VideoPoints

• ••• • •• • ••••• • •
GEOL 6381 Petroleum Geology - Mar 1 2023
Help Tour
© Distribution of this video is restricted by its owner
Transcript ×
Auto highlight
Font-size
00:02 OK. So, um, you missed this story uh for legal
00:08 . That might have been good. . OK. So, uh here
00:14 have uh all these nice figures and kind of told you these are really
00:19 things. Uh The worst thing, student of geology, which is all
00:24 us. I'm, I'm even a of geology. The worst thing we
00:28 do is assume that this shape means thing like a transgressive beach or a
00:36 beach. You know, they, mean a lot of different things depending
00:39 where they are. And uh in words, you can get a repeat
00:43 this motif in several different depositional settings have faces that mimic each other in
00:50 different parts of uh of the whole uh series of uh systems.
00:58 what is, what is wrong with one? I, I mentioned something
01:02 uh OK. Um First of there's something wrong with the title of
01:15 . So this is a well into , right? So, would that
01:20 a turbidity sequence or would it be else? And we, we would
01:27 it a turbo. In other it's a rock and it was formed
01:32 turbidity, but it's a rock. this is a turbo that was formed
01:38 uh turbid currents. Uh But, know, just to say that's a
01:44 sequence. Uh again, as a , I might think, well,
01:48 is what Turbid look, this is , this is one turbidity sequence,
01:54 it's not, it's a whole bunch turbidity sequences. Each one of these
01:58 upward things would actually be a sediment from a turbo uh event. A
02:06 event that's been preserved as a OK. OK. So what,
02:12 about this? What about how it's even coming up here like this doesn't
02:29 anybody. What did I tell you ? Look, somebody in here has
02:35 a class and knows that the turbo coarsens upwards. Somebody in here knew
02:41 when I was talking about the Bama that so you would expect it to
02:48 more porous as, as it goes . Right. Right. In other
02:53 , normally these things are building out a massive amount of accommodation space and
03:00 they build out uh sediments, you , you're expecting uh further sediments to
03:08 out here. And as that's building , it's actually a pro gradation type
03:14 uh where it is. And so the actual channel is shifting C word
03:20 it's building up and to get a like this almost always, um you're
03:27 see a coursing upwards. In other , this one will be coarser than
03:31 one. This one will be coarser the one below it. This one
03:35 be a little coarser a little bit . So the bottom one is gonna
03:39 like the toe of the first the toe of the second one will
03:43 out over top of that toe and up here, the flow of the
03:47 one will will flow. In other , there's no no issue with accommodation
03:52 but flow velocity, we still got angle. So it will go a
03:55 bit farther the next time and the one will go a little bit farther
03:59 the next time. And as you know, it's sort of like
04:02 a trajectory like this, a given bases within the turbo system will be
04:10 like this through time and through you know, it'll be, it'll
04:14 moving upward in the sequence and it be moving down depositional difference. So
04:22 again, you know, now, it possible that something could look like
04:27 in a turbo section? Yes, is if you're in a, a
04:30 where it was building out, and some reason, most of the energy
04:33 going up here and this side was getting a small amount and it was
04:38 kind of a grading instead of but normally they will prograde because you've
04:43 this rush of sediment coming down. if it's gonna build out on this
04:48 it's gotta have the force and the and sediment load to get at that
04:52 . It will probably push past that and create a new toe.
04:59 Here is uh another thing um showing uh how this can be a little
05:06 different for certain things. Here. says a fluvial channel. Uh And
05:12 , if it's a fluvial, I say it would have to almost be
05:14 distributor channel to look like this or very big channel uh where you had
05:20 gradation of uh the foul way through being filled in with coarse grained sediments
05:27 uh and not near the uh point . In other words, it's not
05:32 there. It's almost a chute uh of the, of the river that
05:36 a chute that was straight, like distributor channels get really straight because it
05:41 straight jet flow and it pushes straight and races out into the ocean.
05:47 . And uh here's the bell shape and you can, and I'm not
05:49 read all these, but you can at this. And uh I think
05:54 thing that's really obvious that this is of a generalized shape. This is
05:58 at how it might actually look. uh and you see here, this
06:05 deep sea fan, OK? That's a turbo. OK? And it's
06:11 you that it's coursing upwards exactly what was trying to explain to you.
