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GEOL7325 Petrophysics and Formation Evaluation - Day6 10-14-23 PM
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00:00 When I exercise, you know, as that was, we talked about
00:09 meaning of them, we talked about . Basically, we called it a
00:15 to do the exercise about again, think the key idea here, which
00:21 I noticed wasn't really recognized was that is one data set, completely different
00:28 set, completely different data set, different data set. And all of
00:33 exponents are the same independent of the set. So those exponents like m
00:40 gives you an idea what's going on M can vary, right? Uh
00:46 there are mixed four systems in So again, whether you look at
00:51 the data or just the inner granular just the mixed what I call mixed
00:56 or just the buggy carbonates, you the same exons. In addition,
01:01 hopefully some intuition as to why this close to one. This is close
01:07 two etcetera. Why this one is than these? There's a very,
01:12 recrystallized, very uh small pores, very irregular lattice of pores. So
01:18 small number makes some sense and then we move on to. So hopefully
01:27 some sense of what we're doing now it means and how from a formation
01:32 plot, you can extract the four . That was really what that uh
01:39 was about. So how about Right? So here we have,
01:44 doesn't mean isolated, this really means embedded ferocity due to claves. So
01:49 is about dispersed clays. We're gonna about clay distributions in more details in
01:54 a few minutes when we hit the sands. So again, the exponents
01:59 to be the same associated with a system for this to make any
02:04 We're not gonna have to spend a of time. So if you go
02:07 the rocket catalog again and look at classics and look at the classics that
02:14 , have small amounts of clay associated . You see that Archie's equation comes
02:22 close to working. It's a little off, there's a little bit of
02:27 which is presumably due to sorting, it comes pretty close to its lope
02:31 two. And also uh it's actually 17 and also uh it extrapolates pretty
02:38 to F one P of one. just like we did in the exercise
02:44 . So what happens if we add ? Might you think what's gonna happen
02:48 our formation factories, simpler core more complex core system? What's the
02:56 gonna look like in a clay this clay, right? So, so
03:06 would expect to have a large value them. If you plot that
03:10 which are the circles, you find your formation factors all are above this
03:17 . Again, you have increased virtuosity . So this formation factor is a
03:27 of the play and it will cause to vary from something like one point
03:32 to about six point. So if have a sand, that's uh where
03:40 four space is completely filled with this clay or M will be significantly
03:47 So this is the major contributor to . You also can have effects such
03:52 isolated velocity and things like that, generally they aren't a dominant effect.
03:59 again, an M of two would somewhere up here would be a fairly
04:05 sand. Clean sands are 1.6 something that. So we can make the
04:10 we can fit just like we did clean sand gave you 175 if we
04:16 for the granular porosity in a clay this first clay, right? What
04:22 got was 1.75 for the matrix and one's fun, right? It's actually
04:27 than one. So, so what that mean when we looked at the
04:32 lambda? Do we need to go to that? That meant as we
04:36 that ferocity, our virtuosity actually went . Should I show you that
04:46 Don't have to makes no sense, all the sense in the world.
04:52 trust me and look it up yourself of the, all, all the
04:57 ? All right. So that and, and again, depending on
05:00 we put all of them, just circles, the sand through the clean
05:05 . So the main thing to take from this is the clay complicate the
05:09 system. You expect the actually the value to increase as you add this
05:17 legacy. So M is if measured is actually uh pretty diagnostic of what
05:25 systems are there. Then the last we have to talk about this is
05:32 . So other people have recognized this , uh Slumber JSLB uh made some
05:40 with fourth sound and helium. And actually looked at the, you
05:44 why would you do that on Because that's a super fluid. A
05:50 fluid is super fluid and therefore this stationary at the boundaries doesn't hold
05:57 It will just flow and it'll be more analogous to a resistivity. And
06:02 they did that, they found that got the same formation factors for permeability
06:09 they did for resistivity. Uh What gonna show you is actually significantly
06:15 You can just follow within a two . Uh kind of what the development
06:21 K permeability is just 1/8 a um a tortuosity right here, uh the
06:30 divided by an R squared. And for Archie's equation, right? This
06:35 the same thing we've looked at several . So if we remove the R
06:40 right, we actually get to a analogous property. So when you do
06:46 fits and carbonates for resistivity and permeability , you essentially get all the same
06:53 . So what that means is that tortuosity, the flow is analogous for
06:59 as it is for electrical connectivity. if I understand how my resistivity
07:05 I have real insight into how my behaves. I have real insight
07:10 OK. And the bugs gonna act same way for for a permeability.
07:15 as we account for changing pore this uh boundary condition, uh the
07:22 can just move straight across it and not increasing tortuosity, you can do
07:27 for plastics. And here this is different. I think the intra granular
07:33 isolated processes in the clays, Or classics between resistivity and permeability
07:40 And the difference here I think is to the bound water in the
07:44 which actually makes in inter granular that actually more tortuous because that bound
07:51 can't move, that'll mean more in minute. That's, that's basically what
07:56 wanted to cover. And again, can calculate the lamb as you can
08:01 all of that. There are other I can show, but I want
08:04 get on to shay sands. So are important because the bottom line,
08:10 give you real insight and flow electrical of the sound. Now, we're
08:16 with our Cheese equation. So we're talk about shale sands. So this
08:26 uh a natural extension to our sand to our clean sand models. And
08:36 Archie's equation breaks down now is the that our assumption of a nonconducting
08:42 right, uh is not real just the recording. So what we have
08:53 clays. We talked about way back the beginning of the course, we
08:57 about the influence of clays and we about ca I exchange capacity. We
09:03 about isomorphic substitution of ions or aluminum is plus three. If I for
09:12 , which is common to substitute a , which fits in that matrix pretty
09:17 . Uh What happens? Possum is one, aluminum is plus three used
09:24 be balanced with aluminum. What's gonna now can end up with excess negative
09:33 , right? And those plus three no longer there. All we have
09:37 a plus one. We have two negative charges. So this makes rocks
09:42 fun, right? Because we uh have a rock, we have a
09:47 core system, lots of length scales in it. What do we
09:51 Now? We fill it full of po polar fluid, we now add
09:56 constant charge density boundary condition for the . So all of these things interact
10:01 worse than that, we dissolve this polar molecules and its solt or whatever
10:08 have. All these ions running around with charged surfaces. So hopefully,
10:13 not a surprise that that would influence connectivity. Why do we care about
10:19 ? Hopefully, I've impressed on you importance of electrical measurements. So what's
10:25 happen if we have clays and our is more conductive than we think it
10:31 be. We're gonna interpret that if use Archie's equation as not as much
10:38 oil and therefore we are going to our economics wrong. We will have
10:46 oil than you think. This is good thing, right? You become
10:50 hero, you find oil, Uh I have heard nobody complain about
10:55 more oil if we get a petro correctly. So this is not
11:01 It can be significant corrections in it's significant as we will see for
11:07 water, the freshwater shay sands and at high oil saturations, it's gonna
11:15 a big difference in our calculated right? So there's the Y
11:22 And so it reduces this. And another meaning for effective ferocity to talk
11:28 what that means in this case, what happens with my permeability is gonna
11:33 greatly reduced. We talked about that of the first weekend we were in
11:39 . So it's gonna lower the ferocity water. We cannot uh we can
11:45 about what the meaning of ferocity Now in more detail, our original
11:50 for ferocity was what our void It was our storage capacity.
