152:06 | the potassium signal is in weight The thorium signal is also in P |
|
| 152:11 | . So you can see that in particular case where my gamma ray is |
|
| 152:15 | 600 my uranium P PM looks like almost at 60 right? So I |
|
| 152:22 | see that this increase in the uranium in the gamma ray here is all |
|
| 152:27 | this uranium signal. I've got pretty a constant clay content as I go |
|
| 152:33 | here. Um But I wouldn't know if I didn't have this spectral |
|
| 152:39 | right? Then I've got my resistivity . I've got density and neutron |
|
| 152:47 | So if I were to look at and say, OK, where do |
|
| 152:50 | have the highest play content relative looking my density and neutron tools? So |
|
| 152:58 | neutron porosity is looking like it's close about 40% here. The bulk |
|
| 153:04 | I'm having a hard time reading But how realistic do you think this |
|
| 153:11 | 45% ferocity is it's a shale, the way, right? So this |
|
| 153:22 | , this is all about, I so many clays in here. This |
|
| 153:27 | one of the first things I look when I see this big crossover and |
|
| 153:32 | not gas. This time, the neutron crossover here is telling me if |
|
| 153:38 | need to pick a background shale to these logs, I would pick it |
|
| 153:43 | where my neutron ferocity is very high to what I would estimate for density |
|
| 153:50 | . So this is my background shale region in here, they're essentially laying |
|
| 153:56 | on top of each other. Uh is the start of my source rock |
|
| 154:01 | , right? So my very high toc there's maybe a little bit more |
|
| 154:07 | content here in this zone than there here. So, and then there's |
|
| 154:12 | clay here based on that relationship between neutron and density. So if I |
|
| 154:17 | gonna pick regions in this zone where wanted to put a frack, I'd |
|
| 154:22 | wanna put it here and here and the region where I had more |
|
| 154:31 | So just looking at the gamma ray the density neutron and give us a |
|
| 154:37 | lot of information about TOC which of , we gotta have. All |
|
| 154:45 | Uh and brittleness. So that's why spend time looking at the gamma ray |
|
| 154:52 | here. Completely different from, I , if you were in a sandstone |
|
| 154:57 | a limestone, which one would which interval on the gamma ray would |
|
| 155:00 | be most interested in here? gamma or cold gamma, the |
|
| 155:12 | So you'd be looking here. Oh it's a limestone. Oh It looks |
|
| 155:16 | a limestone. So maybe this is carbonate reservoir, right. This is |
|
| 155:21 | , where I would be looking if were in a conventional setting here, |
|
| 155:25 | looking at this very, very, hot gamma. All right. So |
|
| 155:33 | Schlumberger tools, you know, I know if you guys knew that the |
|
| 155:39 | uh calibration site for the gamma ray somewhere on U of H campus. |
|
| 155:44 | . What they did is they had cement line borehole and they doped the |
|
| 155:50 | at various depths with different amounts of . Uranium and thorium eight inch |
|
| 155:58 | They logged the cement lined borehole. knew the position of each of those |
|
| 156:04 | changes. They measured the gamma ray and that's how they came up with |
|
| 156:10 | we call the API units. And equation which is how we could estimate |
|
| 156:15 | total gamma ray if we know thorium in P PM, uranium concentration in |
|
| 156:23 | PM and weight percent potassium. So total gamma ray is given by this |
|
| 156:31 | . So if I have a spectral ray, I can back out how |
|
| 156:36 | of that gamma ray signal is from and the uranium is most likely associated |
|
| 156:48 | , with what organic? Yeah. if I back this stuff out, |
|
| 156:55 | can then OK, what's my And I can calculate my sale index |
|
| 157:03 | , which is the gamma ray in zone of interest minus the minimum gamma |
|
| 157:09 | on the log divided by um the ray of my background. Shale minus |
|
| 157:17 | minimum gamma ray. Yeah. And I can calculate a shale index. |
|
| 157:22 | I'm not sure if this is the slide problem with the shale index is |
|
| 157:27 | tends to overestimate clay content. So get a little further in the |
|
| 157:32 | There are a couple of additional relationships allow us to take the sale index |
|
| 157:39 | calculated from the gamma ray and correct . So what they did was they |
|
| 157:44 | shale index. They did X ray analysis. They're like, hey, |
|
| 157:49 | , the clay minerals in here don't with this. So they developed relationships |
|
| 157:54 | corrected the sale index from the gamma calculated this way to clay mineral |
|
| 158:00 | which is what we're really interested Why would that be, what else |
|
| 158:07 | potassium and thorium been besides clays? , there's other men of feldspar. |
|
| 158:20 | any kind of uh lots of heavy have those two elements associated with |
|
| 158:25 | especially heavy elements, heavy minerals have thorium associated with them. So, |
|
| 158:30 | , there are other mineral components that potassium and thorium. And that's why |
|
| 158:35 | I just take that as a shale , I tend to overestimate the volume |
|
| 158:41 | clay. Did you have a It's um I don't know that there's |
|
| 158:56 | particular uh cut off for that. I said, usually for a source |
|
| 159:01 | , we wanna have at least two is on the order of four. |
|
| 159:10 | most of these like I've done a of work in the uh Eagle for |
|
| 159:15 | 10 12% organic carbon at low thermal . So, uh but that's not |
|
| 159:24 | . And again, that's 8%. we, we typically double that because |
|
| 159:28 | the density if we assume a carri density of 1.2. And our cor |
|
| 159:34 | is 2.65. So we should actually bump it up a little bit more |
|
| 159:39 | that. And a good shale background density should be on the order of |
|
| 159:47 | uh grams per CC. If you're look to pick a background sale, |
|
| 159:51 | talk about that a little more. right. So this is um these |
|
| 159:59 | are, they did this work uh part of the Gas Research Institute on |
|
| 160:04 | shales. Uh This is actually a good paper if you go look it |
|
| 160:08 | , a lot of the analysis that currently do is based on papers by |
|
| 160:15 | and Leffel. Um So it's, worth looking up, but basically what |
|
| 160:21 | found was a relationship between the volume Kogen which is shown here on this |
|
| 160:27 | . Uh and the P PM log pm of uranium on the X |
|
| 160:34 | So if I know if I have and I was deposited in the right |
|
| 160:42 | , so that uranium corresponds with TOC can estimate the volume of Carro in |
|
| 160:48 | this relationship. No, how do get toc from the gamma ray log |
|
| 161:02 | I don't have a spectral gamma. basically, it has been noted that |
|
| 161:10 | a linear dependence when we have significant of the gamma ray on TOC. |
|
