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GEOL6363 Carbonate Sedimentalogy - Day5 02-03-2023
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00:00 Okay, so Technically this is the of the Third Badge three. Thank
00:24 . Hold on. Okay, so this is the start of badge three
00:43 badge three is mostly devoted to a discussion about carbonate play types. And
00:49 it's a culmination culmination of everything we've about for the first two weekends.
00:54 ? You're gonna see the application of from uh, grain types and sedimentary
01:00 to die genesis to environments of deposition and things like that. And there's
01:09 thing that we haven't formally talked about as part of the play type of
01:13 . Right? There's three. There always three elements associated with the play
01:18 . There's a reservoir. Obviously we about how you create or modify reservoir
01:23 . There's a ceiling faces that you . And we talked about some of
01:26 potential ceiling faces like evaporates. There's a way to entrap hydrocarbons.
01:32 talk about other mechanisms later. The thing we need to talk about is
01:37 source rocks. Alright, so before get into a formal discussion of carbonate
01:42 , let's talk about carbonate source And let me tell you that when
01:47 started this business many moons ago, thought carbonates could be a source
01:52 Okay, everybody thought oil and gas from a shale until they realize that
01:59 a minute. The only thing that organic material that's mature enough in a
02:04 is a carbonate and then when people into typing or you know, contrasting
02:09 geochemistry of the source rock with the of the oil or gas. They
02:14 that this stuff has to be coming a carbonate source rock. Okay,
02:20 carbonate source rocks are well established As you see here, there are
02:23 critical element in play evaluation, Sometimes it's a die genesis that makes
02:28 breaks the carbonate play by destroying reservoir . But sometimes it's the lack of
02:34 good source rock in the basin that your potential for good play development.
02:39 right. And you're going to see they're they're carbonates of source major hydrocarbon
02:45 around the world. What's interesting about carbonate source rock is it actually has
02:50 lower what we call T. C. Cut off. T.
02:53 . C. Is total organic carbon we're going to define here in a
02:57 as a proxy for determining the yield hydrocarbon from a source rock. And
03:06 part of the reason for that lower . O. C. Cut off
03:09 it's a more efficient generation generator of . It's made up of marine and
03:16 algal material, which is comprised principally lipids. The same stuff that clogs
03:22 arteries. That's lipids. Alright. the interesting thing about lipids is they
03:27 break down a lot more efficiently into or gas compared to the wood.
03:32 coli material that you normally get associated with the terrestrial shale or marine
03:38 Okay, so the the reason why thought for a long time that that
03:48 could not be source rocks. That back to this diagram That was published
03:53 1962. And Harry Gaiman worked at Research flat. It's actually the same
04:00 that I worked at for eight years uh just might I always found this
04:06 boggling that this paper even got Because what he's doing here is he's
04:11 apples to oranges. All right. you can see he's he looked at
04:16 plus shale samples from all over the and he just did the standard toC
04:22 . Right? And he came up an average of a little bit under
04:28 for the mean or average T. . C. For shales. And
04:33 where the historical 1% T. C. cut off comes for a
04:37 shale source rock. Okay. And he analyzed a little under 350 limestone
04:43 from all over the world, except of comparing the same kinds of deposition
04:49 , most of the shells are associated more bass channel settings, right,
04:55 that gets pushed offshore into deeper Alright, so baseball shales, maybe
05:01 associated with turbine sites and things like . What he did here with the
05:05 stones is he was across the whole . Everything from a tidal flat to
05:10 grain stone to a refill limestone to base in a limestone. Okay.
05:16 so he averaged out the T. . c. for all those different
05:19 and he came up with a .3 so .25 point a little under
05:26 you can see where it falls in here. And he concluded on the
05:31 of that, the carbonates have no rock potential. But it really was
05:35 comparing apple storage is right. If compare some of his baseball limestone examples
05:43 his baseball shales, they have comparable even higher T. O.
05:46 Values. Alright, so like I , this poisoned industry for essentially almost
05:52 decades wasn't until the late seventies the started to realize that wait a minute
05:58 of these basins, as I the only thing they have source rock
06:02 is to carbonate limestone, the Okay, so let me start this
06:11 review by just refreshing your memory here some of the criteria that we use
06:16 identify source rock interval. This applies the classics and carbonates, right?
