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GEOL6363 Carbonate Sedimentalogy - Day5 09-10-2021-Part2
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00:01 Okay let's uh finish up the the part of this lecture Technically this is
00:08 15 seismic expression of carbonates. Although all sort of linked together on one
00:14 file. So let me briefly talk the application of seismic data to
00:19 And then we'll talk about some of pitfalls again of the using seismic data
00:24 to identify prospective plays or to model off of seismic. You can see
00:32 we've used seismic data to understand our fizzy graphic setting. In other
00:37 trying to decide if we're dealing with platform to base in transition or more
00:41 a ramp like succession of carbonates. then I would say even more we've
00:46 to chase the bumps right on seismic for the reefs and mounds so called
00:54 of course trying to find ones that also poor. So that's obviously the
00:58 . Okay so start with some old data. Like you see here
01:04 I'm not an interpreter as a I come in and work with companies
01:09 usually come in after the fact because companies, most U. S.
01:13 drill off of seismic first. They try to incorporate rock data into their
01:18 for play development. They just play of the seismic. And so I
01:23 in after they've already drilled off the to try to figure out either what
01:26 hit why the play didn't work again that they collected rock data but you
01:32 see this is old two D. but it's pretty typical of a you
01:37 that platform to base in transition. can see the interpretation here. The
01:43 carbonate platform. Again, the on wedges of material. The target here
01:49 the bump at the margin that's always in southeast asia to be some sort
01:55 platform margin reef. And it turned to be that. But I want
02:00 to appreciate that just because you see on seismic doesn't necessarily mean it's a
02:06 . That kind of topography could be by anything from cursed to just a
02:11 of stacked shallow water cycles of That may have nothing to do with
02:18 that could be fault bounded on a scale to create that topography. So
02:23 would be the other question that you to ask before you commit to drilling
02:27 like this first? Well, whether is reef or not, where do
02:39 get good reef development on these carbonate riverfront? Really? Yeah, but
02:50 side of the platform, is that ? And what else? Open ocean
02:58 , Right. And not a leeward . Remember this problem with the leeward
03:01 reef was. It may start to , but then it gets shot in
03:04 back by settlement being pushed off. . So yeah, the first thing
03:09 want to know is, you what's my orientation with respect to the
03:13 ocean. And then you'd also want know what else? Right? Where
03:17 I paleo geographically? Am I along equator. Am I in the strong
03:23 wind belt And or am I in gentle easterly trade wind belt? All
03:28 this makes a difference. Right? respect to to brief deposition. So
03:33 know, but a lot of those never get asked by seismic interpreter.
03:37 interpreters trained to look for these kinds relationships and that's it. All
03:42 They're not there to they don't have background ask those questions about what controls
03:46 distribution. For example, in the and then the other historical uses to
03:53 to, to to show the evolution of platforms. They're not static.
03:59 told you restore not static, they debris. They expand, they coalesce
04:03 bigger restructures. Well, carbonate platforms the same thing. And here's an
04:10 today. This area of great bahama is all shallow water. This is
04:14 stand up water right until you get here toward the margin and uh but
04:20 in the late cretaceous early tertiary it actually a series of smaller scale platform
04:25 by deep water and payments shown by blue and what's obviously happened. The
04:32 shed material they filled in the in . Everything is now coalesced into what
04:36 map is a one broad carbonate But this map is based on a
04:41 line shot across this part of the side of grand bahama bank and you
04:50 see what today is. Andrew silence . Andrew's bank bimini bank over here
04:55 the west. There is one of embodiments. So then All right.
05:02 are you surprised to filled in I mean I showed you this diagram
05:07 last week right? To make the . You know if you want to
05:11 the sea level game, it doesn't any sense, right? Because pro
05:16 means falling sea level up, building static sea level. And what's the
05:24 here? The story here, That's leeward side of this margin.
05:28 And so that's where you expect to a lot of material by just the
05:32 winds. But back in the cretaceous were 25° basically where you are
05:39 which is in the general easterly trade . So you would predict that this
05:44 not going to be coarse grained This is going to be mud and
05:47 sized material because just like today in Bahamas, that's all the trade winds
05:52 shed when they're weak. Okay. the only way to get coarse grained
05:57 into this is the big storms but episodic so they're not going to account
06:02 a great thickness of grain stone All right. Yeah. And then
06:09 want you I want to remind you even a carbonate ramp has expression alright
06:15 sometimes is mistaken when you go down the more distal part of the
06:20 This is data from permanent west texas Andreas. Is that unit? I
06:25 in the Permian? The upper which is highly productive. This is
06:29 one that yielded billions of barrels of from carbonates and I want you to
06:36 that every ramp does what as you out, every ramp as you go
06:40 starts to roll over as you go deeper water, your substance increases.
06:45 you see this rollover effect. there's a rollover effect right here.
06:50 the caveat here is that some people that to be a shelf break or
06:57 little mini platform margin or something like . No, this is deep
07:03 You're in the world of crime, and bracket pods. By the time
07:06 get out here you're shallow high energy are further up debt. Okay.
07:12 field does not even produce from high energy carbonates that produces from these
07:17 cylinders that lived down the slope. right, the woods and tidal flats
07:22 all that other stuff. We're way here to the west. Okay,
07:27 be careful of that. But also going to see when I get to
07:30 of these play types that roll over is also where you sometimes in the
07:36 nuclear these pinnacle reefs Right? That up having 802,000 ft of vertical
07:44 But they start off in deep they take advantage of that subtle topography
07:49 kick off. All right. And as I said historically, we've used
07:55 data to find the buildups or try find the buildups. This is the
08:00 List of criteria that people have applied two d. Data of But you
08:08 , thickening to the build up thinning of overlying cycles. Drape on
08:14 disruption. The seismic event mounted or tree internal character a sag effect under
08:21 build up. If the build up more porous than the underlying sediment or
08:25 pull up effect if it's the other around. Okay. And so the
08:32 . All right. The risk from d. data. Exxon published this
08:38 back in early 90s. All Having worked for Exxon, I told
08:43 I started with Exxon and worked there eight years. I never thought Exxon
08:46 publish a diagram like this. They never want to admit that they weren't
08:52 at everything that they did. But give him credit. All right.
08:57 published this and this is a publication is essentially a postmortem of 60 case
09:08 Drilled off of two d. seismic . So every one of those prospects
09:13 interpreted to be a type of build . Okay to be a porous productive
09:18 up. All right. And this the postmortem evaluation. Alright. And
09:25 actually was involved in some of the for some of these examples when I
09:29 at Exxon. All right. And here's the breakdown. It turned out
09:33 more than 50% of what they thought a build up when they drilled it
09:38 evaluated it with a logically was not a build up. Okay and so
09:43 the breakdown of the 53% breaks down this some time. Okay. No
10:03 up penetrated. This is the breakdown no build up in red 28% build
10:14 a dry 13% build up and a discovery for Exxon. So enough reserves
10:22 make money And then five got success but not enough hydrocarbon to justify
10:32 Okay that's the marine actually That's in that's not that far off line of
10:41 success rate. 16 Success off the D. Data was considered pretty
10:47 All right So this is the way when they did the postmortem The 53%
10:54 the case studies. You can see different percentages based on the color but
10:59 of what they drill. We're irrational . Some of what they drilled were
11:03 mounds. And I've seen this data Southeast Asia. You look at the
11:07 D. You see a beautiful bump lap drape you see a sag effect
11:12 that support us Miocene reservoir, Reef . They drilled it. They didn't
11:17 amounts of carbonates as all shale. this is what happens sometimes. All
11:24 then. Salt got drilled volcanoes get all the time for reefs. That's
11:29 common when they couldn't blame it on geology. Then they started to blame
11:34 on the data which is sort of cop out but multiple effects on migration
11:41 migrated diffraction effects. Here's an even cop out bad data. Here's more
11:47 the problem over interpretation of data. right. Because like I said,
11:54 , who were the seismic interpreters, they could get off the street or
11:58 of the university that they could All right. The interpreters were not
12:03 carbonate geologists. They were could have somebody came in from school with a
12:08 in India's metrology but they would train what to look for on seismic
12:14 Okay. And then they would drill of that. And so here's here's
12:19 here's a famous example over interpretation of . There was a there was a
12:24 study Our prospect pushed in Western Canada in the 80s, Late 80s,
12:30 90s by a little company called Canadian . All right. And Canadian
12:38 the guy put together this prospect out the middle of the shale basin
12:41 the show based I was talking about right. And so the middle of
12:47 arts and shale, does that make ? That you would get a reef
12:52 in a shale basin? No, when you you saw the seismic,
12:56 had all the attributes that I just to. Right? And I said
13:01 in. The economics suggests it would been the biggest discovery of a reef
13:06 in Western Canada. And so that companies right? That attracts money and
13:12 eventually found somebody to drill it. of course it turned out to be
13:15 pile of shale, but this is point right over interpretation of data.
13:21 guy that put the prospect together didn't carbonate geology. Alright. In
13:27 the carbonate expert in the company quit this because he said I'll risk my
13:33 job that this is not going to in as a carbonate reef. And
13:39 drilled it anyway, he quit. was Jack Winnie. All right.
13:43 I referred to before and Jack went work for. Jack had already found
13:50 discoveries for Canadian Hunter, but he to work for the survey and All
13:56 , so that's the breakdown of the . And then where they did drill
14:01 up? This is the breakdown. it didn't work because the source rock
14:05 it wasn't even there or it was porosity, which is the dye genesis
14:12 of the story. Sometimes it was leaky seal. Sometimes they drill below
14:16 oil water contract contact. Sometimes it great discovery. Okay. Mhm.
14:22 , if you go back to that , they will tell you where all
14:25 the examples come from. Right? and you can see so they vary
14:30 age from lower paleozoic to the tertiary reef complexes. All right.
14:37 build up. First time. That's . No build up Is 53% and
14:47 . And then this is all but not all of it worked because
14:51 was dry or not enough hydrocarbon. . First All right. 10 out
15:04 16, Well, 13, out 16 wells was commercial discovery for
15:12 Okay. Right. 13% of that diagram, which is 60 case
15:18 13% of the time it worked. actually like I said, not that
15:23 . That's the risk. I you see they made that's where that's
15:30 enough. Also, well, make off of that prospect in terms of
15:38 the amount of wells to be the drilling cost all the other depends
15:46 big it is. I mean, they when they say commercial discovery,
15:50 talking about just for that one not for their whole program worldwide.
