VideoPoints

• ••• • •• • ••••• • •
GEOL6363 Carbonate Sedimentalogy - Day6 02-04-2023 AM
Help Tour
© Distribution of this video is restricted by its owner
Transcript ×
Auto highlight
Font-size
00:02 All right, good morning. We're to continue our discussion about the
00:11 The different reservoir types associated with the play type, which were the platform
00:19 ramp related wacky stones and pack And we finished with this slide yesterday
00:25 the Permian talking about some of I think the clear fork uh,
00:32 from the central basin platform, These stacked tidal flat units that are
00:37 Ized. Now we're going to move into the cretaceous. I'm going to
00:40 you some variations on a theme for development associated with, with the different
00:49 of cretaceous settings and die genesis obviously an important part of this because you
00:56 to create the reservoir quality in these fabrics. So we're going to start
01:02 by coming back to south texas. talked about the, the Edwards or
01:08 city reef trend is a play type , right. That platform margin Ruta
01:13 complex that occurs in this position right and now we're going to come up
01:18 the inner part of the platform. can see from the light blue
01:22 it's all mapped as mud stone. actually not a mud stone. It's
01:27 more of a little wacky stone to stone texture. But when people look
01:33 it in core, they see this fine grain texture and they can't really
01:38 the political character, but that's the platform interior. That's the low energy
01:43 critic carbonate and there are a couple famous old fields that are developed in
01:48 position here. And if you ever from Houston to san Antonio, You
01:56 where Bucky's is in Luling right on 10. And when you come around
02:01 , you can actually, sometimes your open in your car, you can
02:05 smell the oil. And that's, the stuff that's still seeping from these
02:09 fields like Luling and darts Creek field are discovered back in the 19 twenties
02:17 these are platform, interior restricted, colloidal wacky stones and pack stones that
02:24 been demonetized with secondary porosity development. , so There's there's a location of
02:30 fields relative to the platform margin. inner part of the platform, you
02:35 see, we're 50 or 60 miles from the open ocean. And these
02:42 exist where they do in part because fall controlled and because there's such old
02:49 , nobody's really studied them from the of the digest history to see if
02:54 faulting is part of the story for demonization uh or whether it's related to
03:01 else. But the faulty is important you'll see in a minute because it
03:06 to trap the hydrocarbon. Right? these plays are actually sort of classical
03:11 controlled plays, okay, how I this off and this is what the
03:36 fabric looks like in thin section, can see the reserves associated with both
03:41 and Doris creek and yesterday I made point about a lot of these reservoirs
03:46 pretty small and scale cabin creek was 75 million barrel oil field. And
03:53 , that's oil in place. That's recoverable. You never get all the
03:57 in place out of these out of rocks. But you have to be
04:02 with these numbers here. These are good numbers. I mean Luling is
04:05 a giant oil field. If if buy the oil and place numbers and
04:13 look at the fabric here and thin . This is the classical fabric we've
04:18 talking about when you take a what call the by model or pollen mold
04:23 rock where you have fine grain right? You have sand sized fecal
04:29 , you have sand size the scale fragments. This would be a mollusc
04:34 . Remember the plating morphology of the the grain. And what gives dramatized
04:39 is always the MMA critic matrix. then for reasons we talked about what
04:45 during the advanced stages of demonization. reach out the remaining calcified material.
04:51 this is a mixture of what people call inter crystalline ferocity in the MMA
04:56 matrix. And then multi ferocity related leaching of the presumably calcified mollusc or
05:04 cal citic colloidal fabric. Okay, , and then on top of
05:08 as we've talked about many times, ? You get a fracture over
05:12 which helps tie some of this porosity . And if you look at the
05:17 section again, this is from a old paper, 1933. You can
05:22 the, you can see the other of the story here is the
05:27 Okay. And these faults and trap in the Edwards. Okay. And
05:34 see they later even trapped oil in austin chalk and and some of these
05:38 sequences as well. Right. That's different play type that will talk about
05:44 today. All right. So this pretty typical of the platform interior.
05:49 you dilemma ties it, the model back to the slide here, the
05:58 model that everybody's invoked here is the model. Remember when you have up
06:04 of apa rights. People think these flow down dip and they say that
06:09 if you were talking about the Atlanta yesterday and fredericksburg, if you go
06:16 of fredericksburg, there's actually an active where they're mining evaporates their mining Edwards
06:22 evaporates the gypsum wallboard and that's thought be the source of these fluids.
06:28 ? So the magnesium rich fluids generated precipitation of gypsum was always thought to
06:35 down, dip and demonetized the active of the Edwards and the brown
06:40 And this map is actually still So that's that's the that's the old
06:46 , right? Up dip, evaporates dipped organization. I think that could
06:53 challenged today if we had the rock , but you know, these fields
06:57 so old, There's not much rock around to look. Okay. And
07:06 bringing you into the Jurassic smack We talked about the politic play types
07:14 . Right. When we talked about grain stones and the production that occurs
07:18 the northern gulf rim. There's an littlefield. Littlefield is a giant field
07:25 uh is a giant oil field that over here called jay field in right
07:30 the border of Alabama and florida. it's smack over aged, but it's
07:38 not from analytic material, but from restricted, polite little paxton fabrics associated
07:45 a more restricted subtitle environment. so this is where jay field
07:51 It sits in this sort of restricted basement here and again, as part
07:58 the ramp profile that we talked about common and the smack over. But
08:03 not an area of politics and deposition you can see the numbers associated with
08:10 . So it's it's a it's a typical upward showing sequence and the smack
08:16 . But here doesn't culminate into a grain stone like we saw in the
08:20 classical parts of the smack over, only shallows up in these restricted,
08:26 subtitled colloidal sediments. Now, if look at the if you look at
08:30 rock here and thin section on the right, you see these holes that
08:34 like the size and shape of It's right. And this is what
08:38 thought for a long time if you work for Exxon and I worked for
08:44 and I've seen the course from J . In fact, it was always
08:48 of a internal training exercise that we . And we laid out a series
08:53 cores where you could see the transition the original limestone fabric to fabric that
08:59 like this. All right. So original limestone fabric was a polite little
09:03 stone. All right. So P probably mostly fecal pellets surrounded by lime
09:10 . So what gets stolen? Monetized is the critic fabric and then for
09:15 reasons we talked about before the remaining citic pe Lloyd's reach out to give
09:21 this fabric. Okay. And so is not a politically related deposition.
09:27 is these are restricted subtitled burrow portal . But you see the numbers here
09:34 the size of the field and more , part of this part of this
09:42 . More important aspect of this field the timing relationship. This is early
09:48 Where the critic fabric got replaced, grains got leached out because there's no
09:55 or suturing of the holes, There's no collapse of the porosity.
10:01 , this tells you this is dull urbanization, early secondary process.
10:05 is one of the ways we we to time things right and look at
10:09 barrel depth here, 15,500 ft or that's pretty deeply buried. I think
10:16 we had this discussion about the Uh the other weekend, I mentioned
10:22 example from Montana from 25,000 ft of that looked just like this? All
10:28 . So it tells you how strong dolomite is in resisting later pressure solution
10:34 ferocity at depth. Okay. So what we see in a platform interior
10:41 is the unique, favorable dia Almost always people invoke harmonization to,
10:50 create that ferocity. And as I , most people think it's relatively
10:56 intuitively. You you would think you to get those dramatizing fluids in democratic
11:03 while it still has some permeability. . But what I want to do
11:08 is I want to show you another to make ferocity and these MMA critic
11:14 that has nothing to do with the . And the concept here is die
11:19 chalk. Now, later we're going talk about the unconventional plays called de
11:25 chalks, right comprised of the tonic microfossils and nana fossils.
11:31 I want you to appreciate this is using the term talk a little bit
11:34 here. Um the mud loggers call fine grain micro porous limestone chalky.
11:44 ? That's an old textural term that's around in the literature. Going back
11:49 the fifties and the mud loggers use a lot to characterize micro porous.
11:54 critic limestone. So that's that's why turbo is around. But I'm modifying
12:02 with the term die genetics. So appreciate it's different than what we're going
12:05 talk about for the deposition. All and you should be familiar with the
12:10 between these two types of deposits. . So what is a digest
12:16 It's a porous fine grain but shallow . The critic limestone, it's very
12:22 in appearance and texture to the classical water deposition all chalks but there's no
12:28 or plank tonic constituents. Okay. they don't occur in shallow water,
12:33 the foraminifera. They occur out in water. And uh so what's what's
12:41 about the digestive talks? Is there only shallow water but they usually because
12:46 in shallow water, they start off higher amount of genetic material. Remember
12:52 and talks will go through this in later today. Remember those constituents are
12:57 stable Lomax calcite. Right? The forums the plastic houses here is the
13:03 fossils we call co colas they're all calcite constituents. So they're not as
13:10 dye genetically. But here with the chalks and shallow water we start off
13:15 a mix of a ragged ICT and heimat calcite calcite. And so there's
13:20 be a lot of more secondary porosity with the digest. Talks. Of
13:26 the controversy always in the carbonate community the timing of that secondary process
13:33 Some people want to make it Some people want to make it due
13:37 shallow burial. Where the arrogant I starts to dissolve out and some people
13:43 it's to be deeper. Right. it could be any of those.
13:46 . So you have to evaluate each chalk on its own merits.
13:52 But I want you to appreciate this another way to create reservoir quality in
13:57 or tidal flat related. A critic stones. So to illustrate this,
14:03 gonna start with the classical Digest chalk from the Middle East. This is
14:10 the fabric was first really documented back the 60s and 70s. And this
14:16 a map of some of the producing both offshore and onshore and uh an
14:24 in abu Dhabi. Alright. Remember United Arab Emirates or all these different
14:30 basically that are loosely loosely united and Dhabi has production both offshore and
14:40 And I'm going to show you data a giant oil field called bahasa,
14:44 is one of these registry complexes that developed along the periphery of this little
14:51 inter catatonic basin. Okay. And of the production occurs as you would
14:59 from the rudest reef related debris as talked about yesterday. Right. Usually
15:05 reef cores are tight baffle stones. baffle stones, they don't have good
15:10 permeability to be productive. So here of the production is the rudest grain
15:15 . But what's interesting is there's co production that occurs back in the platform
15:22 you see this millennial ID, these football shaped one or two millimeter
15:28 multi chambered venting forums. They only in these protected settings behind the
15:34 Okay. Or further in from the ocean. And so this is a
15:39 back brief if you will lagoon. . And the rock looks like this
15:45 core. And you say that's I mean that looks that fabric.
15:52 that modular fabric we've been talking about is created by a mixture of two
15:57 . The first process is burrowing so model, the appearance that you see
16:03 is due to sea floor burrowing. later this stuff gets buried. And
16:08 are the wispy micro style lights that through the fabric and they modify that
16:13 texture to create this notch ular Okay. And historically we never view
16:20 as having great reservoir quality. We this as a tighter. Why don't
16:29 stop it for a minute? We're stop for a minute. Okay.
16:35 little bit of a technical difficulty So we're back and again. I
16:40 saying, if you look, you historically this kind of fabric is not
16:44 quality. This is the kind of that seals other porous reservoirs.
16:50 But if you put water, if take a water bottle and squirt water
16:53 this core face, that water just right in. It's amazing how micro
16:58 this fabric is. Excuse me. you can see this in fence
17:07 Excuse me. This thin section is impregnated again with the blue epoxy resin
17:18 we will use to highlight ferocity and just riddled with a blue hue.
17:23 ? All this blue you you see this thin section photo micrografx is the
17:28 micro porosity. This is all. micro porosity created is such a fine
17:33 that you can't see exactly what's being out. And that's why we call
17:38 micro fungi porosity. And what you appreciate is that the samples from about
17:45 little over 8000 ft of burial. I don't know if the numbers are
17:50 your side on your view in terms processing permeability, This is 21%
18:00 Okay. Which is pretty high for kind of burial depth and 87
18:07 Darcy's permeability. Alright. And what's about this rock fabric is it produces
18:14 . Okay, so this is your introduction into a reservoir that's capable of
18:21 oil from this fine micro ferocity. the reason why it produces oil for
18:26 a is the gravity of the oil quite high. Right? So it's
18:30 lighter, what we call lighter less viscous. Right? So it's
18:34 easy to move this stuff through the the process. Okay, If this
18:41 a gas reservoir permeability would be no . Okay, But here it works
18:47 of the higher permeability. And also fact that you have a lighter gravity
18:52 . Okay. And when you look this and with the scanning electron
18:57 you don't see the coca lists and like that because this is not a
19:02 water deposit. This is a shallow restricted subtitle limestone. But if you
19:08 at the fabric, you can see that's smooth by dissolution. And then
19:12 can see crystals that have more sharper boundaries. That's the stuff that back
19:17 . Right? So it's a donor story that we've talked about before,
19:21 you remove stuff by dissolution, but can put some of that back in
19:26 calcite cement. Of course the timing be all over the board here can
19:31 due to exposure to fresh water because genetic material. It can also be
19:37 to porosity being generated during shallow You remember our discussion about marine barrel
19:44 genesis where reaganite dissolves under hundreds of of burial. That's another potential mechanism
19:51 explain the prostate. But in this the this process is mostly created during
19:58 dia genesis because of the relationship of microprocessor and blue to things like style
20:04 . Right? The process along the preserved close to the skylight. Remember
20:10 process? It was their first, should have been preferentially cemented by calcite
20:14 generated along the skylight. And then have micro leaching of calcium. Dick
20:21 grains. And I told you our weekend that when we see calcified material
20:27 in the subsurface. That's usually a flag for burial dissolution. Okay,
20:37 . And then having showed you Now, let me bring you back
20:40 south texas and there's a number of in south texas that occurred behind the
20:49 margin. Okay. And these are of the bigger gas fields and one
20:57 called word field that occurs in Lavaca and the other is called Dill.
21:01 Worth. That occurs, and I Mcmullen County, which is this county
21:05 here and again, these are interesting they occur miles behind the platform margin
21:14 in a low energy restricted back reef . But the common thread here is
21:20 they're in a highly structured area behind platform margin. So faulting is probably
21:28 of the reason why we developed these platforms anyway, right, they create
21:33 the black ball thing creates at the for steep margin, but there's another
21:39 trend that runs back through here behind margin that runs along the strike behind
21:45 platform margin. And both of these produced mostly from this digestive chalk
21:53 Okay, and Word field is the , You can see the original gas
21:59 places 820 BcF average processes, only perms are really low. Again,
22:08 it's micro porosity dominated. But this doesn't have to be fractured for
22:14 because gas will come out of that low permeability. Okay. And
22:19 can see the data on this diagram 1985. And uh, this diagram
22:26 trying to explain how you generate all secondary micro porosity. These democratic carbonates
22:32 occurred. Miles in from the edge the platform and their solution was to
22:41 the MMA critic deposits build up above level to make these islands.
22:47 so essentially a bunch of mud banks shallow, up above sea level.
22:52 see this today in florida Bay. know south of the Everglades or some
22:56 those mud banks actually by storms get piled up above sea level, they
23:01 vegetated and you know, that's that's interpretation because back in the 19
23:08 we only knew of one way to secondary processing that was by exposure to
23:12 water. Now, I've showed you other ways to make secondary prostate,
23:16 ? Marine burial, die genesis during burial and then deep burial dissolution.
23:24 , uh, just people have reevaluated . And let me, let me
23:31 show you a couple of things about field, right? It's moderately deeply
23:36 13,000 ft. And there are a of things here that suggests the timing
23:43 the porosity is deep barrel first, documented leeching of these calcified skeleton
23:48 And then you see again, secondary preserved along or cutting the style
23:54 That was a timing indicator. And not only as The original gas
24:02 place 820 BCF, but there's almost barrels of condensate that's been produced condensate
24:10 the light liquid hydrocarbon. Okay. I think the other thing I want
24:15 to appreciate here is I think this a red flag for the timing of
24:20 of the ferocity is that these pools high amounts of carbon dioxide.
24:27 And so the carbon dioxide, many us think is a byproduct of this
24:32 dissolution. Right? You've all put on the limestone, right. What
24:38 off of this carbon dioxide. So 7% is pretty high. And
24:44 think that's a red flag. But way you proved this again is to
24:48 at the rock. I don't have 10 sections to show you for word
24:53 , but I can show you stuff Dilworth Field, which I've worked in
24:56 a bit of detail. And this part of that Anadarko NMR study that
25:03 told you last weekend I got involved where we looked at the Edwards trend
25:08 along and sampled and and evaluated for and Perm with the with the core
25:15 . And then we looked at the sections to evaluate the amount of Micro
25:19 macro porosity. So, here's the thin section view from a sample at
25:25 . It's a little bit shallower. about 11,500 ft. And the measured
25:31 17%. The permeability is 8.5 million . And you look at the standard
25:37 section, you see a little bit blue here, but you don't really
25:40 the porosity. All right. And can see Dilworth is not as big
25:45 word field. Only about 225 BCF gas in place. All right.