06:21 obviously need adequate T. O. . And whether it's oil prone or
06:26 prone, I guess that the price depends on the commodity price, write
06:31 history of the oil and gas business we go through these periods where we
06:35 oil, we want gas, And we're willing to charge more for
06:39 or the other. Um you I I'm not sure where we are
06:46 now, I guess we're still probably oil prone because the price of oil
06:50 higher than the equivalent for price of and then you need sufficient maturation
06:56 right. If your basin doesn't get buried thermally, there's not a thermal
07:02 in the basin, then you're not to generate any kind of source
07:06 And then of course timing is everything respect to the generation of the oil
07:11 gas and entrapment in a potential reservoir trap. Right? So, you
07:18 , that's always that's always the risk any expiration is hoping that you've been
07:24 to time this out, right? got your traps set up, you've
07:27 the reservoir quality in place before the starts migrating into that potential reservoir.
07:33 of course the other consideration is the pathway. Right? And then related
07:39 this would be migration distance to Sometimes your potential reservoirs is tens of
07:45 away from a potential kitchen. And not only do you have to worry
07:50 the pathway of how you're going to it from the kitchen to the to
07:53 reservoir, that you gotta worry about pathway. Alright, so again,
07:59 to remind you, T. C. Measure total organic carbon,
08:02 the amount of organic material in Iraq of petroleum yield. The other thing
08:09 companies think about is organic matter Again, this depends on whether you
08:13 your your source rock to be more prone or more oil prone. Uh
08:19 you'll see in a minute. The rule of thumb is that the more
08:23 shales, things that are derived from terrestrial organic material stuff that's moved offshore
08:32 marine environment tends to be more gas and the carbonate organic material which comes
08:38 the organisms that live in the water mostly tends to be more oil from
08:43 . All right. And so in literature you'll hear people talk about the
08:48 and types essentially this is another reflection the organic matter type and this is
08:54 of the terminology that you'll see used the literature. What I've noticed is
08:59 lot of companies have their own internal of characterizing these different carriage in
09:04 But essentially in the marine setting, dealing with what we call marine algal
09:10 the so called amorphous, where you quite tell what it is, but
09:13 not terrestrial derived. These tend to , as I said for lipid related
09:18 or oil prone, herbaceous or structured would e coli material, this is
09:24 kind of stuff that makes up most the shale source rocks and these tend
09:29 be generally gas prone. Alright, . We're gonna do a little exercise
09:35 , just to sort of put this perspective here. Uh there are published
09:41 technologies like level of organic metamorphoses, lom thermal alteration index. Uh these
09:50 the technologies that people use to determine level of maturity for a potential source
09:57 . Okay, so maybe somebody hold slide open while I go to the
10:01 slide, we're gonna do a little here and just talk about how this
10:06 gets applied to a potential example Of course, for this exercise,
10:13 we want to know is where is potential source rock? So you can
10:16 there's been one borehole penetration on the of this uh cross sectional view which
10:22 based on regional seismic data. You see the carbonates and blue. You
10:27 see the red would be the evaporated . The sand stones would be yellow
10:32 the little dots. And then you see some of the Shelley sequences shown
10:36 the light blue with the little horizontal . Okay, and so this being
10:44 carbonate seminar. Right. We're interested potential reservoir source and seal relationships.
10:50 what would you in for first of for potential reservoir based on this seismic
11:02 ? Where's your carbonate carbonate right Right. What a bumps usually signify
11:09 seismic, some sort of build up reef or stack reef complex. Some
11:18 of build up. Okay, so , as we talked about some of
11:22 seismic. Right, companies chase buildups there, hoping that part of that
11:28 up is preserved ferocity. Okay. then what would be the likely trap
11:35 your build ups with sitting on Yeah, that price. Right.