15:57 . But yeah, if they find giant Oldfield, that's going to pay
16:00 a lot of this. Right? some of these are giant or
16:05 So All right. But so having that now, if I show you
16:11 seismic line, would you drill If you had to put your own
16:15 in? I mean, it's easy say this. If you had to
16:17 your own money in or not, you drill it? I mean,
16:20 see the bump, you see the lap and drape, you see the
16:23 effect right here. That's the build here. And if you drill
16:26 you would have drilled a billion barrel field from Libya. Right. With
16:31 ft of vertical relief, Almost 1000 of pay. Initial production of 40,000
16:37 a day. And the reserves are 1.5 billion barrels of oil. And
16:43 is one of those downslope pinnacle reefs we're going to talk about as a
16:46 type later. You'll see the more data for this for this example.
16:52 I mean, these are one wonders, right. These are these
16:54 like little haystacks. It only takes well to develop. But look at
16:59 the reward here. If you can him. Okay, of course you're
17:03 to source rock and arguably it's even primary migration from the source rock right
17:08 the end of the reservoir. All now in this seismic line. This
17:13 more modern data. This is from 90s. And this is Western
17:18 There's a pinnacle reef in here. you see it? Mhm.
17:23 it's in the keg river. All . It's down here. In
17:29 it's very hard to see the effect on two D on three D.
17:33 would stand out beautifully is a little . But I gave you the counter
17:39 slide to this. It's given me one of my seismic buddies and Calgary
17:45 you can see what he relied on make the interpretation. He looked really
17:49 the differential compaction effect. The strip in the see this in the slave
17:53 overlying the keg river. That's really picks up that build up right.
17:59 some of these build ups are 600 over 1000 ft thick. All
18:05 Great vertical thickness. Not a lot areal extent unless they coalesce into bigger
18:10 features. And then one last example to remind you that not all,
18:17 all build ups on a parent buildups seismic are due to reefs. This
18:23 seismic data from the Jurassic smack over the U. S. Gulf
18:27 We'll be talking about the smack over lot in our next lecture. All
18:32 . As one plate type and these actually McKamey patent field is actually fall
18:39 . That's what creates the initial topography that creates a basement. That creates
18:44 basement structure down slope, right in water. And on top of that
18:49 evolve the zulu to grain stones and build a couple of cycles of sedimentation
18:54 give you thickness and to give you seismic expression. So here's the
18:59 There's the fault controlled topography. And McKamey patent, which is 140 two
19:06 barrels of oil equivalent field. It produces gas and condensate. Um,
19:13 seismic expression is due to the fact you stack these cycles of sedimentation to
19:17 you that vertical thickness. It has to do with reef. Okay,
19:22 sometimes sacked grain stones give you seismic . I'm going to show you tomorrow
19:28 . Another example from Western Canada where reactivated basement faults stack the small scale
19:35 interior cycles to give you subtle seismic . That company's mistook to be baby
19:42 reefs. It had nothing to do brief deposition. All right. So
19:47 are these are no these are These are ramp related carbonates. The
19:56 part of the ramp is where you your main mutual complex. But then
20:00 you go down the slope into the , if you create basement topography,
20:04 can put who is on top of ? Or you can put reefs or
20:10 you could put both of them there . All right. But in this
20:14 of suicides and there, you'll see examples tomorrow where civil reefs.
20:20 so that's the pre existing topography influencing played development. All right.
20:28 All right then let me finish up little case study here. And I
20:31 you the paper on which this is spe paper. So that's on
20:37 but it doesn't have the colour diagrams hasn't in black and white. This
20:42 uh Edith Wilson is a friend and . I used to teach internally for
20:49 . And so when I taught for Back in the 90s, they gave
20:53 this, she gave me this slide to use and some of my seminars
20:57 them. It's a beautiful little case because it shows you the the caveat
21:03 trying to model porosity off the Right. Companies try to do that
21:09 two D data. Right? They acoustic inversion to try to model areas
21:14 better porosity on a seismic line and relate that back to a play or
21:19 these type. Right? And you it even more now with three
21:23 Data, right? Three D. allows you to to to figure out
21:28 map these blobs of better porosity. already know where we're headed with
21:34 Right. It's not enough to know have ferocity. You need to know
21:38 kind of process it is, Because that controls the permeability. And
21:43 conversely, just because you don't have ferocity doesn't mean it doesn't have good
21:50 . Right? It can it can both ways. So, that's the
21:54 of this little case study. this is also a case study that
21:58 us ahead of our play type But it's a it's another case study
22:04 what I'm going to call uh, these platform margin or ramp related grain
22:10 . Okay. And we'll talk in next lecture about the big play in
22:16 Arabia and uh, there's a huge oil field called Deano field in green
22:23 on the western side of Qatar, ? This big peninsula. This is
22:28 major oil province here and this field a comparable scale and and reserves to
22:35 of the big arab D fields in Arabia. All right. Everything basically
22:40 up in the same direction here, reflecting some regional fall control and the
22:47 of the of this play. All . So That's that was the
22:53 Right, do hunt oil field was back in the 40s And then back
22:57 the late 80s and early 90s, opened this area first for Jurassic
23:04 All right offshore. And then later opened it up for permit. And
23:09 where they discovered that giant gas field Northfield offshore between Qatar and Iran.
23:18 . They sure waters and the Arabian . So Amoco went offshore and shot
23:26 d seismic out here and they used inversion define areas of better porosity
23:34 And then they tested those with drilling characterize the traps and I'll show you
23:41 they found. Okay, So I , I think I told you
23:46 I taught a course here in Doha I had a friend at work for
23:50 who was mapping the geology, surface . Well, our first day we
23:55 right across this way to look at of these Sakas over here. And
24:02 is a view you get. When drive west, There's Dukhan Oilfield,
24:07 see how they found these oil fields in the 40s, big dome
24:11 outcrop, normal structure. That's the . This expression of these huge Anne
24:16 with 1000 or 1500 ft of I mean, so easy to see
24:24 they could find those. Okay, the main producer the main sequence that
24:30 oil in Qatar as in Saudi Arabia the arab D. Okay. And
24:35 you can see it's overlaying by the scale carbonate evaporate cycles. That's basically
24:41 you get the soccer deposits that are local seals for these reservoirs. And
24:47 everything is sealed by this really thick hydrate called the hip And hydrate.
24:52 has to this has to be a , shallow basin will evaporate given the
24:58 of those evaporates. Okay, uh . The song get sonic process up
25:09 city. It's telling you ferocity. ? So within the carbonate, you've
25:15 some areas that are tighter. You some areas that are porous. And
25:18 look at the evaporates. You see it reflects back to the right,
25:22 ? That's tight evaporated deposits as you'd . There's no sonic response here to
25:30 of, right, for the And . The massive and hydrated.
25:35 so, the arab D. As is in Saudi Arabia is made up
25:39 these stacked repetitive cycles. Little leopard cycles that go from the critic wacky
25:45 into grain stones. The cycle thicknesses 100 ft 30 m or so.
25:51 they repeat over and over again. then eventually there they are. Top
25:57 by more massive and hydrate. All . So Sasha or perhaps laguna evaporates
26:05 the top and the grain stones are a mixture of p lloyds and skeletal
26:13 . New IDs. All right. , sometimes better sort of do a
26:18 of grain stone, but most of it's a mixed grain stone.
26:22 And then you need to know that within these cycles. You can delay
26:29 any part of one of these opportunities . And more massively replace Part of
26:35 cycle with 20 to 50 ft of . Alright. And you're going to
26:41 sometimes the dolomite increases the ferocity. the dolomite just replaces the limestone and
26:48 and has no effect on the reservoir . Alright, so, they went
26:54 . They did acoustic inversion. They these areas of better porosity And it
27:00 out that these are low relief traps only 100 ft of closure. All
27:04 . Not the big skill traps like showed you for Duan and a
27:09 These to receive what the rocks what their reservoir quality was and what
27:16 ability was to yield hydrocarbon. So, they did capillary pressure analysis
27:22 figure out what would yield hydrocarbon. , some of the stuff they encountered
27:27 these low relief traps look like Good grain stones with pretty good
27:32 excellent permeability. Of course this would hydrocarbon. Alright. And then they
27:39 some rocks that look like this. ferocity. But the perm dropped
27:44 Right. Uh Edith called these pack and muddy grain stones. I would
27:50 use the term muddy grain stone because stones are not supposed to have any
27:54 . Right. Right. So, would be a better way to characterize
27:57 below my Pakistan? Hi, mud . Okay. And these have
28:03 but they have four permeability. And you did the cat pressure, because
28:08 of this process is micro prostate would yield hydrocarbon. The rock was saturated
28:15 , the note wouldn't produce. So it's a waste sound. And
28:19 of course the basil part of these was mormon critic. Like you see
28:23 wacky stones and sometimes lime mud Still pretty good ferocity because the high
28:28 of micro porosity, but no firm speak of. And this stuff but
28:32 yield hydrocarbon. Alright, and then of the dollar stones they encountered look
28:37 this pretty good porosity. Pretty good . That would yield oil, lower
28:44 , but still good permeability. Even would yield hydrocarbon. Okay. He
28:49 couldn't predict it. Right? You predict where we come in. Sometimes
28:53 would replace them. A critic Sometimes it will replace the grain stones
28:57 the top. Okay, so this the breakdown of their petro physical
29:04 All right. You can see the grain stones always yielded hydrocarbon. Premier
29:09 Dolomites always yielded hydrocarbons. But look the average porosity, it's just
29:14 Right? And then anything that was critic, even though it had good
29:19 , never had good permeability. These always the way sounds. Okay.
29:24 obviously for a low relief trap like . What percentage of that trap is
29:28 stone? Just a small percentage. rest of it was all waste.
29:34 , so they realized very quickly, not going to they're not going to
29:38 their money on these low relief All right. But they provided a
29:43 little case study here because what's the to be learned? Alright. They
29:48 the acoustic version from their two data or they did the acoustic
29:53 The bright spots are more porous. dimmer spots are less force. So
29:59 lesson to be learned is it's not to know that I have ferocity.
30:05 need to know what kind it Right? And conversely, some of
30:09 areas of dimmer response could be permissible that are capable of yielding hydrocarbon.