11:57 that's not really right. Once we clays, what ferocity is is we
12:01 measuring the amount of water in the . It's fully grid saturated. Why
12:08 that? Because neutron logs will measure bound water uh no getting around it
12:16 it's even worse than that. They see the oh groups in the
12:20 So they're getting around with the neutron measures. So why did we talk
12:26 using a grain density which we did the clays as that higher? Number
12:32 something like that because we wanted to the density measurement porosity comparable. So
12:38 get rid of all the water and calculate what it is from the
12:42 Remember we did that. So our definition for porosity is the amount of
12:49 assuming it's 100% water saturated. We measuring the amount of water in the
12:54 . This is just about log Uh I can't separate the only tool
13:01 know of which we can talk about you want to talk about uh for
13:06 last lecture. But the NMR can bound from free fluid bound fluid from
13:12 fluid. So it can discriminate between two water types travelling. It's one
13:18 its strengths. Bye, hopefully recognize . So when you see and I
13:24 looked this up the other day, what is, what is the grain
13:27 of smite? And it ranged from to 2.8. Why is that?
13:34 some people are measuring it uh actually with the ambient community am and
13:44 right. So it's picking up all water that you can dry a clay
13:49 , you can put it on a and you can watch it pick water
13:53 real time out of the atmosphere. . That's not a trivial effect.
13:59 are incredibly sensitive anyway, way your , but it's quite easy to measure
14:04 of this place picking up water if have dried them. So you want
14:08 dry them appropriately, right? To the grain that that's why you measure
14:13 very low values, right? And what it shales they complicate, as
14:18 mentioned, the effective production rate and effective porosity, lower permeability and you
14:25 get the wrong value right for my . Um So I can't use Archie's
14:33 because of that. This is just look at possible kind of uh what
14:38 with clays. And you can see g uh when we invade and we
14:43 actually a significant variation in the You don't get uh a huge
14:50 You can see where my sands If I draw a shale baseline on
14:53 , I have a sand here. have a sand here and these resistivity
14:57 quite low. And so even in conductive sands, you actually can produce
15:03 a bit of oil. So it's to make this correction you can miss
15:08 this clay correction was so important. first, my operation assignment was in
15:14 San Joaquin Valley, freshwater shay really fresh water almost to the
15:19 You can drink it. And so really, you couldn't see the oil
15:24 arch equated or wax and Smiths. you saw was the clays come and
15:29 is the clay connectivity overwhelmed with the dependence. It made our lives very
15:36 . We didn't know what logs to resistivity really didn't work. We tried
15:40 EPT electromagnetic propagation tool, the dielectric , we tried the NMRs. All
15:47 this. It was really too early the to quantitative we can talk about
15:52 . Once we get there, you miss a lot of oil because of
15:57 . So again, I actually like and talk about it more in a
16:01 class. But uh this is a sat, right? High porosity,
16:06 permeability, not a lot of You can find anywhere particularly fun to
16:11 at these dents. Yeah. So are where other grains have contacted these
16:17 . And the number of grains that connect to another grain is called the
16:21 coordination milford. So that's actually has high impact on a lot of properties
16:27 velocity. You see how many grains to some of these, right?
16:31 this one, it's 123456 and that's on one side you could see.
16:38 um just in case you hear grain number, that's what it means.
16:44 a similar term called poor coordination Which is how many pores are given
16:49 bodies can ask you have to deal that. A lot of this
16:54 So we have Kale and I there's clay types that we talked about.
16:57 this is a bit of review. can see that Kale and I basically
17:02 booklets, they can see that we see that's actually quite a nice one
17:12 there. And that's very diagnostic because I should be able to show particularly
17:20 group a picture of a clay like . And you should be able to
17:23 me what clay type that is just at it. Um And just to
17:29 comment on this, this is the size in this. So we zoomed
17:34 from the earlier one and you can that this is a dispersed clay,
17:38 distributed on a length scale, much than a grain size. That's gonna
17:43 important for determining what its rock properties . It's gonna behave very different from
17:48 structural clay, from a clay So here's a zoom in it actually
17:56 a pretty picture of that Kale Unite , right? Main the main attribute
18:02 why you typically worry most about kale night is the fact that this can
18:09 you change salinity or you flow at high rate. This stuff will come
18:14 the core walls and plug fourth So fines plugging is is a common
18:21 of this stuff. Once you've plugged four throat. It's really tough to
18:25 it up. This stuff doesn't dissolve easier than the courts. So get
18:30 out of a force force system. uh tough. Also, if you
18:35 a flow test, you can see if you're doing it in a
18:40 it'll flow one way and plug Then if you flow the other
18:43 it will unplug at least for a until you go back and plug the
18:47 going the other way. So common this one's chloride. So pretty
18:54 it's it's uh actually pore lining. these clays will actually line the
19:00 The main thing it does is it will get a fine pore structure associated
19:09 , with it. That can be the poor space, three quarters of
19:13 poor space. In fact, when I first came to shell,
19:17 bought a field that uh actually this impacted. Uh probably a lot of
19:24 have done this, go into a room to buy a field. So
19:28 just show you what they want to you gel engineers. Uh It wasn't
19:33 but other people went into the data . They didn't show any picture like
19:37 . They showed the production based on typical reservoir at that ferocity. We
19:43 have only produced maybe 25 30% of oil in it. So gee these
19:48 are dumb, right? They're selling to this field at a great
19:53 So we get back and what we was that uh basically there's huge water
19:59 out of this. And when they at the thin sections, they found