11:42 don't they make good sealing faces. there, dense and it's hard to
11:47 fluid through evaporate. Alright, so would essentially be what we call
11:51 graphic trapping, right? We built topography, we've encased it in
11:57 Of course you could argue about how or how shallow those evaporate deposits
12:01 We talked about those different models last . Alright, so those two parts
12:09 the story look pretty good. You got a potential reservoir, you
12:12 the good trapping mechanism here. What's third question? Right, where's your
12:17 rock? So let's just go through and and work some of this
12:21 Right. You've sampled A and And C. And D. And
12:30 can start with we can start with . Which is the evaporate,
12:35 And what's the T. O. . for that evaporate? .05%.
12:40 we can throw that out the Right? Because again, if you
12:43 use the shale cut off right. 1% that Gaiman argued would be the
12:48 for a good shale source rock that's near. Right? So throw that
12:53 the window. All right, so what else do we have? Um
12:59 can start with a the shell, good about that thermal alteration index is
13:09 high. Right, That suggested you've the right temperature to cook it?
13:13 with the limitation 0.5% T. C. Right? That's below the
13:19 that you want to see for a shale source rock and then if you
13:24 up to D the other shale, got great. T. O.
13:27 . Right? 3%. But what's problem here? It's not only
13:35 but if it was mature, how you get it into your reservoir?
13:39 the problem? You'd have to do we call top load. You have
13:45 bring it down from the top and go against pressure. Right? Go
13:54 the Tennessee of when you cook stuff place. What's the tendencies tendencies want
13:59 go up? Right, So, got two things working against you for
14:05 for D. Right. It's not and you've got to go through a
14:11 of that. Bright, gotta go against the gradient, right? To
14:17 it into that reservoir. So, are you left with B which is
14:22 the reef? Okay. Again, don't know what kind of reef systems
14:28 are. All right. And there's there's no vertical scale here, but
14:34 I Well, let's just leave it that. All right. So,
14:41 is B .35%? All right, . Right. The thermal alteration index
14:49 good. So, the question you know, is that capable of
14:56 hydrocarbon or not? Alright. I a lot of people would say probably
15:02 . Right, based on the shale . But if you walked away from
15:06 relationship, you would have walked away some of the pinnacle reefs in the
15:10 basin that were developed during the salary . All right. We haven't talked
15:16 pinnacle reefs yet because there's no modern to these pinnacle reefs, but these
15:21 reefs that develop out into the but not in the deep part of
15:24 basin. So you come off of platform and you basically ramp down into
15:29 deeper part of the basin where you down is where you develop these pinnacle
15:34 . And you're gonna see that sometimes things are I mentioned one example from
15:40 last weekend when we're talking about seismic and I showed you a giant oil
15:46 in Libya. That's a pinnacle And these pinnacle reefs are on the
15:50 of 400 - 600 ft thick. they have yielded several 100 million barrels
15:59 oil and a few TCF of All right. But the average
16:04 O. c. of this material .35%. Okay. And so what
16:10 illustrates is that it carbonates, you can get lower than 1% T.
16:18 . C. Because of the more nature of carbonates to break down efficiently
16:24 oil or gas. Okay, So, So let's talk briefly about
16:33 conditions that are required for preserving organic . All right, in the world
16:37 plastics, .2 and .3 are the that most plastics geologists consider.
16:44 And in terms of trying to preserve material, you have a flu real
16:49 pushing stuff out. You have a pushing stuff out into the marine
16:54 How are you trying to preserve that material that comes out with each flood
16:58 . You're trying to preserve it by with really high rates of sedimentation where
17:04 bury that stuff quickly, Right? you produce so much at a rate
17:08 than the destruction on the sea floor you preserve it. Okay. But
17:13 carbonates, we don't think in those and carbonates, we think more in
17:17 of the quality of the bottom Right. And to preserve organic
17:22 What do you want? You want or what we call anoxic bottom conditions
17:27 the oxygen level is so low on sea floor that you can't even have
17:33 bodied worms living in that sediment. , They can't burrow, they can't
17:38 oxygenated water into the sediment. And so most of the models for
17:46 organic material in the carbonate are are towards that rationale, how do we
17:52 an oxy on the sea floor. . And so these are some of
17:56 things in the literature that have been . All right, The the most
18:00 way is the first point here, stratification through temperature changes in the water
18:07 or through salinity changes in the water . You create density stratification by creating
18:13 different layers of density or salinity. are you inhibiting your inhibiting movement of
18:18 oxygenated water with the bottom water. that's what allows you to preserve or
18:25 an oxy on the sea floor and organic material. Okay, now modification
18:31 this would be upwelling that occurs along or leeward margins of continental shelves or
18:39 platforms. Right. And this is happening today off of western part of
18:45 America, like off of Peru. right. So that that's a limited
18:50 of preserving organic material on the sea . Uh, people have talked about
18:56 , what they call Meso scale These are areas of local upwelling that
19:02 up on a carbonate platform, you see the scales that they propose
19:07 km across for scale. So instead being more widespread, uh,
19:13 these are local zones of anoxia. , this is more of a hypothetical
19:20 because people are trying to explain some the sweet spots, say in sequences
19:25 the Eagle furred in south texas, ? The cretaceous eagle furred, which
19:29 not only a carbonate play, but also considered a source rock.