30:17 , now for them it was never to work economically because they were
30:21 And the traps were too small. you're playing this to any other carbonates
30:26 . Right? There's a valuable lesson be learned here. And that's really
30:30 takeaway of this case study. All right. Any questions about
30:37 So the bottom line is right, like well log response, seismic response
30:42 not foolproof. You always want to integrate with a logical control to understand
30:49 small scale faces or play relationships. want to try to integrate that data
30:55 your seismic interpretation. Obviously. What you do in a more mature basin
31:00 you don't have a lot of well . Well this is where you bring
31:04 established geological case studies to guide your of the seismic. And that's the
31:11 point of our Next lectures after the one. When we get in our
31:16 type discussion, that's the whole point my discussion is to give you some
31:21 forgiven geological time period for a certain topography. What would you expect in
31:28 of play development and then what are analog that can guide you if you
31:32 into this game of trying to use data to look for play potential.
31:40 . Any questions about this? Mhm. The largest test for its
32:01 for gases that I don't know. , I actually looked at a lot
32:11 rock from, from that. I for one client when they opened it
32:16 when they opened it up for Thank you. Part every company
32:24 two core their expiration wells. So company, every major oil company was
32:29 there. Every shelter to Exxon to . All the, all the major
32:38 have to court their exploration wells, not just the target. They have
32:43 court from the top of the permit the base of the permit.
32:48 So you're talking about cord wells over ft thick. And then they required
32:54 this documentation. They required a a every foot for PNP data and then
33:03 thin section analysis Just saw back in mid 2000s. I worked for Canada
33:10 this. All right. I probably at Okay, several 1000 thin
33:18 All right for them. And I just one of several people during construction
33:23 . And for each thin section we to provide a detailed description. We
33:26 to provide so many photographs church. had to put these into these big
33:32 that had all this data with a of the rock and pictures of the
33:35 section and all the the analysis. the government got attached for every
33:41 Well, I looked a lot of is that supposed to what it
33:48 All right. Forest old stone. everywhere. Mhm. This great
33:56 Mhm. All right. Why don't take a little five minute stretch break
34:01 come back and get set up. last thing to talk about before we
34:05 into play types brief lecture on carbonate rocks. You're going to get more
34:09 this detail I'm sure from you're geochemistry a couple a couple of months but
34:17 whenever that was several weeks. So, let's start back up at
34:26 . Let's start back at 3:30 Yeah. Yeah. Mhm.
35:18 Okay. Mhm. Yeah. All . Mhm. Uh huh.
35:53 Yeah. Yeah. Yeah. Right. Mhm. Mhm.
36:57 Yeah. Mhm. Yes. Yeah. Yeah. Yeah.
39:25 Mhm. Yeah. Okay. One thing on the agenda to sort of
39:36 the setup for our discussion about carbonate . Remember I said carbonate play represents
39:43 interplay between reservoir source and seal. talked about how to create reservoir quality
39:49 preserve it. We've talked about what to the ceiling faces, why they
39:55 tight and impermeable. We haven't really about carbonate source rocks. So,
40:00 short lecture on that, I'm sure get much more detail about this.
40:05 , when you do your organic geochemistry , but obviously, carbonate source rocks
40:11 a critical element in a play It doesn't mean every carbonate source rock
40:16 to be linked to carbonate source There obviously, lots of shells that
40:21 the oil and gas to carbonate But I may have mentioned this when
40:27 started in this business, uh, in the late 70s, nobody thought
40:33 could be the rest uh, source . Everybody thought oil and gas had
40:38 come from shale and it's based on study that I'm going to share with
40:42 in a minute. Also done by believe it or not. And since
40:49 people, you know, people just on these geological scenarios for these basins
40:56 the only thing they had any organic was the carbonate rock. And they
41:01 by, by geochemistry typing the oil to the source rock that the
41:07 Our major can be major source Okay. And what's interesting is that
41:14 lot of these carbonate source rocks have historically. The carbonate source rock has
41:20 lower toc cut off in shale. , that used to be, you
41:24 , a good shale source rock with . Now people say 2% or something
41:29 that. Uh there's some carbon a rocks that have less than that,
41:33 still you'll as much or more And the reason for that has to
41:39 with the makeup of the organic material the way it breaks down to oil
41:43 gas. All right. So, bottom line is that the lot of
41:47 carbonates systems, not the organic not derived from wood, e coli
41:52 , not terrestrial drive, just drive marine sources. And what that means
41:56 that marine organic material breaks down a more effectively to oil or gas.
42:02 right. So here's the here's the from a published paper by Harry Gaiman
42:12 used to work for Exxon's research lab in Houston Uh published back in the
42:18 60s. And I think this biased for a long period of time,
42:23 still amazes me that this paper ever published because what he was doing was
42:28 apples to oranges. And so what did was he was an organic
42:35 And what he did was he you see the numbers here, he
42:40 1000 shale samples from all over the and he analyzed them for toc total
42:45 carbon, which is most of, know, is a proxy for the
42:50 the ability to yield hydrocarbon. higher the TOc the more organic rich
42:56 , etcetera. All right. And , you see his analysis here and
43:01 came up with a mean Value for the shell samples of about 1%.
43:07 so that's where the historic 1% cut comes from. For a good shale
43:12 rock. All right. And then took 346 limestone samples from all over
43:17 world. Except instead of sampling from comparable deposition environment. Right. Most
43:23 these shells are deeper water. What he do? He sampled lime stones
43:28 all over the place. So tidal and reef lime stones. Hewlett grain
43:35 , some based on lime stones. he came up with this number of
43:40 , less than 2.25%. And he that all carbonates have no source rock
43:49 . Look at those low values. right. Except when he looked at
43:53 few numbers he had for baseball Some of these numbers were over
43:58 Okay. It just amazes me that ever got published. Alright. And
44:04 interesting that I was working with some at the lab here in Houston In
44:10 late 70s. And and then they they were working the slur in Michigan
44:16 and the only thing that had any material was a carbonate. Right.
44:24 all the shells were immature or over . They couldn't be yielding oil.
44:30 so they figured out geo chemically that stuff was coming from these carbonates.
44:37 . But with very low average docs than 1%. So, but this
44:43 , this bias industry for a long until companies just stumbled on these examples
44:49 it had to be coming from a a source rock and some of these
44:52 . Alright, so a couple comments about the criteria and then we'll talk
44:57 the environments where people think you have have, what kind of environment you
45:02 to have to preserve organic material and I'll share with you the case study
45:07 . Just you get a feel for TOc values associated with some of these
45:12 well documented carbonate source rocks. So are the criteria that companies commonly used
45:18 identify source rock but potential obviously, toc. And of course whether it's
45:27 prone or not because oil has always the better price, sufficient maturation.
45:33 , of course timing is everything. need the timing, the maturation to
45:38 with the development of the reservoir in trap. And of course the other
45:43 we've, we've talked about is migration and pathway issues. Right, So
45:51 , you appreciate what that is, ? No questions about that organic matter
45:56 . This is the type of organic that produces a distinctive organic compounds.
46:01 influences the type of hydrocarbon generated, it's going to be more oil prone
46:07 gas prone, of course, some this depends on the later maturity
46:12 but these are the so called Karajan . The companies talk about and what
46:17 found is every company has their own classification scheme, but but basically it
46:23 down to there are marine Karajan or matter types and these tend to be
46:30 prone. Where is the source of material is coming from the organisms that
46:34 in the environment. Right? algae, Marine sources. Okay.
46:40 then there's the terrestrial derived material, wood, e coli material that tends
46:45 be more gas prone. And then a there's a another type called amorphous
46:52 they can't really tell what it but that tends to be oil
46:55 etcetera, etcetera. All right. this is pretty typical classification scheme that
47:00 lot of companies use. So, here's uh here's a little we'll do
47:05 little exercise here and I skipped Of course she doesn't look like you
47:11 your notes with you. So I over a alteration a chart that shows
47:17 the thermal alteration index and how it back to maturity whether it's going to
47:23 immature over mature, whether it's more generating or gas generating. So I
47:29 have to sort of tell you what numbers mean. But it's in your
47:32 that. And so here's a let's play a little game here.
47:37 expiration target. All right. This a this is a strata graphic section
47:42 off of a two d. seismic . You can see where basement
47:46 It's about 2, 2 km You can see a carbonate succession right
47:53 with little bumps. So what would think the bumps represent some sort of
47:59 . Right. And you can see they're now encased and evaporates. And
48:06 this, you have a shale and a sand above that. Before you
48:09 into the carbonate. And then you see the evaporates through overlaying that operates
48:13 lane by another sand and then a and then another sand and then surface
48:18 . Alright. And so this being carbon a seminar. What would be
48:23 expiration target? Obviously the bumps. now, what would you want to
48:31 ? Right, well, dear Reservoir be the bump. Right. Seal
48:42 . Right. Great, great Graphic trapping good. Four way closure
48:46 the way around these. So that good. All right. So,
48:51 the last thing you need India source . Right. All right.
48:58 let's look at the lower shale a look good. From a toc
49:08 Right. Doesn't meet our requirement of to 2% toc. All right.
49:13 go to see that's the evaporate. , toc. Forget that the d
49:22 toc, but enough. You know numbers here, But that basically means
49:28 . Right. It's too shallow. then what else would you have to
49:32 ? Yeah, let's just assume that was a mature source rock. You'd
49:38 to do what something. Right. would have to migrate through the
49:45 So that that sort of counter that's of counterintuitive, Right. Plus,
49:50 people don't think you can top Right. Everybody thinks the oil and
49:54 wants to go up. I we'll we'll have this discussion later,
49:59 uh, so what are you left B? All right. So here
50:03 have this chance to invest all this . All right. And it's all
50:08 off of what whether B is has for quality or not. So,
50:13 got an average toc of .35% as , uh, an amorphous. So
50:20 going to be oil prone and the operation index looks good. Right?
50:25 like you can generate oil. what's the scary part? The average
50:31 . Right. So yeah, if walked away, you walked away from
50:37 salary in michigan basin that has produced 300 million barrels of oil and several
50:45 of TCF of gas from this source With an average toc of .35%.
50:55 . And what is this? This a basin of limestone co evil to
50:59 deepwater pinnacle reef. And where is organic material coming from? It's coming
51:05 from stuff washed off of the reef the deeper anoxic basin. All
51:10 In fact, the TOC numbers increase you come up to the reef.
51:15 . But the average toc is only . So this is the example I
51:20 talking about where at Exxon, They this is where they figured it
51:25 Okay. Yeah. Well, well is back in the days of conventional
51:42 where nobody fracked. All right. didn't frack source rock. So I
51:48 know if companies have come back and trying to this is basically what's called
51:51 A. One carbonate and the in michigan basin. And we're going to
51:55 about this as a play type But everybody just drilled the bumps.
52:00 ? And there's a die genesis story this. I'll come back and talk
52:05 this in more detail. But they drilled the bumps. Okay.