25:52 , you know, you look at process number and you look at the
25:55 section, you say, where's the ? Well, the process he stands
26:00 when you use the white paper Now, you see all the blue
26:04 . Okay. And this is in why we use the while we use
26:10 white paper technique to see that blue ferocity. And then look at the
26:15 thing that you pick up here that didn't see in the previous photograph.
26:19 a style light. And you're actually down on a style light where the
26:23 are coming up at you. Because of the orientation of the thin
26:28 relative to the core plug. And your timing indicator where you see the
26:34 amounts of blue porosity preserved along are cutting. You see it cut parts
26:40 the style light. That's that simple crosscutting relationship that tells you that
26:46 form during burial. Okay. And where I think the structure is very
26:53 for providing the conduit. Right? mean, these are pretty high porosity
26:59 for moderately deeply buried limestone. And think the implication here is that the
27:06 are coming up along these deep seated . Right? I told you when
27:10 come out of frenetic basement rock, going to be acidic and they can
27:15 carrying base metal sulfides and in what we see associated with this process
27:20 . Is in placement of some of base metal sulfides CCP ride? You
27:27 Marcus side, see galina, you salaried, you all know the difference
27:32 . Kalina is the lead sulfide mineral , right? Zinc sulfide mineral.
27:38 then what else do you get All right. Before it looks like
27:42 ? Under cross Nichols, it's ice tropic, which means it turns black
27:45 stays black. And and then you even mega quartz, right? Mega
27:53 comes from granite basement rock. See this all fits together here. The
27:57 and the fluid composition. This is kind of chemistry that you want to
28:04 deeper burial secondary process development. And I took you through a case
28:10 yesterday from the Haynesville and the Remember those olympic gas reservoirs in east
28:16 . And I made the argument that had that late stage exotic non carbonate
28:21 , that is also a proxy for sea default influence. Okay, so
28:29 really starting to get into this discussion about paying attention to the deep seated
28:34 . Alright, so the questions you ask, you know, when you're
28:40 into a basin, you don't know about it. I mean obviously paleo
28:45 , right? You want to know I said relative the equator and all
28:49 that we've talked about. But I say the other key question you want
28:53 start asking is what's the nature of deep seated structure, right?
28:58 Where are the strike slipper wrench fault . Those are the things the title
29:03 and those are the potential conduits for like this. Okay. Alright.
29:10 appreciate the nature of a diet. a shallow water limestone undergoes secondary process
29:18 for this. Mostly micro ferocity. either micro molding or generally micro buggy
29:24 . The timing can be earlier timing be much deeper. You have to
29:28 that on each case. Studies on rock. Data from each case.
29:35 you look at Alright, and then me finish this discussion by talking about
29:44 other part of the story, With respect to the ramp ramps just
29:49 have restricted carbonate behind the Excuse me the the ramp crest. But what
29:58 when you go out in front of ramp crest, you slowly increased water
30:02 out into deeper water. You also into more of a critic fabrics as
30:08 go into deeper water. Okay, that outer ramp setting. Before you
30:13 to the basal equivalent. Alright, let me show you uh the nature
30:20 the or the potential to create plays that kind of setting. And I'm
30:24 to do that by coming back to central basin platform. Alright, so
30:28 talked about vacuum field, we've talked north Robertson. Um I'm going to
30:37 about a field up here called Seminole that occurs right here. It's another
30:42 oil field in the Permian and uh produces from dramatized down ramp. The
30:50 in this case, you still in wacky stones and pack stones. Member
30:55 the few selections are those big benthic that are centimeter scale. Okay.
31:02 you can see the reserves are over billion barrels of oil in place.
31:09 my first consulting project after I left was actually to work Seminole field.
31:16 was hired to describe 5,000ft of core build an internal architecture for the field
31:24 they were coming off a primary And as they always do, they
31:28 to water flood right? They tried sweep out more oil by pushing water
31:33 the reservoir. But they didn't understand internal architecture. They didn't understand the
31:37 plumbing. Right? They didn't understand cyclist city because the cycle contacts as
31:43 talked about our vertical permeability barriers. ? And that controls the movement of
31:49 . And so their water floods They didn't really understand what they were
31:53 . And that's what led to this . Alright. And the profile here
31:58 the classical ramp. We I showed the same diagram for vacuum field when
32:04 talked about the ramp crest dualistic grain , that our dilemma ties right
32:08 Seminole produces from this down ramp setting . Okay, produces from these few
32:15 wacky stones and pack stones. That's only faces that produces its seminal.
32:22 . And the reason why these other don't produce is because And hydrates,
32:27 plug the porosity. All right. unlike vacuum, the United grain stones
32:33 are all plugged with and hydrate, finessed reciprocity associated with the tidal flat
32:38 here. All plugged with an So this is the only faces trend
32:44 produces right And the and hydrate is part of the story here for creating
32:51 . Remember we had this discussion about dissolution being driven by passage of calcium
32:59 fluids. Right? That either in late stage cal sites or late stage
33:04 hydrates, calcium sulfate. And so you see this happen, it occurs
33:11 burial. This is not early evaporate placement. This is later because there's
33:17 pressure solution in these rocks. And the grains have already been leached
33:22 after burial because the grains are sutured and you can actually see some of
33:27 and hydrate replaces some of that pressure fabric that runs through the grains.
33:32 . And so we talked about this little bit uh before right, you
33:39 after this is this is an example everything got demonetized first. All
33:45 And then later another fluid came through start leaching out some of these demonetized
33:51 cell in its and the fuel cell its were already replaced by dolomite that
33:56 gets leached out. You see the of the centers here and then you
34:01 how everything expands and you eventually create mold like you see there.
34:06 so this is dolomite dissolution during Okay. And the only rock that
34:15 here is rock that looks like these upper photographs right here. So
34:21 everything is replaced by dolomite before dissolution because look how well preserved the development
34:30 , Houston linens are here. a little bit of and hydrate,
34:38 brown that you see here in this piece is hydrocarbon. Alright, that's
34:43 stain. So in a in a , the broccoli looks like this where
34:51 fuselage knits are Delaema ties, but relatively well preserved and you have more
34:58 between the few solutions. Okay. what you don't have is a lot
35:04 an hydrate. There's a little Okay, now look at the other
35:10 fabric and the same faces trend though of the rock looks like this where
35:15 of the few cylinders have been leached . But the poorest dolomite fabric in
35:22 is now tight. Okay, In words, there's no permeability is still
35:26 ferocity. In fact, if you at the primacy logs between 46 and
35:33 , they would be identical. You tell these apart on a proxy
35:37 Okay, all you would know is got good proxy but obviously this rock
35:43 permeability and this doesn't right, because all isolated molding ferocity? There's no
35:50 in this fabric never produces. And so what's going on here,
35:56 that where you have a greater emplacement anhydride, You have a greater degree
36:01 dolomite dissolution, leading to this molding . But what happens when you reach
36:08 dramatized grains? Some of that fabric back into solution and re precipitates
36:15 Right. And that I think explains you get the tighter matrix here.
36:21 tighter matrix needs no permeability. You've to be in a fabric that looks
36:25 this for production. All right. then this field is made up of
36:30 a series of these program, additional . They build out a back
36:35 they procreate out. So every cycle deposition has a interval that looks like
36:42 . That is productive, right? of course, once that was
36:46 then they knew how to selectively water uh rock that looked like 46 right
36:54 they're on to tertiary recovery where they're sweeping carbon dioxide through the rock.
37:01 , buddy, appreciate the setting. , so we're down the ramp.
37:06 where you get the critic fabric as , but you've got to do something
37:10 genetically. I've never seen anybody describe chalk fabric and a deeper water.
37:18 , ignore what I just said, not true. So just forget about
37:22 . But usually historically in a downdraft , you've got to do what you've
37:27 to delimit ties this fabric to create porosity. Okay, so usually that
37:33 demonization or it could be delimitation followed another fluid to create this kind of
37:40 of the of that fabric. Alright, so let's summarize the platform
37:46 is uh and ramp related wax stones pack stones is a setting. Historically
37:54 don't associate a lot of good reservoir to unless we know something's going on
38:01 . Alright, but the shallow restricted or tidal flat environments or the deeper
38:08 settings go out in front of the crest. They have potential here.
38:13 you've got to do something favorably die , either demonization or some sort of
38:20 limestone. Die genesis creating a digest fabric that we talked about. But
38:26 , don't forget that financial prosperity can locally preserved in some of these tidal
38:31 successions and can can yield hydrocarbon. that's a possibility. And you'll see
38:39 later today, when I take you judy creek in the Devonian.
38:44 the good news about the setting again this is where we get the multiple
38:49 cycles that are relatively thin. These are the classical 123 m thick
38:55 to repeat over and over again. The traps are usually strata graphic,
39:00 you saw there can be a fault , right? Either trap the hydrocarbon
39:05 also to drive the die genesis like showed you for the word field or
39:12 field. The seals are again, Mick rights or vap rights. And
39:17 said before the source potential could be issue, right? If your way
39:23 from the open ocean and you think kitchen is out in deeper water.
39:27 where you had some restricted or anoxic to generate tighter curving. Okay.
39:36 that's the list of the samples. right. Alright. Any questions about
39:45 play type? Why don't we take 10 minute break here Then we'll start
39:54 at 9:00. Okay, we're gonna up our discussion of the what I
40:03 the conventional play types by going through last type, which I refer to
40:08 basil or down the ramp mount Alright, so we're using the term
40:13 here to characterize any type of build . And build ups again can vary
40:21 scale from things that are a few ft thick to things that are over
40:26 ft thick. And build ups include you remember the enduring cloven classification scheme
40:32 ripple lime stones. The term mount can be used from anything from a
40:37 stone to a lower energy baffle stone that occurs either in shallow or deeper
40:45 . But here we're talking about relatively water buildups. Alright, so we're
40:51 about the transition from the platform margin the basin, but never in the
40:56 parts of the basin. Alright, this is where you come off of
41:00 platform and you start to ramp down deeper water. And this is the
41:07 where you can nuclear it and evolve , these different buildups. And the
41:15 of the buildups is controlled by strata age, because it all depends on
41:20 time period you're looking at. If looking at the upper paleozoic, you
41:27 have any uh Organisms capable of building thick buildups more than about 100 m
41:35 . So things like cry noise and zones and fileted allergy can't make these
41:39 thick buildups. Alright, contrast that what we have in the lower paleozoic
41:45 the storm atop roids, they can vertical pinnacle reefs are over 1000 ft
41:50 and corals can do the same thing deeper water. And for example,
41:55 tertiary. Alright, so this is you think about this from a player
42:02 , right? In terms of the of reservoir source seal and trapping
42:08 this is probably the most ideal carbonate type. Alright. You build great
42:15 thickness and in some instances, so thick the ferocity. Uh you
42:23 case this stuff in deep water, or shales or sometimes even evaporates.
42:29 so you end up with excellent graphic trapping potential. And if you're
42:36 basil carbonates or shales are the source , then you're really close to the
42:41 rock. Right? And arguably there's long distance migration, theoretically the stuff
42:48 migrate very quickly into that potential Alright, so this is really a
42:54 interesting setting here. If you appreciate controls the occurrence and distribution of these
43:01 of of build ups. Right? one of the key controls again is
43:09 topography that exists as you go out deeper water. I showed you the
43:14 line last weekend when we're talking about seismic expression of platforms and seismic expression
43:21 of ramps. And I mentioned that you go further out down the ramp
43:26 the into the basin, you start get this rollover effect. If you
43:31 on the seismic line here where the arrow is and I told you that
43:35 people mistake this to be like the crest or a ramp margin, whatever
43:41 means. I'm not sure what that . But but no, this is
43:46 a this is not a focus of water, High energy. This is
43:50 deeper water part of the system where rates of substance are starting to
43:55 And you see the ramp rollover. so that's creating some topography in deeper
44:01 . And it's actually this topography that up nuclear waiting a lot of these
44:06 called deeper water based anal buildups. . Whether it's the classical pinnacle reefs
44:12 the lower paleozoic or whether it's some these low relief upper paleozoic buildups related
44:19 things like Quran noise or Phil analogy things like that. Okay, so
44:25 that, appreciate that effect. The way to nuclear these things is to
44:30 structure, Right? Reactivated basement faults things like that that create bottom
44:37 And they too can be the site nuclear waiting these kinds of water buildups
44:42 deeper water. So let's just get into some of the examples here.
44:48 just gonna go through geological time here give you a feel for the way
44:52 build ups are put together. All . So, we're gonna start in
44:55 Devonian. This is Western Canada from . And you're looking at a ramp
45:02 . Okay. That goes out into deeper water. And that transition zone
45:09 the ramp starts to roll over showed on seismic is the fairway where you
45:14 all of these buildups developed. And this is a play type that
45:20 knew existed back in the Back in 60s. Alright. And it was
45:27 by serendipity that they discovered these plays this position right here. And that
45:34 usually typical. Once they discover the type, right? It's just a
45:38 of shooting a dense enough seismic grid find all the producing pools.
45:43 But you can see they're they're basically major trends here. The team in
45:48 trend here, brazo Over here. can see some of the numbers associated
45:54 these miscue pinnacle reefs. The issue one of five major carbonate mega sequences
46:01 are oil and gas productive in Western . Let me just show you what
46:08 things look like in core. These build ups are created by the
46:15 corals. Remember we talked about the types of paleozoic corals. The
46:21 corals, Little horn shaped corals. ? And then the tablet corals are
46:26 ones that are like soda straws are oriented. And they have mostly the
46:32 partitions like you see here in this piece. Alright. So a lot
46:37 internal porosity to begin with. But the lime stones which you see here
46:43 this photograph are not productive either because marine cement. So you see this
46:50 brown colored material between the corals. the situation where a lot of the
46:56 was plugged on the sea floor by cement. Alright. Or or typically
47:02 plugged by mike. Right, Because what are these things they're growing
47:06 deeper water and they're not high energy . Okay. And so what are
47:12 trapped in between their their branches? tracked mud. All right. More
47:16 a baffle stone. So envision these as a baffle stone and not as
47:21 high energy frame stone because they're in water. So the lime stones are
47:26 the reservoirs. Usually you have to something die genetically. You have to
47:32 ties this fabric. And so what you do when you have corals and
47:37 position with mud between what gets demonetized is always the muddy fabric. And
47:43 what do you do during the advanced ? You leech out the remaining cal
47:48 corals. In other words you produce that looks like this. Okay.
47:53 so this is that classical uh ferocity we've seen at different scales. For
47:59 lot of dramatized carbonates, right? you have by mobile or poly model
48:05 with big elements and finer sand or , it's always a finer grained stuff
48:10 gets demonetized first and then you reach the remaining in this case, corals
48:16 ? To create that porosity and So you can go to the core
48:22 in Calgary and have them pull out from this field and you can pick
48:27 a piece of rock about this long of core. Right? And you
48:32 look from one end to the other a telescope. You're just looking down
48:37 the leeched coral. Okay. And when you see a permeability here of
48:42 Darcy's, that's what it's related Okay, so that's the beauty again
48:48 dramatizing some of this refill fabric. have that potential to create the super
48:53 fabric. Okay, so that's an . And these were not strom atop
48:59 . These were the tablet corals. interesting that if you look at the
49:04 of the five mega sequences in Canada the cake river, they are pinnacle
49:11 related to as you go out into basin, but the, the,
49:16 major organism are strom atop rights. . and the three D.
49:24 that's been shot now in in the basins, in Western Canada, you'll
49:31 some maps of this later, all different little sub basins that occur in
49:36 . Um, these pinnacle reefs to reefs again occur as you come off
49:41 main platform and ramp down into the part of the basin. But they're
49:46 along that edge. Right? Not the deepest parts of the basin.
49:50 the seismic has been shot here shows a lot of these pinnacle reefs,
49:55 single pinnacle reefs here, our new on reactivated basement blocks. Alright,
50:01 the initial topography. And what does , What does that pay? Low
50:06 do for the system? Well, first thing it does is it localizes
50:11 Quran idle deposits. So you see here on the lower left, you
50:16 the purple at the base. Those deep water creek noise there. The
50:20 thing that occupies that paleo, high trap material. Right? They build
50:25 mounds. Okay, But they don't any, you don't have any reservoir
50:30 . But they shallow up to a . And then what do they get
50:34 by? They get replaced by deep . The term dendritic means little finger
50:39 branching corals. Okay, so these deeper water corals that take take advantage
50:45 that topography. On top of the droids. They create a little bit
50:49 topography. Then people think these corals need light. Right? So this
50:55 the I mentioned there are two types corals today, Hermit. Ipic,
51:01 the shallow water corals affirmative pick they that symbiotic relationship with the algae.