06:15 that's why this one should look more that. And here's something uh
06:22 this is out of one of the U T, the Bureau of Economic
06:27 at U T uh for a Had these really neat uh master's thesis
06:33 were turned into studies of their field or like reservoir studies. This was
06:39 of them and um the person came with this uh uh channel faces here
06:48 uh this is a second, you it a second bar. We,
06:52 usually call that a secondary barrier. the primary barrier. In other
06:56 the ocean's out here. Uh But a storm, a big storm,
07:00 might get uh some uh uh overflow the entire island and it pushes sand
07:09 in here and builds up sort of secondary barrier. In other words,
07:12 , uh if you get on the side of West Bay and Galveston,
07:15 find lots of sand deposits where, uh the big storms have, have
07:20 it out since I have this Uh like this, I can,
07:24 can go over uh one of my peeves about people that study hurricane
07:30 And one of the things that happens if there's a, a low point
07:34 a barrier island and a hurricane is too big, it comes through and
07:41 pushes through here and you get something looks like a little fan out here
07:45 it's a wash over fan from a surge. Ok. And some people
07:52 study these things will tell you you know, they reached a point
07:55 their core where they had solid It was really thick. Well,
08:01 imagine if these fans, you have a category one or two that hits
08:05 weak spot in a, in a barrier island, it's got a
08:08 spot. You a fan build out they have another one, it builds
08:11 , it builds out eventually it builds into the channel. So, so
08:15 you drill down a core into you hit this thick sand, the
08:19 sand is not as they put The mother of all hurricanes,
08:24 they try to try to quantify it being a major hurricane event. And
08:30 and uh they leave it at that looking at this diagram, what do
08:34 think would happen if you had a hurricane? Would you end up having
08:40 right on the other side of the ? That was a really thick sand
08:44 on everything I just said. But happened is this whole island right here
08:51 just probably be plane right off. stuff would get in, deposited in
08:56 channel because it's a hole. So a combination space. And so some
09:01 that walkover falls into that. But thrust of it, it happens here
09:05 the time when Boli Peninsula got overwhelmed 19, the 19 ft surge or
09:11 ft and 11 inch surge. The ft, the house with 19 ft
09:16 didn't disappear. Uh It went, went way inland and if there were
09:21 boats there, they went away, know, they weren't, they weren't
09:25 around there, uh, right behind barrier island. That was a big
09:28 surge. It pushes it all the in. So the way to tell
09:32 big storm surge, uh would be , um, to see sand development
09:39 onshore and past a secondary barrier. uh how does it relate to petroleum
09:45 ? It has a lot to do the development of these faces, how
09:49 map them out and uh and how going to uh produce them.
09:55 typically a title channel is, is , a pretty uh forest system.
10:01 It can have larger particles and bigger and bigger pore throats. Uh If
10:07 look at the title inlet, the the tidal delta and sometimes there's a
10:12 tidal delta, they'll have a little more mud in them because they're,
10:14 moving with the ties and they drop fine grain sediment on top of them
10:19 it gets buried with sand. Uh , uh we might talk about uh
10:25 this, in the course of that there's a uh couple of reservoirs
10:30 um the Title Inlet has uh filled with cement because it was more porous
10:38 flowed, cements could be precipitated. when you get to the tidal deltas
10:43 because there's some clay to slow down transport and the permeability wasn't as
10:48 The porosity there was kept open long for it to get charged with
10:52 There's uh up in Alaska, there's tidal deltas that uh that actually are
10:57 big producers rather than that, than channels. OK. And here uh
11:02 the other thing is, is combining this together. Uh The geologists can
11:07 up with a really good picture of type of sandstones they have some of
11:12 uh faces and micro faces. And , uh it's really important uh to
11:19 this both in a vertical sense, then be able to look at the
11:24 where you don't have cores and calibrate to it. So you can come
11:27 with that aerial faces pattern. And kind of gives you uh the shape
11:34 your potential reservoir bodies. When you're to map something out like this.
11:37 other words, there could be a here. For example of this porosity
11:42 the barrier core like a Tom o'connor . The barrier cores were preserved,
11:47 porosity was preserved and this is where reservoirs would be, would be in
11:52 uh things. And they had pro ones uh that prograde it forward through
11:57 . So they had a series of uh these things uh that were
12:01 grading like this as you went to South East uh down in South
12:11 OK. And um also uh you see kind of uh the organic contribution
12:19 the oxidation contribution here just in these sandstones and that sort of thing.
12:24 then the offshore shelf muds stones, you can see some uh abrupt
12:29 This is the base of the Uh this would be the top of
12:34 core. So uh what would this be transgressive? So this here's the
12:43 and an offshore is starting to uh , as this thing as the delta
12:49 regressing. The uh offshore deposits come top of it. Here is um
12:56 chore that I look at. Um I got blackballed by the uh Corp
13:03 engineers. Um they had, they storing this but the US Geological Survey
13:11 uh had a, had a um one core, the Clubhouse Crossroads Core
13:16 which this one came from, but had a lot more uh chores like
13:19 in a different area. Uh But was in a particular formation that had
13:25 wavy and lasure uh deposits in So, what are the two different
13:32 that we talked about that? That happen. You remember that where
13:51 where you alternate between coarse grain and grain sandstones over very short distances?