52:09 for conventional reservoir quality. Okay, just an interesting sidelight there. But
52:17 what are the conditions required for for organic material uh in the world of
52:27 ? These are the two that people more concerned with, right? They're
52:31 to preserve it by either overwhelming the with greater productivity than destruction on the
52:37 floor. Right? So like off a Mississippi delta, you're just dumping
52:42 this nutrient rich sediment. And you're that you either produced so much of
52:48 so quickly that you preserve it or bury it quickly. Right. But
52:52 the world of carbonates we're more concerned the quality of the bottom water.
52:57 right. We're looking for situations where anoxic on the sea floor, that's
53:02 the best way to preserve it. ? We're not dealing with Delta kinds
53:07 systems where you you buried the stuff quickly that you preserve it.
53:12 So the question then becomes how do create an oxy on the sea
53:17 Well, the common way and the the most common way is probably by
53:22 stratification where you create temperature or solemnity in the water column. And by
53:29 that, that inhibits the mixing of oxygenated water with the bottom water.
53:35 so if you can do that, create low oxygen on the sea
53:39 And what's the first thing that All the calculus organisms disappear.
53:45 They can't live there. But then else disappears? All the borrowers?
53:50 once you remove the borrowers, then basically create a world of anoxia and
53:55 how you preserve organic material. All , So the upper water column can
53:59 you can still have carbonate production that column, right? You can have
54:03 microfossils and anna fossils. But the is creating an oxy on the sea
54:07 . Okay. Yeah. And then limited would be again, areas of
54:13 along western and leeward margins of right where you get the low oxygen
54:19 upwelling along those margins. That creates . But this is pretty unusual
54:26 two other mechanisms in the literature. pioneer was trying to explain some of
54:34 organic rich sweet spots in the eagle in south texas. They came up
54:40 this concept of these missile scale Eddie's local upwelling areas where again, on
54:47 a bigger scale, 10, km , they proposed this has not been
54:53 alright, But they just proposed that might get these local areas of an
54:58 related to that. And then the , the last model here is really
55:05 . This is actually proposed by our chairman at rice. I teach part
55:10 at rice and uh and his name Cindy lee and he's an igneous patrol
55:18 by training. But he published his a couple of years ago proposing that
55:24 might be local algal blooms and some these sequences like the Eagle for to
55:29 austin chalk where the algal blooms. . These red tides basically consume all
55:35 oxygen in the water column. And that low oxygen water impinges on the
55:40 floor, it's going to create areas local anoxia. So, it's a
55:45 an intriguing idea. All right. irrespective you've got to preserve the organic
55:53 . All right. So, the of the models have been invoked for
56:00 carbon a source rocks are related to where you create an oxy on the
56:06 floor and you're gonna see that most the examples are associated with these reducing
56:13 , none of these are deep water . These are all shallow interpret tonic
56:17 . Alright. Arguably, never more a few 100 m of water
56:22 All right. And then just saying the marine realm, there could be
56:28 local zones of oceanic upwelling off the leeward sides of these platforms, there's
56:34 example of the restricted platform interiors and lagoons where you can squirt some oil
56:40 of these anoxic settings, evaporating This has been proposed, right?
56:47 get a lot of organic material associated evaporate basins. I showed, I
56:53 you the coastal Selena had all that bacteria in it. The question
56:58 is there enough there to make And then secondly, what would you
57:02 to do? You have to get out of the evaporates and get it
57:05 the target? So that's I think probably suggests that's not going to be
57:10 viable. And then the last example has to do with the lackluster in
57:15 you trophic lakes or lakes that are organic rich, highly uh nutrient
57:22 Okay. And if you know anything the clustering carbonates, it's not uncommon
57:29 the lake centers to be highly organic . And then the reservoirs are the
57:35 deposits, usually plastic sands, but carbonate sands made up of things like
57:42 cods. Remember we talked about Oscar could be could live in fresh
57:45 All right. Uh huh. again, the key here is to
57:52 anaerobic conditions or anoxic conditions. And the definition. Alright, so,
57:59 an anoxic setting, you would get no calcified organisms, you get no
58:04 body boring organisms. Okay. And you can see you can have this
58:11 where there's still not enough oxygen for curious organisms, but there's enough for
58:15 . You're going to see in a aerobic setting. The toc basically drops
58:20 nothing. All right. So as as you get any over printed
58:24 the toc drops to nothing. All . And then aerobic would be where
58:28 get both borrowing and calcified organisms. right. So it turns out now
58:35 all these case studies have been developed . You can see that most of
58:39 famous examples of the of the big source intervals are associated with these isolated
58:52 basins. Again, these are intricate shallow entry platonic basins. All
58:57 So that would be la luna, is source most of the oil and
59:01 in Venezuela and Colombia Austin chalk. people consider the base of loss and
59:08 to be self sourcing. We'll talk this uh uh tomorrow, I guess
59:16 afternoon and then smack over formation. so called brown, dense right is
59:23 is the source rock interval. The Permian bone springs and other big carbonate
59:28 rock biggest biggest one in North America the Governor in western Canada That sits
59:34 the origin shale that we just talked . And it has anywhere from 16
59:39 18% t. o. c. then here's the slurring a one carbon
59:43 we just talked about with an average A .35%. All right. In
59:49 , here's some data from the diver they match the core studies with the
59:54 structures in the TOc And as I , basically wherever it's anoxic where you
60:00 this classical black laminated lime mud stone , you get high TOC values as
60:06 as you get any bite probation. , this would be the dis aerobic
60:11 . I was just talking about. at the TOC values. They dropped
60:13 nothing. All right. So in words, Iraq has to look like
60:18 has to be black and laminated. it starts to look like this,
60:22 TOC drops to nothing. Okay. seems to hold for every carbonate source
60:29 that I've seen documented. All And then local zones of oceanic
60:34 This has been invoked in the A couple examples. One in the
60:39 in the Middle East and then the Korea formation in the western U.
60:44 . So, but this is on western side, Right? Where you
60:47 upwelling, the trade winds blow like that causes upwelling along the western side
60:53 that platform. Okay. We see happening today in the world of plastics
60:58 of areas like Peru Right? You you get up well in here that
61:05 minimum layer, low oxygen minimum layer on the sea floor. That's where
61:11 get local zones of anoxia but this not carbonate. This is plastic.
61:17 . And then you trophic lakes these especially these are nutrient rich lakes,
61:22 ones that are saline and alkaline. famous example of this, an outcrop
61:26 BDS and Green River. This is a carbon a source rock and it
61:31 up to 40% toc some of the samples. I don't know if you
61:35 this, but back in the early when the price of oil was relatively
61:40 . Back then 40 or $50 a , which is really high compared to
61:45 . Um They companies like Exxon actually mining this stuff in outcrop,
61:52 Oil shell and this is their mining a source rock from across. All
61:57 from the from the Green River in . Alright. And then last example
62:03 the restricted platform interior reef lagoons. example supposedly is the Jurassic Hanifa.
62:10 I actually think the Hanifa fits more the reducing basin story but it's it's
62:15 interpreted also to be were isolated lagoon or platform interior. Alright,
62:22 again, when I started none of were thought to be source rocks.
62:26 you can see the breakdown of the values for the different units. We've
62:31 talked about Eagle ford in south Alright. Again, I'm not seeing
62:39 numbers yet but I've seen values Presented talks up to 8%. All
62:44 I think it's probably a lot higher that in places. What's it.
62:48 I find interesting is the austin chuck I worked the austin chart for my
62:53 And you can see now published values to 21% at the base of the
62:57 . Alright. Really interesting. All . You do. Yeah.
63:06 I think that's a way for some take a chunk of rock and they
63:11 it down. Okay. All So summary side and obviously carbonates the
63:20 important. Only gas reservoirs toc can highly variable. It depends on
63:26 Mhm. How you preserve it? preserve it by creating reducing conditions on
63:31 sea floor areas of anoxia. And as I said, mostly carbonate
63:38 rocks have a lower toc cut off . Not that you need it when
63:41 have values like 29% or 18%. the bottom line is that these things
63:48 break down much more efficiently. Uh oil and gas compared to the
63:52 E coli organic material. All Mhm. Right. So obviously we're
64:01 a minute we're going to start our about carbonate play types and source rock
64:07 to be factored into that, but doesn't have to be a carbonate source
64:10 , it could be a shale Okay, any questions or comments about
64:19 sorcerer. Mhm. None of those shales. Those are carbonates there,
64:35 mud stones with organic materials. So organic rich lime mud stones.
64:42 Or wacky stones. It could be stones. But the key is that
64:46 black. They're laminated their organic there's no borrowing. Okay.
64:56 Take one more break here. Take five minute break. We'll start back
64:59 four and we'll get into our source our carbonate play type discussion, which
65:06 going to consume the rest of the . Part of Mexico part of this
65:12 . Okay. Yeah, yeah. all sitting there. You're ready to
67:17 . Okay. All right. So left handed first rate. What do
67:25 do would you do? Crisis? just trying to write, write
67:32 Just trying to write, but why aren't you using your left hand?
67:38 huh sort of stuff. Okay. right. Two. Okay. So
68:00 is the beginning of lecture 17 and gonna start with some introductory comments about
68:09 and event eventually unconventional carbonates. And , I guess the first thing I
68:15 to tell you is I use the conventional, unconventional differently than most people
68:20 it today. Right. The unconventional today are the shale plays or the
68:24 fine grain, organic rich carbonate plays the chalks. But I use,
68:30 been using the term unconventional and conventional back to the, To the 80's
68:37 I view conventional plays as those that historically chased because of their good size
68:42 expression or because of their unique compositional . You know, like a long
68:47 margins and things like that. Things could be imaged off of off of
68:52 . And I viewed the unconventional play as being the ones that they didn't
68:55 as much either because it didn't have expression or because they were die genetic
69:02 and a little more risky companies wouldn't him as much. So I just
69:07 you to know how I'm using this unconventional. Right? It turns out
69:11 a couple of my examples of of plays are what people today would call
69:17 place to. But I just want to know that I'm using a little
69:21 differently. All right. So you this slide when we started our first
69:28 , several weeks, several Fridays Right? I said every carbonate play
69:33 the three Elements Reservoir Source Conceal. then you need a traffic mechanism.
69:39 historically these traps can be pure strata . They are more typically combination or
69:46 could be just structural structural where they just a structural effect. Right?