51:07 need the algae need the light. there a Hermitage pick the ones that
51:12 in deeper water. They don't need . Alright. And those are the
51:16 that make the famous jewelry. You the red and black coral that people
51:22 to buy. All right. And that's the thought here that these were
51:26 hermit typical types of corals. But built topography and once it gets shallow
51:31 for Strome atop Roids, then the atop rights come in. All
51:36 And there's a gradual showing that changed the morphology of the storm atop
51:41 So, we're going to talk about atop reefs here later in more
51:47 When I take you through judy you'll see usually the change in morphology
51:54 lateral right across the shallow reef, changes in energy and water depth.
52:00 here in these pinnacle reefs, the vertical because you're going from deeper water
52:05 shallower and shallower and shallower. so, your changes vertically and not
52:10 , like it would be in the water reef. Okay. And so
52:14 things started out as one well wonders where one well could develop something like
52:21 . But you can clearly see that things must have coalesced and sorry,
52:27 scale structures. Alright. Some of things take on a tall morphology.
52:33 right. And we know they build the sea level because they are capped
52:38 beaches or tidal flats. Alright. , they started relatively deeper water.
52:43 build up. They can build up sea level. You can see the
52:46 here. This one is close to ft thick there. Examples in the
52:51 river where some of these build ups over 1000 ft thick. Right close
52:56 1200 ft thick. All right, , again, another ideal setting,
53:01 . And what do these things get in? They get encased in either
53:05 water carbonates or actually in this they get encased in deep water vap
53:11 . And so the deep water evaporates the source for dramatizing fluid.
53:17 a lot of these pinnacles are Dolma and that's why they're productive. And
53:24 you know, I showed you last , I showed you some very subtle
53:29 D. Seismic data for the keg pinnacles where it's very difficult to see
53:35 mounted character. And here's the three seismic data where it stands out pretty
53:41 . So, these are actually pretty to find with the more modern Seismic
53:46 , although I think most people have them. Right, because this is
53:49 one of these 1960s plays right? nobody knew existed until they stepped out
53:55 exploration into the deeper parts of basins found these buildups. Okay. And
54:02 appreciate the faces changes are vertical and demonization over print. And what I
54:11 you to do with this diagram is compare the colors between the top and
54:15 . Right? So the deposition all reflects the gradual shoaling of the,
54:21 the strom atop roids. And then at the reservoir faces that mimics the
54:26 pattern, even though these rocks have demonetized, there's still a strong underlying
54:33 control on reservoir quality. Right? I would say in my experience,
54:38 is almost always the case with the . Right? The fluids that came
54:43 are controlled by the precursor fabric or precursor faces. Okay, that's the
54:51 river. Alright, so, so Devonian. Those are the two time
54:55 where you get a lot of these water pinnacle reefs related to the storm
55:00 roids. You get the greater vertical building effect where you get again thicknesses
55:05 1000 ft thick. I think I this before that. What happens at
55:11 end of the Devonian? There's a mass extinction. Everybody thinks to strum
55:15 top roids disappear. Well, they disappear in the upper but I don't
55:22 they they couldn't have gone extinct because show up again in the in the
55:28 . But but they certainly drop off a major reef builder in the upper
55:34 . So what happens in the upper during Mississippi and pennsylvania and permian
55:41 We have this play developed in a setting. But these buildups don't have
55:48 vertical thickness is alright if they get m thick, that's considered to be
55:52 thick. All right. And what's going on here. Well,
55:55 a change in the fauna. This is where the strata. Graphic
55:59 controls everything. So, let's start with the Mississippian. And let me
56:04 about the nature of some of these buildups. You can see there's production
56:10 another number of basins around the S. And Canada related to these
56:17 ups that are driven by basically baffle deposition. So cry noise and bright
56:24 trapping sediment. Some of the larger kids live with this stuff.
56:30 And this is the outcrop analog from Sacramento mountains in New Mexico.
56:39 if you ever drive up from el to uh to uh Alamogordo.
56:47 Which is near white sands that we're about. Right? The gypsum
56:51 Um You'll see the Sacramento mountains as look to the look to the east
56:59 the southern part of the Sacramento you can see these outcrops, you
57:03 walk up to them and climb And although it's quite an effort,
57:08 takes a whole day to do But but what you see here is
57:12 classical geometry, right? These look bread loafs. That's the classical geometry
57:17 these kinds of build ups right? can see they only get up to
57:21 100 m thick. They don't start like this. They start off tens
57:24 meters thick. And what controls the is where you sit along the
57:30 right? If you're too far up ramp still in deeper water where you
57:35 less subsidence, then you get the relief build up. So as you
57:38 further and further down ramp, increased allows you to make greater vertical
57:45 And this would be the sort of other end of the spectrum where in
57:52 in the subsurface and outcrop, we see these things get thicker than about
57:57 m. Okay. And if you at, if you look at
58:02 you can you can see some bedding the sides here. Alright, so
58:06 are two parts to these build There's the reef core occurs in the
58:10 . This is where you get the zones and the big foraminifera and some
58:14 annoyed. All right. And we these things got relatively shallow. They
58:19 to build up the sea level because actually see you can if you if
58:25 climb up here to the top you can actually see the member of
58:31 talked about some of the Bride's own is the fenice, traitor fan shaped
58:36 . They're sort of like the they're the sea fans that we see today
58:42 modern reefs occur in shallow, more environments that are influenced by a little
58:47 of wave agitation. You can actually on the top of this outcrop,
58:51 can see how along the seaward it's just all these prize owns lined
58:56 like this. All right. All growth position. Alright. And that's
59:01 at the top. So that's suggesting this thing was trying to get up
59:05 sea level. Okay, so that's reef core. And then you see
59:09 debris beds here. Those are created storm breakup. Right? And these
59:13 mostly Quran idle with some brides own mixed in and they get slapped off
59:21 any side of that of that build . Okay, so there are always
59:25 parts of these buildups. The so reef core, which is more than
59:28 baffle stone fabric. And then the beds which are more granted stone or
59:35 pack stone fabric. Okay. And skipped over a diagram in your slide
59:40 that shows us too sub environments with of the attributes of each one.
59:45 ? I'm not gonna test you on . Okay, so one of the
59:50 here with the Mississippi and is we lots of print roids and remember Quran
59:56 , zinnia, kana derm. The pieces of a Quran oid or or
60:02 a sand dollar or whatever. Each piece, right. Whether it's a
60:07 of a plate or a piece of spine is one single crystal of calcium
60:13 . And remember that's because it's one crystal, any sedimentation that occurs there
60:19 to latch on to that single crystal Quran Oid or anaconda term. And
60:25 produces what we called syntax calcite Alright. And unfortunately this is one
60:31 the problems with these kinds of creating quality is you have these Quran
60:38 right single crystals of Quran Lloyd's. end up being quickly cemented during die
60:44 by overgrowth or what we call syntax calcite cement. Right. And you
60:50 up that process relatively quickly and earlier the burial history. And so usually
60:57 condemns these kinds of deposits as having quality right? When their lives
61:04 Okay, now if you dolma ties , that's another, that's a different
61:08 , right? You can create the prostate but to create reservoir quality and
61:14 like this, you almost always have do what you have to have a
61:18 phase of burial limestone Dia genesis some acidic fluid coming through the leech.
61:25 , and I'll show you some examples this in a minute. Right.
61:30 historically, unfortunately, right. Crystal reservoirs are hard to find in the
61:37 record that have preserved primary porosity because this segmentation effect. So, let
61:44 take you through a couple of case and the first one in the mississippian
61:49 a field called Dickinson field in the basin. So we talked about the
61:55 basin yesterday we talked about some of tidal flats, cabin creek and little
62:01 field that occur in this part of world. Right? That's a more
62:04 dip setting. Um this is the part of the basin as you go
62:09 to the south and again back until mid-1990s, nobody knew this play type
62:16 in the Williston basin. Alright, was chasing shallow water carbonate plays up
62:23 . And then companies like Kanako as always do right. They start pushing
62:27 envelope with seismic exploration further and further deeper water. And in the mid
62:34 they discovered Dickinson field, which is here. One of many fields now
62:39 have been discovered and every one of fields produces from these downslope mississippian baffle
62:49 deposits. Okay, alright. And is the, is the more famous
62:57 better studied and published on. A of these things haven't been published
63:02 But you can see the data Scale is 100 ft 300 ft or
63:07 m is comparable scale to what I showed you for the outcrop and uh
63:13 , which was in the Sacramento moderately deeply buried. You can see
63:18 faces core and the flank and what you get in the Intermountain areas which
63:24 deeper water, you get that charity . The church is related to the
63:28 pickles that we've talked about. The punch pickles live in a little bit
63:32 water. That stuff gets dissolved early burial mobilizes, creates the church modules
63:38 things like that has no reservoir quality . Alright, so for Dickinson,
63:46 , the main reservoir is the limestone . These more MMA critic baffle stone
63:53 . But they produce because of a of primary and secondary processing. So
63:58 shelter ferocity, there's a secondary prostate and multi prosperity. There's some prostate
64:06 with the obviously the primary process of bright zones. And then of course
64:11 a little bit of fractures. so you can see the numbers associated
64:15 that. So in this example the stuff was tight here, the core
64:20 porous and other examples, it's the way. Right, the flank bed
64:25 productive, the core is tight. there are other examples where both some
64:30 are productive. Alright. So it depends on the digest history of the
64:36 . Right, Alright. And I over a couple of other examples in
64:43 slide deck that I'm not going to about Quantum quantum field uh is from
64:48 texas and Qana is the same de setting, but it works because it's
64:56 . The core is replaced by Okay, so that's the Mississippian right
65:04 by crying noise and bright zones. when we move up into the Pennsylvanian
65:09 permian, what do we see appear that we haven't seen in older geological
65:17 and which we will not see in geological periods. And that's that Phil
65:22 algae that we talked briefly about. first saturday we got together for the
65:28 friday. We got together talking about scale of the grains. Okay.
65:33 of algae, people suspect or some of green algae, right? Was
65:37 of a cabbage like morphology growing on sea floor. But then to segregating
65:43 these little plates. Okay. But they grow on the sea floor,
65:47 thought to baffle mud and trap sediment build make buildups okay. They're originally
65:53 genetic so they're prone to a lot secondary dissolution re crystallization. The most
66:01 field where you get this production is A field that occurs in the four
66:06 area in the Paradox basin, you're see it's exactly, excuse me,
66:19 the same deposition on setting down the coming off of a carbonate platform but
66:25 in the deepest part of the And you can see the reservoir.
66:32 The buildups again are made up of fileted algal battle stones and debris.
66:40 what's interesting here is that these things capped by Hewlett grain stone.
66:46 And again, so that tells you you're not in incredibly deep water.
66:51 ? If you cap these things with brain stones. So remember if they
66:56 they are green algae, they need to grow anyway. Right.
67:01 And most of our, most of green algae that I talked about,
67:04 alameda today occurs in pretty shallow right? 10 tens of meters 10
67:11 of water or less. But theoretically and calculus green algae can live down
67:17 about 100 m of water depth. , so today, now we don't
67:21 what it was like back in the record. But but the fact that
67:25 see the philadelphia buildups capped by Hewlett stone tells you they didn't start off
67:30 incredibly deep water and that they did they shall load up right into the
67:35 where you could convert that stuff to high energy galactic grain stone.
67:40 so you can see the numbers associated this good porosity values, good production
67:46 . This is one of the bigger that produces out of these phyllo algal
67:51 . Here's the fizzy graphic setting. coming off of the carbonate platform over
67:56 to the southwest, we're ramping down the basin and you can see again
68:01 classical repetitive cyclist city where you go the yellow Philip algo build up to
68:08 cap analytic grain stone and then it repeats several times. Okay, so
68:14 the other part of the story here there is a cyclist city to these
68:18 ups. Alright. It's not just thick build up a lot of times
68:23 repeat. Okay, so appreciate that . Okay. In fact, if
68:31 look at geological history, going back the lower paleozoic, the evolution from
68:37 to fuel light is actually very, common. Okay, But it only
68:43 because of what? Because of the winds. Okay, because in the
68:47 Bahamas driven by oceanic conditions, It one or the other. Right?
68:53 in other words you couldn't have, couldn't have a reef and you would
68:57 behind it. That pro graded out top of that reef. Right.
69:00 would be impossible in the northern Bahamas . But in a trade wind system
69:06 could have that where it pro grades you could convert from vertical evolution of
69:10 reef get shallow enough and then let trade winds start converting that debris into
69:16 . Okay, so we actually see all the way back to the
69:20 Alright. And it's very common all geological time. And of course I
69:25 you we see it today right in modern still. Alright, so just
69:30 want you to see what these rock look like because I don't have any
69:33 to show you from and I've never with. But I can show you
69:37 from east texas, West texas. , This is the eastern, what
69:42 call the eastern shelf which is really a ramp again in west texas.
69:50 know where Abilene is in west Right, This is a neighborhood.
69:58 me. Mhm. And you're coming what is essentially the land to uplift
70:06 to the way off to the to right of this map and you're ramping
70:11 into deeper water. You're coming down the middle and base and remember where
70:15 central basin platform was in the Well in the pennsylvania, it didn't
70:23 yet. Right, Excuse me. we're ramping down and remember that transition
70:34 where you start to roll over with subsidence. That's where you get this
70:38 again of these down slow buildups. locally these are this is the strong
70:43 of the pennsylvania and these are fileted buildups. They're only about 100 ft
70:49 and they're not they're not huge Alright. Again, an independent would
70:56 a lot of money off of something that. But I want you to
71:00 that the fabric looks like this at time of deposition or shortly after
71:04 It's a mixture of Phil, Lloyd , which is all these potato chip
71:08 fabrics. Some cry annoyed some logos that you see or that's a baffle
71:14 texture. All right. But that's gonna be productive because it's impermeable.
71:20 ? Or it doesn't have a lot permeability. So you have to do
71:23 die genetically. And you can dolma this fabric. But most of these
71:28 produced because of favorable limestone dia So the first thing that happens is
71:35 magnetic fabric dissolves out to give you of the multi porosity. But then
71:41 a lot of the stuff is over by barrel dissolution. You can see
71:48 in the core here, there's a light that cuts this fabric all the
71:53 colored fabric you see here is highly and all the darker gray stuff is
72:00 . Just look at the the process fabric right? How well preserved.
72:05 across, up to and across. actually cutting parts of the style
72:10 That's that cross cutting relationship. That to the style light. That suggests
72:15 this is barrel dissolution. Alright. then what do you see in these
72:19 ? You see leaching of calcium fabrics , which is consistent with burial
72:25 Okay, so I wanted you to and this would look like this.
72:30 . And this field has this, kind of fabric. Alright. And
72:34 thin section it just looks like a . Right? You see all these
72:38 fabric and Prasit e what are the pieces? What is this dark
72:43 These are the you probably don't remember , but the mic, right envelopes
72:47 you develop around some of these precursor grains. Right? When they sit
72:52 the seat floor, they get criticized , right envelopes preserve what happens to
72:58 non my critized inner part of the , it gets dissolved out to create
73:03 porosity and then some of that back with cement. Okay, so this
73:08 all part of that Philip algal Alright, alright, and then just
73:15 finish the story here, this is is a little bit of a confusing
73:19 here, but that's basically the central platform. Again, this is the
73:25 basin. We were talking about uh of those philadelphia mounds in this position
73:31 here, if you go to the end of the midland basin, there's
73:34 big structure called a horseshoe atoll. . Which is obviously structurally controlled.
73:43 there is Pennsylvanian age philadanco buildups associated this as well as build ups that
73:51 more Quran idol. All right. I'm going to show you some data
73:55 a field here called Salt Creek where production is not from the fileted
74:01 There's no filler and algae. It's Lloyd's and fluids. The new.
74:06 stacking over and over again. But look at the distribution of these
74:11 right there. Mostly nuclear waited along eastern side. Okay. And that's
74:20 paleo trade wind direction right during the . That was a strong easterly trade
74:25 effect. So again, I don't this is fortuitous. Alright. And
74:30 see there's very poor low production There's a few fields on this
74:34 but most of the production, most the pool development is on that eastern
74:39 . You get a number of these reefs developed here sack rock is probably
74:45 of the bigger ones. All right. And these built up close
74:50 sea level because they're capped. Oftentimes analytic material. Right? You go
74:54 either fileted algae to you as you from crying nodal buildups to you.
75:00 okay. And so you get this cyclic city. Okay. And that's
75:08 to be expected. Right. And gonna be that. There's gonna be
75:13 internal uh distribution of the porosity controlled that deposition of cyclist city.
75:21 Alright. So let me show you rock data from Salt Creek. Just
75:25 finish up this part of the It's one of the smaller 250 million
75:30 oil field and some of the fabric from Quran nodal material. But look
75:39 the you see the porosity, there's of the Quran roids. Alright.