| 161:17 | so the TOC is M or the of the gamma ray uh toc weight |
|
| 161:24 | plot if we have one mgr plus where B is the gamma ray intercepted |
|
| 161:30 | toc. So what do I have have here? I gotta have a |
|
| 161:34 | of TOC measurements. And the gamma log, I may not always have |
|
| 161:39 | , especially if I'm going into a area and drilling for the first |
|
| 161:45 | Uh Unfortunately, there's not one portable for this. So again, local |
|
| 161:50 | would be required. And the reason this doesn't work out all that well |
|
| 161:56 | is that the amount of uranium that's with TOC varies within and among |
|
| 162:03 | And it depends where you are in depositional setting. As I said |
|
| 162:07 | we wanna be near a maximum flooding . Uh So the top of a |
|
| 162:12 | systems tract or the base of a stand systems tract in sequence photography |
|
| 162:18 | Um as we move up in the stand systems track more and more detrital |
|
| 162:24 | from the continents is being added to system so that uranium signal goes |
|
| 162:30 | even if I have uh a high and that's part of the problem. |
|
| 162:37 | this is um um data from Plumber that shows for a number of different |
|
| 162:46 | , what the relationship is between the ray API and COC. It also |
|
| 162:51 | tell me what thermo maturity this is either. Right. So I really |
|
| 162:55 | know a lot about this. I know what formations these are, I |
|
| 163:00 | know their thermo maturity. I don't , um a depositional setting or anything |
|
| 163:06 | that. But you can see that most of them except for this blue |
|
| 163:10 | , which kind of goes counter to , there tends to be a fairly |
|
| 163:14 | relationship. If we got rid of blue points, those outliers would probably |
|
| 163:18 | a lot better art squared. These should have done some data analytics, |
|
| 163:22 | know, throw out the points that matter. Right. Doctor Myers there |
|
| 163:27 | the points that don't agree. I you don't like that. I think |
|
| 163:30 | teacher is. All right. So Macker took a different approach. Uh |
|
| 163:41 | a good paper if you're interested in this stuff up. And he proposed |
|
| 163:45 | different methodology for getting TOC from the ray log. So he's got the |
|
| 163:51 | percent of TOC is the background gamma minus the gamma ray in my zone |
|
| 163:58 | interest divided by this constant times A A is the slope of the cross |
|
| 164:05 | between the gamma ray intensity and the density. All right. So one |
|
| 164:10 | I'm assuming here is I've just got standard gamma ray. I don't have |
|
| 164:14 | spectral. So I don't know uranium . So the first thing I'm gonna |
|
| 164:19 | is I'm gonna take my log data I'm gonna look for a relationship between |
|
| 164:23 | ray and bulk density. So so remember when we were looking at |
|
| 164:32 | log curves in the Woodford, I , OK, my background shale is |
|
| 164:37 | be here where I have essentially the organic content based on the gamma and |
|
| 164:46 | have the highest clay content based on separation between my neutron and bulk density |
|
| 164:54 | . So in any type of this , we're gonna try to pick a |
|
| 164:58 | shale out of the section. So I would just use this as |
|
| 165:02 | background shale gamma ray. OK. here is a plot in a particular |
|
| 165:15 | , uh showing bulk density versus camera they've got a calculated regression. They |
|
| 165:22 | tell us what the regression is, it looks pretty good, you |
|
| 165:26 | So this is a case where I use this relationship to give me an |
|
| 165:34 | of to c in the formation. this shows the distribution of total organic |
|
| 165:44 | calculated using their um their methodology plotted a core determination. And in |
|
| 165:57 | it looks pretty good. So overall too bad of a relationship, |
|
| 166:06 | if we can see this going we should do a pretty decent job |
|
| 166:13 | estimating toc and this kind of a just using the gamma ray. |
|
| 166:19 | of course, we're also using the here as well. And we care |
|
| 166:27 | getting the TOC right, because that is where the pores are, that |
|
| 166:32 | saturated with hydrocarbons in these formations. the TOC is gonna largely control the |
|
| 166:41 | of the prize if you will. . Yeah. Well, they, |
|
| 166:57 | mean, no, they, these really old wells. Yeah. |
|
| 167:05 | I'm not sure that anyone has actually it with both methods. Um |
|
| 167:12 | it would be. Um but, probably someone had, but again, |
|
| 167:17 | can't remember what year this paper was . 81. We certainly were not |
|
| 167:24 | of shales as reservoirs at this we were looking for a source |
|
| 167:28 | That's all we were looking for. And probably, and obviously they related |
|
| 167:34 | to local measurements of TOC. Um not nowadays, even though we don't |
|
| 167:43 | a spectral we're gonna have in our log data from the well site. |
|
| 167:49 | we actually collect cuttings God willing we . Uh but it's expensive. So |
|
| 167:54 | we don't um you're gonna have bulk data that bulk chemical data will give |
|
| 168:00 | a uranium signal. So that's another that you could validate it without a |
|
| 168:09 | . OK. Another way of estimating was proposed by Quinn Passy and others |
|
| 168:17 | Exxon in 1990. Uh And it's the Delta Laar method and it is |
|
| 168:26 | an improvement over the basic gamma ray bulk density estimation for TOC. So |
|
| 168:33 | was based on two key observations, transit time like the bulk density is |
|
| 168:39 | function of organic matter content resistivity increases thermo maturity increases. So if we |
|
| 168:49 | the logs appropriately and look at the separation between the transit time and the |
|
| 168:56 | resistivity that should be related to And they did in fact prove that |
|
| 169:01 | was related to TOC. So here appropriately scaled logs. So here's my |
|
| 169:10 | ray just got a B uh bulk ray now no um estimate of uranium |
|
| 169:18 | . Um This is geochemical analysis from in that uh zone. So we've |
|
| 169:27 | you guys know anything about rocky valve , huh? OK. So S |
|
| 169:36 | is the, that's as one is generated as two is potential. So |
|
| 169:47 | is the potential generated hydrocarbons and then is the estimated toc and measured |
|
| 169:55 | OK. Uh So clearly you can that the top of this unit |
|
| 170:01 | although we've got something happening here as and we see a little bit of |
|
| 170:08 | . So the sonic is shown in dash curve and the resistivity in the |
|
| 170:14 | curve. And the separation between these lines is related to the TOC. |
|
| 170:22 | this separation is what we call the Lager. I kind of agreed especially |
|
| 170:27 | the top here with the maximum excursion the gamma ray. So basically to |
|