69:52 we I said that you know each those three elements, whether it's a
69:58 faces or reservoir faces or source rock are always influenced by these bigger scale
70:04 like de positional faces or digest And then we talked about some of
70:10 other factors that control the de positional or the dye genesis. Right?
70:15 we've talked now about barrel history pore chemistry that comes along with that.
70:19 talked about fizz a graphic setting at two different scales. Right? The
70:24 scale and global scale of which is you sit relative to the equator and
70:29 the the local scale, which is bottom topography. That's our two M
70:33 models that we've been talking about. hope you appreciate now the influence of
70:39 , right. Age determines who the were. And that controls some of
70:44 play types also controls the starting meteorology the digest potential for some of these
70:50 . Sea level history. We talked this last weekend. The role of
70:55 level in carbonates is mostly to provide accommodation and then the major changes terminate
71:01 of these packages of sedimentation. And climate doesn't just mean rainfall or no
71:08 . That also brings into play the winds systems we've been talking about.
71:12 right, So, and then the rock story. I just gave you
71:19 . So, I just want to one more comment about why carbon a
71:23 rocks seem to be more effectively broken into oil and gas. It's because
71:29 start off with the this material lipids, apparently the same material that
71:36 our arteries is what makes up a of, a lot of the marine
71:41 organic material and carbonate system. an interesting thing about lipids is that
71:45 breaks down a lot more effectively into or gas. Then woody, woody
71:51 Coley material. All right, and that's that's a characteristic of all
71:56 these carbonates source rock examples. All now, several lectures ago when I
72:04 you to the our discussion about modern , I showed you this schematic cartoon
72:11 a platform to base in transition. I believe I made the comment that
72:16 along the stem positional profile you could carbonate play developed, but it depends
72:22 the age. Right? And I , you know, like pinnacle reefs
72:28 very common in the rock record, not every geological time period. They're
72:32 in the slurring devonian, they they come back again in the
72:37 they disappear, they come back again the tertiary. All right. And
72:41 have no modern analog for this. of our none of our all of
72:46 ocean basins are too deep for these of pinnacle reads to develop. All
72:50 . So that's the age effect that have to factor in. All
72:54 So, what I'm going to offer is a classification scheme for carbonate
73:00 Both conventional and this includes some of unconventional as well. Where I'm going
73:05 try to relate the reservoir distribution and to the source and seal faces,
73:12 do it within the context of fizzy setting. Okay. And again,
73:19 context of Fizzy graphic setting has to two scales. Right. First,
73:24 has to be at the global scale you need to know where your base
73:27 sat relative to the paleo equator because defines whether you're in a tropical or
73:34 or cool water belt. Right. you're at relative to the equator.
73:39 then the local fizzy graphic setting would the bottom topography. Alright. Is
73:43 more platform? The base in transition is it more ramp to base in
73:49 . And then what does geometry me means? What happens is you give
73:53 systems time to act? Do they pro gradation? All geometry. Do
73:59 build aggregation? Allele build up Okay, that's what I mean by
74:04 . All right. So, you're to see my break out here of
74:10 play types the conventional plays. You how they relate back to a position
74:16 a deposition. All profile. All . So, you can think in
74:19 terms forgiven age sequence. So, I would call the more conventional plays
74:25 be the platform margin or ramp crest grain stones, platform margin reefs.
74:32 don't get these in ramps right? they're only limited to the platform
74:36 Platform out and carbonates which again, usually associated with the platform to base
74:41 transition. And then either platform interior ramp related. The critic wacky stones
74:48 Pakistan's obviously to create reservoir quality. have to do something favorable in terms
74:53 die genesis. All right, we'll about that. And then the basin
74:58 down the ramp mountain buildups. This include the high relief finical reefs.
75:03 would include low relief buildups we see the upper paleozoic like. Okay,
75:08 then the unconventional plays, the force carbonate deposits. Will they relate to
75:13 off of a carbonate platform? Or even a ramp? Right, You
75:17 actually shed material from the shallow Parts of ramps down, down into
75:22 basin. Alright. Basin all de chalks would be the second unconventional
75:28 And then fall control, digested And then I've listed because this is
75:35 listed in the literature. Sabah conformity plays fractured carbonate. Slow custom
75:41 microbial carbonates. And I actually put reservoirs as part of this while Church
75:46 not carbonate there normally associated with the water based on all parts are down
75:52 ramparts of these carbonates, successions. right now, I don't know if
75:57 notice this, but I posted uh bibliography on blackboard and the bibliography covers
76:05 of these plays, including these. , even though I'm not going to
76:09 talk about these, I just don't time to do that. Okay,
76:13 it turns out that what people call conformity cars placed sometimes are one of
76:19 other play types modified by cars. , when I go through these other
76:23 unconventional plays, if they get curse , I'll tell you that. And
76:28 tell you what effect that had on quality. Okay, the same with
76:32 carbonates, Right, The concept of carbonates is a misnomer because fractures don't
76:38 enough ferocity to account for the volume hydrocarbon for what people call fractured
76:46 And what do they normally call fractured reservoir reservoir that has low matrix ferocity
76:53 permeability. Usually permeability. Okay, role of fractures is to improve the
77:01 . You still have to be producing some other kind of ferocity in those
77:07 in order to account for the volume hydrocarbon that's produced. Okay, and
77:12 custom carbonates, I'm not going to talk about them because I I don't
77:17 any experience. So there is no examples of this and the subsurface that
77:21 know of. The famous examples are in china or they're in the subsurface
77:28 brazil. And some of these low carbonates also turned out to be microbial
77:35 . Okay. In other words, travertine deposits that people have talked about
77:43 with these like Custer and carbonate or reservoirs turn out to be produced by
77:49 carbonates. Alright, so I just you to know that I've lumped them
77:55 here, but I just don't have to talk about these. All
77:58 but where we encounter somehow conformity cars these other play types or fractured over
78:05 , I'll talk about this. And role that place. Okay, all
78:10 , so here's my evolving diagram, just changed this uh about a month
78:19 . Uh even though I talked off this in these terms for a long
78:26 , I decided to add this lower to the story here, basically,
78:30 you see here is a plot of versus position along a deposition profile.
78:38 . And when I first drew this back in the 80s, I intended
78:42 to be a platform to base in . Right. So of platform,
78:49 , high energy platform margin the right? Usually the slope angle is
78:55 than I indicate for this cartoon here then the deeper water basin.
79:02 And then, sorry, this is computer acting up again. Um right
79:10 , you know, the more I at this, every time I
79:12 just gave this lecture, I realized this little bump could be what this
79:17 bump could be the ramp crest. . And you could have a ramp
79:22 like I showed you for abu Dhabi weekend with the title flat back here
79:27 then what would be different between here here and here and here would be
79:32 slope angle and the depth of the . Right. And the ramp model
79:36 slope angle is a lot lower going into the basin and the basin never
79:41 really deep. Okay, remember the hundreds of thousands of meters of water
79:46 here but tens of meters 200 less 100 m of water depth out
79:53 Okay, so, and then you see the play types, how they
79:59 to a position along a platform or . Okay, so carbonate sands would
80:06 in this model right here, The political sands or skeletal sands derived
80:11 reef. So the reefs would occur this position here, but there would
80:14 no reefs on the ramp to speak . Right. Certainly no linear platform
80:20 reefs like we get in in the or great barrier reef. Right.
80:25 right. If you got ramps, you got the reef in a rat
80:28 , you have to have older pre topography like I showed you last week
80:32 the abu Dhabi example, little fringing in front of an island. All
80:37 , right. And then, carbonate sands displaced on lapping wedge right
80:44 . You could do the same, guess, over here, you can
80:46 this, put it in this position here and then in the basin,
80:51 could have uh, widespread chalks with sheet like geometry, right? Developed
80:58 in deep water or, And the part of the basin of the
81:05 Right. And then in a both , you could have down the slope
81:12 . Okay, pinnacle reefs or other relief mounds, They actually don't occur
81:17 the deepest parts of the basin. occur in this transition zone from the
81:22 to the basin. But both could mounds in that setting right there.
81:27 then what about the platform material? platform material can be widespread sheets of
81:32 or mud. Of course, if mud, it has to be
81:35 Klay favorably altered its carbonate sands that produce from primary porosity in a ramp
81:42 . What would you have here? would have more MMA critic settlement.
81:46 . I didn't we don't have any in these ramp interiors where their grain
81:51 dominated right there. My critic. then with respect to low relief build
81:56 , you can have low relief buildups , but you wouldn't get it in
81:59 ramp interior. It's too restricted for refill organisms to live. All
82:05 So everybody understand what the geometry means like pro gradation all ribbon like aggregation
82:13 along the strike of the platform Alright, we're can't pro grade.
82:18 can reach camp program. So, those geometries only relate to the carbonate
82:26 or reefs along the platform margin then course that the sheet like only relates
82:31 the sands and muds that occur in platform interior and then mount like just
82:35 build up topography, recognizing you can the scale of a low relief mound
82:41 is tens of meters high to one is over 1000 m 1000 ft
82:46 Okay, 100 m More than a meters. Sick. All right,
82:52 ft 1000 ft thick. For 300 six. That's what I meant to
82:56 . All right, okay. You what I'm trying to do here.
83:00 trying to get you to think about play potential that exists along whatever deposition
83:05 you've resolved from your regional data or data. And then what's the next
83:12 you need to factor in the Right? Because you have to think
83:17 each of these profiles in terms of age cretaceous different kind of fun to
83:23 to the salary in all right salary different kind of funny compared to the
83:28 tertiary, like the miocene. Different builders of mounds. Right.
83:33 age. Ages of critical. All . So you have to factor that
83:37 . All right. And then of you need to factor in your regional
83:42 geography where your base and sat relative the paleo equator because you need to
83:48 whether you're in a tropical or subtropical temperate water climate. Alright. And
83:54 you use these maps and you can Blakey's maps. I don't have anything
84:00 Blakey other than he tends not The only he only puts the equator
84:05 some of his maps. Right? have to guess where is the 30°,
84:09 the 60 degree? So the maps I prefer are the ones like
84:15 Published in 2002. These are referenced the back of your bibliography. They
84:20 you the equator. They show you 30. They show you the
84:25 Okay, Member 30-30 is tropical but the tropics only go from the
84:32 to about 21, and then a north or south of that. And
84:39 they show you that they show you direction of the trade winds,
84:43 So they take the guessing out of way the winds blow. Right?
84:47 in that 30 north to 30 Trade winds blow out of the eastern
84:53 , But they don't blow 5° on side of the equator. That's the
84:58 . And then the wind shift from West once you go north or south
85:02 30. But that is then when into the cooler water, which is
85:07 good for shallow water, carbonate deposition foods or reefs. Okay.