75:45 there's dissolution of fabric between the Quran and the limestone. Okay, see
75:51 fabric here. This is barrel right? It's barrel dissolution because the
75:56 Noise were already sutured when they started be attacked by some sort of acidic
76:02 . Right, So I said, , if you want to get crossing
76:06 criminal fabric, you've got to either ties it or you've got to reach
76:13 . Remember beach in freshwater. So this has to be barrel
76:20 some sort of asset fluid coming through it goes after the calcification range.
76:26 see the leaching of the cal citic , south of the walls of the
76:32 are dissolved a lot of times. don't appreciate that in a normal thin
76:36 , you don't see that ferocity, when you throw the white paper technique
76:40 it, you see that micro Same with this stuff. Even some
76:44 the muddier fabric is riddled with secondary . Again, look at all the
76:49 solution seems to run through that the that you have a high degree of
76:54 secondary micro porosity. Despite that pressure again, is the argument that this
77:00 burial dissolution. Alright, And then sort of the clincher right there.
77:06 style lights floating in that micro You can see the leaching of Democratic
77:12 leaching to some of the Quran odle . Right? So I suspect nobody
77:18 done a detailed study of Salt but I suspect that part of the
77:22 here is the faulting again, to the conduit, but that's something to
77:27 worked out later on. Okay, is one demonetized field in this trend
77:34 Reineke that I'm skipping, but you the slides there, right, That's
77:39 old chevron field. And you can here for Salt Creek what caps the
77:44 reef sequence politic grain stones again, . And some of that stuff has
77:49 . And some of these some of yields hydrocarbon as well. Okay,
77:54 one field that is dramatized all the of those fields that I talked
77:58 our limestone. Alright. And another sequence where there's pinnacle reef development is
78:08 Jurassic. Okay, again, up the 1990s, nobody knew that this
78:15 type existed in east Texas. This discovered by accident. We're just pushing
78:22 in to the deeper part of the . So, I'm going to show
78:26 some of these these gas fields that associated with the pinnacle reefs. They
78:32 from a mixture of these Calgary sponges corals. And some people think there's
78:38 microbial over print on some of this . Look how deeply buried this stuff
78:43 14-17,000 ft. And the heights again from 100 ft to 1300 ft.
78:50 , that's controlled by your position on ramp as you go into deeper
78:55 Greater substance, greater thicknesses. And yeah, some of these things
79:01 to explain the difference in the The problem here in east texas is
79:06 highly over pressured. And what that is it's very difficult not only to
79:12 them, but it's very difficult to and recover rock data. Okay,
79:17 for that reason, they're very poorly from both the deposition allow and die
79:23 standpoint. Okay, so I showed talked about east texas salt basin yesterday
79:31 we were talking about the Jurassic upper , Haynesville or Gilmer limestone, analytic
79:37 stones. I told you there was stone deposition on the western flank related
79:42 salt tectonics. And then we talked the other flank over here on the
79:49 , where you got those linear sand systems that pro graded to the east
79:54 a deeper water basin. This direction . Okay, and where people discovered
80:01 pinnacle reefs, That's on this side the basin, which interestingly turns out
80:05 be the windward facing side of the . Alright. And so I was
80:12 yesterday about the shallower part of the up here. Do you remember that
80:17 ? It was there was a bunch yellow blobs that I said, we're
80:21 related to salt related structures. Either punch ups or salt withdrawals and
80:26 one of those features had an soul with it. All right. And
80:32 those were discovered. And then companies marathon and the Amoco. And then
80:38 some other companies, they all pushed expiration down the ramp into deeper water
80:44 they found this fairway of pinnacle Okay. And you see what they
80:50 the term shelf edge here. What that mean to you? Shallow
80:55 Right. Break off, drop off deeper water. No, that's
81:00 There's just no shelf edge because this a ramp. This is where you're
81:04 like this again. And the subsidence starting to increase. That's that rollover
81:09 again. Alright, this is out deep water. This is not a
81:12 called shelf edge or platform margin. . Ah but this is this is
81:19 seismic on which that is based, ? They see they see this stuff
81:23 like this and they see this feature here. Well, that's that deeper
81:28 rollover effect we've been talking about. . And so they recognized up dip
81:33 clinical reefs here. They recognize pinnacle here at their so called shelf
81:39 Now, these are the pinnacle reefs are 100 or a couple 100 ft
81:43 . Right? Because they're more up less subsidence And these are the ones
81:49 get up to 1300 ft thick. then you get too deep and you
81:53 you lose the pinnacles. Okay, there's still part of that ramp profile
81:57 not a deep water basin, but thickness is controlled by position along that
82:02 ramp. Okay. And there is little bit of rock data has been
82:07 and published on. And this is can see what dominates these things
82:13 cal correa sponges. There are these like corals, right? So called
82:19 or branching corals. Remember in our model, they occur in deeper
82:26 right? Or they current shallow protected . But this is that deeper
82:30 So they don't like to be in energy. Right? So they
82:34 So these are deep water reefs at to begin with. You see
82:38 All right. And because people see debris, they assume that these build
82:43 made it up to shallow water. there's no evidence that they got up
82:46 beach or tidal flat. The fact you see this debris doesn't really prove
82:51 right. It just proves there was big storm. Okay, They tore
82:55 stuff up. You know, if go if you go look at modern
83:02 today, right? You go out the deeper parts of these reefs.
83:05 the sperm group structure we were talking the other last weekend, Shallow set
83:12 set that goes down to about 45 ft of water. If you snorkel
83:16 those on a day where there's a swell coming in in the winter,
83:20 20 ft waves are breaking over the . If you snorkel down in that
83:25 spur and groove. You see that being actively rippled in 100 ft of
83:31 and 50 ft of water. that's just the day to day,
83:35 swell. Okay. Imagine what a when a hurricane comes through, how
83:40 that effect is gonna penetrate. All , So it's not uncommon in these
83:45 reefs. You see this even in Devonian that I talked about before for
83:48 keg river, you see these grain beds all through this build up.
83:53 ? That doesn't mean it built up shallow water. That just means that
83:57 impacted by these major storms. But it's because people see this grain
84:03 that they think you build up into reef flat or something like that.
84:07 . I'm trying to caution you that too deep to do that.
84:11 I mean, you could do but nobody has shown that you've actually
84:14 up into demonstrably shallow water environment. . All right. I guess we
84:26 some power outages here or something. that's good. Really weird.
84:34 everybody appreciate what I'm saying. So are these are classical painting reefs and
84:41 they're highly over pressured. So it's to get a lot of good rock
84:44 to to look at. But this some of the published fabric. All
84:49 . And then the timing of the genesis. Again, part of the
84:53 why people thought this built up into water, was they see this kind
84:57 fabric where the corals are leached Right? Remember the corals are
85:02 See the Mc right envelope again goes the edge and then the lead the
85:07 gets leached. Alright. And people , oh, that's fresh water.
85:12 . I must have built up the level. Got exposed in fresh
85:15 That's the old mindset. Again, secondary prosthetic waste of fresh water.
85:20 I've showed you that this process could created during shallow burial and not have
85:26 to do with exposure to fresh Right, And then look at
85:30 These are these are calcified grains that leeched. Right? There's your red
85:34 that there's something else going on here leach that calcium fabric requires acidic
85:40 All right. And there's lead zinc in this stuff as well. There's
85:45 stage saddle dolomite. Sorry, look the this is a shallow water refill
85:51 . Why are the coral lights plugged nick. Right, okay. See
85:55 doesn't make any sense. Right. you're in a shallow water, if
85:59 build up the shallow water, all Mc. Right. Should be winnowed
86:02 . Okay. The fact that you've the here in the deeper water setting
86:08 these things are are growing. I just want to appreciate all the
86:14 skewed towards this. These reefs building close to sea level early die
86:19 But I don't think that's consistent with setting or with the fabric.
86:25 nobody explains the late stage saddle Nobody explains the lead zinc mineralization.
86:32 ? There's some of this foul, that I was talking about comes in
86:36 a late stage cement or replaces the . Lot of dissolution. Democratic
86:43 Well, that's exactly what you'd expect be attacked by aggressive acidic fluids.
86:49 . Small scale fabric gets is more dissolved out than the coarser grain
86:54 Right. Alright. Food for All right. And then the last
87:00 here in the smack over is remember talked about the polls yesterday in Arkansas
87:07 . Right. And they build They programmed out but out in deeper
87:13 . If you create some basement you can actually put buildups on that
87:18 topography that our time equivalent to the politic shoals. Or if you have
87:24 , if you have salt tectonics and water, you can do the same
87:28 of thing. You can put wreaths top of some of those buildups.
87:31 . And so Cardinals is not a field, but it's the best documented
87:40 from the smack over. You can of see it's these are low relief
87:46 . They're made up again of the sea operated fabric and debris.
87:51 but they're taking advantage of that structural . Okay, Alright. The last
88:01 to talk about here would be the you into the tertiary. So if
88:06 ever get involved in working Southeast There are 15 sub basins in Southeast
88:13 that are oil and gas productive from and three of them have major production
88:21 these clinical reefs. Alright and North Sumatra basin is one example,
88:29 basins. Another room field is a gas field with 11 to 17 TCF
88:36 gas in place. This is mobil's , It was just basically mobil oil's
88:43 cow for decades. And then what in the 90s production started to drop
88:49 dramatically? I don't think it's fortuitous that's about the time when mobile merged
88:55 Exxon right to create Exxon mobil. I'm going to show you that data
89:01 a room field in a minute and Qasem Utara is a is a one
89:07 these pinnacle reefs that produced up to barrels of oil a day.
89:12 so these are prolific hydrocarbon reservoirs. mostly Miocene age. They're they're conical
89:20 to 1500 ft thick but they clearly to create these bigger structures. They
89:28 from Coralville frame stones and associated which includes some of them a critic
89:33 . So the mic right, also riddled with secondary prostate. That's the
89:37 port type source rocks are older or equivalent based on lime stones or
89:43 Good strata. Graphic traffic relationship although many of these are structurally controlled
89:49 by the basement faulting. That's what off the build up. Okay.
89:54 so appreciate the setting Again, we're off these Miocene carbonate platforms. So
90:00 could be carbonate production associated with the . And then you come down the
90:05 right? You ramp down into deeper . That's where you get all these
90:08 blobs of pinnacle reef deposition. Less thick as you are. More
90:14 , dip thicker as you go, down, dip. A rune is
90:18 famous example. Look at the size the structure, you can see the
90:23 that's five km right? So this a huge structure. Probably not one
90:29 reef to begin with be my guess stuff coalesced, shed debris and coalesced
90:36 up to 1200 ft thick. And appreciate the reserves here. It's not
90:41 the gas, but almost 800 million of kind of say. I
90:46 that's a lot of money. All . And again, high degree of
90:53 . All the white. You see diagrams of core pieces is microprocessors.
90:58 there's microprocessor. We in the there's microprocessing Democratic matrix. All
91:04 I mean, this prolific reservoir. , so, lots of examples like
91:09 in Southeast Asia. Alright, so summarize again in this setting we're generally
91:17 with. Unlike what we saw for platform, mound carbonate up on the
91:22 . Where was pancake shaped? Not a lot of vertical thickness,
91:25 great areal extent here. It's the way around. Right. Great vertical
91:30 , but not a lot of areal unless they coalesce into bigger scale
91:36 H determines the scale as we talked . Right, if you play the
91:40 paleozoic Mississippi and through Permian, you not going to find thick buildups
91:47 Greater than 100 m. Again, faces donations to be expected. Not
91:54 laterals O nation. We get in shallow water reef system. Same point
91:58 reservoir quality being tied in depth of , die Jack history. Excellent
92:03 Graphic trapping potential. The seals are the time equivalent or slightly younger based
92:09 limestone, shales or evaporates and source is not a problem. Right?
92:14 out there close to the kitchen. , arguably primary migration into some of
92:20 buildups. Alright, I think we've about just about most of these.
92:25 showed you the seismic data uh last from Libya, right. For that
92:33 uh called idris. Our interests are ft of build up with 1000 ft
92:41 pay over a billion barrels of oil place. Right, Alright. Any
92:47 about this last conventional play type. , let's if there's not, let's
92:58 let's take a Take another 10 minute or so. So, about five
93:05 after 10, we'll start back All right, okay, so,
93:14 just gone through the five conventional play and again, just to reiterate,
93:20 call them conventional because historically these are plays that companies have chased either because
93:25 their fizzy, graphic setting or because their seismic expression or both. And
93:33 we're going to get into a discussion the three unconventional plays are listed
93:39 The force of carbonate deposits, the de positional chalks, and then the
93:44 control digest place. And so let's first with the four soap carbonate
93:52 And I showed you this uh cartoon we talked about modern carbonate environments.
94:01 . And we're talking about uh baseball . And what happens when we come
94:07 of the basin and come up toward edge of the carbonate platform? We
94:11 into a situation where the closer you to the platform edge, you start
94:16 see mixing of material derived from shallow with the deepwater background sediment, which
94:24 be represented by gray in this diagram . And obviously the closer you get
94:29 the platform edge, the more you the coarser and coarser grain fabric.
94:35 , and then what was the other we talked about as the stuff gets
94:38 off into deeper water, it can into thicker packages. Right? So
94:44 storm layer basically superimposes carbonate sand or debris on other debris. And you
94:52 up building these thicker and thicker All right. And we talked about
94:58 key the orientation is right. It a big difference whether you're on the
95:04 or windward side of a platform, sides or the sides that preferentially shed
95:10 of the material for a given unit time. The shedding is controlled by
95:16 prevailing wind systems and obviously major storm ? But the strength of the trade
95:25 determines the scale of the sediment that off. Right? So, you
95:31 , now the general easterly trade winds only push carbonate mud and still size
95:36 persistently off that leeward margin, stronger winds system like we talked about for
95:42 can shed that material but also bring lot of carbonate sand as well.
95:48 right. And the shedding again is at point sources, it's along the
95:54 of the platform, anywhere along the . So we call this line sourced
96:00 and material just doesn't come from the of the platform. It can come
96:04 more platform interior settings and have had material pushed over the edge as
96:10 All right. So, Uh, know, in this model, the
96:16 element is the proximity to the trade influences. Okay, so you have
96:22 be in that belt between 5° and on either side of the equator.
96:28 you're in the doldrums, right, on either side of the equator.
96:32 can't use things like winds to push and you can't use things like hurricanes
96:39 push sediment into deeper water. you've got to come up with some
96:42 mechanism. Okay, that's why it's critical if you're chasing this play to
96:48 about your paleo geographic setting. and where your basin of interests at
96:53 to the equator. Was it in doldrums or was it outside the doldrums
96:58 then, you know, that's gonna how far away from the equator will
97:03 how strong those trade winds were. . So I'm gonna actually contrast this
97:10 a couple of different case studies. famous case study is the, is
97:16 to the field we talked about in yesterday, uh that produces from rudest
97:23 along the leeward margin of the golden atoll or platform. Alright. We
97:29 this discussion yesterday about why these reefs because of the trade winds and a
97:34 central lagoon. We also talked about course modification of that play. All
97:40 off of this. On the western are a string of fields here shown
97:43 red. Alright. And the biggest most well studied is poza rica field
97:49 occurs in this position right here in rica produces from a wedge. Another
97:55 of these on lapping wedges of shallow derived rudest material. Okay, and
98:05 , the source of this material is the roofs up on that leeward margin
98:10 shallow water. Right? And so storms that break up these rudest reefs
98:16 obviously push some of that material into water. But once they break up
98:22 rudest reefs to generate the grain as I showed you for keiko's platform
98:27 day to day, stronger trade winds also do what they can push that
98:31 sand over the edge into deeper Okay. And again, if you
98:36 at the paleo geography for this time the middle cretaceous were at 15° north
98:42 the equator. And that's in the of the strong easterly trade built.
98:46 right. So, yeah, east historically don't shed when we're facing open
99:00 facing sides Historically don't shed a lot material into deep water. They tend
99:05 have it thrown back up behind the in the shallow water to make the
99:09 flat. Okay? They say you have reefs. There are reefs and
99:19 can see some produce. Okay, let me see what I've got coming
99:24 here. No, I don't have . But I can I can go
99:29 and address this issue in a Let me do that in a
99:39 Okay. There are reefs on that . Okay. But they don't shed
99:46 the same degree. I've already showed a couple of times in earlier
99:53 I showed data from the Bahamas. data. The Bahamas where the little
99:57 coalesced and they asymmetrically shut off the side now. And the wind.
100:02 facing side. There's hardly any shedding off of that. Okay. And
100:07 showed the same thing for Western Um All right. The old concept
100:13 they shed equally. All right, that's not true. Alright.
100:18 it's always a symmetric shedding. And always great to stop the leeward and
100:23 off the windward side. Okay. , I want to come back.