13:57 these are centimeters here. What would be? Um ok. Ok.
14:18 . Ok. So it could be this could be the base of waves
14:21 uh storm, storm wave, it's down and it and it stirs up
14:27 mud and sand. There may be lot of fine grained sediments but
14:30 but it will start to winnow out sand and make little sand ripples on
14:34 of the clay bottom. And then later on, you'll get the
14:38 stuff coming in a little bit stronger then maybe another storm event. This
14:42 a storm episode. The other thing that what most people would and I
14:49 this out when I was talking about earlier, but what most people would
14:52 this would be a title or something that's uh has to do with a
14:59 over a levy because levy, levy over bank deposits are periodic and
15:06 And so, you know, you'll some coarse grain material and then you
15:10 the fine grain floodplain muds, then coarse grain stuff and then fine fine
15:16 muds. So you can get this of thing in three completely different
15:21 And uh again, seeing the core maybe getting some information on the Biota
15:26 it helps you determine whether it's a deposit or something that's related to a
15:31 stream system. And how does that reservoir continuity character bodies? And that
15:38 of, does that have any impact that at all? It has a
15:44 impact. If, if this is deeper water, you're gonna be looking
15:51 for sandstones that might be related to turbo deposit. And or an offshore
15:56 , something that's developed like an offshore , which is gonna be maybe a
16:01 sand body. It's very long but it might be uh not all
16:06 thick, something like a, a barrier island almost under, under
16:11 Uh But some of these things get big. And uh in the Gulf
16:14 Mexico, we often call them sheet because they extended, you know,
16:18 thickness, you know, laterally for long or longer uh parallel to the
16:23 and a little bit shorter uh perpendicular the coastline. But uh that affects
16:29 knowing that environmental deposition tells you that your target sand bodies are gonna look
16:34 . If this was a title you would be looking for something that
16:39 like this in terms of sand which is completely different. If it
16:43 , if it was a um um play or something like that, it
16:48 be a completely different sand body that would be looking for very similar types
16:53 structures. But you, you need have a way of figuring out what
16:58 setting you're in to use those sedimentary to the fullest extent. And you
17:02 , the sedimentary structures, the composition the texture are all things that we
17:07 to try to figure these things out on whether the prose was preserved or
17:19 . And uh oftentimes the deep the bars are really big. We didn't
17:25 offshore bars for a long time because geology, the knowledge in
17:29 students of geology, we learned what onshore. Then we got our feet
17:35 on the beaches. Then we got little bit deeper with small boats and
17:39 we went a little bit deeper but too often with some Texas A and
17:44 boats and stuff like that. But really didn't get into the deep water
17:47 until oil companies started drilling in deep . And, uh, and so
17:53 , uh, it's like that. , uh, but yeah, by
17:56 large, I, I think a offshore bar would be a great thing
17:58 find. But if the pro the could be uh not preserved in,
18:03 many case, ok. And then is showing the value of our crops
18:09 geologists. And um, this is in the basin and this was on
18:17 3756 Yankee. And uh it was jet ranger two. So it had
18:22 power so it could actually get over mountain and, uh, you could
18:26 the elevation on it and, they're really neat things to work in
18:31 of the access to vehicles like that really incredible. Uh, when you're
18:36 geologist working for an oil company and research center. But, uh,
18:41 again, this rock section right here buried underground over here. And,
18:49 , that's not even, even though is a big outcrop several 100 ft
18:54 maybe 500 ft high. It's nothing to some of these tilted rot and
19:00 blocks that you would get from a valley when, uh, when the
19:03 ups uplifts this thing. And you've these, uh, beds on a
19:07 bending over and you have these huge that are thousands of feet high.