| 170:35 | this appropriately one resistivity log cycle has be set equal to 50 microseconds per |
|
| 170:42 | of transit time. And when you the two logs on top of one |
|
| 170:47 | with those scales, this is when appropriate to make this delta log R |
|
| 170:56 | . The cool thing is OK. here you noticed it was with Sonic |
|
| 171:01 | thing is you can do it with ferocity tool. So you can also |
|
| 171:04 | a delta log our measurement with the tool. And with the neutron |
|
| 171:09 | if you don't have an acoustic although it would really shock me if |
|
| 171:13 | did not have acoustic log. And this is the relationship between that um |
|
| 171:21 | transit time and the self related TOC . The neutron operate operated POC from |
|
| 171:32 | Lagar and this is the bulk density the calculated TOC from. So which |
|
| 171:40 | looks like it gives you the best . So I'm basically looking around the |
|
| 171:59 | bit line here. Yeah. So acoustic log is the one that does |
|
| 172:05 | best job. So if we have acoustic log, this is the measurement |
|
| 172:10 | or the estimate of TOC that we prefer to use. So we basically |
|
| 172:15 | measured TOC estimated toc from delta log and this is the relationship between or |
|
| 172:23 | transit time and measure TOC. So do we get delta log R? |
|
| 172:30 | how do we get um TOC from ? So the delta LR equation is |
|
| 172:40 | by delta LR is equal to the of the resistivity in your zone of |
|
| 172:45 | divided by the resistivity in a background plus 0.02 times the transit time in |
|
| 172:55 | zone of interest minus the transit time a background shale. And if I |
|
| 173:04 | this delta T resistivity separation, I be fairly confident that I have a |
|
| 173:11 | toc that delta LR separation is linearly to TFC if I know the maturity |
|
| 173:19 | if I can estimate the maturity. again, it's a function of the |
|
| 173:22 | maturity. And I already told you this R shale and BT Sha |
|
| 173:29 | So I'm looking at my zone of and a background sha and then these |
|
| 173:36 | similar equations for the neutron and density . So how do I get? |
|
| 173:43 | is the craziest thing ever? So obviously you've talked about paralysis before. |
|
| 173:48 | you guys have like a geo organic ? All right. Did they talk |
|
| 173:52 | thermo maturity and like vite reflections and that stuff? Did they talk about |
|
| 173:56 | level of organic metamorphism? Lom? , no. OK. So of |
|
| 174:07 | the methods of thermal maturity, this like the most subjective and it really |
|
| 174:11 | me that this is what Exxon chose use as their estimate of thermal |
|
| 174:16 | We'll look at what it's based on you can tell me how subjective or |
|
| 174:20 | you think it is. But basically I really want is toc, so |
|
| 174:25 | need to get TOC from Delta Lard this is the equation that I use |
|
| 174:30 | that. So this is the separation the logs and then I've got 10 |
|
| 174:35 | to this power for this lom is degree of uh organic metamorphism. So |
|
| 174:42 | is basically somehow related to vite reflectance thermo maturity. All right. Um |
|
| 174:52 | so at any given delta log RT decreases as the level of organic metamorphism |
|
| 175:01 | . So here basically you've got a , a cross plot of delta log |
|
| 175:06 | and thermal maturity. So you basically your delta log R. Let's say |
|
| 175:13 | two, you go to your level organic metamorphism and then you can basically |
|
| 175:20 | the toc of the Y axis. you can see that as Lom goes |
|
| 175:25 | or thermo maturity goes down, your goes up. So this is how |
|
| 175:33 | is defined. It's basically the color the organic material varying from yellowish or |
|
| 175:42 | brown to slightly darker brown to dark to almost black and black. |
|
| 175:49 | So uh luckily if you have this scale or if you have vite |
|
| 175:56 | so you'll notice here. So here's of organic metamorphism. So we've got |
|
| 176:02 | color here, we've got a thermal index. Oh And here the Holy |
|
| 176:07 | vitro Night reflect its all right. if you know your ro or some |
|
| 176:12 | equivalent, you can estimate your level organic metamorphism way more trustworthy than trying |
|
| 176:20 | interpret these colors, in my Now, now with now that we've |
|
| 176:24 | like image analysis tools. I historically, when I was doing this |
|
| 176:30 | , it was all by your right? You would estimate the color |
|
| 176:34 | that was related to the COC. we could segment on the basis of |
|
| 176:38 | GB color statistics and we could actually . So nowadays, this might not |
|
| 176:45 | so bad, but one of the you'll notice is here, you have |
|
| 176:50 | isolate the organic material. And I you guys talk about how the heck |
|
| 176:54 | you do that? If you're gonna actually measure vite reflectance on an isolate |
|
| 177:02 | do this kind of work on an isolate? All right. So you |
|
| 177:07 | crush the rock up not too but you make it into small |
|
| 177:12 | First thing you do is you um it in HCLHCL will get rid of |
|
| 177:19 | the carbonates when all the carbonates are , you put it in HFHF will |
|
| 177:26 | rid of the silicates at the What you'll have left is pyrite and |
|
| 177:32 | organic residue. And historically, we made our Miron reflected slides out of |
|
| 177:38 | . We said, OK, that's we care about. We're not gonna |
|
| 177:41 | about getting rid of the pyrite. if you then took that and did |
|
| 177:46 | heavy liquid separation on it, you actually get the pyrite out as well |
|
| 177:50 | there are other chemicals that will actually the pyro. But um it, |
|
| 177:59 | , it's a lot of work to the organic material. OK. So |
|
| 178:07 | can also estimate lom from other All right. So here's my s |
|
| 178:12 | peak. All right. So milligrams hydrocarbons per gram of rock. So |
|
| 178:18 | say my S two peak has a of 40. Um Then I would |
|
| 178:24 | over here to whatever my lom value and then read the toc of the |
|
| 178:29 | axis. Uh You can see though uh there's a lot more variability for |
|
| 178:36 | type two pyrogen than there is for type three pyrogen. And so here |
|
| 178:40 | really just the only possibility we have is to have a acid stimulation. |
|
| 178:49 | was published in Crane's Petro Physicals Actually a really interesting and good |
|
| 178:55 | You can purchase it pretty cheaply on internet if you're interested. Um You |
|
| 179:01 | look at their website. So basically they did is they related level of |
|
| 179:06 | metamorphism to Vitron Night reflectance. So curve was from Hood in 1975 and |
|
| 179:14 | they made a fit to it or the, it's not a curve but |
|
| 179:20 | , the blue measurements are actual measurements organics. There's a polynomial fit from |
|
| 179:26 | 75 and then this is their So, uh if you know vite |