100:32 go back to an earlier lecture and the slide and let me go through
100:36 and then we'll come back and address issue. Alright, so poza
100:42 Is this red wedge right here? right off of the leeward margin and
100:48 can see it's really thick up against platform and then it tends to feather
100:53 . Alright, so this is a diagram that shows that, look at
100:56 scale that's 200 m. So that's 100 about 500 m thick Right
101:03 Okay. And then over a distance 2468, maybe 10 miles, it
101:11 right? It feathers out into the water carbonates. The Nueva is equivalent
101:18 the eagle furred in texas. All , so that's a basin on
101:23 probably organic rich. And that's probably only the seal to the post.
101:30 everything's tilted. Remember we have the tilting. That was the previous diagram
101:34 that So that wedge of material pinches into the deep water away to
101:43 so it's structural strike a graphic trap it's also probably close juxtaposition with a
101:49 source rock. So the oil is coming from the Nueva or it's coming
101:54 the upper Tamaulipas and deep water Alright, so, appreciate the
102:01 Right now. This is not one event that can't be All right.
102:07 has gotta be multiple events of All right, and not all of
102:13 has to be storm related. Some this could just be the day to
102:17 trade wind effects that we've talked This is exactly what we see on
102:22 persistent shedding on on a windier Okay. And we know that this
102:27 is shedding a deep water because these features right here are lenses of pelagic
102:34 . Alright, There's actually an old published back in the 70s that claimed
102:38 the to Barbara Limestone was a low reef. All right. That you
102:44 sea level and that's why you got up here. Alright. There's no
102:50 that scar certified, But they argue by dropping sea level, you just
102:55 shift your reef down here. All . Just because you change sea level
103:00 mean you magically shift these belts. had this discussion uh, last
103:05 Alright. So, I've looked at . I'm gonna show you what this
103:09 looks like in a second. There's evidence for it is that you reach
103:12 . You don't see reef cores surrounded grain stone debris. You see grain
103:17 debris mixed in with little lenses of pelagic limestone. So, here's the
103:24 for post a recon and I'll show what the rock data looks like.
103:28 , it's made up of producers from turbo tights and debris flows,
103:34 the average process is only 8%. a mixture of primary and secondary processing
103:39 seals. As I talked about our online mud stones combination trap source rock
103:46 debated, but it's an offshore All something. It's either the Tamaulipas
103:52 or uh I wouldn't wave of water . The published reserves are 2.7 billion
104:01 , but you saw this number on diagram. Uh Bureau of Economic
104:07 which is here in texas. Which was supposed to be a the
104:15 arm of the state, right? keeping tabs on the state owned lands
104:21 west texas. Alright, keep I this before. They've actually turned into
104:27 worldwide consulting company now and uh, doesn't make consultants like me very
104:32 right? Because they're taking our but they got involved in a newer
104:39 study of the Costa rica field. shot new seismic back in the Late
104:47 . All right. And now the have been bumped up to 4.5 billion
104:52 of oil in place. All this is a field that's been producing
104:57 1930, still producing a little bit oil. Alright, this is what
105:07 the reservoir faces looks like in Right? When I was with
105:12 for some reason, we got a to look at a bunch of uh
105:16 scores in Houston and this is one them. All right. And the
105:22 , the brown that you see here not mud. It's oil stain.
105:26 , so this is this is the stone breakdown material. The rudest
105:32 Okay, there's no mud in this here. Every once in a while
105:35 find little black lens of pelagic Okay, this is what it looks
105:41 in thin section. This is the product of the rudest. We talked
105:45 the rudest or principally or a genetic they break down under these smaller pieces
105:51 are fortunately outlined by the Mc right that we've talked about, right,
105:56 formed on the sea floor. And later the stuff got introduced into deeper
106:01 and later it dissolved out. And of course nobody knew how this
106:08 in deeper water. But we had discussion now that this is probably due
106:12 that marine barrel die genesis during shallow . The Iraqi starts to dissolve
106:18 It gives you the secondary multi process is the blue color. The red
106:23 is primary inter particle ferocity with good . The green would be isolated,
106:30 intra particle ferocity. Right? So is what poza rica produces from.
106:35 right, I do have the Okay, good. So, so
106:43 at we, we talked, I you this diagram yesterday and we're trying
106:47 explain the reefs. Right? You reefs on both sides. You get
106:52 reefs on this side obviously because it the open ocean. And then like
106:57 told you, we see this on the trade winds accentuate the barrier reef
107:03 platform margin reefs. They really make thrive better. Okay, so that's
107:08 surprising. Alright. And then we about why you get this reef over
107:13 now. This makes perfect sense. on the Caicos bottles I just talked
107:17 earlier. Right. This is the you'd expect to shed most material.
107:21 question is why don't you get you get reefs on this side here?
107:25 remember everything is structurally tilted like So Pemex thinks that most of these
107:32 that are below the oil water contact they've given up on them. All
107:37 . They think they're wet. All . I think they missed a play
107:41 . Because what do you get as I said on the leeward margin.
107:47 reefs tend not to shed material in deep water. They tend to throw
107:52 back to make that mature reef It is one or two kilometers across
107:57 scale. Alright. So most of shedding on this side should be back
108:01 , into the lagoon. Right. then factor the structural tilting.
108:07 that ferocity is going to do what going to pinch out into the tight
108:11 . Oh, sediment. So I there's a play here that back here
108:17 Pemex has given up on. All . They don't realize they just assume
108:21 . I think they assume that there's shutting off both sides. But they
108:26 play this side because they think it's the old water contact. Okay.
108:31 I told you I taught there 10 ago. I didn't tell them this
108:36 it's not my job to tell them to do their work. All
108:39 But I think they really have a here that they could go back and
108:43 somebody could figure this out right, could come in and tap that
108:47 but not the reef, the debris it. Okay, So see this
108:55 was published by Ted Cook. He the chief geologist Rochelle's uh Rochelle here
109:00 Houston. And he this paper was all the different cretaceous plays around the
109:05 rim. He put taylor's here. put the question, I took his
109:10 . Taylor's out when I photoshopped this read through it. And I put
109:15 question mark here because I don't think equal shutting on both sides. I
109:20 , again, I've already already demonstrated with some other examples. Okay.
109:25 right, everybody appreciate, So, wind system. You expect the trade
109:31 to work in your favor off the side, especially when there's a strong
109:36 trade winds. Right? And on windward facing side, you don't expect
109:39 shed a lot of material this You expect to have it thrown back
109:43 behind the reef and shallow water. right. Now There are examples of
109:49 . So deposits in the rock record the Permian. Where when you look
109:55 the paleo geography, the paleo geography you're not in a strong easterly trade
110:02 belt. So you can't use trade . You can't use hurricanes to explain
110:08 shedding. All right, so what's on here? So let me bring
110:12 back to west texas. So you a feel for the lay of the
110:15 . Now, there's a central basin , there's Northwest shelf, Delaware
110:22 midland basin, horseshoe atoll sits up . Alright, actually, right here
110:28 then this is that eastern shelf that talked about before. Okay. And
110:33 see the yellow maps, the distribution what are called Wolf Camp or less
110:39 Guardian or Leonard is the oldest Wolf Camp and Leonard are the older
110:44 aid sequences in west texas. All . And you can see the
110:51 This is the last latest data I've . So it's pretty old. So
110:56 sure it's higher than 200 million barrels . But um let's talk about,
111:03 talk about this play. Alright, paley geographically, when you look at
111:07 midland and Delaware basis for this time the Permian, the paleo geography maps
111:12 you're right along the equator. so if you're right along the
111:17 you can't be influenced by strong trade or hurricanes. And so what I
111:23 curious to to see the distribution of producing fields to see if they showed
111:28 relationship between one side or the other respect to the basin margins. And
111:34 I've just plotted it up here. are examples in the subsurface that produced
111:38 these forces of debris units. And don't see any kind of relationship
111:43 which excuse me, I wouldn't Okay. Because there's no there's no
111:50 with respect to the strong trade Alright. So remember what we're talking
111:56 here, we're talking about anything from of material shut out into the basin
112:02 carbonate sand coming out into the basin amalgamating into greater thicknesses like I showed
112:08 for post a recon. Okay. uh if if you can't rely on
112:13 trade winds, what are you left ? You're basically just left with something
112:18 earthquakes. Okay, that mobilize sheller parts of the profile and in combination
112:27 something like a tsunami could move that from shallow to deep. Okay.
112:33 you've all seen what a tsunami Right. If you remember the one
112:37 Japan years ago. Right. Remember wall of water that moved in,
112:42 up houses and busses and moved it . But then it turns around and
112:47 pulls it all off shore. so that's the kind of energy that
112:51 would be talking about in a tectonic active earthquake belt. Okay. And
112:58 that's the thing I want you to about right tectonic activity, earthquakes and
113:05 some of the studies that have been for these permian examples in outcrop in
113:10 texas shows that these things are mobilized shallower water and then they moved down
113:18 these channels, right, distributor very . And they shoot off into deeper
113:24 ? They shoot out into deeper water they run out of gas.
113:28 And then what do they start doing multiple events? They start building
113:32 They built topography, Which is Okay. And this topography gets thick
113:38 to have seismic expression. Alright. I think you can see that anywhere
113:45 this profile from shallow water, even the slope, you could reactivate
113:50 Right? And bring it down. it out into deeper water.
113:54 So I want you to appreciate the of the line is the development of
114:00 kinds of features here that look like on seismic. Okay. See the
114:08 . See how they map out on seismic data. All right. And
114:12 see these enclosed contours and they see isolated fix. And what's the word
114:18 comes out buildups, Right. these are in situ buildups,
114:25 In fact, I've been involved in study here with the client here in
114:29 . Right? He he called me and he said I've got I've got
114:33 build ups out in the middle of middle of the midland basin. I
114:37 really in the middle, deeper Yeah. The deeper part. And
114:42 I want you to take a Right, tell me what they
114:46 And I've seen this on seismic. got some core data and the seismic
114:52 just like this. Okay. But was a little suspicious, right?
114:55 this is too deep a setting. what is, what's the background sediment
115:00 in the middle part of the middle . It's black shale. This non
115:04 carries black shale. Alright. That's the kind of world you want to
115:07 in for reefs, right? For . So I went and looked at
115:12 stuff and I'm gonna share you share you what some of this stuff looks
115:16 . They're a couple of published fields . They give you a feel for
115:19 this is. It's basically debris. ? Sometimes it's cemented material, sometimes
115:26 blocks and people have actually described blocks size of houses that get moved out
115:32 the middle and basin. But most it is finer grecia sedimentary Greta and
115:37 grain stone debris. Some of it limestone. Some of his demonetized lot
115:42 complicated die genesis. But this is some of the rock looks like in
115:47 . So this is from my clients . I can't tell you exactly where
115:51 is or anything. But uh, his permission, I'm showing you the
115:56 data. And so you see this sedimentary Gretchen. Okay, this is
115:59 die genetic Bridget. So this is that probably was starting to be cemented
116:06 the on the slope, right? then got reactivated by tectonic activity and
116:13 re mobilized and moved down And these are coming from all over the place
116:19 on differences in composition and texture. some as you'll see come from shallow
116:24 , some of it's coming from react remobilize slope buildups and things like
116:29 You see how the black shale gets up in this. So that tells
116:33 this stuff is being shut out into world of the black shale. Sometimes
116:38 graded normally graded right? With the wretched class at the bottom and find
116:44 wretched class toward the top. Sometimes see it the other way around.
116:49 right. Like you see here where finer grain and then this is probably
116:52 episodes, right? This is the of one episode in the start of
116:58 . Of course the grain episode coming and then sometimes you get these impressive
117:04 of grain stone intermixed with the black Calgary, a shale and some of
117:09 are up to over 10 ft thick great ferocity. Alright, that's probably
117:14 one event. Again, that's probably couple of amalgamated events. Okay,
117:19 you appreciate what's going on here, . And this has to be driven
117:26 some sort of tectonic activity. You know, we don't really understand
117:30 very well and what they do to yet, but I guess we're
117:37 we're waiting for the Azores I guess fall off. Right. They really
117:45 the lasers are gonna collapse here sooner later. Right, that the volcanic
117:49 is going to collapse. If that , what are you gonna do,
117:52 gonna generate a tsunami all the way the atlantic. And what's it gonna
117:56 into the Bahamas? All right. guess when that happens, we'll see
118:02 tsunamis due to some of these shallow carbonate successions. Alright. Huh.
118:15 , there there are earthquakes, but of them at least historically, none
118:20 them are generated a tsunami in the . Right. And you know,
118:26 have lived in the Bahamas since the . Uh, I mean, they
118:31 there for a long time, but terms of recorded history right back to
118:36 british and french and obviously the spanish occupied areas like keiko's going back to
118:45 Like 1600s, 1700s. Okay. mean bringing all of this at one
119:10 or Yeah, I mean, maybe one of those units, the grated
119:16 , Maybe that's one big tsunami goes . I mean, we don't
119:21 we don't, we we don't have in the modern or younger carbonates to
119:26 at, to know that that tsunami . So, so again, this
119:33 more food for thought really? And somebody can show, you know,
119:37 have looked at tsunami deposits like after Jakarta or Indonesian earthquake, earthquake and
119:43 . Right? That really decimated part Sumatra. Um that one that,
119:49 tsunami went all the way across to southern southern India. Right. What's
119:57 island off of used to be called now, it's called? I can't
120:02 the name? Uh yeah Sri Lanka uh, but those are plastics,
120:10 plastic. So people looked at that . Right. And we're still waiting
120:16 something to happen to these shallow water carbonates. Alright. And if you
120:21 at the, these are just thin that I took from different pieces.
120:25 right. Just to give you a for variations on a theme here.
120:30 are the green algae, right? is like the, the alameda of
120:35 younger carbonates. This is what we in the paleozoic. These lived in
120:40 water. There are magnetic and then stuff here is from those down slow
120:46 . Okay, Where you get the droids and the bride zones and which
120:52 that problematical and cluster. So this stuff that's probably been re mobilized from
120:57 of the downslope buildups that we just about. You get in the,
121:02 the permian in pennsylvania and then you see some of the stuff coming from
121:06 water with you. It's okay, and colloids. And then we've talked
121:11 the Dia genesis, right. This genesis never made any sense for this
121:16 be early freshwater dissolution because you're out really deep water Alright. But until
121:24 documented marine barrel die genesis, you never prove that this wasn't freshwater die
121:30 , but conceptually it never made any , right. Not only would you
121:34 to really drop sea level on the basin platform, which is a dry
121:39 anyway, because they're vap rights associated it during the Permian. Right.
121:43 , that didn't make any sense in of making a lot of fresh
121:47 But you would have to do what have to move that freshwater lens down
121:51 somehow get it through the black shales get to these debris flows.
121:57 All right. And then it turns a lot of this process, he
122:02 burial related. It's either shallow barrel of the arrogance or it's like
122:10 You can see again the stylized ferocity , which again, it's hard to
122:15 in a normal thin section view, with the white paper technique, you
122:19 out the style lights, you pick the micro porosity. This is burial
122:23 after the styling. Okay. And the style lights maybe as we talked
122:29 , they may be a conduit for of these fluids. All right.
122:34 sometimes the material that comes off is finer grain material. All right.
122:40 , you know, there's unconventional play the Permian, now called the bone
122:46 , right. Which is thought to is fine grained limestone, also organic
122:53 . Alright. And it also is same age. Guardian. Okay.
123:01 you know, this is the outcrop that you see in some of the
123:06 outcrops along the highway from, from paso to Carlsbad. Alright. It's
123:12 the Lamar limestone. I mean, a little bit different age. This
123:16 younger, but it's the same right? This is that settle out
123:21 grain, organic rich carbonate material, get slopped off into deeper water.
123:26 right, and the bone springs, , You get these limestone units
123:31 they tend to, it's interesting that tend to preferentially occur on the leeward
123:40 of the central basin platform. if you look at, if you
123:43 at the Paleo geographic map again, don't I don't ever take those maps
123:51 , right. You know, they where the basin is and it looks
123:55 it's right along or close to the degree north of the equator, I
124:00 , so you don't know for but when you see something like
124:04 that might suggest that there were, know, there were some trade wind
124:10 because this stuff is mostly plastered that leeward or what would have been
124:15 western margins. So, I this is something you have to struggle
124:19 trying to figure out where this stuff coming from. So, but you
124:23 , the bone springs is a major rocket in the Permian Alright, it's
124:29 , its source is a lot of oil and gas and both the carbonates
124:32 the classics. Right? The Permian sites that people chase are sourced by
124:39 bone springs. Okay, so this , it's the sign, lapping wedges
124:43 material, fine grained material to it's very similar to what I described
124:47 the western side of great bahama Remember that 90 m thick wedge,
124:53 material that got slapped off. So , this is something that anybody that
124:58 these areas has to struggle with. know, when you're close to that
125:04 transition point between the doldrums and the tropical trade winds or tropical trade winds
125:12 . Okay. All right. Any about the four slopes? I give
125:18 a feel for the nature of the . All right. Again, what
125:23 I want you to take away from discussion this weekend is to, you
125:27 , be able to understand the elements these different play types. Right?