19:12 , but you actually stick stuff Uh, you know, stuff
19:16 um, uh, our crops uh, and you're able to see
19:25 that are buried deeper in the uh that, that, uh,
19:29 you might want to drill and get out of. But up here they've
19:32 exhumed or uplifted and because they were , uh they weren't, they didn't
19:37 matured along the riffs, the remnant , uh along the uh uh east
19:47 of Brazil and the west coast of . The uh the, the subs
19:52 , some of the subs salt out are exposed like the point in
19:57 And I can't pronounce a Portuguese uh over here in Brazil. But you
20:02 actually sample the source rocks and you say, you know, if we
20:07 drill under the salt over here, would run into the same kind of
20:10 , uh source rocks and of the T O CS were extremely high
20:14 the Carros were just the right type generating oil. And so that kind
20:19 thing really helps. So our studying our crops are important for the
20:23 industry. OK. And so, , from cutting and corn and,
20:29 and our crops, you can figure all sorts of things in terms of
20:33 provenance of the sands where they're coming . And of course, there's a
20:37 suite of depositional environments between the ranges in the ocean mass. If it
20:44 to be a meandering system and you're away from that source. If you're
20:48 to that source, uh you might to deal with sands that uh are
20:53 to uh break down and, and into solutes that could be precipitated and
20:59 cements and that kind of thing. it has a big impact on reservoir
21:03 in terms of uh the types of you may or may not have and
21:08 and the various types of uh brain and uh sorting that you might
21:14 In other words, uh what type sorting, what type of texture am
21:17 gonna find in this particular area that have to deal with in terms of
21:21 and permeability, uh quality enhancers or ? OK. And this is just
21:30 you uh that um you can uh a lot of information most of the
21:36 is ferocity. You can see how of these uh uh grains are getting
21:42 chloride coatings on them. And so because the grains are uh sort of
21:49 essence kind of growing, uh you're coming up with ways to elude
21:54 porosity and also to block pork the pore throats get smaller and smaller
22:00 , as you get more and more , it also makes the flow of
22:04 uh slow down and that looks like fluid inclusion right there. Um Here
22:09 just showing you how chloride plates and they may still have a lot of
22:15 , but they're very small and the becomes very, very uh uh very
22:22 on these things. So any time have something like this forming in a
22:26 , uh it can cause a lot problems. This uh this kind of
22:31 structure is, is not too different from, from what we would
22:36 Uh and a chalk in the North that had that open structure and had
22:42 . Uh But uh it wasn't so as this to where you'd have a
22:46 of pore throats blocked off uh in particular example. And, and that
22:51 be filling in, you know, ferocity and permeability in some of these
22:55 here where we have that ferocity. uh this is a recent paper.
23:02 um And this, this is kind to show you the value of having
23:06 scanning electron microscope. Why would we to even look because we can see
23:11 of the details. Why would we uh sidewalk cores and look at thin
23:15 so that we can see these things disrupt, remove porosity and disrupt
23:22 And uh when we get into Another thing that we're looking for uh
23:27 be things that are uh uh would the brittleness of the rock versus things
23:34 don't increase the brittleness of the rock brittleness is something uh that if we
23:39 flexure of a bed, uh if any structure at all, there's gonna
23:42 some flexure and you could create uh better avenue for uh things such as
23:49 fracturing to uh to be opened up uh actually fill in that in some
23:56 the chalk fields in the North for example, uh the open framework
24:01 filled in and the uh and the nano fossil chalk was, was turned
24:11 very brittle rocks. And when there uh diapers and whatnot that uh cause
24:18 to flex it fractured and then, it was charged. So, in
24:21 North Sea, you have this open thing with nano fossils like that like
24:27 of carts. And you also have brittleness from the carbonates uh that when
24:32 uh flecks are gonna fracture because they're . If you had silicate muds in
24:37 , they might just ooze around like , they're more plastic in nature.
24:42 the silicate um plays quite often uh , are more sealing and uh and
24:49 likely to develop natural fracture. And , that's again why they're looking for
24:55 these carbonate minerals or carbonate muds versus muds or, and that's what the
25:02 shale is, is the silicate, lower that b shale goes down,
25:05 higher the carbonate goes up, the brittle it can be and have a
25:09 fracture. OK. Another thing uh when we get samples out of a
25:17 bore, you know, if we the oil, we can look at
25:20 oil and see what its history its maturation history, how mature it
25:24 . Um And even kind of get hint of uh where it's come
25:30 But if we get uh Carros out the rock, we can also look
25:35 see what the generating capacity of those were. In other words, I
25:41 it's a real simple minded thing to that total organic carbon is important,
25:46 there's different types of organic carbon. uh therefore you look for the quality
25:52 the carros and not just the quantity the carriages. If you have good
25:57 carros, then T O C becomes important thing, right? It's not
26:02 important that you, you study it you know that it's good.