85:16 And in your slide set that I you, I put more diagrams and
85:21 going to show you here just to you how, how these basins can
85:25 around depending on the geological age. in the slide set that I gave
85:30 , you're gonna see a map that like this with three dots a red
85:36 for the Permian basin today. The dot, which is the western Canadian
85:43 basin today. Okay. And then blue dot is, is the tertiary
85:53 Libya. All right. It's a called certain based on one of the
85:58 hydrocarbon provinces in Libya. Okay, let's go back to the salary in
86:06 let's just watch these dots move Okay, You need to appreciate that
86:11 things migrate right. The continents Right. So you're basins move.
86:17 right now that the seller in, a there's the uh, there's a
86:26 in. Right. And where is ? It's right on the borderline between
86:32 right south of the equator. That's to being close to the doldrums.
86:38 again, I would never take these and and and definitively say that's exactly
86:45 we were. I've used the geology prove whether in the doldrums or whether
86:49 in the strong trade Wind belt. going to show you how you do
86:53 with this lecture. Then you can where the Permian basin was. It
86:57 almost out of the tropics, right the south side of the equator.
87:02 then look at Libya, it's out the tropics, it's in the cooler
87:06 climate. Back in the cellar in right, okay, lets go
87:11 look what happens here. The Permian up. Look at this dramatic migration
87:15 Libya, it almost comes back up the subtropical belt and the Devonian really
87:23 move right now, the Devonian it moves up into the easterly trade
87:30 belt. All right, the strong trade wind belt, the Permian is
87:34 the strong easterly trade wind belt, south of the Equator and now Libya
87:39 moved into the gentle easterly trade wind south of the Equator. Carboniferous,
87:47 Permian. Look at western Canada. , it's moved out of the world
87:50 carbonates. It's out of the subtropical . Right, It's into temperate water
87:57 . More plastic dominated. All but look at the permit. It's
88:01 hanging around right, it's right close to that line of demarcation between
88:06 doldrums and the strong easterly trade wind . All right, okay, so
88:16 is one of the first things you do when you get thrown into a
88:18 basin. Let's go back through the times of interest and find these maps
88:25 try to figure out where your basin . Okay, tropical subtropical along the
88:34 , cooler water. Right. And what part of the tropical subtropical
88:38 Because that determines the strength of the ? That also determines whether your area
88:43 interest is windward or leeward with respect those strong winds. Okay,
88:50 Okay. And and again, I want to belabor this, but it's
88:55 to good to repeat these relationships. right, but you are familiar with
89:00 , what we're talking about, tropical subtropical built Doldrums, right 5°
89:07 either side of the equator. And the easterly trade winds stronger from five
89:12 to 22 on either side, weaker 22 to 30 on either side.
89:18 . Yeah. All right. having said that, we're gonna get
89:23 our first group of uh play conventional play types. These are the
89:28 margin, ramp crest grain stones. this will be the only example where
89:34 is a play type will go through the rest of this afternoon. Then
89:38 pick everything up tomorrow and go through rest of them. All right.
89:42 for all the five conventional plays that going to talk about. I put
89:47 a little cartoon like this that tries show you the inter relationship between reservoir
89:53 and seal. All right. So , these grain stones obviously tend to
89:59 in high energy settings right? Oftentimes along the margin of a steep platform
90:05 at the ramp crest position. And again, if the sand bodies can
90:09 grade, they end up with a like geometry, that's appropriate additional geometry
90:14 was talking about and then what over them eventually because of procreation. It's
90:18 back shoal. The critic carbonates, ? That provides a top seal for
90:24 reservoir and then your source rock is an offshore nearby baseball shale or
90:30 Alright, now, couple of first about this style of play development and
90:36 first is the role of paleo Alright, why do these high energy
90:43 stone bodies exist? They exist in because of the paleo topography.
90:49 You need favorable paleo topography that is agitated by whatever mechanism. All
90:57 And so to illustrate that here's an from the laura Curtis Edwards trend in
91:04 texas. All right, there's the trend that we'll talk about as a
91:07 type tomorrow. And then this is broad, low energy. My critic
91:13 represented by the green and orange and . Okay, but look at what
91:18 when you come up onto this little high called the Belton high, which
91:23 a structural extension off the land to . The landau uplift is a a
91:29 pre Cambrian paleo high, right green battle It essentially, it was a
91:34 features through actually goes to positive going back to the camera in and
91:40 that itself is a positive feature into upper cretaceous. Alright. And so
91:46 belt and highs of structural extension off that and look what happens when we
91:51 up onto this belt and high, developed this thick Over 100 ft thick
91:55 Hewlett Grain Stone. But look where at the scale bar here We're well
92:02 100 km in from the open How would you get Heinrich Bulajic sand
92:09 100 km sent from the open ocean this is titled current dominated, remember
92:15 title current examples last weekend we're always to the platform margin. Right?
92:23 cannot open platform. That was the to 1 m per second,
92:29 Half a meter per second example. then when you had in payments cutting
92:33 in, you could increase that, title strength by two or three times
92:39 that effect would only carry inboard Up the platform to maybe 20, km
92:44 the most here we don't have an payment and here we are 100 plus
92:50 in from the open ocean. So the other part of the story
92:57 The trade winds? Right, this the role of trade winds, they
93:01 agitation in board. You're not dependent a platform margin. Right? You're
93:06 generating the waves out in the basin moving them up on the platform when
93:12 wind blows, it gets rough. look, you get local wind wave
93:16 . I showed you the video, ? That's the kind of agitation you
93:21 that comes on right away as soon the wind starts to blow, as
93:24 as the wind sets down, nothing . Okay. So this is one
93:30 the first principles the interplay between paleo and energy. But here, the
93:35 has to be created by the trade because you're that you're so far
93:40 There are only two ways to make It's tidal currents or persistent wind wave
93:45 . Alright, How far from built is the I'm just saying post
93:55 we don't know for sure because stuff's stripped off, but there's a land
93:59 uplift. Right? So, you where the land adoptive is today,
94:04 of fredericksburg. Right? Yeah. not I don't I mean, I
94:09 think it's 100 miles maybe 7 60 miles, something like that at this
94:16 . Still right, extensive, yeah, yeah. All all of
94:21 is shallow water. All of this shallow water carbon except around the land
94:25 uplift. All right. The laptop a positive feature. All right.
94:34 the problem is that all this stuff been stripped off later. Right.
94:38 uplift. And with the classic deposition the in the tertiary water part of
94:47 may have been underwater. There may been a beach up against it.
94:51 may have been a fringing reef up we don't know, but we don't
94:54 anything preserved. All right. But showed you how Reese could grow on
94:59 basement. I showed you the example very, very reef. Alright,
95:03 , so to the south east of Stuart city, that's just that's the
95:09 right? That's a ancestral gulf of . That's deep water pelagic carbonate
95:14 Alright. We'll talk more about the in detail as a play type
95:20 And then the second thing about these stones is I want to remind you
95:23 every one of these brain stone whether they're allergic or skeletal or a
95:28 of fluids and skeletal material. Every stone has two parts the active part
95:37 the stable part. Right. And talked about the difference between the
95:42 Right? I mean, you should need to really understand this. You
95:46 , How do you tell the active the stable, Right. The activists
95:51 agitated every day or on a frequent . So it's good clean grain
95:57 no mud. Right. Good preservation sedimentary structures. Right fits you?
96:02 it's pretty well sorted, Right? allow skull of material because nobody wants
96:05 live there. And then what was stabilize stuff still shallow, but it's
96:12 it's not actively agitated. So seagrass at least back to the cretaceous
96:21 poorly sorted, a lot more skeletal there. Right. So it's going
96:25 be preserved as a uh usually as pack stone with varying degrees of
96:32 Right, right. Low muhammed Or it could be a poorly sorted
96:37 stone off off some of the All right. And why do we
96:41 a big deal about that? Because had to do with ferocity preservation.
96:45 , poorly sorted, well sorted. bury it. Which one loses frosty
96:50 . It's always the poorly sorted. , I think I mentioned this last
96:54 in my experience, no matter what , die genetically. It's the active
96:58 of the Greenstone belt. That is reservoir. And it's a stabilized
97:03 That is a side or top seal that reservoir. Okay. All
97:09 so let's just get into some of different examples here. Mesozoic examples.
97:14 start with that. And the first would be the Jurassic smack over formation
97:19 Arkansas and Louisiana. Although there's a trend that runs from east texas to
97:27 . And this is the general starting for the smack over. This has
97:32 out mostly for for Arkansas and You see the light blue here is
97:37 is the high energy grain stone All right. You can see the
97:42 of the smack over. I used turn brown dense before. That's that
97:46 pelagic carbonate was still stone that's probably from the Mississippi river. And then
97:51 red and brown here represent more of back show lagoon and the red beds
97:56 evaporates. That's basically the Buckner. . It's a different formation, but
98:00 part of the deposition all sequence. . And then you can see what's
98:05 that, right? The nor flip stones and then there's a Warner anhydride
98:10 that and the low in salt. right. So this is the trend
98:16 the northern gulf rim and this trying exist down into Mexico too. And
98:22 is some production from roughly equivalent carbonates Mexico. But the history of this
98:29 is the initial discoveries were made in Arkansas ah probably from surface seeps such
98:36 I'll lot of these things are So back in the 20s oil production
98:42 southern Arkansas and then it gets a bit deeper as you go into northern
98:49 is basically a limestone trend. So reservoirs from about 2000, about eight
98:54 9000 ft of burial. Okay. then what did they do? They
98:58 by trend ology. The trend in east texas. I'm about to holler
99:03 my computer. And what happens you get into a gas and condensate
99:12 because it's more deeply buried and what to happen to these rocks over
99:16 they have to be Dolma ties to productive. Alright. And then the
99:20 was pushed this way Mississippi Alabama florida here it's a mixture of oil and
99:29 production. But these are more deeply reservoirs 12-20,000 ft or more. All
99:34 them have to be dramatized to be . Okay, so let's just focus
99:41 on the classical area in Arkansas and . You're going to see the ramp
99:45 is applied the southern Arkansas, northern of Louisiana until you get down here
99:51 what's called the state line Robin. ? There's a bunch of a lot
99:55 little riffs and false systems that cut here. There's also some some pre
100:01 topography that comes into play here to some of the Jurassic deposition. But
100:06 faulting is probably more important because it these basement highs and those basement highs
100:13 where down the ramp, right? they create paleo topography and overall deeper
100:19 setting. So the classical model deposition for the smack over is the ramp
100:27 very similar to what we talked about the modern for the Arabian gulf.