|
| 179:32 | or can estimate it from what if did paralysis, what work can you |
|
| 179:41 | the an estimate of ro from paralysis from what, what do you use |
|
| 179:49 | T max? Which is the temperature which your S two peak reaches its |
|
| 179:54 | . All right, there's a lot hair on that relationship. It's got |
|
| 179:58 | , there's a lot of variability but got ways we can estimate RO, |
|
| 180:03 | we can estimate RO, we can to an LOM. If we |
|
| 180:07 | if we can get to an we can use delta log R to |
|
| 180:11 | TOC. So here is a TOC . Um I believe this is from |
|
| 180:22 | acoustic. Yeah, this is from sonic. So we've got the TOC |
|
| 180:29 | the sonic, we've got the gamma and then uh measured TOC from |
|
| 180:38 | And in general, there's a pretty relationship between the TOC estimated from delta |
|
| 180:45 | and that measured in the lab. in addition to that tends to follow |
|
| 180:50 | gamma ray pretty well. No, problem with TOC estimates in the density |
|
| 180:56 | we already talked about this. We have fac issues or breakout issues that's |
|
| 181:02 | cause some error. Um The toc the gamma ray as well is influenced |
|
| 181:09 | the depositional environment. So we need have this anoxia, we need to |
|
| 181:13 | in the transgressive systems tract at the at the maximum flooding surface. Uh |
|
| 181:20 | even if the TOC value is the at the TST and the top of |
|
| 181:24 | HST sorry uh transgressive systems track high systems track up here. I have |
|
| 181:31 | lot more terrestrial input so I could terrestrial organic material. And so I |
|
| 181:38 | have a, a high toc but , I don't have the uranium |
|
| 181:44 | So my gamma ray is not gonna . So we just have to be |
|
| 181:47 | with that. And then the only here is that we gotta have some |
|
| 181:51 | of thermal maturity. So here's the for K from that. Um Not |
|
| 182:05 | I can't read the actually here. But this is the delta L RT |
|
| 182:12 | uh with a mean of 5.2% and standard D VA then of 1.5%. |
|
| 182:18 | is probably again from the acoustic Uh And I have 374 individual estimates |
|
| 182:25 | TOC. In contrast, here's le data. So this is what I |
|
| 182:31 | in the lab. I have a of 505 volume percent, which is |
|
| 182:36 | pretty close to what I estimated from log a standard deviation though that's a |
|
| 182:42 | higher about 2.2 but I only have measurements. So this gives me a |
|
| 182:49 | more robust estimate of the toc. I can probably afford to do the |
|
| 182:58 | for in the lab. OK. into estimating play content. Uh why |
|
| 183:08 | we care about play content? I a racket plays are ductile lay means |
|
| 183:21 | can't crack it. So that's why care. So we're gonna go back |
|
| 183:27 | our calculation of the shale index. If we just use uh the gamma |
|
| 183:33 | shale index. That means that this the gamma ray measured in my zone |
|
| 183:37 | interest minus the minimum divided by the value of the gamma ray minus the |
|
| 183:45 | value. Um And that approach assumes the gamma ray max is only about |
|
| 183:53 | content, which we're hoping it's not our particular case, right? So |
|
| 183:59 | we figure out a way to estimate content and back the uranium out or |
|
| 184:05 | gonna have a problem of buying the ray. So if we don't have |
|
| 184:11 | spectral gamma ray, how do we between these two? So one workaround |
|
| 184:20 | we can try to use Smacker's If we see a correlation between bulk |
|
| 184:26 | and the gamma ray intensity, then assume that the lowest gamma ray is |
|
| 184:31 | background shale value. Or if we density neutron data, we can look |
|
| 184:36 | the biggest spread in the density Um We do have to be careful |
|
| 184:42 | this case, the um lowest gamma associated with this could be carbonates. |
|
| 184:50 | we we have to be a bit . Uh usually a good background density |
|
| 184:57 | a background shale is about 267, over 27 is probably a carbonate. |
|
| 185:04 | just keep that in mind. All . So there are several relationships then |
|
| 185:12 | I get my shale index, how I get play content? So the |
|
| 185:18 | thing is that V shale equals the ray index. And that would be |
|
| 185:22 | wrong, but a lot of people it, then there are three other |
|
| 185:25 | . The clavier method shown here, steer and the Bateman, which basically |
|
| 185:32 | a gamma ray index factor that basically the Bateman equation to vary between the |
|
| 185:39 | and the cyber relationships. OK. here is a comparison of the true |
|
| 185:50 | of shale uh with the gamma ray um and how we would estimate the |
|
| 185:59 | of shale using these various parameters. what we found was when we used |
|
| 186:04 | ray diffraction or ftir mineralogy, this model which is just assuming that the |
|
| 186:13 | is the gamma ray index way overestimates sale volume. Hence, we end |
|
| 186:19 | with pavier and steer which do estimate shale volume that is dramatically lower than |
|
| 186:27 | linear relationship. So it's always better be conservative. Um And so |
|
| 186:35 | we would use either the clavier or cyber model to estimate clay content or |
|
| 186:40 | take an average between the two, like that rather than this linear relationship |
|
| 186:45 | has been found to universally overestimate clay . So basically, if I know |
|
| 186:53 | gamma ray index, I would just up to whichever one of these |
|
| 186:58 | So you can see that here, say I have a gamma ray index |
|
| 187:01 | 60. If I use obviously the , I would say I had 60% |
|
| 187:07 | volume based on Claudia, I would 40% shale or clay volume. And |
|
| 187:18 | on uh cyber, I would have the order of maybe 34% shale |
|
| 187:25 | So that's almost a 50% decrease in estimate of play content. And in |
|
| 187:32 | case, I'm, you know, if I'm up in this region. |
|
| 187:36 | I use this, I'm probably not to attempt to crack. If I'm |
|
| 187:39 | here based on this, I might try to crack. So it's, |
|
| 187:46 | important to know. Um And to one of these two estimates, which |
|
| 187:52 | far better than just assuming the linear . Now, I can also estimate |
|
| 188:02 | we already kind of looked at this looking at the separation on density |
|
| 188:08 | If I have both density and neutron my logs as ferocity, then I |
|
| 188:16 | use this relationship here to get the volume from the density neutron. And |
|
| 188:23 | may actually give me a better estimate , of, of clay contents than |
|
| 188:29 | gamma ray relationship. So we should at multiple estimates of the same |
|
| 188:35 | Uh And of course, if we the same answer, we, we |
|
| 188:38 | a nice warm fuzzy feeling. If don't, we then need to look |
|
| 188:42 | which one we think is the most . And if I don't have my |
|