26:06 when we do unconventional, what is that you already know when you're working
26:10 unconventional, at least in the United , what about source rock, you
26:18 , uh about unconventional and in almost uh place that we do her horizontal
26:25 with uh correct, we knew there oil, right? It's usually we're
26:33 for a source rock that we're hoping been totally depleted. It hasn't been
26:41 completely drained. In other words, hasn't all been cooked out and migrated
26:47 gone to a reservoir or gone to sky as uh Audre Masada would
26:52 and oxidized. Ok. So you're for something like that. The key
26:57 they're usually in regions where we produced from that source rock in a conventional
27:03 . And because of that, we that we have good carriages. So
27:08 that point with an unconventional system, real key is where do I have
27:13 T O CS? Because the high T O CS is likely to have
27:18 more oil in place and likely to more oil trapped in place in places
27:24 have low T O C. It's a, it's just a simple
27:27 And, and again, you the cars in that in that source
27:31 are probably good because we've produced a of oil that was, was cooked
27:35 of the migrated from and trapped in conventional reservoir. So uh so T
27:42 C and the volumes total organic carbon , and the volumes from that total
27:47 car carbon. In other words, get a T O C here and
27:50 we figure out ba basically the volume the thickness and the widespread distribution of
27:55 shale. And again, these uh , I think it's important to remind
28:01 geologists that the fine grain sediments are , very extensive sand, sand units
28:07 not OK. Sandstone units are typically sand bodies, uh you know,
28:14 a channel coming through and, and then the channel belt might be
28:19 where you have lots of channels on of each other. But that floodplain
28:22 huge. Ok. You go offshore channels. Uh whether uh it's something
28:31 to the shoreline like a turp turbidity type thing and the turbid or if
28:36 something that's parallel or subpar to the , are you working on the AC
28:46 it's hot in here? No, a welcome interruption. You're doing a
28:55 thing, I think. Yeah. you know if there is a system
29:00 back on yet? I say the by. Yeah, because once
29:08 starts running, we wanna shut the . Yeah. Ok. Ok.
29:13 you, sir. Ok. anyway, uh geochemistry, uh petroleum
29:23 , of course, is a really uh thing to take or learn
29:27 And uh in petroleum geology, of , I uh I touch on the
29:32 of it, but again, there's aspects of it that are simple enough
29:39 important enough to make sure that we about them as geologists. And uh
29:43 of them is total organic carbon is really important number, whether it's conventional
29:48 unconventional. Uh you know, if drilling a well or if you look
29:53 an exhumed out crop and you see T O CS, you know,
29:57 buried somewhere offshore. That's a good that that uh varied sequence that you're
30:05 on drilling. For example, in , in Ghana, you know,
30:09 had some things that they could see they knew there were gonna be
30:12 high T O CS and good quality . Uh in the North Sea,
30:17 outcrops along uh along England and, Europe. But more importantly, even
30:23 , the Cambridge clay that we see a big producer of oil and gas
30:27 the North Sea is outcropping in uh Zoo Rocks uh in Iceland and also
30:34 to Greece. And uh in Svalbard another island that, that has uh
30:39 exhumed that's popped up and has shown Jurassic section for us to look
30:45 So all of these things are very . So um vinite reflects in reflect
30:54 of course, uh one thing that look at in terms of maturity,
30:59 can get these grains and if they're beyond the mirror, uh you
31:05 it's, it means it's been cooked good. We, we reach a
31:09 where uh we know we're in what call the oil window. And uh
31:15 can also fingerprint these things to a way to figure out where that oil
31:20 from. Uh in the larger scheme things. Once you've developed an understanding
31:25 that whole area, for example, North Sea, they've got the Kim
31:29 clay sort of figured out if uh reservoirs have been sourced by something
31:34 Uh they know what the fingerprint of those oils are too. And
31:38 and if you know the source, uh you have a better chance of
31:43 the route of migration to that In other words, the one above
31:48 , if you have a source above reservoir, it's not likely to be
31:51 one that's feeding it. So you to find something that's deeper in the
31:55 like some of the permian uh sections are full of gas now. But
32:00 in some of the younger things in tri acid, uh may have uh
32:05 things that aren't from lower paleozoic, from, from the permian itself that
32:10 charged it and it helps you to and figure out um in a given
32:15 where that source is coming from and the migrational pathways. And this is
32:21 uh showing you a gas chromatograph and it's retention time and minutes and as
32:29 cook these things, as you flame , uh certain compounds uh uh turn
32:36 uh a volatile and of course, takes longer for the heavy things to
32:40 to that point and for you to it pop up in the, in
32:44 uh detector. Uh But here you see um anybody uh wanna tell the
32:51 what 27 might mean there's 27 A 27 B. What, what do
32:57 think these numbers mean it's related to mass? But it's uh it's actually
33:11 carbon number. In other words that chains had, had uh Usually had
33:18 atoms, 29 uh carbons in that . So the chains are getting bigger
33:23 bigger uh as you go through here uh uh they take longer and
33:29 to to uh to cook out and and that gives you a and it
33:34 a thing that looks like a So we can kind of compare what
33:38 had in this well, to what had in that. Well, uh