20:03 there was this pervasive chloride through right? Lining all the pores that
20:09 up all this water, right? small pores and the oil never gets
20:15 it. So you have, you're leave huge right up. They're gonna
20:19 huge water saturations. Maybe you will get up to 50% water even with
20:26 high columns. And you can't get into this. So can be cost
20:32 100 million, right? For shell buy this field and it was a
20:36 waste of money, right? I'm , what this porosity, the porosity
20:45 this stuff should ask professor, but could be 50% 40%. So,
20:58 it can lock up if, if , you can lock up quite a
21:02 of water. That is the bottom according to look at rocks according to
21:08 what the lithic is hard to know the clay is. The other thing
21:13 chloride is, it typically has a low caine exchange capacity. And so
21:19 really doesn't have a big signature on electric block because of that, we'll
21:25 why that the ion exchange capacity is mechanism through which clays contribute excess
21:32 So a lot of money here, ? Sure. That's more than
21:36 This is Maronite. This one is kind of fun. Just because with
21:41 little bit of imagination, you can this being close to a hexagonal
21:46 Why does it have that structure? similar as to why bees build honeycomb
21:53 ? Why do bees build honeycombs? ever worried about that, wondered about
22:00 . It's the way to get the efficient use of that space. You
22:05 the walls as far apart. It's complete tiling of the structure. Why
22:10 Mount Rite have that? Because it's charged and this is one that has
22:15 highest iron exchange capacity. And so clays want to get as far apart
22:20 possible from each other. And therefore this is a very typical structure for
22:27 to form. Why is this stuff ? Uh because it swells. So
22:33 not gonna go into the details of scientifically film. I ask uh professor
22:39 do this that just because of the structured, it can actually get layers
22:44 water in between the different layers of . So you can get up to
22:48 , 15 layers of water. So go to fresh water. This stuff
22:52 actually uh swell quite a bit, had a student saturate a sample that
22:59 had a lot of swelling clays in . Uh It was saturated with a
23:04 salinity grid and he just blew it oh fairly high salinity. Yeah.
23:18 typically what you do is you'll add because that reduces the swelling of
23:23 right. So many a drill bit twisted off because of this stuff.
23:31 , I think I already talked about that's expensive. So that one's a
23:36 one to know because it can be . Fibers still lights right? A
23:41 bit down the chain. In terms Cine exchange capacity, this stuff grows
23:46 actually grows in fibers right across the space. Will e included it greatly
23:52 your pore throats. And remember how pore throats were halo at what radial
24:02 went like r to a power. was that? Power? And Laurie
24:09 four and she's right went like the power. So even a factor of
24:13 rate lower reduces your permeability by two two times two times two. A
24:19 of 16. So you reduce you will greatly reduce your permeability.
24:25 only the difficult thing about this stuff that if when you are measuring it
24:30 looking for it, if you do conventional drawing, you will plate all
24:34 stuff in four wall, you don't this. So they uh if you
24:41 this, you should consider doing what's critical point drawing, you measure properties
24:46 that takes this thing up above the point, you don't get a phase
24:51 , right. So it will leave geometry more intact. So you might
24:56 doing that can be fairly expensive, it's not, you just have to
25:01 it at a higher pressure and temperature get out beyond the critical point of
25:06 . Uh But again, this could a disaster in terms of firms.
25:10 you plate this all against the four , you may get 100 times the
25:14 you would get if you did it . Again, to this first
25:22 much smaller than grain size. well, it depends what you're worried
25:32 . Yeah. So sure. So , they're typically what, what happens
25:37 , I'm not the expert in the on this, but what what will
25:41 is as you bury, for a smack type, it will transition
25:45 light, et cetera with temperature and source of tasing and things like
25:49 So even in the same basin, can get a variate like the
25:53 you can get a variation in the type with depth. So and typically
25:58 form chlorides. This is why we to start to get in trouble.
26:02 , you uh you, you probably have a source of iron to make
26:05 . It's typically associated with that. depending on your mineralogy, depending on
26:10 fluids the clay has seen, you get different clays. So you,
26:15 , you just have to look for to, to know if it's
26:19 But you should be worried about clays you should be worried about their distributions
26:25 it will affect all the rock You get asked on the final which
26:31 are affected by clay. Every one them, every single one ferocity
26:38 we talked about resistivity logs, we've about uh all of them action will
26:43 affected by it. So no matter rock, all the rock properties and
26:48 . So it, it is the to worry about again is why I
26:53 , I, I don't know why called Archie Cementation Factory. That's a
26:57 to be called the Archie Clay Gives you insight into the amounts of
27:03 the value of them like we've talked . So we need to, to
27:07 some things associated with clays bound Uh is a big one. This
27:12 real, by the way, it's just nomenclature bound water is different from
27:19 water bound water. What we mean this case is electrostatic bound. So
27:26 that means is the found water will associated with the clay minerals and their
27:31 charges. How did we get This isomorphic substitution, right? Or
27:38 with other other other atoms, So potassium iron, et cetera.
27:46 again, in general, this because is plus three is about as high
27:50 you get direction you go towards negative . OK. So again, I
27:56 about what fun this was. Now put in this polar liquid that I
28:01 about. It's got plus charges and charges, right? We think it's
28:07 , right? It's an ionic And so when you dissolve that in
28:10 strong polar solvent like water, it dissociate. So the sodiums are floating
28:16 the chlorine are floating around where do sodiums potentially wanna go? They want
28:22 cancel out those negative charges on that . OK. And these are called
28:28 clay counter ions. They are canceling the negative charges on the clay.