19:35 And they see the sweet spots of kind of scale. So this is
19:38 this idea came from that you have local Eddie's that somehow created an oxy
19:45 the seaport. And then the last point here volcanic activity. This is
19:51 of interesting during the Eagle for during chalk, for example, in south
19:56 , we had local scale volcanic activity volcanoes release ash to the environment.
20:04 ash is thought to because of the and nitrogen associated with some of the
20:10 deposits that's thought to create local blooms the sea floor. Right eye zones
20:14 productivity, basically what we call the tide. Right? And we get
20:20 tides today on the gulf coast, get red tides today off of
20:24 The red tide does what it consumes oxygen, right? That phytoplankton consumes
20:29 oxygen and then that oxygen poor water thought to impinge on the sea
20:36 kills the organisms, kills the borrowers allows you to preserve organic material.
20:41 , so those are some of the have been proposed. Alright, So
20:46 you broaden this out into the overall models for preserving organic material, that
20:53 prime model is the so called reducing where you create either density stratification or
21:01 . Either upwelling or uh um some of relationship back to the those meso
21:11 upwelling effects or the volcanic effects that talked about. Okay, so these
21:18 are not deep. So one of requirements for preserving organic material is not
21:22 depth. Right? We talked about the first day, water depth doesn't
21:26 the borrowers, right? It's the quality controls the borrower's. Alright.
21:31 then local zones of oceanic upwelling. is a modified type of model limited
21:38 the leeward or uh leeward sides of continents or platforms. You trophic lakes
21:45 into play for like Custer and We're not going to talk about the
21:49 settings for for carbonates. Alright. there are major oil and gas deposits
21:55 areas like china where they get these accumulations about plastics and carbonates and the
22:03 you trophic means nutrient rich. So nutrient rich water again favors this.
22:09 blooms right to consume oxygen on the level, on on the floor of
22:14 lake. There's one or two case where some people have argued there's restricted
22:23 of oil and gas from these more , deeper platform, interior or reef
22:28 . And then some people have actually that the evaporating basins are a sight
22:33 preserving organic material and it's not the oxygen level. It is the uh
22:41 fact that it's so restricted, the thing that can live there is sign
22:44 bacteria. So, the cyanobacteria thought generate the breakdown of cyanobacteria sought to
22:50 the oil or gas. All And if you look at a modern
22:55 setting, whether it's a basin in rock record or whether it's the coastal
23:00 . Like we talked about last weekend areas like the southern Bahamas, there's
23:05 lot of organic material there. The question is, do you have
23:09 volume to make a big enough source ? That's the first issue,
23:14 And the second issue is how do get it out of that deposit.
23:20 , sir. So in the you'll you'll see people use these three
23:27 anaerobic or anoxic dis aerobic and Right? So, these are the
23:33 of anaerobic means abundant dissolved oxygen. to support not only soft body burrowing
23:40 on the sea floor, but to calcified organisms living on the sea
23:46 And then this aerobic, you can the oxygen level is defined being between
23:51 two values. Alright. Not enough support calcified benthic fauna, but enough
23:56 to preserve soft body to allow soft organisms to burrow. All right,
24:02 you're going to see what Even with limited calcified fauna, If you have
24:06 organisms, you're still not going to organic material on the sea floor.