33:41 you um migrate from 11 part of system to another. In other
33:47 if I have a reservoir here, 25 km away from the source and
33:52 have one up 50 km, there be some uh a change in the
34:01 based on the flow might, might leaving uh heavier stuff behind and the
34:08 are gonna be moving faster, might higher. Uh There's, there's even
34:12 opposite reason for that to happen, uh a reason for the opposite pattern
34:16 happen. But uh it gives you idea of what's changing from one reservoir
34:22 you get farther and farther away. that helps you get a, an
34:25 picture of how far this thing can and what types of uh fluids will
34:30 . So it's a really good Audrey Basada has told me in the
34:34 that he can tell uh from looking the oils from one reservoir compartment to
34:40 next, that they're not the same because getting around that one permeability barrier
34:47 makes some different compartments. Uh is result of a different uh actual flow
34:53 to fill each one of those compartments uh as as they were being
35:05 Ok. So uh when we, we look at these things, um
35:11 know, we have carbon, it buried as it goes deeper and deeper
35:14 the section, we go from diogenes cato Genesis to meta Genesis. And
35:20 these are degrees Celsius uh that we're at. And uh so as we
35:26 things deeper and deeper into the rock , so it's uh it's convenient that
35:33 top one is, you could think it as shallow. This one is
35:38 and this one is deeper still uh we get into higher and higher uh
35:44 thermal regimes, uh more and more happening to that oil. And um
35:53 is kind of showing you what We start out here. Um hm
36:02 is as we get higher here, getting, we're, we're putting more
36:05 more heat to it. And uh this is adding more oxidation to it
36:11 we start out with these three different of vinite. Remember I told you
36:15 was, there's a quality issue with or uh um or the Carrigan type
36:25 . And so here we have um three vinite and it's called vinite and
36:31 is woody and structured material. when it's less structured, it's called
36:38 . And then as it's mostly unstructured material, it's called Lipton. And
36:46 do you think it's called lipide? does that sound like it's slip it
36:55 ? Right. So, we go less lipid rich to more lipid
37:01 Does it say that up here Excuse me? Oh, yeah,
37:09 did. I read that. Ok. I'm trying to look at
37:14 whole thing at one time. Sorry that. Yeah, but that's exactly
37:17 it is. And uh what type uh system has mostly lipid rich and
37:23 characters. There's one particular depositional environment geologists usually don't know about. But
37:35 , it's like the king of Giant basins, the custard systems that
37:50 that are saline, but they're not fluide dominated, they're sodium bicarbonate and
37:58 sodium chloride, but sodium bicarbonate. because of that, the sodium bicarb
38:07 because you have all that bicarb, pulls the calcium out of the,
38:11 of the water system and therefore the doesn't form with phosphorus to make
38:18 And phosphorus is one of the three limiting elements. And everybody in the
38:23 I think knows um when you go go by a little pond and it's
38:28 all this gooey stuff and smells really and it looks like it's a very
38:39 biodegraded that that's basically a lot of got in it. I don't know
38:44 you remember. I think they've stopped it, but a lot of our
38:47 had phosphorus in it. So, there was effluent from any of
38:53 uh, even our uh, the sewage that was processed still had
39:00 lot of phosphorus in it. And was putting a lot of like
39:03 uh, the Great Lakes and whatnot putting a lot of phosphorus into the
39:08 and it, uh made these what we call eutrophic. They're being
39:12 by, overproduced. You have bio productivity on the surface. It dies
39:17 it absorbs all the oxygen in the column and kills everything. And something
39:21 that happened in the Green River, is why have you ever seen the
39:24 fishes? Ok. Well, that stayed into the system. It
39:29 they didn't have a sewage system set by the, by the uh big
39:35 sloss and whatnot that might lived back . But they uh but the
39:40 the solutes in the system were keeping phosphorus active in the system and not
39:45 it out when it got high. uh and so productivity was very
39:49 Marine sediments are usually in, in realm and uh they have spor,
39:54 have pollen. They also have some uh algal mass too. And so
40:02 can generate oil and they generate Um This one right here,
40:08 uh it generates most of the oil you get to the temperatures that it
40:12 generate gas. Most of the hydrocarbon already gone. So a lot of
40:17 lake sediments that are uh Lipton nights liquid rich lipid rich and unstructured algal
40:25 uh Bactero coccus brown eye is kind the universal and perpetual uh blob of
40:32 and they're probably still growing it You know, Exxonmobil is probably trying
40:35 grow it to, To make uh or whatnot. Uh but it's uh
40:40 know, you can't grow it as as 500 and 600 million years of
40:45 history to, to create as much as we're using. And nevertheless,
40:50 uh this is sort of as, we cook it more and more it
40:53 from the dia genetic process, which on the other page to the cato
40:59 pro process to the meta genesis process where we get gas. So as
41:04 overcook these uh um uh carros, it's in Vitro, Exxon or lipinate
41:15 we uh as we cook these carros and crack them down thermally. Uh
41:21 go from something that might have some gas to oil, to uh to
41:28 gas. So the older that source is, and the more it's been
41:32 , the more likely we're going to agenesis and gonna end up only with
41:35 , a gas source. And here uh a good example of this.