28:36 are the source of the additional these clay counter lines, they can
28:42 along this surface to a mechanism called conduction and increase the effective salinity of
28:52 brine by having an additional contribution, ? Everybody see that that's basically the
28:59 we are going to explore for the being higher than they think it should
29:05 cool. What's even more fun is water is polar, you'll get these
29:11 surrounded by six water molecules, That's what fits around the sodium and
29:18 that is our definition of bound It is the six water molecules surrounding
29:25 sodiums. They are electrostatic bound. the way, electrostatic forces are
29:31 much, much bigger than other forces . So you will not get these
29:38 charges off, doesn't happen. It something like 60,000 P si of pressure
29:46 dislodge these found water molecules. So we take a mercury curve, I
29:53 we're gonna do that later, you have to correct your mercury curve for
29:57 bound water to get what an oil curve will look like. There's and
30:04 seen this done in, I just a paper where people didn't know what
30:07 were doing and, and didn't know the fundamental physics here. A
30:13 published paper, I'll show you exactly to do that. So we have
30:19 counter ions, we have bound water we have free water out here,
30:23 ? It's not electrostatic bound. The other thing that's important, not the
30:28 other thing, but another important thing this is dynamic. These waters will
30:33 on and off this surface, And so if I have even have
30:37 isolated clay site, these water right can go from free water to
30:42 water back to free water. So can still get these things to
30:46 I can still get these charges OK. But I'm coupled to the
30:52 of the water, cleared everybody that the mechanism for the salinity dependence of
31:01 of of the clay count that we're see in a minute that cuffing on
31:06 off to clas go on, then get to effective porosity. And there's
31:14 many definitions here, almost as there papers related to it. So typically
31:21 uh what how we will use effective porosity is the bulk volume fraction of
31:29 water because that's the water that's really to move. The found water is
31:34 more tightly bound and really is not free to move. OK. That
31:40 up in the end of our lock cetera, right? So total porosity
31:43 occupied by clay bound and non clay water or by found water and free
31:50 , the other use for that, ? And then in shale sands,
31:57 ? These uh these clay Conine will to the electric conductivity. And what
32:02 means is that everything else being equal G will give too much water.
32:08 will calculate to what you are underestimating it can be significant the amount of
32:14 you have in your formation. And have found more and more recently,
32:20 are ignoring this, don't understand Don't understand what Wax and Smiths is
32:26 that we're gonna use to solve this at least help us solve it,
32:30 ? But I really think it's important at least have an awareness and we'll
32:34 about when it's important to make this correction, right? Be worth a
32:40 of money. OK. So this another look at the problem of attempting
32:47 solve co we all know what that , right? What is the sub
32:54 zero? What does the zero stand ? No oil? So connectivity,
33:02 is one over ro, right? this is this is the right the
33:09 , it's just a water saturated the connectivity of the water saturated rock
33:14 the connectivity of the brine we are it. So this is the a
33:19 expensive way to look at what my of my plate conduction is is to
33:25 take a rock, you saturate it a given blind, you wait for
33:30 to equilibrate, which can be weaker, depending on the current ability
33:35 the play. We then change the . Typically, we go from high
33:40 to low. It's easier than going other way. And we measured the
33:46 of the rock as we do And a couple of things show up
33:50 this, right? That one over freshwater versus shay one over a,
33:56 I said, and they're all measured a water stage, reach 100%.
34:02 one is the clays turn on with slim. So the clays become more
34:09 until you get an excess connectivity that's at high, right? So
34:19 I've told you the answer as to this happens. But we'll go in
34:22 detail in a second as to So what we're trying to understand is
34:26 this excess connectivity is because we don't to assume Archie's equation holds. We
34:32 want to assume that's due to less than we think there is,
34:37 Then they actually everybody OK. With the problem is, why we're doing
34:42 ? Why it means a lot of ? Wow. So this is again
34:49 , you can see remember when I that uh a Archie's equation just scales
34:54 the connectivity of the grid or resistivity the brine. That's this curve is
35:00 simple scaling, right. My my of the rock is simply proportional with
35:05 connectivity of the brine. When you clays that's no longer true. It's
35:10 more complex salinity dependence. And if extrapolate even this linear portion, I
35:17 get back to here man. So co is equal to, it's equal
35:25 my connectivity, my uh a formation , right? It's easier for me
35:32 say we don't get ro it's equal RW times F, not sure what
35:40 over is. All right. So have, we, the model should
35:45 for all of these effects on the trying to be them quantitative. That's
35:51 Archie value. And this is my . So now we have to,
35:57 , we have to be a little careful with our nomenclature. We have
36:02 and silk and they, we just into this. Uh one of our
36:06 gave a paper right and got beat because people talk about clay size particles
36:13 well as clays. So you have be careful with that because there are
36:19 screens that are clay size, typical rock more accurate, they will call
36:27 clay and it can be 50% silt . So if these things are are
36:34 complex, their properties are more complex a pure clay. This is one
36:39 the problems with poor prediction. People don't account for that correctly. So
36:46 have clay size. These can be mixture of clay, minerals and
36:50 et cetera. So be careful whether using it in the context of the
36:55 size versus actually in, in a what we mean by that.
37:00 And it's used interchangeably petro physicists, geologists usually correct. Petro physicists,
37:08 . They understand better than you have worry about how they're using the
37:14 what context it is. So the clays I've talked about probably getting bored
37:20 this. These are the four you should be able to identify what
37:23 look like. You just looked at again, right. What moon light
37:28 like versus fibril light is particularly uh distinctive books. Chloride is poor lining
37:37 , right? Melanite swells I talked and I also mentioned this already.
37:42 it will undergo diogenes with temperature and of potassium. You can get melanite
37:50 actually uh form right cool. And this was invoked for a long time
37:59 the source of geo pressures in the , I think recently that's been significantly
38:06 and people are arguing it's just about rapid burial rates. Ok. So
38:13 is a fun topic of mine. group has recently published quite a bit
38:18 this and how you get these and different impacts on the rock properties which
38:24 will discuss. So we have laminated again, longest length scale that's clays
38:30 on a length scale, significantly longer a grain size. Yeah, structural
38:36 are clays with characteristic length on the of a grain size. So you
38:41 of those you can think of those replacing the for example, quartz grains
38:46 a sand then dispersed clays which I you are distributed on length scales less
38:52 a grain sauce. OK. So have very different properties on resistivity,
38:58 very different properties on how the porosity , very different effects on how the
39:03 change. One we just published right. This is a little bit
39:09 in cheek, right? Fans can cleaned. So this first clay this
39:15 actually a really nice lab for We have a data set where the
39:20 first clay is something like 25% ferocity the shale clasts and laminated clays are
39:27 like 12%. So this makes a difference on figuring out how much macro
39:35 I have versus micro porosity and therefore my rock properties are. So we'll
39:42 more about that in a second. that's something to be aware of.