24:12 , then, anaerobic or anoxic means not enough oxygen to support even soft
24:19 growing organisms. Okay, So if look at you look at all the
24:24 studies now that have been well I'm going to share some numbers with
24:28 at the end here, most of classical larger carbonate source rocks, some
24:36 which are listed here are associated with so called reducing basins. Again,
24:42 of these are isolated, interpret tonic that arguably were never deeper than a
24:48 100 m of water depth. so we're not talking about gulf of
24:52 water deaths. We're not talking about deep water based on the settings we
24:56 about for the Bahamas last weekend. , and again, the key here
25:03 is to create some sort of density where you can't mix surface oxygenated water
25:10 the bottom water. Okay. And know from one of the famous case
25:16 that was documented back in the eighties a study by two S.
25:21 Geochemist Working the Bernie Formation in Western . This is a world class carbonate
25:29 rock with up to 18% t. . c. And their detailed
25:34 their core studies and mapping of O. C. Uh in the
25:39 shows that as soon as you get kind of by observation On the sea
25:44 , the T. O. s. dropped basically to zero.
25:48 . You've got to have well preserved laminated fabric. You've gotta have rock
25:53 looks like this. Okay. As as you get any by observation in
25:58 rock, the T. O. . Drops to nothing. Okay,
26:02 that's a requirement for almost all of world class carbonate source rocks, no
26:07 what you think the mechanism is to organic material. Okay and then I
26:15 , there are a couple of examples people have attributed the preservation of organic
26:21 to oceanic upwelling and anoxia. Uh is not an uncommon phenomenon along Western
26:28 leeward sides of either carbonate platforms or shelves. We see upwelling occurring
26:36 Off the leeward side say for keiko's platform. This cold oceanic water
26:41 up alright, but it's not it's producing a red tide or anything like
26:48 . But you can imagine a situation does today occur off the western side
26:55 South America. Like off of Peru Ecuador where sometimes the sub dwelling effect
27:01 promote the phytoplankton production. They will the oxygen will create an oxygen minimum
27:10 that then impinges along the slope or the leeward part of that margin.
27:16 so you get local zones of anoxia the sea floor. Okay. So
27:21 that's the mechanism off of these unique of the platform. Right. Remember
27:25 trade winds, Trade winds blow right left on this diagram, right.
27:31 the trade wind affected part helps promote upwelling that you see along the western
27:37 . Alright. And then I mentioned in continental settings in inter mountain
27:44 we talked about the potential to develop . Remember that discussion last week,
27:50 member of white sands in New That's an example of that. But
27:55 in a rainy or climate, you're gonna get evaporate. You're going to
27:58 the what are called you. Trophic , right? If these are saline
28:03 nutrient rich, then you can preserve material in some of these lake
28:09 Your reservoir would be the shore classic sands, right. Sand stones
28:15 could be what kind of freshwater carbonates we get? We could get the
28:21 the getting old sucks. All The remember those little valves organisms.
28:35 astro cats that we talked about briefly the first day, first weekend ostro
28:42 can live across the board from a marine setting to a brackish water
28:47 They can even live in freshwater lake . Okay, so some of these
28:51 lake systems, they have the Our roster cod beach deposits all right
28:56 the margin of the lake. And probably the most famous example of
29:01 here in the in the U. . Is the is the E.
29:05 . C. And Green River formation in colorado and other areas in the
29:11 US. Alright. And they actually a while they actually mined this
29:17 It was so T. O. . Rich. Some of the Green
29:20 has up to 40 45% T. . C. Alright. And this
29:26 the kind of stuff that the chinese chinese restaurants, the chinese reservoirs for
29:34 from and in western china. so these are I think older paleozoic
29:44 . Alright, Alright. So here's summary now of all these different world
29:52 carbonate source rocks. All of these been proven by geochemistry to be linked
29:58 a oil or gas reservoir in that . And you can see the variability
30:03 the numbers here. Alright, so luna is the big source rock that
30:11 most of the hydrocarbon, both in and Colombia. All right. Austin
30:16 is really interesting. Not only is Austin chalk and we'll talk about this
30:21 from a reservoir standpoint tomorrow. Not is the Austin chalk reservoir, but
30:26 a it's a self sourcing reservoir. basal part of the Austin chalk can
30:31 organic rich. You can see the up to 21% T. O.