| 188:47 | data, both in terms of I can use these very long uh |
|
| 188:55 | where the volume of shale is A B. Uh And so matrix is |
|
| 189:03 | neutron. This matrix refers to the matrix. So this is the neutron |
|
| 189:09 | in the matrix. This is the porosity in my zone of interest. |
|
| 189:14 | is the density in the matrix density the fluid. Um Yeah. And |
|
| 189:21 | , that's basically all of the parameters we've listed here. This is the |
|
| 189:25 | density from the log measurement. that's the, I've defined all the |
|
| 189:36 | . OK. All right. So this probably tells us is especially if |
|
| 189:46 | don't have a spectral gamma or I need to estimate shale or clay |
|
| 189:51 | content. But it can be Uh The organic material impacts all of |
|
| 189:57 | logging tools that we use to estimate shale volume. Uranium impacts the gamma |
|
| 190:03 | . The hydrogen associated with organics is by the neutron tool and the low |
|
| 190:08 | of the organics impacts the density So one work around here is to |
|
| 190:15 | density versus gamma ray. If we a relationship, use the gamma ray |
|
| 190:21 | to estimate toc use the observed. that case, we can use the |
|
| 190:27 | uranium toc relationship to estimate the uranium of the shale. Then use the |
|
| 190:34 | equation. Uh that describes the influence uranium, potassium and thorium on the |
|
| 190:41 | of the gamma ray to remove the of the uranium and then calculate the |
|
| 190:46 | index just using the potassium and And even then, we would probably |
|
| 190:53 | want to use either the cyber or clavier model. So here's an example |
|
| 191:00 | attempting to do that. So I'm at two points, I'm looking at |
|
| 191:04 | A and point B I think this B, I'm not really sure anymore |
|
| 191:10 | one is, which I know A here. B is a little |
|
| 191:14 | It's one of these points. All . So again, the total, |
|
| 191:19 | toc in a volume percent is the gamma ray minus the gamma ray in |
|
| 191:25 | zone of interest over 1.378 times the of this line. OK. So |
|
| 191:33 | point A, my toc is 1 minus 2, 25 divided by this |
|
| 191:43 | times these numbers, you can read as well as I can. What |
|
| 191:47 | I end up with? I get volume percent of POC and for point |
|
| 191:54 | I get 15.2% uh toc. Now go to this relationship and I estimate |
|
| 192:03 | content, I've got my volume percent Carro in. So I can just |
|
| 192:06 | this relationship to get uranium in P . Then I can enter the gamma |
|
| 192:12 | equation removing the uranium and get the ray signal solely associated with thorium and |
|
| 192:21 | . And then I can calculate the ray index using that. So the |
|
| 192:28 | ray minimum is gonna be used a clay free formation like a limestone or |
|
| 192:34 | . This is my background shale. And this is my result of interest |
|
| 192:40 | now I have the gamma ray, log minus you. OK? For |
|
| 192:47 | A, I got a gamma ray of 0.95 and four point B I |
|
| 192:54 | a gamma ray index of 0.57. Of course, that's the maximum value |
|
| 193:00 | could be. Uh So I would not use the linear relationship. |
|
| 193:08 | sorry. So basically, this works to about 85% clay. When I |
|
| 193:14 | either clavier or cyber, this works to be on the order of 30 |
|
| 193:23 | using those other models. So given , where would I want a |
|
| 193:39 | So if I go back to even here, I still have a |
|
| 193:45 | clay volume. So it's only in regions where I would most likely be |
|
| 193:51 | to put away a really decent All right. OK. Now I |
|
| 193:59 | Doctor Myers talked about Sonic. I no idea what slide I'm on. |
|
| 194:03 | I don't know how much more I left. Um I don't know if |
|
| 194:07 | need to go through the operation of acoustic tool. All right, I'm |
|
| 194:14 | go through this then. OK. we all know how the acoustic tool |
|
| 194:25 | . The vertical resolution of that tool somewhere between 1.5 and 3 ft. |
|
| 194:31 | of course bed ignition shales varies from thick down to the millimeter scale. |
|
| 194:38 | any uh velocity that I measure is average of multiple layers, the particle |
|
| 194:45 | that's associated with the P wave is to the well bore. So in |
|
| 194:50 | vertical, well, I'm measuring perpendicular bedding, measuring the vertical velocity. |
|
| 194:56 | I'm in a horizontal well bore, measuring parallel to the betting my compressional |
|
| 195:03 | . And if I'm in a deviated bore, then my compressional arrival is |
|
| 195:08 | between vertical and bedding thing, parallel , sheer waves. On the other |
|
| 195:15 | , propagate perpendicular to the well bore they will actually split and propagate at |
|
| 195:21 | velocities in different direction directions if the is anisotropic. So basically, if |
|
| 195:30 | if this is the well bore I've got a vertical well bore and |
|
| 195:34 | I'm looking at velocities around it and are differences in the acoustic velocity, |
|
| 195:42 | north, south and east west from well bore, I will see my |
|
| 195:47 | waves split and propagate in different directions associated in velocities with that different that |
|
| 195:59 | isotropy um in a horizontal. the splitting looks like once your wave |
|
| 196:10 | going to propagate along individual bed. bedding plane parallel and the other one's |
|
| 196:16 | pro propagate in the vertical direction or to the bedding. This works out |
|
| 196:21 | be important because the anisotropy of these is huge. OK. What we |
|
| 196:29 | assume about a shale is that it transversely isotropic. That means that with |
|
| 196:34 | z axis of symmetry. So that that if I go in that circle |
|
| 196:39 | the way around my well bore which vertical, the velocities are the |
|
| 196:45 | There is no anisotropy. The major is between perpendicular tetting and parallel to |
|
| 196:56 | . In that case, the compressional in a horizontal well bore is given |
|
| 197:01 | this equation. So the square of compressional velocity in the horizontal well bore |
|
| 197:07 | two times the square of the sheer in the horizontal well bore minus the |
|
| 197:15 | of the sheer velocity um in the direction plus the square of the vertical |
|
| 197:25 | velocity. All right, that's just we interpret relative to whether we're moving |
|
| 197:34 | to the betting or perpendicular to betting parallel to it. The young's |
|
| 197:40 | I know you guys talked about Young's um in shale reservoirs, this e |
|
| 197:47 | is really variable. So the horizontal modulus is typically much greater than the |
|
| 197:54 | Young's modulus. And so sometimes, know, we estimate the young's modulus |
|
| 198:02 | . This delta ev is the horizontal the vertical Young's modulus divided by the |
|
| 198:09 | Young's modulus times 100. And this ev is actually related to clay |
|