39:47 is a nice picture of this up . I like this picture a lot
39:51 it it really does display what's going . We have a clean sand,
39:56 have a uh a lamination. You see this is connected as a length
40:01 much longer than a grain side, ? So here you think of this
40:06 as replacing the massive sand, A structural clay, right? Structural
40:14 that basically be distributed on the order a grain size. You can take
40:18 of that as replacing a grain. you have a dispersed clay, right
40:23 is distributed in the poor space. characteristic lengths of a clay platelet,
40:29 , significantly less than a grain right? Yeah, I,
40:40 I missed that. Yeah. Well, so you, you're interested
40:53 the volume of clay and how you that? Ok. Well, and
40:58 left the room but, but where get that is, is you,
41:03 get it about actually best way to it is visually, right? So
41:08 can identify the petrologist can identify structural this first place and lamination,
41:15 So it's about uh and we I I have a phd working on
41:23 to get this from the logs, ? So we, we could,
41:26 talk about that in a little So they will have very different effects
41:31 the logs. And so we, will see what the impact on logs
41:34 , particularly the porosity log in there . Yeah. Well, typically there's
41:48 end member that we can call a sand that would have no clays in
41:55 . So it may not exist in particular reservoir, but there certainly is
41:59 theoretical end member to our distribution. are all great questions that I become
42:05 little clearer when we talk about Thomas plots in a second. So I
42:09 hang on to the idea if it's not clear and ask again.
42:15 that's it should help again. We this first place. What would you
42:21 this guy? I would call that and I, I would, I
42:25 call this one with core lining You can see here's my fiber
42:31 right? So just cartoons or how distributed. Yeah, you should be
42:37 to draw up, reproduce pictures that like that demonstrate their properties effect on
42:45 . This would be structural plays. would be floor lining clays like a
42:52 . This would be poor bridging So even at a common porosity,
42:57 distribution can have orders of magnitude. is a large scale over here can
43:02 orders of magnitude impact on what the is. Not a trivial effect,
43:08 the distribution. So how do we it? Which is what you're
43:13 Uh I want you to read the of this. You want me to
43:17 it to you do it yourself. I want to emphasize the distribution of
43:23 and sandstones and its effect upon OK. So different distributions, effective
43:32 in different ways. This Thomas diver is actually very common. I've heard
43:39 it used all the way from the of Mexico to the Middle East.
43:42 lots of people are doing it. of people who believe it. It's
43:46 high impact idea on how it affects rock properties that I don't think it's
43:52 used quantitatively about and that's what we working on to improve that.
43:58 Thomas EC worked for Shell uh Stiver actually a consultant. So here's what's
44:06 a Thomas diver plot. And what have is we are plotting a gamma
44:11 , very cheap, inexpensive tool density over here. OK. We make
44:18 cross plot of those. What we is this is actually a Gulf of
44:24 example, right? For what's happened , this is the shale end
44:30 I think these are labeled, shale end points. We have the
44:33 sand end point. This is your theoretical no clay whatsoever. There's no
44:39 and the lamination in this sand So these are actually pretty close to
44:44 these points. So that would be sand with no clay lamination and no
44:51 clay, structural clays. We're gonna for the moment mostly because if you
44:59 three unknowns, how many measurements do need? So we only have
45:05 we only have two measurements. So of the explanations is that these points
45:11 here are related to structural clays. can talk about how to deal with
45:18 if you want, at least I will explain to you why that
45:23 What's the point at the bottom? is my clay filled sand. So
45:29 I can do is completely replace in clean sand. I can completely replace
45:36 pores with dispersed clay. So all here, what's happening is I have
45:41 shale lamination. These blue lines are of constant net growth. These lines
45:48 lines of constant sand gravity. So top line everywhere along this line,
45:55 line has no dispersed clay. Now changing is the nectar growth we've assumed
46:01 is linear. So 50% negros is along this line. And this is
46:08 a growth of one. This is growth of zero. So pure shale
46:14 , clean sand up here, varying to gross lines of constant net to
46:19 are these blue lines and then lines constant sand porosity are these orange lines
46:28 . So what they are right? we they are constant but the nectar
46:33 is varying as we move along the as we cross the blue rock this
46:39 . So these in this direction is effect of adding shale lamination. So
46:45 of things that may not be obvious the plot is my shale can actually
46:51 porosity as I move along this This is my clay filled sand quite
46:56 low porosity. And what happens as add shale, my porosity gets
47:01 If I have a clean sand and add shale lamination, my porosity gets
47:07 if I have a horizontal line which this one's close. What it
47:11 is my shale porosity, my shale porosity is equal to my sand
47:17 So my porosity doesn't change as I this massive sand, which is the
47:25 , clean sand plus this first clay the clay lamination. Yeah.
47:32 maybe it's obvious to this group, usually there's there's a fair amount of
47:36 interpreting this. So a couple of I could ask, how do I
47:42 the porosity of this? What's typically is that people is in the original
47:52 Dier paper, they assume that the porosity and the dispersed plate porosity are
47:57 same which I just told you is always true. We had this 11
48:04 field where the first ferocity was twice shale fro the play elimination process,
48:11 ? So that's one thing we're correcting , right? Actually can prove the
48:18 . So how would it this point my sand, my clean sand completely
48:26 with this first clay, the entire space. So what would my porosity
48:34 ? It would be my sand porosity my clay porosity, right? Clay
48:41 is the amount of water per unit of clay. And the sand porosity
48:48 my core space normalized in the bulk . And so if I want to
48:52 the amount of clay for bulk including this first clay, I need
48:57 multiply those two just like PSW did , right? Different normalization that cleared
49:05 . This is sand. The times might be his first click determines that
49:12 . So why do we have this for the paper? Pretty famous
49:19 by the way, this title This is at the heart of what's
49:27 on here. It does fit. . Why does this plaque work?
49:37 the impact of clay of velocity depends its distribution just like the title
49:46 So what happens is I reduce the much more quickly by adding this verse
49:52 , I'm directly putting clay into the space. Only thing I can do
49:56 reduce porosity lamination there. Its effect porosity depends on the relative porosity of
50:04 mass of sand and the shale If the sand is a higher
50:10 we will than the clay lamination, will reduce porosity. If we replace
50:15 sand with something that has right. sand ferocity is lower than my shale
50:21 , we will increase the porosity. here clearly, you can see clays
50:26 its distribution effects will determine their effects the porosity. Logs pretty dramatic
50:37 Best way to reduce porosity is to clays in the floor space. That's
50:41 very steep line. Fact, clay may have no effect on it for
50:47 . What's the effect of structural claims we haven't talked about yet? How
50:52 we get points up here? We replacing in this model, we are
50:58 quartz grains which have what ferocity zero clays that may have 20% 30%
51:09 So the only thing a structural clay do is increase the porosity.
51:16 So all three of them have very effects. Yeah. Dang that to
51:25 that to gross is 100% to growth 0 50% halfway. So I talked
51:31 that all the way along the maybe hopefully this is clear.