30:35 . Or higher. The Eagle ford south texas the same thing.
30:39 It's considered the unconventional carbonate play where just directly fracking to get the oil
30:46 . But there's there's a reservoir part the story for the Eagle for
30:50 And you can see the numbers at 8%. And we'll be talking about
30:54 smack over here, talked a little about the Jurassic Hanifa last weekend for
31:00 cyclist city. And you can see numbers. And then here's the big
31:05 granddaddy from a conventional subsurface source Is that Giverny formation in Western
31:12 All right. And then here's the a one carbonate that I modeled our
31:18 exercise off of with the average O. C. is only
31:24 TSC only gets up to 1%. , but it's yielded several 100 million
31:29 of oil and several TCF of gas from that organic rich source rock that
31:36 off the deeper part of that Okay, Alright. So obviously this
31:43 an important consideration in any basin, you're chasing carbonates or classics.
31:49 You want to know not only where my reservoir? Where's my trap?
31:54 kind of ceiling faces do I have help set up that trap. But
31:58 got to factor in the source right? I mean it's pointless if
32:01 don't have the right maturity, you have organic rich deposit, whether it's
32:07 or uh carbonate. Again, when talk about carbonate plays, don't get
32:13 impression all carbonated plays are linked to source rock. They don't have to
32:18 they can be obviously that oil and could be coming from a nearby
32:24 Alright, So, again, for , the key, the key control
32:30 is setting up reducing conditions on the floor. Alright. And the key
32:36 is water quality. It's not rate organic production, it's not rates of
32:41 . These are not the key controls carbonates. It's the preservation right,
32:46 the right kind of water quality on the sea floor. Alright. And
32:51 just keep in mind that you don't to have really high values, but
32:55 interesting that the carbons tend to have higher values than you see for shale
33:00 in some of these bases. Any questions or comments? All
33:12 Why don't we take our why don't take a 15 minute break here,
33:16 then we're gonna spend the rest of day getting into a discussion about carbonate
33:22 types and I'm going to take you what I consider to be more of
33:25 conventional ones. Show you the rationale that, and we won't get through
33:30 of them today. We'll carry this tomorrow morning and then we'll talk about
33:34 unconventional carbonate plays. And Um so start back up at 3:00.
33:47 Okay, so we're gonna systematically work way through a discussion, a formal
33:53 about carbonate play types. Okay, I showed this slide the first day
33:59 started when I introduced the course, play. Every carbonate play has these
34:06 elements reservoir nearby source rock, whether carbonates or shale and the ceiling
34:12 And then you need a trapping And historically most of our traps are
34:21 traps where there's a strata graphic component is controlled by faces, right?
34:29 there's a structural component. The two together to effectively trap the hydrocarbon.
34:35 strata. Graphic traps historically are under . A lot of companies don't feel
34:41 chasing carbonates just from a purely strata standpoint, which I've always found interesting
34:51 they want to see a structural right? They want to have a
34:54 or something like that to provide the up dip seal for travel of
34:59 But there are lots of strata graphic around not carbonate plays. And with
35:05 use of three D. Seismic companies find more and more of these so
35:10 strata graphic traps. Okay, so spent the parts of the two first
35:19 badges really talking about some of the controls on carbonate play elements,
35:24 We've talked about the big scale controls fizzy graphic setting. We're starting to
35:29 a feel for what I mean by . Right, fizzy graphics setting a
35:33 scale fizzy graphic setting at a local . We've talked about the importance of
35:37 , graphic age that controls who the were, that controls their starting
35:43 That influences some of the pathways for genesis that we've talked about whether those
35:48 are principally magnetic or principally cal See all the history, we had
35:53 little bit of discussion about this last , right, when we got into
35:56 positional sequences and cyclist city, so hope you appreciate now that sea level
36:04 not the prime driver for carbonate It's the it's the influence that terminates
36:10 packages or provides the accommodation, but you fill up that accommodation depends on
36:16 local environmental controls that come into play each, each basin. Alright.