100:32 so the ramp model applies to the part of this trend because the eu
100:37 form in a shoreline are close to shoreline position. Right? That's the
100:41 crest. And then what do they they programmed? Right. And they
100:47 grade down. They program it out there. Down ramp critic carbonates which
100:51 grade out over the the brown, laminated Mick, right? Which is
100:55 source rock. All right, And then everything is sealed up dip
101:00 the Buckner red beds and evaporates. right. And the only time you
101:05 high energy with sands developed further offshore in this position here is if that
101:10 system comes into play to create paleo , right? So if those faults
101:16 basement topography in a down ramp, water setting, you can get high
101:21 you is developed on top or as see later, even localized, it'll
101:26 ups. Alright. Mhm. But classical smack over model is the ramp
101:31 shoreline related. And you can I mean some of these sand body
101:37 have pro graded over 30 or 40 . All right. So it makes
101:41 big difference whether you prospect more up or more down dip and the reason
101:47 that matters is because of the digest of the smack over in this part
101:53 Arkansas and Louisiana. So people like former colleagues Jack Winnie and when he
102:01 here in Houston and then later Clyde when he taught at LSU and was
102:07 of a big industry consortium on the over. These guys have done what
102:13 have mapped out these regional diabetic Okay, You look at the update
102:17 of the snack over in light very different kind of digest history.
102:22 down dip part in green, very diet check history and then there's a
102:27 zone here where some of the pools attributes of the blue and the green
102:32 terms of die genesis and porosity All right. Well, obviously where
102:38 of the pools during the green. . So what's what's going on
102:44 Something happened after Jurassic deposition. Something in the cretaceous and the feeling of
102:50 people is that sometime during the the update part of the trend saw
102:56 influence of a regional aquifer system coming from the north. So the yellow
103:01 which corresponds to the update built in previous map, characterized by one style
103:07 porosity development. The down dip part saw that effect. That's the blue
103:12 then there's a transitional zone shown in here where you get a mixture of
103:17 styles of die genesis. Alright, the up dip looks like this.
103:23 call this style of ferocity development. is what we called ferocity inversion.
103:28 compaction dissolution agreed because all the calcite go all the way around the
103:36 There's no collapse of the poor There's no pressure solution. There's no
103:41 between these grains before they got All right. And the implication is
103:47 this is basically fresh water pre attic genesis where the former magnetic whose leach
103:53 generates the pre compaction, low magnesium cements. If you preserve enough primary
104:00 particle ferocity, you end up with good reservoir. If you don't you
104:04 up with what I called heartbreak Right. A lot of ferocity no
104:10 . Okay, that's the update part the trend. There were just a
104:14 of pools associated with that trend. down dip pools are producing from prostate
104:21 like this completely different diabetic history No early die genesis, right?
104:27 early dissolution, no generation of much porosity. The EU is just got
104:33 progressively. They got Suchard. They the burial calcite cement. So we
104:39 about last weekend but you didn't destroy of that primary porosity. So you
104:44 have decent permeability. So you might tens of millions ourselves to a few
104:48 million darcy's of permeability. Okay. why all the pools are down where
104:56 at. All right. They didn't the upkeep, freshwater effects. All
105:04 . And walker creek is is perhaps best example of this. I
105:09 these are not giant. These are giant. Oldfields. Okay, 100
105:14 barrel oil field. That's about as as it gets for this part of
105:16 smack over. All right. In of size. A lot of them
105:19 a lot smaller than that. But can you can get a feel for
105:23 the makeup of of the play in of trapped reservoir seal, structural
105:31 hydrocarbon column, hydrocarbon mccollum is greater the structural closure. So that means
105:37 these are basically strata. Graphic Right, update porosity pinch out.
105:42 basically creates a ceiling effect. All now, what happens when you go
105:48 east texas. When you go into texas, you get the same deposition
105:53 ramp profile, but now the grain up dip along the shoreline. Have
105:58 be demonetized to have favorable porosity. , so here's the map that shows
106:03 the pools. So there are actually couple of different provinces where you get
106:08 development. The classical ramp profile occurs this position up here, closer to
106:14 paleo shoreline. So the big field brian's mills or these fields over here
106:21 brantley, brantley Jackson occur in the parallel Hewlett exam body systems.
106:26 That's the classical ramp model. what's the variation on the thing?
106:31 variation on the theme is the down . There's salt tectonics in east texas
106:36 create paleo structures on the sea So instead of having to use the
106:41 basement faults like I alluded to in state line. Robin, what's providing
106:47 topography here? It's a salt Right. Salt punch up structures wherever
106:51 occur when they pop up close to level, you get into a sand
106:55 . Well, what's going to drive could be titled currents I guess.
107:00 it could be could be the trade agitation, but irrespective every one of
107:05 pink blobs you see there has that would sand body and little reservoir developed
107:11 top of it. Okay. And the other part of the story here
107:14 there's a fault line trend here to comes into play. The faulting is
107:19 so much for the deposition. It's the driving the dye genesis. All
107:24 . It's going to create the opportunity dole immunization, favorable dole organization.
107:29 right. So the reservoir rocks, start out as a lot of grain
107:41 because they're too deeply buried in terms preserving ferocity. I think maybe I
107:48 you, you know, once you below about 12 13,000 ft of
107:52 any early form ferocity tends to be or if it's secondary tends to collapse
107:57 itself. And so these reservoirs are 12 13 14,000 ft of burial.
108:04 so you need to be, you to have a scenario where you create
108:09 rigid framework that holds onto porosity or create the process a depth. All
108:14 . So some of the some of dolomite is early are interpreted the early
108:18 you're holding onto it too much deeper depths or in this example here from
108:23 Hope. See the U. Are already featured before they got
108:28 So this is barrel demonization, creating secondary porosity. So it's a mixture
108:34 a little bit of preserved primary prostate the grains, lot of secondary processing
108:39 the woods leach out. And then a matter of you also tie this
108:44 together by fracturing because the Dolomites are brittle and they're going to tend to
108:49 and connect some of that secondary Alright. So this is one of
108:54 better fields. New Hope Field. can see 400 and 64 BCF of
108:58 produced Over about 30 years. 35 . Alright. And where most of
109:04 reservoirs are mostly associated with the act shoal. Right. Good. Well
109:08 grain stone turns into this on the . But there are some examples of
109:14 more poorly sorted, stable flank of USs cole also getting dramatized and generating
109:20 porosity. And we had this discussion this was a You would political or
109:26 , you would pack stone because these leech do IDs are too widely spaced
109:32 be touching each other? It had have them a critic matrix. So
109:37 got dramatized first the matrix and then got leached out for the reasons we
109:42 about last weekend. The bigger the and P Lloyd's. Right, so
109:46 not great permeability, but what connects all together. Again, the
109:53 Okay, that's the beauty of Anything is you're going to have an
109:57 degree of fractures that helped tie that together. Okay. And then this
110:04 a summary from some of Clyde moore's about the different trap types as you
110:08 expect most of the traps or combination the structural strata, graphic component.
110:13 there are some famous strata graphic and you could call digested traps where you
110:19 from, preserve primary porosity to secondary inversion. With no permeability and that
110:26 as an up dip seal for the . Okay, that's what you actually
110:31 at Mount vernon field in Arkansas. right. Saudi Arabia. We had
110:38 discussion about how big the structures are you are. Look at the scale
110:43 . That's 30 km. All So, you see how this lines
110:47 basically parallel to the do hand to oil field. Do I know field
110:53 cutter that we talked about earlier, the same similar false systems that are
111:00 north south. All right. The model is invoked for the arab
111:06 All right. So, you're high grain stones would occur in the ramp
111:09 position here, deeper water this way then the restricted the critic, lagoon
111:15 red beds and evaporates in that position there. And this is what some
111:20 the reservoir rock looks like in thin . You can see again ah a
111:27 of fluids and p lloyds and some material. And then I told you
111:33 of this stuff gets stolen, monetized Qatar. It's the same thing in
111:36 D. You can get some of stuff dramatize some of that can be
111:41 critic fabrics. Some of that can grain stone. And if you have
111:45 that obviously can be productive. And then the seal, This is
111:51 This is a classical up dip. are the cd evaporates that occur on
111:55 of the arab D. All And most of the interpretations relate this
112:01 Osaka except I think there's an issue when you get really thick examples of
112:09 ? This is probably subtitle and not titles that All right? That you're
112:14 in order to build a greater vertical of operatic fabric. Member of the
112:19 with these fabrics is just because they like this doesn't mean they started out
112:24 this. Okay, They can re and change fabric. So, and
112:31 the last couple examples here to illustrate importance of the trade winds and localizing
112:36 of these grain stone bodies and settings historically based on the northern Bahamas,
112:42 would never look in these settings for kind of grain stone deposition.
112:47 People found this by serendipity. They looking for these grain stones.
112:52 so the first example is a little called Vivian field in uh central
112:58 So there's a border with texas. is a the oldest cretaceous in texas
113:05 called the Mhm. Yeah, It's called the Sligo. Alright.
113:12 the poorest part of the lower cretaceous called the Yeah, no,
113:17 The formation is called Sligo. The part is called Pettit. All
113:21 The term pet. It is used the poorest part of the Sligo around
113:25 gulf rim. All right. And here's this little field called Vivian
113:30 This is producing from Hewlett grain Look where we're at where's the open
113:35 right here. So, how far that? That's 80 km. so
113:41 1 60. Almost 200 over 200 at least. Right. And from
113:47 open ocean tidal currents don't operate that up on a carbonate platform. I
113:52 you at the most 20, if you have an embankment coming into
113:58 of that margin, there's no involvement . That's an open platform.
114:04 So why do these grain stones exist they exist? All right,
114:08 first of all, this is this body system is associated with a structure
114:16 the cattle pine island structure. All , sits up in this position right
114:22 . All right, here's the Where's the field? It's not on
114:25 structure. Its behind the structure. right. So, think about,
114:30 did I tell you when you have topography and the trade winds are blowing
114:35 waves like this? What do they ? They diffract around both sides.
114:42 is what I showed you in Right, well, here it
114:45 And here it is in the Let's create on the backside of this
114:49 feature. Right? To me, fits you know, if the trade
114:54 are principally coming out of the southeast , this fits that tom Bullough effect
114:57 we talked about on keiko's platform. . Yeah, they're gonna trade winds
115:05 gonna come. They're gonna win. are gonna wrap around and they're gonna
115:08 gonna hit behind that paleo high, , and they're going to agitate the
115:12 enough to be agitated? You're going get the grain stones developed and in
115:17 , what do you do? You a series of stacks which show
115:21 Right? They build back. They out. They build back.