| 198:16 | So ha ha we have another way to try and estimate clay volume using |
|
| 198:21 | data. And again, a large of clay implies ductal component, uh |
|
| 198:27 | rock, whereas small values imply So basically, this is another way |
|
| 198:34 | we can uh select lateral landing points a well. And we're gonna talk |
|
| 198:39 | how do we get this Young's modulus the acoustic data, right. So |
|
| 198:46 | sonic log, as doctor, did talk about all these equations? Uh |
|
| 198:51 | doctor Myers mentioned can be used to geom mechanical properties. I have to |
|
| 198:58 | sheer acoustic velocity information. And we some terms the poissant ratio is the |
|
| 199:06 | of the transverse to longitudinal strain. new is e transverse over E |
|
| 199:15 | Then we have the shear modulus which the ratio of the sheer stress for |
|
| 199:19 | sheer strain. So we're looking for resistance to shearing and that's at some |
|
| 199:25 | angle. Uh that shear modulus is to as new and it's the force |
|
| 199:30 | unit area divided by that angle for strains, the bulk modulus. Um |
|
| 199:40 | that means is that when we subject body of rock to a uniform compressive |
|
| 199:45 | , that stress is related to the change by this B modulus K. |
|
| 199:51 | it's the pressure over change in volume to the starting volume. Uh And |
|
| 199:57 | is the reciprocal of compressibility. And , young's modulus, which is what |
|
| 200:02 | were just talking about, which is resistance to linear compression or elongation is |
|
| 200:08 | force pit area applied uh divided by in length over the starting. So |
|
| 200:18 | strains, the acoustic energy that we're through the rock actually imparts a |
|
| 200:24 | It's very small. However, so elastic, which means it's completely restorable |
|
| 200:31 | there's no lasting or resulting permanent So from my sheer velocity, I |
|
| 200:40 | the shear modulus because I've measured the velocity. I know the density because |
|
| 200:45 | run a density log so I can shear modulus. Once I know shear |
|
| 200:50 | , I can come up here. I know the VP because I just |
|
| 200:54 | it, I know the sheer modulus I just estimated from the sheer |
|
| 200:59 | I know the density because I have density log. So I can now |
|
| 201:03 | the bulk modulus. Once I know bulk modulus and the sheer modulus, |
|
| 201:09 | can calculate the young's modulus. Uh once I know the young's modulus and |
|
| 201:15 | sheer modulus, I can calculate poisons . So if I have a vs |
|
| 201:22 | , I can go and a VP , I go through and calculate the |
|
| 201:26 | geom mechanical prop properties at least for small string. OK? And materials |
|
| 201:36 | a high Young's modulus and a low ratio are more brittle. So from |
|
| 201:42 | acoustic log beta, I can basically put a brittleness estimate in my borehole |
|
| 201:49 | figure out where is the best place try to place my breath. |
|
| 201:57 | Problem is sometimes I don't have sheer , right? So if I don't |
|
| 202:01 | sheer data, I could use analog from a nearby well and establish a |
|
| 202:06 | DS relationship or God forbid, he's established model for V PV S |
|
| 202:14 | analog. Well, obviously having a measurement best analog, well, |
|
| 202:21 | OK, established relationships. Now we're getting into la la Land. And |
|
| 202:28 | have to be careful because every formation its own relationship. And so we |
|
| 202:35 | to be careful applying just some sort standard model. There are a couple |
|
| 202:39 | standard models shown here uh from Castagna Greenberg and Castagna where VS is equal |
|
| 202:46 | VP over 1.16 minus 1.36 or Greenberg Castagna relationship shown here. There are |
|
| 202:58 | with empirical data that show the relationship pathology and the VSBP ratio. Um |
|
| 203:06 | in carbonates in sandstones. But here a shale value here, uh varying |
|
| 203:12 | 0.58 to 0.65. Uh Here's another value here, this 1.56 to |
|
| 203:21 | So, um in general, you , if I don't have anything |
|
| 203:26 | maybe I try to do something like to estimate the, the mechanical |
|
| 203:33 | Um all of these slots that I'm you. I've given you the papers |
|
| 203:37 | you wanna go look this stuff And this was a relationship that was |
|
| 203:43 | in a shale gas reservoir where they that the increase in isotropy in Young's |
|
| 203:50 | was associated with increasing clay content. so again, um they didn't see |
|
| 203:56 | very strong relationship between Poisson's ratio and content. So in this particular |
|
| 204:03 | they said we're just gonna use the in Young's modulus and the anisotropy in |
|
| 204:08 | Young's modulus as an estimator of clay So this is another way that we |
|
| 204:13 | use the acoustic data to tell us about the volume of play that's |
|
| 204:20 | OK. And so what does the effect do? It basically increases the |
|
| 204:27 | horizontal stress that I have to apply initiate a fr And this effect is |
|
| 204:35 | by or is proportional to this relationship we have our horizontal over our vertical |
|
| 204:42 | uh young's modulus and our vertical over minus the horizontal croissants ratio, |
|
| 204:51 | So this signage min is proportional to . Uh And this is another way |
|
| 204:57 | we could use this data to OK. How much fluid pressure do |
|
| 205:01 | have to use to actually generate a in the formation? The interesting thing |
|
| 205:11 | acoustics. Uh You should recognize these , Doctor Myers and yours um is |
|
| 205:18 | in addition to the small strain properties we were just talking about laboratory measured |
|
| 205:27 | data, first of all agrees very with log measured acoustic data. Number |
|
| 205:33 | and number two, um the laboratory acoustic data is strongly related to large |
|
| 205:41 | properties like peak strength and things like . So this is just an example |
|
| 205:47 | how uh some measurements and a couple these are laying on top of each |
|
| 205:52 | . There's actually I think there's like or eight data points in this where |
|
| 205:56 | log measured uh compressional velocity um plotted the laboratory measured compressional velocity. And |
|
| 206:05 | can see they essentially fall along. this dash line is the 1 to |
|
| 206:09 | line and this is the best fit to the data. Now, this |
|
| 206:18 | uh where these samples came from. a bunch of these are just laminated |
|
| 206:21 | rocks from the Deepwater Gulf of Those are shown in blue. Uh |
|
| 206:28 | blue triangles. Um The purple circle a debris flow mud rock from the |
|
| 206:34 | of Mexico. The red triangle is calcareous mud rock from the Gulf of |
|
| 206:40 | . And these green squares are samples the Hainesville formation. All right. |
|
| 206:45 | a shale gas reservoir and what we're at here is the peak compressional strength |