36:22 then we talked about climate, not just from the standpoint of rainfall
36:27 absence of rainfall, Novak writes versus , but also from the standpoint of
36:33 wind systems and their influence on carbonate and early die genesis. And then
36:41 important influence of burial right in the chemistry that evolves with progressive burial.
36:48 we put that into the context of different digestive environments. And uh so
36:53 the interplay really of the die genesis the deposition all faces that impact your
36:59 rock quality, impact the reservoir obviously the potential for good sealing faces.
37:09 , and I have suggested now that factor in regional paleo geography or what
37:16 call fizzy graphic setting at a global . Okay. And I've on your
37:22 deck. I've given you a bunch maps that show you how basins migrate
37:28 geological time. Right? How some these basins can be outside of the
37:34 subtropical belt. They can migrate through doldrums, they can migrate back out
37:39 the doldrums into a tropical or subtropical . They can migrate into a cooler
37:44 , temperate climate. Alright. And you want to rely on these maps
37:50 there are a bunch of different maps that have been published, write the
37:54 , you're probably more familiar with the called Blakey maps, right. Blakey
37:58 taught at the the University of Northern . And his maps are nice because
38:07 show you the landmasses versus the And they teach the maps the shallow
38:12 areas of marine deposition versus the deeper areas. But the thing I don't
38:19 about Blakey's maps is they don't he really plot the paleo equator,
38:24 He doesn't he doesn't plot the the latitudes and sometimes his map shows you
38:30 the paleo equator was. You can to that, but most of the
38:34 you have to guess. So the that I like are the ones like
38:38 at the bottom here that show you basically the direction, what they,
38:43 they show you on these maps is surface currents. Right? The arrows
38:47 really the surface currents that they're they're , but what drives surface currents.
38:53 the treatments. Okay, the trade determine how these oceanic currents move.
38:58 so effectively the arrows that you see these maps are the wind directions.
39:03 ? So we talked about tropical subtropical being influenced by the easterly trade winds
39:09 the strength of those trade winds being on how close you are to the
39:15 . But remember right at the five degrees on either side of the
39:19 where you don't get the trade winds , Alright, yeah, Platform was
39:48 21 22°. Yeah. And that's remember characterized it as a as a tropical
39:58 . So just barely fred. so trade wind systems are obviously important
40:08 of our discussion and you're going to me drive this relationship home with our
40:13 type discussion. A lot of the plays and arguably even some of the
40:18 stuff we're going to talk about is by the trade winds, right.
40:23 it's the direction that they blow, also the strength of the trade
40:27 They're important consideration. And frankly, lot of these play types that I'm
40:33 take you through. Never made any . Based on the northern Bahamas bottle
40:39 we went through last weekend. Never made any sense. I
40:42 people found the reservoir right? By by luck, right? They drilled
40:48 off a seismic anomaly or they drilled by accident and they found it.
40:53 it didn't make any sense based on more established models that were in the
40:57 before we started to understand the trade influence. Okay, so you want
41:03 factor that in? All right. so in your slide deck, I'm
41:07 going to show all the, all maps like this that I put in
41:10 slide deck, but I'm gonna take through and just show you how things
41:14 . Okay? But you need to this in Now. What you don't
41:19 to ever do is just rely on maps to tell you, I'm in
41:22 strong easterly trade wind belt and and the driver. You want to use
41:28 geology to prove that relationship. And gonna show you with these play types
41:33 we try to use the geology to that the trade winds were, for
41:37 , the driver for some of these . Okay. Why they occur where
41:41 do, why they have the orientation have. Okay. And so for
41:47 for this exercise here, you see are three dots on these maps that
41:53 should see for everyone that I put your slide deck. The red is
41:57 Permian basin in west texas. We'll about play development and the carbonates for
42:01 texas and new Mexico. The blue is Libya, which is a prolific
42:10 province in the in the lower tertiary even into the cretaceous for that part
42:15 northern africa. And then the black is Western Canada, which is also
42:21 prolific hydrocarbon basin for carbonates, it's everything from um Devonian through Mississippian.