125:32 setting, What controls the occurrence and of these plays? What are the
125:37 ? Right. And what are the different pathways? Right. So you
125:44 you should at least know a good for each one of these play
125:48 All right. Be able to talk one of these reservoir analogs for these
125:53 types. Okay, right. Why we take a five minute stretch break
126:02 and we'll start back up at 10 45. Okay, we're going
126:13 start up with the and go through second conventional play type that I've listed
126:19 . The so called baseball deposition. talks. Then again, there's a
126:25 age control on this play type obviously the deposition of talks are comprised principally
126:33 the plastic microfossils and nana fossils that talked about the first weekend. The
126:39 foraminifera, the plank take calc spheres then the little nano fossils called
126:46 Okay and again they don't exist in paleozoic. Okay, so these are
126:53 mesozoic and tertiary aged potential carbonate So that's the age control.
127:00 So let's start with the I've already you the digest chalk. Alright.
127:07 now let's talk about the other the called de positional chalk here. It's
127:15 different. Right? It's a very grained limestone. Yes but now it's
127:20 principally of the remains of these plastic as I said the globo's foraminifera,
127:27 circular calc spheres. Remember they all these white glassy Lomax calcite test and
127:33 on a fine scale than anna fossils coca list that make up the mud
127:38 in a chalk. But you would see these things with a scanning electron
127:43 . Alright. And this is the deposit that starts off almost dominated by
127:51 , low meg calcite material. Right die genetically. This is much more
127:56 than the so called digestive chalks that in shallower water. Alright. The
128:02 though is dependent on the digest history usually that is tied back to barrel
128:11 and how deeply buried this stuff And whether you can preserve this process
128:17 not. And in a classical I'll chalk that preserved ferocity is almost
128:23 primary micro porosity. Alright. Microprocessor up in the democratic matrix.
128:30 So again, strong age control Again, if you don't know anything
128:37 the age of your rocks. And encounter fabric that looks like this in
128:41 section or with a scanning electron You see the globo's plastic foraminifera.
128:48 know, you're in essentially cretaceous or systems. I mean strictly speaking,
128:55 do get some of these, they them proto global Jurin. It's in
128:59 Jurassic and the upper part of the . But when you get a deposit
129:03 this is dominated by plant IQ You're in a cretaceous or younger
129:10 Okay. And relatively deeper water. . And then the mud matrix that
129:15 talked about. When you look at with the scanning electron microscope, you
129:20 sometimes the cocoa sphere, the armored structure in which the golden brown algae
129:26 . But usually that breaks up into individual pieces that are called co
129:30 the plates. All right. Look tiny they are. That's a five
129:34 scale bar. And then look at ferocity that is the producing ferocity from
129:40 chalk reservoir. Okay. Now you'll everybody called chalk reservoirs, fractured
129:48 Right? Everybody thinks because of the matrix permeability that these have to be
129:54 reservoirs. Alright. And that's not . Always. All right. That's
129:59 supported by the production data. I'll into this discussion with the austin chalk
130:05 in a minute. All right. . So everybody appreciate unique composition.
130:11 ? Remember these organisms don't live in water. They live in the basal
130:17 off of a platform or off the parts of ramps. So, basically
130:22 about 20 to 200 m of water is where most of the Plankton foraminifera
130:28 . All right. And then they and they settle or they get eaten
130:31 they settle as fecal pellets in the water. The vocalists are not a
130:36 basil indicator. They can occur in water, but they tend to dominate
130:40 in these deeper water settings. All , Okay. So first thing we
130:45 to talk about before I take you a couple of case studies is what
130:50 the chalk porosity evolution. Alright, , the first thing you need to
130:55 is, and we know this from deep sea drilling project or the ocean
131:00 project. That the initial process on sea floor for these chalk uses is
131:05 high. It's 70, porosity. right. It's the highest of any
131:10 the of the carbonate textures we've talked . All right. And we know
131:15 the ocean drilling program that physical compaction de watering, in other words bearing
131:21 stuff tense feet will reduce that starting to 5055 prostate units. After
131:30 You cannot achieve further porosity reduction or except by Dia genesis. Okay,
131:38 physical compaction only takes you down to 50, porosity unit threshold.
131:47 so what's going to drive the dia ? It's going to be burial.
131:51 going to be pressure solution and associated segmentation. Remember the donor receptor die
131:59 style lights, Micro style lights reduces volume of rock, generates pore
132:07 calcite cement, that plug nearby Okay. And so actually for a
132:13 reservoir, burial is not a good , Right? Because you're progressively reducing
132:18 with increasing burial depth. So the is, how do you preserve process
132:25 depth? So you have to come with some mechanism to inhibit that porosity
132:31 at depth. Okay, and we'll about those in a minute. Secondary
132:37 . E has always been downplayed or for a chalk reservoir because everybody thinks
132:42 gonna happen to it from a Classical dissolution standpoint, right? That
132:49 back calcite doesn't dissolve in fresh Okay? Yes, it dissolves during
132:54 and pressure. Right, That's pressure . But in terms of early
132:59 there's no way this stuff is gonna in fresh water. Okay, And
133:03 know this based on the chalk cliffs Dover in England. Alright, I'll
133:08 about that a minute. Okay, pressure solution. Right, excuse
133:19 pressure solution in a chalk sequence is not expressed by the classical jagged
133:25 like skylights. It's usually expressed by are called whiskey. Non future micro
133:33 , that's this fabric right here. . And my classics colleagues will
133:39 oh, those are not pressure Seems they would say those are physically
133:44 , primary clay lambda. Alright, I'd say, well, if that
133:49 true, there are two problems with you just said. The first is
133:53 can see the swarms of micro style actually turn into a style light with
133:59 offset. Right? That suggests again linkage. But then more importantly,
134:06 at this feature right here, that's of those what I called ring or
134:10 burrows, right? Oxidation haloed to and shrimp her worm. Okay.
134:18 you see that thing always never cuts seams. The seems always wrap around
134:25 burrow structure. You would think somewhere see the seam cut that stuff and
134:29 never see that. Okay, So tells you the pressure solution developed after
134:34 burro. Alright. And when you at that in detail here, the
134:39 electron microscope, you can see the , the dark color is concentrating all
134:45 all these in sybil minerals like clays organic material, pyrite chords, whatever
134:52 there can't be easily dissolved. But at the partial truncation of this plastic
135:00 , right? That proves that this is a seam of dissolution. That's
135:04 the carbonate materials being dissolved away. right, of course, what happens
135:09 dissolved carbonate goes somewhere into the Tried to be a potential pore filling
135:15 cement. Okay, So when you at a thin section of chalk,
135:21 see the plastic microfossils, right? that's what these are the foraminifera with
135:27 cement filling. Some of the primary the test. But you see these
135:32 seems here. These are not These are not de positional lamination.
135:39 are wispy micro style lights. And that darker material is the inside
135:44 material concentrated along the seams. All . But what a lot of people
135:50 appreciate is how prevalent, how prevalent material is in these in these
135:58 Right. And so the next view taken with is a thin section that
136:03 etched with a weak organic acid just remove some of the carbon A material
136:10 not bleach out some of the And look how prevalent these seams
136:14 As they just run through these chalk . Right. All of this is
136:19 material concentrated along pressure solution. Seems , Of course. The implication again
136:25 that this is the way we reduce . This is how we go from
136:30 , porosity units down to whatever we today in the subsurface. Alright,
136:36 that cement this liberated by pressure Goes into the test of the plastic
136:43 . More commonly it goes into the porosity and democratic matrix. Alright,
136:49 these little tiny you head real crystals are poor filling cement. That's generated
136:56 pressure solution. All right, because of your producing prostate and chalk is
137:02 microprocessor and the matrix. And this what. Okay, so this is
137:08 need to appreciate how the chalk die story works. Right And again,
137:13 are the strategies to inhibit pressure solution enough to entrap the hydrocarbons.
137:21 so you think about these are the white cliffs of Dover in England.
137:29 , Remember what they started with porosity on the sea floor. These
137:34 uplifted about 45 million years ago. . And so they sat exposed to
137:40 water for 45 billion years And they have 50, porosity. So this
137:49 that they don't leach in freshwater. , calcite, stable and fresh
137:53 All right. So the question is you start with a pure calcium
137:58 like we're going to talk about for famous North Sea chalks. Alright,
138:03 do you how do you preserve primary ? Well, you can't do it
138:07 early dissolution semente shin and fresh water this stuff doesn't react. Okay,
138:15 what are you left with either? bury it deeply, which is not
138:20 do any good if you're trying to a reservoir right, you need to
138:23 it down to some depth where it be accessed by migrating hydrocarbons. So
138:28 left with two choices here. Either over pressuring or what we call geo
138:34 and I'll explain these in a Okay. Or maybe um Place the
138:40 relatively early in the barrel history and out most of the water if you
138:45 most of the water from the porosity you eliminate exchange of water in the
138:51 system that basically shuts down your die machine. Okay, so it's tempting
138:57 think that some of these sequences like eagle for the basil lost in chalk
139:02 are organic rich where people think you're out hydrocarbons, that maybe that's something
139:08 comes into play, right? You moving that hydrocarbon. Maybe not the
139:13 mature hydrocarbon yet, but you start it into that ferocity expel most of
139:18 water. Maybe that's the way to . Okay, you're gonna see the
139:23 before the bigger giant chalk fields in North Sea. Is that they're all
139:31 pressure, right? The pore pressure higher than the overburden pressure or
139:37 All right. And how do you do that? Usually do that by
139:41 re deposition where you move chalk deposits shallower water and you rapidly bury some
139:47 the deepwater chalks. And you trap poor fluid in the in the that
139:52 buried chalk. That poor fluid pressure becomes higher than the overburden that's called
139:58 pressuring. Okay. Geo pressuring means you actually have a situation where you
140:04 cooking. If you have if you source rock quality for some of the
140:09 , you start cooking the hydrocarbons in after they've been buried to some
140:13 right? There's already a seal on by cooking that stuff in place.
140:19 increasing the pressure that's called geo pressure in geo pressure. Okay. And
140:26 that achieves the same purpose, Your poor fluid pressure becomes higher than
140:30 overburden stress and that potentially allows you preserve prostate depth. Alright,
140:38 so let's go through the classical North . Let's use the North Sea first
140:42 our basis for comparison to what I'm to show you in the Austin
140:46 Because part of this discussion again is back to our fizzy graphic setting.
140:53 at a global scale, but at more local scale. Right?
140:57 for the North Sea example, here talking about deeper water, classical deeper
141:02 settings. Okay, Where the only of deposit you could get in situ
141:08 be these pelagic related carbonates. so the area we're gonna talk about
141:14 was where the red Arrow is on map. Right? That's the southern
141:19 , Southern sector of the Norwegian sector the North Sea. Okay, so
141:25 part of the of the Norwegian sector the North Sea. Right? They
141:30 this all up for all the different to control. Right. And you
141:37 see there's a bunch of producing pools here, You see Ekofisk is the
141:43 one. Right? That's that big that phillips discovered. And there's just
141:48 you a little bit of history about discovery of Ekofisk, right? Uh
141:54 was back in 1969, I Alright. Before 1969, nobody knew
142:02 were reservoirs. Okay, So that's recent this play is. Right.
142:08 recognized chalk deposits going back to the hundreds, but nobody knew that these
142:14 could be oil or gas reservoirs. , So phillips. Now, Conoco
142:20 was prospecting and this part of the the basin and they were actually chasing
142:30 sand stones and they were using Right? And they were looking for
142:33 little chimneys um on seismic that they were related to these poor sands and
142:40 on top of these big shale All right. And that's actually what
142:45 drilled when they discovered Echo Office. thought they were drilling into a porous
142:51 charged sandstone when they hit Ekofisk. Ekofisk has developed on one of these
142:57 diapers. Okay, and what's unique this part of the of the Darcy
143:04 it's a highly tectonic lee active It's been tectonic lee active going back
143:10 the permian. And you have these blocks and Robbins. Okay. And
143:17 age of these chalk deposits are uppermost and lower tertiary. And so we're
143:24 about a relatively deep water basin with structure. So, people talk about
143:30 1000 ft minimally for this part of North Sea during chalk deposition.
143:35 remember the organisms that make the chalk live in the upper part of the
143:39 column. That caucus would settle down the horse blocks. The caucuses were
143:45 down into the Robins. Okay. then what happened with active movement,
143:51 of the chalk? Who's up on horse block would be do what it
143:53 rapidly re deposit into the drop Right. That rapid deposition creates the
144:00 pressuring. Alright, so all the chalk fields are associated with situations like
144:06 . And so what they talk about the North Sea chalks are the top
144:12 . And a lot of tennis Alright. So the toxin is chalks
144:18 the ones that are not over They produce, they have some production
144:26 and and they have pretty decent but they're not the big giant boomers
144:33 Ekofisk or Valhol that we're gonna talk . All right. The big ones
144:37 all the so called loch ness chalks that active movement tectonic movement would move
144:42 chalk ooze from shallow to deep And it's down here where you trapped
144:47 poor fluid in that rapidly buried And that's what would set up the
144:52 . Alright, so you can see difference in the rock fabric.
144:56 The chocolate is chocolate like this. bio debated. They are buried into
145:02 realm of pressure solution. You can of see this sometimes I refer to
145:07 as sort of a pseudo laminated I don't think these are real lamination
145:12 of the bio innovation but this pressure that sort of gives you that appearance
145:18 laminated texture compare that to the allocation chalks where you see rip up classic
145:23 material and things like that. All . So all the big boomers like
145:28 or Valhol produced principally from the A. Tennis chalks. Alright,
145:34 let me Share a little data with Office first because that was the first
145:38 one that was found back in the 60s. Once the once phillips documented
145:45 play concept Within a few years. mean by mid 1970s, all of
145:51 pools were discovered by just shooting seismic this part of the Norwegian sector.
145:56 right, so here's the data for . What is that? 6.4 billion
146:07 stock tank barrels of oil in Alright, Look at the porosity averages
146:13 porosity, but some of the process up to over 50%. That's almost
146:19 process after de watering. Okay. then look at the Matrix. Perm
146:25 Mila Darcy. When people see people oil companies see these numbers of Mila
146:32 Darcy darcy or less? Sometimes Sometimes analysis .01 .01 .01 Mila Darcy's
146:41 The F word comes out, And the geological upward that comes out
146:46 gotta be fractured, right? It's be fractured to account for the amount
146:51 oil and gas has been produced. right, Maybe we'll address this
146:58 Okay. The other issue is what call ultimate recovery efficiency. Right?
147:05 not enough to know that I found tank of oil. Right? And
147:11 going to calculate how much oil is place. Right? By making assumptions
147:15 porosity and distribution and things like And Now that's where these numbers come
147:21 . Right, 6.4 billion stock tank of oil in place. All
147:27 What's more concern? Right, Is much you're gonna get out right?
147:31 you can sell on the market. . That's called ultimate recovery efficiency.
147:36 right. And historically every everybody's thought a chalk because it's micro porosity dominated
147:45 gonna be pretty low. Okay. I worked for Exxon, none of
147:52 had been published on yet. And actually I'm going to share with
147:57 I got involved in the study of field here. When I worked for
148:01 , I got I got shipped Oslo not so I got shipped us to
148:06 which is over here on this side the of Norway for a couple of
148:11 with a geologist out of the out the London office and Amoco had put
148:17 field up for sale Back in the 80s and uh, next time was
148:23 in looking at it to buy. , so they sent me over to
148:28 at the rock data. They sent colleague over to look at the volumetrics
148:34 what was the big question back You are a right, how much
148:40 gonna get out of this. America going to tell us right, because
148:44 were trying to sell this thing. . So they're not going to tell
148:47 . So we thought maybe 10% Nobody knew right back then. And
148:54 we guessed maybe 10% out of this . You've probably already seen some of
148:59 numbers on my slides right? Where showed the ultimate recovery efficiency for the
149:03 conventional plays, a lot of these will yield 50% or more.
149:09 An ultimate recovery efficiency means primary recovery flood C. 0 2 Sweeps.
149:17 , that's considered to be really Right. So we thought 10%.
149:22 then Phillips published the paper back in , I guess the late 80s,
149:30 ? They published this number 22%,, is higher than we thought. And
149:36 what I hear through the grapevine, I know these guys all retired,
149:42 I knew them when they were working Kanako and working phillips, they told
149:46 that they thought with water flood, they've gone to for Ekofisk. And
149:52 , who would have ever thought you water flooded, find microprocessor chalk?