51:36 if I looked at my sand properties any of these lines, they are
51:41 . So if I were to look a thin bed and I were to
51:44 at the porosity in the sand, would equal this ferocity. All that's
51:51 is I'm getting less and less sand my mix. My n of gross
51:56 decreasing than anywhere else. So what this tell you about the goal?
52:03 look at this plot, we mostly what kind of clay lamination or hovering
52:16 this clean sand line? We get dispersed clays but we don't get very
52:20 below this line. I have seen places where this triangle gets almost filled
52:28 there we are having significant amounts of clay along with the lamination. So
52:36 plot really cheap locks right? Density and a gamma ray log gives you
52:42 , a basic, the basic attributes your clays and their distribution,
52:47 Almost for free. You should be this in every classic reservoir. Why
52:53 you not make this plot straight out tech blog? Right. Click a
52:58 of buttons, cross plot the gamma and the density porosity. Some people
53:05 using weird other things here which is in the original paper, they'll use
53:10 neutron density separation, right? For . No, that's not what you're
53:16 to be doing. You're supposed to plotting here, the density porosity which
53:22 all of the bound water, all the free water because that's part of
53:26 my porosity is changing. This is to be total porosity density porosity.
53:33 have to recalibrate this if you do else. And the interpretation isn't nearly
53:38 simple. There's no reason to do . I see that happening quite a
53:44 . I don't understand it. Right. No, actually we'll
53:54 Uh, so the points inside and are other things that right, laminated
53:59 sand is first place. Um And I have given an exercise, I
54:06 know if we'll have time as to it is. There's various ways that
54:12 give you the porosity, you can the end points, et cetera.
54:21 we're on to connectivity model, How do we calculate the connectivity?
54:26 do we calculate this curved portion and this saturating effect uh to get some
54:33 . So what happened for a long was people would use what they called
54:39 of clay. They would look at gamma ray, they would look at
54:42 gamma ray in my sands, they look at the gamma ray and the
54:45 burn or under burden which by the , the overburden is a better shale
54:50 use like we talked about earlier. . And so they would just say
54:55 I have half the gamma ray, have half the clay. However,
54:59 really doesn't work for lots of One is you just first clay may
55:04 nothing to do with your over burned under bid could be orthogenics.
55:09 completely different origin, they have very properties so they can, they can
55:15 different properties, they can have different rays all of that. So you
55:20 do what you can do. But just be aware if you're doing some
55:24 like that, that uh you're making pretty broad and perhaps not very good
55:30 . Right. So if you've got , there are various things which
55:35 we're not gonna go uh into the or Indonesia model, which are still
55:43 . But uh there's not a good to use these other models at this
55:47 . There was a significant breakthrough in late sixties and seventies and this was
55:52 introduction of the Wax and Smiths uh Monro Waxman and Lambert Smith.
55:59 you're not supposed to do this. would put Indonesia on here too.
56:05 don't differentiate between the different clay That's one of the problems,
56:10 They don't, they don't distinguish between different clay properties is another, it
56:16 make the correction in the correct It's the only thing I can
56:20 Uh but quantitatively, lots of luck it. So, what was this
56:25 model and this new idea, this grew out of things that uh X
56:31 my humble opinion gets too much Ben and Bill Milburn and other people
56:37 introduced the idea that the iron exchange was the origin of the excess
56:44 So they said explicitly that said in these newer models that it's related
56:50 these excess negative charges, they're what uh the clay counter ions. They're
56:56 origin of the clay counter ions. not about shale volume, it's about
57:01 many clay counter ions do I So I need the ion exchange capacity
57:07 get that. So wax and Smith the one we're gonna concentrate on.
57:13 uh Laurie wants to talk about dual , she can. Uh I don't
57:18 it that much. I think it's confusing, doesn't really give you any
57:22 insights in my opinion. All And so you should be getting this
57:29 I don't believe the or log you really need to be doing this
57:34 some sort of core analysis to get caine exchange capacity. And oil based
57:41 is actually quite feasible in water based where you have significant clays as wading
57:47 . It gets harder uh to differentiate solids in your core now. And
57:54 water is a model that was proposed Slumber now SLV. Right. So
58:00 saying, yeah, they're models some than others. So a change
58:06 we are now gonna look in a more detail as to what that
58:10 Uh So this is the origin of these excess charges. It's the origin
58:16 the excess connectivity and this was demonstrated detail by lots of rock measurements made
58:23 . Uh here I here I I should give Ben Swanson credit.
58:28 was highly involved in making those Cocw , right. So uh they
58:33 so they measure the excess connectivity uh doing the making those COCW measurements.
58:40 also c exchange capacity was measured through variety of direct measurements for the cat
58:46 capacity. Paum chloride titration is my because we are directly substituting for the
58:53 and the clays. Uh we could about that for another 15 minutes but
58:59 recognize it's after lunch, it's so have the clay crystal, we have
59:04 negative charges associated with it. We the clay bound water which I pointed
59:09 already. We have the exchange right. Those are the sodiums and
59:14 we have the negative charges making things neutral. The other thing is that
59:20 uh that differs from capillary held Not a lot of people in my
59:27 uh understand that the why they are . So this clay bound water is
59:34 through electrostatic forces, negative charges, charges. Capillary held water can be
59:43 and it's held through Vanderwal forces which much weaker and fall off much more
59:49 . So I can basically at higher pressures, displace capillary held water.
59:55 the small pores wanna hang on to water. More amazing, I cannot
60:02 these ions off. We can doesn't . So we have to correct mercury
60:08 for bound water cool. So we to understand exactly what the ion exchange
60:17 is. Typically it's measured and the of charge a gram of dry
60:26 Yeah, good reason to dry the get this number right. So we
60:33 through AC C right? And we to get to QV for the
60:39 And we'll explain, I'll explain that a second. But first of
60:42 how do we make this UV is concentration of charges per unit four volume
60:49 is the concentration in mill equivalent per . So we multiply the CC by
60:55 density and this is grams per unit . So this is cat exchange per
61:01 . So we're getting the weights out and this will be per volume,
61:06 ? This is the density of the . This is gonna be per volume
61:09 clay. I wanna go per uh want to get to pore volume.
61:15 one minus B is my grain volume the clays or whatever the material is
61:21 is the pore volume. So I to cancel out the one minus fees
61:25 I end up with the number of per unit four Y. So that's
61:31 , this is the parameter you need shay sand bottles, right?