|
| 206:52 | either this sheer or the compressional velocity the relationship observed between those two. |
|
| 207:01 | the peak strength of the material is strongly correlated to the acoustic properties. |
|
| 207:10 | in this case, I found this of interesting actually was that the peak |
|
| 207:14 | and compression at least was good over very broad range of properties. We |
|
| 207:21 | from laminated deepwater Gulf of Mexico mud to a debris flow mud rock where |
|
| 207:27 | the bedding was all over the place uh calcareous mud rock. I'll show |
|
| 207:31 | AC T scan of it. It like cement with rebar going through |
|
| 207:35 | And then um we have Hainesville dramatically much, much older uh and essentially |
|
| 207:43 | pretty close to the same trend in case. Now, we also looked |
|
| 207:51 | peak strength and extension or relative And here we see some differences. |
|
| 207:58 | here, here's our deepwater laminated mud and again, our Hainesville laying right |
|
| 208:03 | top of each other for the sheer compressional velocity. Uh And then we |
|
| 208:11 | our debris flow mud rock which I you can't really, uh yeah, |
|
| 208:14 | can sort of see the CT, CT, this is a core photo |
|
| 208:18 | it and this is the TCT scan the convoluted betting over here. And |
|
| 208:24 | here, my inference is that this is playing a role in the peak |
|
| 208:29 | and extension here because we've deformed it that. And then for the mud |
|
| 208:38 | , this is just um all I'm you is the high density phases going |
|
| 208:43 | the core plug. So these are burls that are essentially mostly going vertically |
|
| 208:49 | through the core plug and they are fact acting like rebar in cement and |
|
| 208:55 | . And that's why that one has strongest strength and extension. So |
|
| 209:00 | not all uh sales are created And CT scanning is a good |
|
| 209:07 | But for these laminated mud rocks that not deformed, we have a pretty |
|
| 209:12 | relationship. But I do want to out that the strength and extension is |
|
| 209:17 | lower than the peak strength and Doctor Myers. Do you wanna say |
|
| 209:22 | about that? Yeah. Again, were all made in Doctor Meyer doing |
|
| 209:32 | lab, these strength methods. So we can see is that the peak |
|
| 209:39 | is definitely related to the acoustic But as we go from formation to |
|
| 209:46 | , that relationship may be different. in each case, we would need |
|
| 209:50 | data to calibrate that uh and the that influence the acoustic log response also |
|
| 209:58 | our estimate of rock strength. So is an example of just looking at |
|
| 210:03 | between various log signals in a number sedimentary intervals in one of the rocky |
|
| 210:12 | basins. So we've got the lower shale, the Maori shale, the |
|
| 210:18 | creek shale and the Thermopolis shale. and this is the range of expected |
|
| 210:26 | uh below 10,000 ft from trend OK. Uh So you can see |
|
| 210:33 | what the range of velocities is for of those. And in general, |
|
| 210:37 | and content will tend to decrease the play content will also tend to decrease |
|
| 210:43 | silica or e especially silica cement content tend to increase it. So we |
|
| 210:50 | content and carbonate cement ferocity will decrease . Pre presence of gas will decrease |
|
| 210:56 | velocity present day overpressure will decrease it overpressure and the presence of microfracture. |
|
| 211:04 | all of those will tend to decrease . So the two things that really |
|
| 211:07 | it here are both just bulk silica or carbonate content. And my inference |
|
| 211:14 | is that a lot of this has do with cements of those various |
|
| 211:20 | Why do I say that this is example again of some work that we |
|
| 211:24 | way back in the day um where were looking at acoustic properties, P |
|
| 211:29 | S velocities as a function of um stress, sorry, here's the velocity |
|
| 211:36 | and the mean stress on the x . Um And we were looking at |
|
| 211:40 | were sandstones admittedly, but we had from 0 to 2% cement in these |
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| 211:47 | , quartz cement, 2% is in noise. It's hard to even quantify |
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| 211:53 | an image much less a point. standard point count, you might likely |
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| 211:58 | it. OK. If you did analysis on a suite of images, |
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| 212:02 | would probably see this difference. But you see here is that as a |
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| 212:06 | of uh increasing cement content, we increasing velocity. And we also see |
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| 212:15 | as that cement content increases the impact the mean stress also changes in terms |
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| 212:23 | the effect on the acoustic properties. this is for both the compressional and |
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| 212:28 | sheer properties. Now, I can tell you that for the same |
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| 212:32 | we did poor volume compressibility measurements and saw the same thing as we moved |
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| 212:37 | way, higher cement concentration, the strength also increased. But here is |
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| 212:45 | the interesting thing that at these at small quart cement content, we see |
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| 212:53 | the impact of the stress here on the compressional and fear velocities is really |
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| 213:01 | to see because the cement is dominating , what would we call it? |
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| 213:11 | contact modulus even at 2%. I that remarkable. Well, it, |
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| 213:21 | a little, they're little. You pictures of it. They're just not |
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| 213:25 | . They're right at points of grain . And so at that, those |
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| 213:29 | of grain contact, it's cementing the together and enhancing the strength of the |
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| 213:39 | . Oh, what time is Oh, well. Ok. You |
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| 213:44 | can reduce size as well as I . This is just another pitch for |
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| 213:47 | Meyer's lab where we looked at single Triax test versus multistage, multistage gives |