115:25 And the key here is to see you have you is this far inboard
115:30 the open ocean? That's the key to make who is as we've talked
115:34 , you need supersaturated seawater, you water renewal and you need persistent
115:42 But you're too far inboard for tidal provide persistent agitation. Has to be
115:48 trade winds. And this is when look at your paleo geographic map,
115:52 suggests your 15° north of the equator on relationships today. That's in the
115:59 of the strong easterly trade wind Okay, so I would argue the
116:04 that you have the zoo. Is far back in is the evidence the
116:09 evidence that trade winds were operative for part of the of the Sligo in
116:15 position. Okay. Mhm. This of strength this I offered them.
116:26 the shoreline. Yeah. This is this is so close to the shoreline
116:32 these are ramp related carbonates. Once get behind that paleo high and the
116:38 for that is this right? The . When you see the shingle.
116:44 fact here that's pretty typical of Remember we talked about this right ramps
116:49 grade out. They back step with little rising sea level. They procreate
116:53 they back step. So yeah, close to the shoreline and more ramp
116:57 profile, but behind that paleo All right. Offshore paleo. I
117:09 . What do you want to see ? So that time Mhm.
117:19 Still afraid someone's going housing. It's . It's this stuff right here.
117:31 this mixture of wood and scale That's the reservoir. Greenstone says mostly
117:38 it's mollusks and calculus allergy and forums stuff like that. But with the
117:43 mixed in. All right. So where they were. Yeah.
117:52 I think that's I think that's a genetic effect here. All right.
117:59 not saying that not seeing thin sections the tight stuff. All right.
118:04 , I can't tell you for But I'm just surmising that they're calling
118:07 a grain stone. That's probably not stabilized equivalent. But it could be
118:12 mean, No, it couldn't be once you stabilize you like sand you
118:17 more skeletal material mixed in. All . So, I would say that
118:20 yellow is the active shoal and actually is for the flank. Were you
118:26 a mix of skeletal analytic material? right. There's still a Greenstone.
118:33 , So the key here is to the fact that you've got these woods
118:36 in and they're this far in from open ocean. All right. This
118:41 not stuff transported back. All This is this is institute carbonate.
118:45 it, sand deposition. It has be driven by the trade winds And
118:49 is this is some of the reservoir looks like this. Right? So
118:54 all of the Greenstone is is I mean it's not all pureed
118:59 You've got these are molluscs with the right envelope. You've got to kind
119:03 terms mixed in. All right. this is also the famous example where
119:07 get that petro physical effect that we about, high degree of high degree
119:12 microprocessor in the woods, But effective ferocity between the grains. This is
119:18 the oil is. This is where irreducible water is. These are the
119:22 examples that have 70, calculated water , but don't produce any oil.
119:29 produce any water. They produce oil free. Okay. And then a
119:37 of related fields that you may or not have heard from. An east
119:40 , Alabama ferry and Carthage field. right, similar relationship. They sit
119:46 up on a cretaceous platform there too inboard from the open ocean to be
119:52 by oceanic tidal currents. Okay, trade winds are the implied Mississippi in
120:03 again, you look at the paley for the Mississippi and in the mid
120:06 area. Again, you fall in south of the equator. Again,
120:12 very close to that Uh 5° south the equator. All right. And
120:20 a bunch of famous examples in the content area. Uh like the Sainte
120:26 and Chester and morrow that are productive analytic grain stones and there's a production
120:36 Houston and payment. You got a . It's a big hydrocarbon province in
120:41 western interior. You can see where at Kansas, mostly Kansas,
120:46 And some of the production that occurs is from Mississippi and uh, mm
120:55 and skeletal grain stones. You can how much oil has been producer.
120:58 billion barrels of oil. All And you can see the old
121:04 right? This is uh, robert back in the Back in the
121:12 What did you interpret all these sand to be related to tidal currents?
121:18 that was the only model that was available. Right. We were just
121:22 to develop the cocoas model for trade . All right. But this doesn't
121:28 any sense because you're up on one these integrate tonic basins, isolated basin
121:34 from the open ocean. You're not to get oceanic title driven currents.
121:39 ? So what are you left with left with the, the trade
121:45 This, this needs to be reevaluated my opinion to look at the orientation
121:49 these sand bodies and see if they're with the orientations like we talked about
121:54 keiko's right. Subtitle sand bodies lined parallel to the fur trade wind direction
122:01 . It was pro grade into the but are perpendicular to the trade
122:06 Okay, that's the kind of thing don't want to be looking for to
122:10 if the trade winds are the which I don't see what else could
122:14 there. I don't see how the currents can be operative in this kind
122:17 isolated interpret tonic basin. Alright. then the last example here from the
122:25 , the Central Basin platform. Uh look at the different maps here,
122:31 of the maps having to have a cut between your little channel between here
122:35 the northwestern shelf, some of them together. Uh but for this time
122:41 the Permian, You were very close to that 5° setting. So,
122:47 not quite sure if you're instilling a trade wind belt or whether you're in
122:50 doldrums, if you're in the what would have to be driving
122:54 you have to be tidal currents. . And if but if you're in
122:58 trade wind belt, then the trade obviously could be doing that. All
123:02 , So, let me skip ahead this map right here. You can
123:06 there's a field here, a big called vacuum field that occurs on this
123:10 of the north west shelf. the question is, what was the
123:15 if the trade winds were operative that would be facing into the prevailing
123:20 , right, You can see where could be some wind wave agitation.
123:23 if you're in the doldrums and you evoke the trade winds, then maybe
123:28 Sanson and channel here could be the to generate strong tidal currents.
123:35 So this is this has not been . Right? I think there are
123:38 ways to look at this, but I want you to appreciate is that
123:42 field here produces from these dramatized ramp brain stones. Right? That's this
123:49 right here. Okay, on the profile and you can see The numbers
123:56 . This is a giant oil field already produced over 500 close to producing
124:01 million barrels of oil. It's stolen analytics, skeleton Pakistan's and grain
124:07 So it produces both from the active stable part of the sand body
124:12 Okay. And this is what the looks like in core. You probably
124:17 see all those little circular grains those are all foods that are dramatized
124:22 then the ramp related fabric or the that it's part of a ramp model
124:29 , is conveyed by the fact that have these aw flapping program, additional
124:35 stones back stepping, pro grading back , pro grading. You end up
124:40 with a series of stacked reservoir Right? That's the great thing about
124:45 as you produce multiple stacked reservoir Okay. Yeah. All right.
124:54 everything I've shown you is mostly related either preserving ferocity or generating ferocity relatively
125:02 . Either by freshwater die genesis or demonization. Although I showed you a
125:07 examples like east texas where some of dolomite comes in late. you also
125:12 to be familiar with the potential to deep barreled dissolution in lime stones.
125:19 the famous example of this is the limestone or Haynesville limestone in east
125:26 So it's younger than the smack. a smack over. All right.
125:31 the setting is along the margins of east texas salt basin and this side
125:38 the basin is driven by salt So every yellow blob is a salt
125:43 of structure again, where you get developed on top and then the theoretically
125:50 more stable flank on this side here you don't have the salt tectonics,
125:55 have sort of a ramp. The setting where the ramp just moves off
126:01 the east, a little sub basin here in this direction. Right
126:05 Right, So all the big famous fields that produced from this trend occur
126:10 this part of the basin. so it's another upwards only sequence like
126:16 talked about for the smack over this the sequence for the east flank of
126:21 of the basin shows up and do , sands, sands pro grade out
126:26 the C word direction toward the east they programmed out they shed material out
126:32 front so they're tempest sites that are out in front that are also gas
126:37 and then what provides the topsail the seal is either the back shoulder,
126:42 Laguna carbon is to stabilize shoal or directly the Haynesville shale? I'm buzzer
126:48 , sorry, it sits right on of that. All right. And
126:52 people think the Boger is also the , right? If that's the
126:56 then the gas had to be top in from above. All right.
127:02 all these famous little gas reservoirs, , rose Gilmer glade water, those
127:08 the big big ones and then over . Okay. And then you see
127:13 blue blob here. This blue blob Was a pioneer prospect that they developed
127:21 a three D seismic. They found reservoir, they found the huge grain
127:27 sand body. This is probably the shoal of the overton field and they
127:34 water because the trap was breached. , This is the only example I
127:38 of where the trap has been breached faulting. Right? Usually when you
127:44 para seeing this trend, you find . All right. So here's,
127:50 showed you this diagram, I think last week to show you this
127:54 I concept right? The active show the east flank is up here.
127:59 are tempest. It's all right. then the whole thing is overlaying by
128:03 booger marine shale of there's a contact you know, the old you find
128:10 literature, you still find in everybody interprets the Haynesville limestone ferocity to
128:16 early related to exposure. Exxon puts type of non conformity right here.
128:23 that look like an un conformity severe conformity. There's no cursed. That's
128:29 pyrite replacing the limestone. You would get that in several exposure.
128:36 Yeah. So this is this is we call a drowning in conformity.
128:40 limestone just got drowned out. They've the straddle geometries. All right.
128:45 uh drowned out. And then later iron bled in during burial.
128:52 The active show looks like this shows high degree of preserve stratification as you'd
128:57 . That's what you see at the of the sequence. And then I
129:00 I showed you these cores before. are all the tempest. It's that
129:04 down dip and they're all gas Right? So, we know this
129:09 formed after oil emplacement because Mhm. We have some of these the Paynesville
129:19 on the east on the west but you're still in the oil window
129:24 the rock looks like this. there's no secondary porosity. It's just
129:29 buried sutured and you preserve from primary . Okay. But in the Haynesville
129:37 the east flank, it's all producers micro porosity. Alright, this blue
129:43 , except wherever the oil was completely that primary priority and protecting the grains
129:53 the later digestive fluids. Okay, , It's 5:00 here. There's no
130:00 in belaboring this. So, when come back tomorrow, I'll finish this
130:04 . I'll show you the timing evidence this barrel dissolution. I'll show you
130:08 role that false played here. They breached pioneers prospect. But I
130:13 the false player role as a conduit the favorable digest fluids, and I'll
130:18 to develop that story. Okay. we'll pick this up tomorrow morning.
130:25 right. So let me stop the . Yeah. So you all know
130:36 coming through here, Right,
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