61:37 I got your number. Hopefully, know what a mili equivalent divide by
61:41 . Yeah. So here's typical numbers this. They actually uh they,
61:47 actually give these in mil equivalents per or milli milli equivalents per 100
61:53 right? And I do that to these numbers, you multiply, you
61:57 get the other one, you multiply 100 g. So Mount Maronite ranges
62:04 can see is the highest. it's the most exchangeable typically. Uh
62:10 you have the most exchange sites. . Chloride and Kale and I are
62:15 of tied for having low numbers. can be actually way down to zero
62:20 then Kale and I, right. just low, my CNL porosity is
62:26 here. Again, this is Laurie out. This ferocity may be something
62:31 50% gala night is pretty high and feel like significantly lower. Bye
62:40 Hydrated density is completely different then. be careful with these numbers. Then
62:46 gonna find them all over the place the literature. You have to ask
62:50 question, how were they prepared when measured the grain density? Did they
62:55 dry them? In order to get right number, you have to eat
62:59 things up to 60 C. You to pull a vacuum on them to
63:02 all the water out at elevated right? Elevated temperature and a
63:08 you can dry them. If you take them to 60 C, you
63:12 not dry them. You just pull vacuum on them, they will not
63:16 them, right? You limit yourself 60 C because you worry about actually
63:22 the clay and its distribution at higher than that. And how do they
63:27 up in a spectral gamma? It's right. Again, this is can
63:31 all over the place. And remember drew an X across that plot,
63:36 showed it to you. So with locally calibrated the other way to worry
63:41 this and why it has an impact that the clays also increase the specific
63:49 area. You remember what that It's the surface area per unit weight
63:56 here is what they're plotting. Interestingly . All these clay types actually fly
64:02 a fairly constant trend on a log clock except for chloride, which is
64:08 over here. It's got two lowest . So why is that interesting?
64:14 that tells you why they impact permeability way they feel very high surface
64:19 They're gonna lock up a lot of even aside from the electrostatic charges,
64:26 ? Florence may. So how do get the amount of clay bound
64:33 Uh one you can run an Mmr if you uh do it right,
64:38 enough data you can get to, can discriminate between the peaks from the
64:43 . The other is uh Hill Mill Klein. I think they're mentioned here
64:48 . This paper was Client Hill Shirley correlated to the impact the difference between
64:55 curves and oil water curves. So , this correction we're gonna make either
65:00 the opposite direction, they measure an water curve. They looked at how
65:06 right, lower by residual uh saturation when we dried them and got this
65:14 . OK. Uh The only thing thing to worry about is that concentration
65:20 that's not a connectivity, that's a at moles per liter. So this
65:26 is just how you convert between moles liter and then parts per million,
65:32 included that for you, right? the fraction of the poor water that's
65:37 this is my bound water fraction is w this times QV. That's actually
65:43 you make your direction to cap That's the correlation they got. So
65:49 can see this is a Gulf of example, you're getting close to
65:54 you can see the example you right? Uh If you have a
65:59 , again, this is the right? This is the amount of
66:03 normalized to the four, right? this is gonna be the most correct
66:08 of how you're gonna ruin your not ce C but QV. So
66:14 you have QVS of 0.6 to 0.7 that's just barely producible. And uh
66:21 it's significantly lower than this, you're down to 0.3 then they're gonna
66:26 OK. If you have more dispersed than this, it's gonna be uh
66:32 better, less the first day, gonna be even better. So
66:35 if you plug these numbers, if , if you plug those numbers into
66:40 , this that tells you that 18% the poor volume is the worst case
66:46 . And 7% would be just But this is how you make the
66:54 right between capillary, how he and bound water or just using that Klein
67:00 Shirley equation to correct notice this is saturation plot, we calculate a bound
67:06 saturation, we just move this over that saturation difference co labs. By
67:13 way, this is exactly what they when they correct their oil water curves
67:17 mercury curves is to make this It's OK with everybody what we're
67:24 And if we had a homework, be able to do this. So
67:28 last thing we're gonna do this lecture that and we're gonna move out over
67:31 the other campus. It should all right. 2 30 we should
67:37 there by three and can be so questions you ask. So we have
67:43 of different normalization. So whenever like uh master suit was working on this
67:49 model, this kind of thing drove crazy. So what are we normalizing
67:55 ? It's all related to this and do we need? Right. So
67:58 have several sources of fluids in the space, which is here bowed
68:02 free water and hydrocarbons. These are expressed in terms of saturation. So
68:08 found water saturation. What are we is the amount of bound water to
68:14 total pore volume? OK. similarly, we have a Freewater
68:21 So when we talk about saturation, normalizing the amount of four volume.
68:27 when we have a, when we this speed, it means we are
68:32 this to the vault volume, which the sand silt and clay,
68:37 So the solids Soros get to another to get from saturation to bulk volume
68:47 . We simply multiply this by a . We've done that gone through that
68:52 several times already. And you will this. If you ever look at
68:58 NMR log, you're gonna need to to understand what these, what these
69:04 are and effective ferocity is related to water. That's B total times one
69:12 the bound water that's gonna give us water. And my hydro is related
69:20 total water. Satur I think correct that. Go on. So wax
69:27 Spence almost done. So how are gonna calculate this excess connectivity? So
69:33 fundamental idea here is that we have effective blind connectivity. This connectivity is
69:41 connectivity of my free water. So I have done is I've added an
69:47 source of iron with their mobility. for remember how I mentioned that that
69:54 the surface conduction, these things are to the surface. They have an
69:59 much like we worried about with the and so we need to change their
70:05 to a concentration in a poor That's what QV does B corrects my
70:12 mobility. So we what we've done we've increased our salinity based on the
70:18 of clay comma we have OK with . And then we correct for their
70:24 by this turn right, the equivalent of those that change ions. So
70:30 simple, our brain is more conductive we have a different additional source of
70:38 to be the origin of that is we're worried about the concentrations of ions
70:43 the poor space. Just like this this, the total total connectivity is
70:50 to the number of ions, air in the water. So these exchange
70:55 , we need to have a comparable . This is a test of whether
71:01 understand this or not, my saturation is assumed to take this form.