149:56 they've done that successfully. They think now going to get closer 35-50 out
150:03 the out of box office. So, you know, they've they've
150:08 to water flood and they're sweeping oil . But what happened to the
150:13 It started sinking This got a lot press about 10 or 15 years ago
150:18 they actually had to come back and a billion dollars jacking up the
150:24 right, Because this is the North , right? Where you get these
150:27 winter storms, you don't want your sitting next to the water level,
150:32 ? It's gonna be Inundated by 20 30 ft swells. Right? So
150:41 the that's equitas story, right? so let me show you the data
150:45 battlefield again. We didn't know what ultimate recovery efficiency was. And what
150:51 done here is I've just taken the that the Amoco published with the Norwegian
150:57 directorate. Alright. And I'm gonna some rock observations here in a
151:03 But basically Valhol field is like Ekofisk sits on a big shale dyp
151:07 Okay, and so it's a big strong graphic trap, you can see
151:13 total column of 250 m vertical. the has published now, the primary
151:20 estimates 24%. They've not gone to flood yet. So they don't
151:26 they don't know in the field yet they don't own the field anymore
151:30 So in the field for a I don't know if you guys still
151:33 it. I think you sold it . Right, so somebody else owns
151:36 now. So did you water Do you know if they water flooded
151:44 ? Okay, so I don't I know either. And I mean sooner
151:48 later somebody's gonna come back and start flooding it. So I'm sure these
151:51 are going to go up, but can see it's mostly late cretaceous.
151:55 the tour formation is this lower moderately deeply buried 2400 m and strongly
152:03 pressured right? The 24000.82 P. . I. Per foot is implies
152:09 overpressure. And again. All so look at how the reservoir the
152:15 is organized. It's broken out into cleaner chalk intervals separated by usually
152:25 Shelly or trudy chalks. Okay. more pressure solution. Lower prostate
152:34 Alright, so, that's how the is sort of segregated The big boomer
152:39 the tour formation. All right, can see 75%. Excuse me of
152:47 the oil has come from the Tour . So, I had a chance
152:55 look at core from the tor formation I was over there. Okay,
152:59 you can see the process. 45 over 50% porosity. Some of the
153:04 analysis from 55 proxy units, like said, that's basically deposition across after
153:10 watering. Alright, So, that the stuff, nothing ever happened to
153:15 after it got buried. Okay. then you see the low perms gas
153:22 ratio here and then the Hydrocarbon saturation than 90%. Right, so,
153:29 lot of this stuff is saturated with . Alright? And look at the
153:35 rates, the initial production rates up 12,000 barrels a day. Alright.
153:40 of course everybody called this a fractured . Right? Even Amoco telling this
153:45 a fracture. It has to be . Right, But I went and
153:49 tried to pick up a piece of formation with 50% ferocity and 90% hydrocarbon
153:55 . I tried to pick it up of the core box and it
154:00 Okay, basically unconsolidated. So you me how that's a fractured reservoir.
154:07 no way. Okay. In America was complaining to us, They
154:13 telling us that not only does oil into the well bore from the
154:18 but chalk comes into the well And they're asking us, hey,
154:24 guys have any ideas how we could the oil through but keep the chart
154:31 the edge of the casing, And remember somebody asked and I hope
154:37 is an engineer and not a geologist they, I can understand an engineer
154:42 understanding. I said, you think could, we could line the casing
154:48 chicken wire, chicken wire, Like you do a chicken cage,
154:53 , with holes this big. And that keep out the chalk? Let
154:58 oil through. Well, how big the coca leaf? Right. A
155:01 microns. There's no way. So stuff actually comes out of the well
155:06 looking like brown toothpaste. Okay, that consistency. It's like squeezing toothpaste
155:13 of the well bored. So they the rock with the oil.
155:18 that's how un brittle. The tort innovation is okay. Now when you
155:26 at the todd and I looked at from the hot, it looks like
155:30 tighter limestone. Right? And the is not so evident until you until
155:35 shoot water on it. Then you it sucked in but it looks like
155:38 more rigid limestone fat that could be fractured. But but look at the
155:43 numbers here, they drop off dramatically to the tour. Okay, So
155:48 we did this evaluation, I I mean, actually my colleague from
155:53 London office actually, you see what booked with the government, they thought
155:57 a billion barrels of oil in But nobody knew the recovery efficiency.
156:03 thought maybe 10%. But my colleague thought He did the volumetrics on that
156:09 . He thought it was actually closer two billion barrels of oil in place
156:13 you could see he was right, . Because now the public's reserves are
156:19 . Alright. But Exxon walked away the deal because managers didn't think they
156:24 gonna make their money, right? didn't think they would get enough oil
156:28 of these chalks, but you definitely enough oil out of these talks.
156:32 right. Alright, So this is classical deep water pure cal citic chalk
156:40 . Right? Not an ounce of to begin with, right? There's
156:45 ragged material here. All right. there's no source, Right? About
156:50 only rag genetic material you could get this truck would be a ammonites floating
156:55 in the ocean dying and sinking, ? But that's hardly any contribution of
157:01 to the rock. Okay, so is the classical deep water pure calcium
157:08 deposits. Okay, so let's think , let's change the setting now and
157:17 to south texas and talk about the chalk, completely different setting.
157:23 you started to get a feel now the some of the carbonate plays in
157:29 part of the northern gulf rim. ? We talked about the older cretaceous
157:33 texas. We talked about cretaceous in . Right, So, you know
157:38 there were older platforms that cut through . Right? And then deepened into
157:43 ancestral gulf of Mexico. So there's pre existing topography that's set up before
157:50 furred and buddha and austin chalk Okay, in the upper cretaceous.
157:56 the setting here is completely different. . It's not a classical deep water
158:02 everywhere for the austin chalk. And arguably even for the eagle
158:07 All right, so, we're gonna through this. We'll see how we
158:13 on time here. Maybe I'll finish before lunch, but here's the outcrop
158:20 that most of you are probably familiar or maybe you're not but there's the
158:24 trend of the austin chalk actually goes the way up into Arkansas southern
158:31 most of Dallas. The city of that the outcrops in Dallas or austin
158:35 , Waco san Antonio. Most of san Antonio is austin chalk. Eovaldi
158:42 rio. And then the stuff actually in uh out here in Big Bend
158:48 Park on west texas. That's the trend. Okay. And then down
158:54 of this and the subsurface, is where you get the producing austin chalk
158:59 extends down in this position here and Northern Mexico is the deeper water equivalent
159:07 everything that I'm going to show you south texas, both an outcrop and
159:12 in the subsurface. Okay, and can see the amount of oil that's
159:16 produced here historically. Right? The first major chalk field in south texas
159:24 called Pearsall. It occurs in the , near the town of Pearsall,
159:29 of san Antonio. So down in position right here. Well that was
159:33 discovered, that was only discovered in thirties. Okay, so there was
159:37 smaller chalk production before that, but was the first big chalk field in
159:42 trend. Alright, And you can what people think there's still another close
159:47 seven billion barrels of oil to be and something like 41 TCF of
159:54 Again, that's a few by these by outfits like the USgs.
160:01 they're making lots of assumptions right about and porosity and distribution and things like
160:09 . So you have to I think have to take that with a grain
160:11 salt but okay so we're we're a bit older here in south texas for
160:20 Austin chalk than what I talked about the North Sea chalks. Most of
160:24 North sea chalks were up here this equivalent. Right? The stricken and
160:30 up into the tertiary. So most the austin chalk is what we call
160:35 ation and Santoni in these are european . Worked out by looking at the
160:40 strategic graffiti of the Kokkalis, principally of the foraminifera. Alrighty, Gilford
160:45 a little bit older. Nueva mentioned when we're talking about costa rica.
160:51 ? That's the mexican equivalent an outcrop northern Mexico for the eagle furred.
161:02 excuse me? Excuse me, been this now for over a week.
161:11 sorry. And then san Felipe would the Austin chalk equivalent that outcrops in
161:17 Mexico. All right, so you at the paleo geography, we're talking
161:23 these different maps, right, that available in the literature and the one
161:29 most people like to show in the seems like is the Blakey's maps.
161:34 ? The guy that used to teach the University of Northern Arizona. And
161:39 can see why people like these They show the landmasses, they show
161:43 deep marine settings. They show the marine settings here. All right.
161:48 so you can see in south they're basically sitting on a relatively shallow
161:55 setting for chalk deposition. Not we're talking about the deep ancestral gulf of
162:02 . Right? And you can see is all part of a seaway that
162:07 up through the western us. This is where you get Niobrara chalk
162:12 in colorado and Wyoming those places. ? That seaway actually extended all the
162:19 up to western Canada. So they're western Canada in the subsurface their time
162:24 chalk deposits to what we're talking about the austin chalk. Alright. But
162:29 setting here is a little bit Okay. And the question is,
162:35 know, the problem with Blakey's maps where are we with respect to the
162:39 equator? He doesn't plot the latitude for you. Some of his maps
162:45 show you where the equator goes and it. All right. He doesn't
162:49 the zero. He doesn't plot Doesn't plot 60. Alright. And
162:54 if you question is where were you , were you in a subtropical setting
163:00 were you actually North of 30 that you in the colder, temperate water
163:06 ? Right. And if you look the maps that I told you,
163:10 like write that, show you the the wind direction. I told
163:16 remember, look at the legend the I think it says here,
163:23 the arrows represent. Maybe I took out. Yeah, I told you
163:30 already. Right. These arrows, speaking are showing you the surface
163:35 Right? The movement of the surface , but that means that they are
163:40 by the surface winds right there reflecting trade winds. Right? So the
163:46 that you see here is not the of the wind. Is the deflection
163:50 the currents against the landmasses. so, the prevailing trade winds are
163:55 we talked about, right. When along the equator, they're out of
163:58 eastern quadrant. Okay. And when go north or south of 60 story
164:05 , the wind shift out of the right through the Western lease. All
164:09 . See that. Okay, So let's go back to south
164:13 So, if you believe this uh here's south texas. Right?
164:19 you get austin chalk deposition? Where we? We're north of 30.
164:25 . That's outside of the subtropical Right. And so that means you're
164:29 a cooler water climate where you shouldn't a rag a night. Okay.
164:35 get any rag genetic material and you be persistently influenced by things like hurricanes
164:43 your hurricane belt is basically limited. subtropical settings. Yeah, hurricane may
164:48 across like this and then spin up the north like it does today.
164:54 . Right. Sometimes it will come in and hit Houston and then it
164:57 spin up through the continental us. you wouldn't expect that to be a
165:02 effect on deposition. Right, Hurricane . Right, sir. This is
165:08 problem with these maps. Right? don't want to rely just on these
165:11 . You want to use the geology prove the relationship. All right.
165:15 so actually Austin Chalk sits at the reaches of the subtropical belt.
165:23 It should be south of that 30° because of this. All right.
165:30 gonna see there's lots of Aragon night parts of the Austin chalk. There
165:35 things that were lived on the sea . There were magnetic mollusks, green
165:41 , rudest are described. Alright. some of the other some of the
165:45 stuff, Brutus fragments. And then are these things called um council sponges
165:56 look like corals. But they're sponges are calculus that are magnetic to begin
166:02 . Okay, So you've got all skeletal precursor regulated material there Actually you
166:10 But actually you it's in the Austin but there to scatter to its
166:18 We're not talking about a factory for . It's you don't see any of
166:22 in the subsurface or or outcrop. you see the evidence of bud's right
166:28 , phosphate ties. Because that's what when you shed into its in the
166:31 water that get replaced by foss fatty . So that means that somewhere up
166:37 there had to be a factory of water where you're making new IDs
166:42 You don't make goods in cold All right. So, you know
166:45 their tropical subtropical So where that is ? That's probably up north of san
166:53 and the balcones fault zone where the has been all chewed up.
166:58 So somebody has to go in and micro sample that stuff to try to
167:02 if they can find that update Nobody's done that or looked.
167:07 And then there's lots of carbonate mud the Austin chalk? Obviously these are
167:10 stones that pack stones, not all that mud is due to co
167:15 Uh for reasons you'll see. And so carbonate mud is not very
167:20 actually in a cold water climate, water climate. And so if you're
167:25 a setting where you can get a genetic scale of precursors inuits, there's
167:30 reason why you couldn't have the mud cal curious allergy. Alright. That
167:34 also generating some of that arrogant needle . All right. And then the
167:39 lacks very little solicit plastic material. ? There's some clay material. There's
167:46 , volcanic drive material. Uh there's a little bit of quartz.
167:51 You don't get a lot of quartz the Austin chalk. Alright, Most
167:54 it is silt or fine sand. . And then where the volcanoes pop
168:01 into the chalk and create reefs around or even into the younger anna
168:07 you get reef deposits with the raggedy . Okay, so you see how
168:11 geology is suggesting we're not in a water or cold water temperate climate.
168:17 still in the northern reaches of of the subtropical belt. Okay,
168:24 water was warmer. It would have influenced by the greater degree of hurricanes
168:30 tropical storms. Okay. And you'll where I'm headed with this discussion
168:34 Okay. Alright, so from our yesterday, remember we talked about paleo
168:43 began paleo highs. Now that's the principle of carbonate geology. You always
168:49 to apply this to any sequence that evaluate. Right, What's the pre
168:56 de positional topography? Right. That's to be structural. That's going to
169:00 de positional inherited from our older carbonate classic sequences in the basin of
169:06 Okay, so this is the kind stuff you need to think about when
169:10 evaluating how the Austin chalk is set , deposition aly, and how it's
169:15 to respond die genetically with respect to barrel history. All right, So
169:22 first major influence in south texas is landau uplift. Right. I told
169:26 already talked about this. This is frenetic battle if this is a positive
169:33 going all the way back to the and in south texas. Okay,
169:38 it stayed a positive feature even during chalk time because we see the austin
169:45 thin out up against the towards the to uplift. Right. The problem
169:50 it all gets sliced up by the fault system that runs from Austin through
169:57 Antonio. All right. And then do we have off of that?
170:01 have a structural extension called the SAn arch. Right, this is that
170:06 basement rock that extends off the land to the southeast. Okay. And
170:11 think everybody's pretty confident this is frenetic because there's no salt associated with
170:19 Right? Get salt to the you get salt to the southwest.
170:23 for that reason I think people think frenetic basement and then there's structural extensions
170:28 come off of the sand market And the famous one is the Pearsall
170:32 . You'll see a map of this a minute that goes to the
170:36 Well, the parasol arches where they the first big Pearsall chalk field back
170:40 the thirties. Okay. And then are all these other regional fall trends
170:45 then there's inherited paleo topography from the and Stuart city Edwards, right.
170:52 Stuart city. I showed you what Edwards was. Right, Brutus reefs
170:56 I told you underneath that was the brief trend of coral strom atop roid
171:00 rudest. So that builds topography. ? And then there's time equivalent faces
171:06 it that build topography. There are in the Sligo up on the platform
171:12 built topography. Okay. And then gets drowned out by the Georgetown.
171:20 . Austin chalk. Edwards gets drowned by the Georgetown. Alright. And
171:26 what comes on top of that? Del Rio? The del Rio is
171:30 the clay in the subsurface, but actually a marine are delicious, marine
171:36 has got carbonate and Shelly material and the buddha is a cleaner pelagic
171:42 not very deep water and then eagle is deeper pelagic carbonate. And then
171:48 you're going to see Austin chalk is water relative to the Eagle food.
171:53 So there's a deepening effect that occurs the buddha and eagle furred. And
171:59 in my mind the eagle for Austin chalk is really what a continuum
172:04 shallowing chalk deposition. Right? When think about it on a grand
172:10 that's really what it is. Alford is the deeper water, organic
172:15 equivalent. And then it gradually shallows . All right, but it stays
172:20 baseball all the way through its Right. So I showed you this
172:26 yesterday we were talking about the Edwards deposition. Right? And how the
172:30 stacked on top of the Sligo. right. So this is the land
172:34 uplift and there's some of the structural that we've talked about that we're going
172:39 talk about. I've already mentioned the fault system. That fault entrapped the
172:47 Laguna carbonates. Right? There were sized cars trough. This is that
172:52 system that runs behind the platform margin we're gonna come back and talk briefly
172:58 cards trump because this is this is area where companies like E.
173:03 G. And marathon uh four or years ago started producing these monster rates
173:09 of the chalk. Right? If you got three or 400 barrels
173:14 oil a day in the in the that was considered to be really
173:18 Right? And then the horizontal drilling jacked it up to 1000 barrels a
173:23 for a while, But they were four or 5000 barrels a day from
173:28 current strong and that's to me that that there's something unique going on there
173:34 will end up talking about here in minute. All right, so here's
173:38 map view that just puts us in , There's the land to uplift.
173:42 the sand markets arch, here's the arch that extends off of it into
173:48 maverick basin. So here's one of negative topographic features here, right.