41:41 and we'll talk about this uh in detail when we get to uh different
41:47 of exploration how it impacts it. here's depth and meters in a given
41:52 that has a certain um Level of Flow. This is a sort of
41:57 typical one. The reflection of the the carris goes up as they get
42:03 and cooked more and more as they of like charcoal and not really reflecting
42:08 at all to where they're like shiny . In other words, are going
42:12 really compacted, really altered carbon. They get very shiny. Um uh
42:22 is supposed to be the reflection of uh of a mirror. And so
42:26 you're above one, you're reflecting more than a typical mirror would reflect.
42:31 so this is getting to something where reflective, very highly reflective. Uh
42:38 uh Every oil company that had a developed their own scheme of where the
42:43 window was here. You can see .8 is about the middle of the
42:48 window, right? And uh so something that's really important. So,
42:55 if you're an exploration geologist and you're standing on the coast and you're thinking
43:01 offshore could be buried deeper, uh deep would it have to be buried
43:06 that source rock to be uh deep to be in the oil if you
43:15 a thermal uh profile, that looks like this. In other words,
43:22 this bitter reflect profile reflects the thermal of of these rocks. In other
43:29 , it's getting hotter and hotter as go down, just pretty much like
43:37 . What does that tell you Let me make. How about you're
43:42 , uh, you're standing on a in the coastal plain of say,
43:47 Carolina? Ok. How deep do think the sedimentary rocks are, if
43:54 standing on the coastal plain? In words, how deep can you drill
43:58 to get to basement? Anybody have rough guess? Would you think it's
44:07 or deeper than the Gulf of Mexico ? I think. Ok. The
44:17 , the east coast is gonna be . The, in other words,
44:19 east coast, you got the Appalachian are really close, right?
44:25 And so, so the thickness of beds coming off the Appalachian Mountains is
44:30 be really thin. You have to farther offshore before you get these thicker
44:36 that we had in the Jurassic and the Cretaceous. Ok. So
44:40 the coastal plain, uh you there's been thermal subsidence but it's been
44:46 gradual and very slow. You get and um they all from Mexico,
44:52 had some of the, you we've got some plate tectonics going on
44:56 caused things to just sink in and a lot of accommodation space. And
45:01 we have uh a really deep uh uh that's got a huge sediment
45:06 Um You know, we used to that the, The basement might be
45:10 some parts of the Gulf of Mexico ft and it's probably not that far
45:15 uh from where it really is. , we have uh a great big
45:19 sediment pile. You drill a well . Uh you probably have to
45:25 I would say at least to 12,000 to get close to, to
45:29 if not deeper because there's this really sediment wedge. OK. I know
45:34 have to get Right here. you'd have to get to about 15,000
45:38 to hit the oil that I know there in something we call the
45:43 OK. But no one's drilled it there's a city here. But uh
45:47 a point of fact, there's probably huge reservoir right underneath us.
45:52 Um You'll never convince anyone to drill because of the environmental and the public
45:58 that might happen. So, um and you have to know what
46:02 turtle structure and a half turtle structure too to, to understand why it
46:06 be there. Uh Nevertheless, uh the east coast, they drilled some
46:12 right on the coast. They got the outer banks and they went a
46:15 bit offshore and they couldn't get really sections because the basement comes up too
46:21 . Uh You, you go to uh where we're at right now,
46:25 could drill Tens of thousands of feet you hit basement uh offshore. And
46:31 and at, and at least I say 15,000 right here. Of
46:35 if you go, if you go Austin, Texas, uh you don't
46:40 to drill as far because we've got , uh we have igneous rocks like
46:44 rock. So we'd be going closer closer to the original source of some
46:49 the sediment. OK. So, , uh this diagram right here actually
46:56 an exploration geologist where he, he's to find Uh oil and gas sources
47:03 a, in a basin. In words, you go to a strange
47:06 and the sediment tree rock veneer that might be able to figure out with
47:10 . Magnetics is only 4000 ft thick that basin. You're not gonna have
47:15 source rock. Uh If you think basement might be sedimentary rocks and
47:21 not real crystal in basement uh that older and it's deeper than you could
47:26 a source rock. And so this a really important diagram for petroleum
47:32 OK. And here is just showing oil generation. And of course,
47:37 this is when you um uh have uh a source rock and you heat
47:43 up and cook it and figure out what it's uh here. It's 1%
47:48 zero cc. It's type two. curves are gonna be different.