71:08 what does it mean? It means my oil does not affect my bo
71:13 connectivity is or my free water conducive all I'm doing when I add oil
71:19 this, I'm replacing free water with . So my concentration of ions in
71:26 free water is the same. I do not like I've said several
71:31 now, I don't displace the clay ions with an oil column. So
71:38 happens is their concentration in the poor is getting bigger? What this means
71:45 my clay effect is getting larger with increased oil saturation. So the more
71:52 I have the bigger the impact of clays. That's one of the reasons
71:57 is important. What I what have not added when I do this,
72:04 changed to the effective connectivity of the concentration of ions and brine. What
72:10 haven't done, get some water but it, I haven't done is
72:16 haven't included the tortuosity of the So that's what I'm doing here.
72:24 the A, I've never seen anybody that. Thank you. I've never
72:29 , never seen anybody include this in sand calculation. But all I've done
72:34 is I plug it in for CW Archie's equation. So just this is
72:39 increased connectivity. So it's Archie's equation an additional source of connectivity. That's
72:46 entire J Sam. Then if I'm to assume M equals N equals
72:54 which uh happens quite a bit as can see uh that depends on the
73:00 of clay. This exponent can range Shay sand where I have to deal
73:04 it from maybe 1.8 up to 2.3 on how much clay I added.
73:11 . So I can simply solve this my connectivity, right? Which I
73:18 , right? Knowing my saturation, appears in two places used to be
73:22 bigger deal and people were using slide . Now it's not such a big
73:27 can be easily iterated on a It isn't a big deal. All
73:32 . How do we obtain DNQV? way that uh you're supposed to do
73:37 is you're supposed to get this from go in, you cut a
73:43 you, you measure CCS and then can correlate to that something like the
73:48 ray. So I have a gamma here. My gamma ray is connected
73:52 the amount of clays and like this and I can directly uh generate
73:58 From that. This model is for first clays only. It does not
74:06 say that the original paper honestly doesn't the impact on connectivity of structural clays
74:13 model the impact and connectivity of the lamination. It's modeling this first clay
74:21 is this just this factor that counts the back. It's a surface conduction
74:26 . So those clay common orions are mobile than the ions in the free
74:35 . Why does he have a salinity to it? You might be asking
74:42 go back to a picture. Best is way back here. Thought there
74:54 a better pitching back here. So talking about this salinity thing. Why
74:59 that happen? OK. Why it is because the higher the salinity,
75:06 ? You have discrete clay sites. you were to look at an actual
75:10 section, there's clay over here, clay over here, clay over here
75:14 very fresh water. What happens is have to get the clay counter ends
75:19 this clay site over to this clay over to this clay site to get
75:24 to contribute at low salinity. There's ions to couple on and off the
75:29 . So what happens is I increase salinity actually gets easier to couple the
75:34 on and off the clay site into brine. If you were to think
75:41 what really should be happening as I , not really should be happening,
75:45 the actual mobility of the clay Conan actually goes down with increase of
75:51 And when I measure dielectrics, that is what happened. So we're
75:57 So we've explained basically everything the source the excess connectivity but the salinity dependence
76:05 and then how to calculate this, ? The P you actually people typically
76:11 up in a chart. So that's in the original paper with the
76:17 dependence. BC Thomas added the added the effects of different ions uh and
76:27 . And this is the last We'll wrap up the Shali sand
76:30 When do you use it? This a look at Archie's equation. This
76:34 wax and Smiths inverting for saturations. so the difference, the only difference
76:40 is this term OK, related to . So the whole impact of this
76:46 how big this term is relative to . OK. So if this term
76:51 calculate RWBQV over SW that's less than we can ignore it relative to
77:00 we can use a equation. If bigger than that, you really ought
77:05 think about making a great connectivity model doing this, right? The other
77:09 I wanted to point out is if water saturation is one right? Uh
77:16 it's just RWVV and the water saturations . So high oil saturations where if
77:23 really want to use it, then this is up by a factor of
77:27 . So it becomes five times more . When do we typically want to
77:32 ? This is that water? So you're looking at a formation,
77:39 it's got its original high oil It is more important to use it
77:45 if I go in and make measurements the lab at 100% water saturation,
77:49 impact will get significantly bigger. So will miss right? Oil,
77:55 That you might not think you should cannot ignore this saturation effect while I
78:02 time explaining what its origin was. this might be the last you hear
78:09 me, of course, depends on we do next Friday. So we
78:15 decide you have a choice. You get a geologist to talk to
78:21 Yeah, or me. She will about uh unconventional for a couple
78:27 However, we want be willing to her or I'm going to come talk
78:31 the bar won't hurt my feeling by way. So what do you want
78:36 do? We should give her a to think about it. Nobody cares
78:44 you don't care. You're probably gonna me up because I'm supposed to be
78:49 . Of course, if you think value, I will tell you the
78:54 to talk about unconventional is that the are different. It's a very
79:00 you evaluate it in very different right? So it's interesting to contrast
79:07 to what you heard during the course this day, how the rules break
79:12 . If you start applying this conventional in an unconventional, you're gonna look
79:19 . So that's up to you. the other hand, the argument for
79:23 NMR is, it's pretty commonly You can get information from it.
79:27 can get no other way, you get things. Basically, it has
79:32 length scale in the measure. So fairly directly, doesn't give you direct
79:39 . It comes pretty close, it you the size of things. For
79:44 , they can discriminate directly oil from , they can give you bound water
79:49 pre water. Oh Yeah. No, we're all things that would
79:58 pretty inspiring life. I can ask what stage effective medium models do or
80:05 could do continue mechanics if you I'll ask you a question about
80:10 No, no. Fair enough. enough. The exam, the exam
80:13 only cover material the course. Actually good question. You what, how
80:26 questions now we're not. What percentage this be unconventional versus this versus NMR
80:34 B I'm gonna give you, we're post uh an example final,
80:42 I'm gonna post that. And so gonna have next Friday principal. It's
80:47 hours she's gonna lecture for probably 2.5 3 and we're gonna go over this
80:53 exam for an hour. So it it will compare to this. It
80:58 not be identical to this, but will compare. So just don't get
81:04 , it will cover a comparable It will have a similar format and
81:10 in complexity and we only have one . So it's not really fair to
81:14 you with everything, right? Trying be fair. Not always. So
81:22 wants to prepare for this if she's do it. So we need to
81:26 her unconventional. All right. And , thank you. I thank
81:37 All right. So she'll give the and then I'll give the, I'll
81:41 the course for review. So we'll both be here. We'll go
81:45 there. All right. So actually like you and I, this isn't
81:49 last you'll hear from. It's I wanna do Shay Sands just because
81:58 , it's not understood very well. everybody know he knows how to get
82:11 building
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