173:53 of these intricate tonic basil sags up the up on what was a drowned
173:59 platform right during Sligo and Edwards time then the Atis Costa trough cards
174:06 This is basically that, that linear fault system that I talked about for
174:15 and word field, that's basically running through this setting right here.
174:21 and then there's another little basil sag here. East texas salt basin that
174:26 up there. Okay, But as know, and you see this in
174:31 , in the Eagle furred, Everything this direction in the chalk and
174:36 Eagle furred, it's not very clay , right? There's not a lot
174:41 our delicious material. So everything to southwest of the san Marcus arch is
174:46 clean carbonate. Okay, But when go to this side, everything becomes
174:54 are delicious, right? So everybody that the clay material is coming probably
174:59 Arkansas, from the watch Utah's and pushed down this way but a lot
175:04 it is blocked by the san Marcus . Okay, so san Marcus arches
175:09 shallower deposition with respect to chalks but built up the sea level. At
175:14 there's no evidence for that. But it certainly certainly blocked a lot
175:19 the clay material that would want to pushed this direction by the trade
175:24 right? Longshore currents set up by currents would would try to push that
175:28 to the south southwest. Okay. everybody have a feel now for sort
175:33 the regional elements here? We're going sort of put this in perspective with
175:37 to some of the chalk production. , before I get into the field
175:43 , let me let me share with the work that I did for my
175:52 . Alright, because I did a evaluation of the Austin chalk. Nobody
175:56 looked at the chalk regionally from the in central texas down into the subsurface
176:02 nobody had carried this into the northern . All right. So, I
176:06 interested in looking at the regional de setting and then looking at the digest
176:12 of the chalk from the outcrop and data that I could get my hands
176:17 . All right, So this is summary of how I broke out
176:23 the outcrop and and, and subsurface in uh south texas and northern
176:32 Alright. And originally I used the shelf in basin because when I was
176:37 grad student, we didn't talk in of ramps and steve margin platforms.
176:42 . We talked about shallow water shelves deeper water basins. Right. And
176:47 you're gonna see what I call the and what I call the basin.
176:52 bothered a lot of people, especially with the classics background because they associate
176:57 word basin with ancestral gulf of Mexico President gulf of Mexico water depths.
177:03 . And I've told you and we don't use that. We don't
177:07 a water depth No. two A . Right. Is that relatively deep
177:12 area off the platform or off the ? And I told you, you
177:17 , it could be 100 m of depth, right? Or it could
177:22 thousands of meters of water depth. . But you know, I I
177:27 so much criticism in the literature for interpretation that I decided when I started
177:33 about the chalk and I do I a daylong industry seminar on the on
177:39 chalk because of all the interest. changed this. So, people better
177:44 what I was talking about. All . So now I use the term
177:47 a ramp and outer ramp and then term basin is used for the really
177:51 water equivalents. Okay. So what's difference between the inter ramp and outer
177:57 , overall lighter colored lime stones, lot of macro fauna, many of
178:03 are originally or a genetic. So lots of arrogance in the system to
178:07 with. There's no what we call betting. And let me define what
178:12 mean by rhythmic betting. That's alternating and deep in limestone, repeating over
178:19 over again. Alright, you don't that in south texas and the outcrops
178:23 you don't see that in the Where do you see that Northern
178:27 Okay, that's a classic classical deepwater of betting on a really deep water
178:33 . Alright, shallow water trace These are the burrow structures that people
178:39 about, both for classics and That the inter rap is the world
178:44 calcio sponges. You'll see what these like in a minute. Oyster bayou
178:50 maybe you want to see what things like but they look like corals but
178:54 they're sponges of originally magnetic. What? Mr As you all know
178:59 Mr Buy homes are like Right in classic model oyster bio terms occur where
179:06 inner parts of bays, right? Galveston bay. In the world of
179:11 , oysters have wide range distribution. , they can occur in deeper water
179:17 current shallower water. So oysters don't the same thing and carbonates that they
179:22 in the world of plastics. intense by erosion. More glass tonight
179:29 with this. Alright then contrast that the outer ramp, it's darker
179:33 overall limited macro fauna where we find macro fauna it's coming in as storm
179:42 . So stuff removed from shallow water deeper water by storms. And so
179:48 precursor magnetic material is more restricted. , the good rhythmic betting only occurs
179:54 the true deeper water basin. Overall deeper water trace fossils and block.
179:59 I again, it's not that it comes in with the storm
180:03 Okay, so look at the inference for water depths. It's very difficult
180:08 put numbers, water depth numbers to sequence. Okay, so I said
180:15 of meters has to be deep enough to get the pelagic microfossils,
180:24 But still shallow enough to give you lighter color the magnetic material.
180:30 And so I think you'd have to minimally tens of meters a barrel of
180:36 depth. Right. And then the wrap is a transition right from actually
180:41 of meters of water depth to, knows, 100 m of water depth
180:45 you get to the Sligo drop And then of course deeper as you
180:49 into the ancestral Mexico. All alright, so here's my original
180:56 right? There are quarries in san that I studied extensively. Right,
181:02 represent the shallowest part of this That's the part that I mapped as
181:06 part of the shelf. And then by definition was relatively deeper off of
181:12 , but this bothered people calling this basin, even though I was on
181:16 of an old cretaceous platform system. , so I changed it now called
181:22 the inner ramp. The outer Where does this go? This goes
181:26 to the landau uplift. So somewhere here and the landau uplift has to
181:33 a shallower water equivalent. Right? you may do it. Maybe a
181:37 , who knows? Right, somewhere all would have lapped up onto the
181:41 landau uplift. Okay, alright, this is what I call the inner
181:46 and that includes the that's limited to part right here. This is what
181:50 call the outer ramp and you can my database with the dots. That's
181:54 data, outcrop data about here by Rio. And then what I call
182:00 true deep basin would be where you off the Sligo platform margin.
182:06 that would be the ancestral gulf of . And that's pretty deep out
182:12 And even I would argue even deeper you go into northern Mexico, you
182:17 see I have three measured sections out the northern part of northern part of
182:23 . Right? Again, I don't time to go through this. I
182:27 a whole day doing this, but me just summarize just trying to give
182:31 a feel for the regional setting here terms of de positional environment.
182:38 so the up Dipak crops look like . This is a excuse me,
182:48 is a quarry on the north side san Antonio that doesn't exist anymore.
182:53 been filled in, I think there's high school football field on on top
182:57 this now. But you see it's colored. Right? You don't see
183:01 classical rhythmic betting You don't see these dark and light layers, shale,
183:07 , shale, chalk. Alright, is a river section outside of
183:12 Same relationship. When you look at you look at the sediment it's light
183:19 but it's loaded with all this macro . Right. This is not the
183:23 of thing you'd expect to see in chalk sequence. Right? These are
183:27 genetic malice, their oysters. There other magnetic fauna like the calc
183:35 I talked about right there. Gaster , things like that. But when
183:39 look at them, a critic matrix still the world of microfossils.
183:43 So it's deep enough for micro fossil . Right? Which again based on
183:50 modern is a minimum of say 15 m of water depth. Right?
183:57 it's still shallow enough to give you lighter color still shallow enough to get
184:01 lot of a Reaganite deposition. And then look at what's happening to
184:05 organisms are being bored. Remember the of boring where shell structure gets cut
184:11 by a boring worm or boring sponge something like that and they break down
184:18 Dragon Knight into mud or silt sized . Well this is the way we
184:22 finer grained material to the environment. , so you're adding finer grain or
184:28 to the system and then arguably could of that precursor might be a Reaganite
184:36 related to things like the calculus algae don't leave a body fossil.
184:42 But they rapidly produced a lot of mud like we talked about our first
184:47 . Okay, Everybody appreciate what I'm here. So this is really unique
184:52 . All right. This is not the deep water North sea chalks.
184:58 , Then contrast that with the outer outcrops. That's the Langtry section down
185:04 Highway 90 outside of del Rio. you can see there's some channels that
185:09 this. That's part of the delivery for moving stuff from shallow to
185:14 And then here's the northern Bahamas. , this is what happens when I
185:20 too much northern Mexico. All This is the classical rhythmic rhythmic betting
185:28 you expect to see in the really parts of the, of the
185:31 Okay, this is on the highway Laredo and south texas and Monterey.
185:38 . The big industrial city in northern , the dark layers are the the
185:46 and the light layers are, I'm , of the shell and the light
185:50 are the chalks. Okay. And course, when you know, just
185:55 a side here, I'm not gonna you on this, but just so
185:59 know, right? There's a big in the carbon a community and even
186:04 classics to relate a lot of this betting or cyclist city to uh,
186:13 changes, Right? Milinkevich cycles. you ever heard that term?
186:18 There are changes in the orbit of earth around the sun, right?
186:24 different tilting earth changes. Its axis differently on a on a cycle
186:31 On a time basis. Right? talk about 10, 20,000 year
186:36 40,000 year cycles, 100,000 year And so a lot of people want
186:41 relate to cyclist city to that. , But you're not very far away
186:47 the sierra madre oriental, right? starting to make this major mountain
186:52 right? That ends up being related the rockies in colorado. Right?
186:57 same age. So what are you ? You're building topography. You're shedding
187:02 , Right? So this cyclist city just be due to shedding periodically,
187:08 classics right? Every time you shut lot of fine grained classics, you
187:12 down your chalk production, right? the coca list the golden brown algae
187:16 light. Right? Because remember they're the upper part of the water
187:21 And so this may have nothing to with changes in orbital movement or frequency
187:28 things like that. All right. called psycho strategic graffiti by the
187:33 If you ever encounter that literature. ? People are trying to relate to
187:37 graffiti to this external uh four Okay. And then here's the
187:46 right? None of this is classically bedded. All right. You see
187:51 see changes in color. You see in stratification style. The basil.
187:57 chalk often looks like this because that's good source rock where it was
188:02 Alright, preserve that stratification. For we talked about before. A lot
188:07 the chalk looks like this. highly burrowed, light colored. Some
188:12 the chocolate. The subsurface varies from color to dark colored biter baited to
188:17 stratified like you see here. but no change in the environment
188:23 This is all relatively deeper water. is that outer ramp part of the
188:28 while you're still up on the drowned platform. But what's interesting here is
188:34 in the subsurface? Well, this the background sediment. You start to
188:39 stuff like this mixed in with All right. This is some of
188:43 Iraq genetic material coming from shallow This is a storm layer about this
188:48 that punctuates the rock that looked like I just showed you the previous
188:53 Or sometimes you get what are called tubular tempest tights. Remember we talked
188:58 the burrows going down, putting outside , going down, putting outside chambers
189:04 you get a storm layer on the of the ocean. Right. That
189:09 stuff is gonna do what it's gonna pushed down and that's what these
189:13 These are the side chambers of those back filled with that coarser grained material
189:20 a lot of shallow water material, netting material block tonight. Things like
189:24 . Okay, so you see what doing here, we're mixing, we've
189:28 a we've got a mixed bag a pelagic system. Up up dip,
189:33 , That's the inter ramp that I you. But then some of this
189:36 gets mixed down into the deeper water of the trend. Alright, how
189:42 you do this? You do this hurricanes? Okay, so that's why
189:46 think it's really critical that, you , you're in a sub subtropical setting
189:51 I I showed you last weekend what did on keiko's and I showed you
190:00 diagram like this from Caicos, where day after the hurricane, the mud
190:05 that platform being put on suspension. ? So here's an example of the
190:09 thing from Bermuda Bermuda sits in the stream, right? Technically, it's
190:15 a cold, cold water climate, ? It's about 40° north of the
190:20 today, but it's a tropical setting of the warm Gulf stream waters coming
190:26 through here. So this is all carbonate deposition on Bermuda platform and some
190:32 it involves lime mud deposition and you see what happened after this hurricane came
190:38 . It puts somebody's suspension as I , it stays in suspension for days
190:43 weeks, gets drawn off into deeper where it settles out. Okay,
190:49 apply this to the Austin, chalk ? The update part, the update
190:58 interparty inner ramp, right gets hit hurricanes, Hurricanes move mostly east to
191:04 . Right. Alright, so here's texas gets hit by these east east
191:10 west. Movie. And hurricanes. the strongest winds out of the northeast
191:16 ? So they hit south texas. are they gonna do? They're gonna
191:20 push mud and sand material that Well that's the direction where we see
191:27 of the shedding in the austin Okay but see what you're doing
191:32 You're mixing but we're deeper water, more pure cal Civic talks with the
191:39 magnetic mud, magnetic sand sized Right, This changes the game.
191:46 . Nursey pure calcite mineralogy here. or reaganite low medical site changes the
191:56 of your die genesis story. so let's just see how this translates
192:02 preserved ferocity. The inner ramp. , This is the outcrops right?
192:09 Austin San Antonio. Remember what we with on the sea floor,
192:15 reduce it to 50 55 porosity units de watering And now we have 20-25%
192:23 the average. The range is up 31% porosity for the outcrops.
192:29 so we have to explain how we from this number to these numbers.
192:35 no pressure solution in these outcrops. ? All the regional data suggests they
192:39 had more than one or 2000 ft sediment or rock on top. That's
192:44 enough if you believe my 1000 m for making pressure solution. Okay.
192:50 physically you don't see pressure solution in outcrops. So what's driving the dissolution
192:57 limitation? It's the fresh water die , right? These are outcrops.
193:02 any organizing the system is going to dissolved. That's going to create
193:07 But it's also gonna create poor filling . You remember the volume change when
193:12 go from a rag a night to ? Almost 9% excess calcium carbonate.
193:18 , so that's what would happen. right. But you could do this
193:22 even exposing into fresh water just during burial. That arrogant. I would
193:26 dissolve before the onset of pressure Okay, So that's the only thing
193:33 can rely on to explain how you from 50 55% porosity 8-31% porosity.
193:42 , so this is what the you see the process preserved in the up
193:47 into ramp stuff right here is the photographs to sustain with the lizard and
193:52 . S for calcite. The blue the porosity. This grain, is
193:57 grain right here, ferocity, not in the atlantic foraminifera. You see
194:02 blue hue that runs in the MMA matrix that's preserved secondary micro ferocity.
194:10 , But the question is, is of that due to dissolution of magnetic
194:15 . Right, Okay. In other , is the update stuff also a
194:20 chalk. Right? Remember the digest reaganite stuff got dissolved. Alright.
194:27 this is something that hasn't been worked yet. But I think I think
194:31 of this process probably is related to leaching. It's just hard to prove
194:36 there's no rag and I left in system. Right? Everything's been stabilized
194:41 . Lomax calcite. Alright, so the up dip into ramp stuff and
194:47 the subsurface stuff varies depending on where at. The average porosity For the
194:55 reservoirs is 5-8%. So you have go from 50, porosity to five
195:03 . Easy to explain in the subsurface pressure solution and calcite. See
195:08 So now it's a question of how you how do you preserve process at
195:13 long enough to entrap the hydrocarbons. ? So you take advantage of any
195:19 has been introduced. Right? That's stabilize earlier in the barrel history.
195:24 if if there's enough dragon, I are you gonna do? You can
195:27 a rigid framework that resists later pressure . So there are some places in
195:31 trend where the proxy is higher than would expect for that burial depth and
195:37 like that may come into play. . And then otherwise there's no evidence
195:44 overpressure in your geo pressure range at in most of the established fields in
195:49 texas. So either some of these areas of better process are due to
195:56 like early hydrocarbon emplacement right? Where bleed in oil during shallow burial from
196:01 eagle furred or austin Austin chalk or have something like barrel dissolution.
196:07 so we'll talk about that later when get to the field studies. So
196:12 me finish up here and we'll break lunch. This is the this is
196:16 proxy trend for the chalk, Compared to the North Sea chalks.
196:20 overpressure chalks are deeply buried, but still have the highest Prasit ease for
196:24 reasons we talked about, right, shut down your pressure solution to a
196:28 extent. But even the normally pressured because they're more pure calcium talks still
196:34 higher porosity, even though they're more buried in the Austin chalk. And
196:39 here's the austin chalk. Overall lower Prosise loss quicker and shallower barrel
196:47 And I attribute this to a different . And the fact that you start
196:50 with this mixed Aragon night cal side . Right? And you have no
196:56 to preserve ferocity through overpressure Giorgio pressuring least in the classical south texas
197:03 Okay. All right. So when come back from lunch, I'll take
197:07 through a couple of the case studies then maybe address this issue about whether
197:11 get dissolution in the austin chalk or . Right. In other words,
197:15 it also a digest chalk in the . Alright, so I think I
197:25 know the data points here. I'm wondering if he just got a few
197:28 points and he just connected the It's never it's never clear from this
197:36 . It could be two separate Yeah. Um It's just not clear
197:41 his paper how he put that Okay. That's from the show lead
197:49 . All right. Any questions before break? Alright, So everybody online
197:55 start back up about one o'clock, ? Should be noon right now,
198:01 I'll see you guys an
-
+