47:53 I don't have it here. I'll about it a little bit more in
47:55 , another lecture, but the curves be different depending on whether it's
48:02 um, or, uh, the Tonight and the bit in the vinite
48:11 , of course, when we go , uh, we're gonna see a
48:15 bit of Exxon, we'll see a bit of Lipton and a little bit
48:19 vitrine in those, in those rocks we see something from offshore because you're
48:22 drainage from the, uh, from shelf edge and that sort of.
48:29 . Um Maybe I explained this too . And of course, that story
48:33 me uh kind of worried about the that the recorder wasn't on. But
48:40 but nevertheless, uh we're moving along I, I think we're gonna get
48:44 this. Um uh We will be about uh bias stratigraphy and its impact
48:52 briefly. Uh I just wanna jump to, to get, give you
48:58 idea where we're headed. Now, are different wells offshore the Gulf of
49:04 . And uh this is a Wheeler and so these gaps are gaps in
49:10 and those gaps in time are breaks uh depositional events. In other
49:17 the yellow stuff is a depositional event there was something that either broke that
49:23 up like a normal fault can break up. And uh and also uh
49:30 can have uh a flooding surface, get condensed interval and uh you've got
49:38 nice rock accumulation rate and all of sudden it disappears and it looks like
49:42 a break in. So these are we call depositional events or episodes.
49:48 the blue stuff in here is either break like a nonconformity, a normal
49:54 or a condensed interval where there's been limited amount of uh deposition. And
49:59 problem is is that when we drill well, there's no brakes in
50:03 well, uh this, this base here sits right on that thing
50:09 The base of this episode sits right . In other words, the whole
50:14 is right there. So when I this well, all the way up
50:19 next to this, well, all way together, I might be
50:24 for example, this rock to something all the way down here at the
50:29 . Because if I push that all up in, in uh feet,
50:35 it might look like that sandstone is across from that one. And why
50:39 this important? Because if I was reservoir engineer, I might actually see
50:45 sand and in a well go right it and because look at these gaps
50:50 look at that gap, that sandstone that sandstone might have the exact
50:54 those episodes might have exactly the same character and they look like they're straight
50:59 like that, but in time they're . And therefore, uh and I'll
51:04 it right now, one of the important things in reservoir characterization is figuring
51:10 the top and the bottom of the if you don't know where the top
51:13 the bottom are in time, you're misc correlate everything. And,
51:18 this is something the oil industry is issues with right now and Exxonmobil is
51:22 be coming, uh, to ask questions about it uh, in a
51:26 or two. Uh, but uh, because, uh, any
51:31 you are familiar with sequence, Stray , uh Peter Bale at Exxon came
51:37 actually was o and he came up it. It was a way of
51:41 why things might be truncated or lapped . And, uh, he knew
51:45 day one that bio was critically But a lot of people when you
51:50 doing unconventional, you just think of rock unit as, as a,
51:55 a resource. That's a, that's extensive body that lasts forever. But
52:00 still oil and gas and sandstones. need to figure out what's going on
52:03 sandstones to get more and more recovery these uh conventional sources and that's what
52:09 doing in, uh Suna and Guyana now. And, uh is,
52:14 looking at conventional resources that are bigger all of West Africa and Brazil
52:21 And, uh, so it's really anyway, with that, I'm gonna
52:23 you guys go and thank you for up. We had, let's see
52:29 we had seven people who is missing . Mohammed. Hope he's ok.
52:38 , by the way, I'm gonna you again, I really liked
52:42 uh, your write ups and, , the, uh, I haven't
52:45 the grades yet because I want to my recordings together and get my T
52:48 from the professional program to put it together and load it up on
52:52 But, uh, But your grades from 100 to 98. And,
52:58 , I felt bad about giving people . But, but, um,
53:03 was really impressed that many of you looking at the data and you saw
53:08 the narratives, you completely saw straight the narratives and uh hit really hard
53:14 , on uh what was critical in data. And I really, really
53:19 that. I, I actually didn't you would do so well. And
53:22 and I'm happy to see that uh the students today are uh really uh
53:29 know, kind of current and up date and really trying to figure things
53:31 . I think that's really important, as geologists because concepts are sometimes more
53:37 than details, you know, and uh the details, you
53:42 we can arrange details in a way confuse what the overall concept is.
53:47 just like these things. Uh we about motifs and well locks, you
53:53 to get some detail in there to clarity. But once you get
53:56 you can see the overall picture a better. And I think you guys
53:59 something like that with your paper. , so thank you. Very much
54:18 . See you next time. Ok. Are you guys still
54:23 Yep. All, all good. , I'm gonna stop
-
+