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| 213:55 | much better results. We only need use a single core plug. We |
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| 213:59 | get good estimates of elastic properties that need for food for modeling as well |
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| 214:08 | good estimates of the peak strength. And then this is probably exactly the |
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| 214:13 | model to use, but just an of a rock properties, a rock |
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| 214:19 | model in the lab. This is more cool model. Doctor Myers. |
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| 214:23 | think you prefer the cam clay Yeah. Yeah. But basically it |
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| 214:36 | kind of goes to show you how would estimate various rock parameters using uh |
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| 214:43 | measurements. And again, what we want is brittleness. There's a definition |
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| 214:49 | brittleness here we realize we're running out . Um but basically, uh this |
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| 214:57 | is probably the best thing that you do, which is a ratio of |
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| 215:01 | compressive compressive strength to the tensile which is why I showed you |
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| 215:06 | So these are my measures of compressive and this is my measure of, |
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| 215:10 | tensile strength. That's the reason that showed that be careful of these definitions |
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| 215:19 | brittleness. They are out there for , Jarvie 2007 and Wang 2009, |
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| 215:27 | they are using here is bulk And I hope that at least some |
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| 215:32 | what I showed you in terms of effect of cement on velocities. And |
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| 215:38 | have to take my word for it I don't have the slide in |
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| 215:40 | The effect of small volumes of cement strength properties that it's not just the |
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| 215:45 | mineralogy, it's the origin of the that matters. So if I have |
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| 215:52 | substantial amount of quartz or calcite cement here, then all bets are off |
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| 216:01 | terms of, but I don't know from bulk mineralogy. Uh This would |
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| 216:05 | like quartz from X ray diffraction and calcite and play from X ray |
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| 216:10 | I need to know the volume of phases and I don't have that from |
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| 216:14 | assumption. So just keeping that in and then this is a parent brittleness |
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| 216:21 | several shales in the US. Although is a limestone, here's the |
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| 216:25 | which again, really is mostly a silt stone. Here's the Woodford |
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| 216:31 | um the Marcellus and the Bossier. so as we're moving from Barnett Woodford |
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| 216:40 | Bossier we are basically increasing clay content decreasing the apparent brittleness. And then |
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| 216:49 | are just some trends between various logging . So here's acoustic velocity versus resistivity |
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| 216:57 | various uh formations. And we might these kind of relationships uh to estimate |
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| 217:06 | . So probably here would be the brittle formation I have. This is |
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| 217:13 | maori, I can tell you it a lot of quartz cement in |
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| 217:16 | That makes sense. Uh Here, got the neutron ferocity versus the sonic |
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| 217:23 | . And again, now the neutron goes up. What, what does |
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| 217:27 | mean in general? Like content goes because it's seeing all the hydrogens in |
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| 217:37 | clay. So again, now I'm at this one and again, it's |
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| 217:41 | maori. So I can look at in various log measurements to also get |
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| 217:47 | estimate of brittleness. And here the ray versus acoustics doesn't really tell me |
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| 217:56 | . Uh There are also, published uh relationships between um ferocity and |
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| 218:05 | or young's modulus. Uh Again, a published relationship. It's good for |
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| 218:11 | it was calibrated. Other than I probably wouldn't use it. And |
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| 218:16 | um we're looking at converting dynamic. in a log all the properties, |
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| 218:23 | measure our small strain, we call dynamic properties. In the lab, |
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| 218:27 | measure large strain properties, we call static. So how do we go |
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| 218:33 | a dynamic property to a static This is one set of measurements that |
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| 218:38 | of models that we could use to that and there good. OK. |
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| 218:43 | of stuff in a short amount of . But again, um, very |
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| 218:47 | ways that we would use the log from uh the standard tools that we |
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| 218:56 | to estimate rock properties and shales as to how we would use them in |
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| 219:01 | red. Yeah, gonna shut that and probably, I didn't, it's |
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| 219:46 | gonna be questions or |
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