42:34 , for carbonates and then the younger and the Jurassic and cretaceous also are
42:41 with that part of the world. right, so just watch, just
42:45 these these dots move around. so this is middle salary in time
42:50 you can see the western Canada the dot or I'm sorry, I guess
42:55 the black dot. That's yeah, the black dot. The blue dot
42:59 here in Libya. Where was It was in a cold water climate
43:05 outside of the tropic subtropical setting, latitude south of the equator. That
43:11 you in a cold water climate. you wouldn't have had shallow water carbonate
43:16 . Permian basin was just on the edges of the subtropical setting. If
43:21 was influenced by trade winds, would been influenced by general easterly trade winds
43:26 on what we talked about. And here's the slurring for western Canada,
43:32 is sitting where in the doldrums, ? That darker belt. The dark
43:37 is the doldrums. Okay, and it would not even been influenced by
43:42 ways and what else would have not influenced by hurricanes? Right, hurricane
43:49 of storms because they're pushed by the winds. Then we go in the
43:55 and you can see again, the devonian is still in Canada is still
44:01 right along the edge here between the and the stronger trade winds. Do
44:06 see Libya's migrated up to the Okay, alright. That's early Devonian
44:13 Mississippi and early Carboniferous is basically Mississippi you can see how these things are
44:20 to migrate around. Right? So just want you to appreciate that these
44:25 are gonna move through geological time. need to factor that into your
44:29 Right? Where is my base of relative to the paleo equator that tells
44:35 tropical subtropical or cold water temper And if you're in a tropical subtropical
44:42 , you're going to be influenced by easterly trade winds unless you're along the
44:47 and then you have to sort of whether you're likely to be influenced by
44:52 trade winds provide more general easterly trade . Okay. You want to be
44:57 about those potential influences, but you to be using the geology that you
45:03 . This is where the geometries of bodies and things like that come into
45:07 to help you figure out whether I influenced by stronger trade winds system or
45:12 more gentle trade winds system. all right. And then the other
45:20 is your fizzy graphic studying a local . So last weekend we contrasted the
45:25 end Member models right? The ramp the platform and you had a question
45:31 the exam to basically contrast as to Member models, but as I've said
45:38 several times, it's not enough to , I have that kind of bottom
45:43 . You need to know whether your or ramps face into the prevailing wind
45:47 how strong that wind was okay or from it. Right? Because you
45:52 have carbonate platform. This leeward to prevailing wind or if you have an
45:57 platform right? Like we have today the Bahamas, what side was when
46:02 , what side was leeward? We about the importance of that not only
46:07 shedding, right? And the strength the trade winds determines whether it's carbonate
46:12 that comes off the leeward margin or it's mud size material, but the
46:17 winds and the strength of the trade as we talked about dictate what kind
46:20 settlements accumulate on the platform. so so I hope what I wanted
46:29 take away from our discussion last weekend to appreciate the impact that fizzy graphic
46:35 can have on all these different styles shallow marine carbonate deposition. Right?
46:40 showed you by contrasting the northern Bahamas the southern Bahamas, how it influences
46:47 occurrence and distribution and some of the types that occur up on the
46:53 Right? I showed you those isolated on keiko's platform occur well up on
46:58 platform, interior because of the trade agitation. But we don't really see
47:02 like that in the northern Bahamas where trade winds are much weaker. We
47:07 contrasted the U. S. And occurrences and distributions from the northern Bahamas
47:13 the tidal currents to the southern Bahamas are driven by trade winds. You
47:18 how the composition and texture of the interior varies again depending on the strength
47:23 the trade winds. And I showed two ways to make tidal flats.
47:29 that is more influenced by the easterly winds, one that's more influenced by
47:35 winter storms and then always in a subtropical setting, there's still an over
47:40 of the big storms on tidal flat . And then we talked about the
47:46 platform margins in terms of shedding. , well whether it's grain, stone
47:53 carbonate sand, that's gonna be the easterly trade wind effect versus the more
47:58 critic clapping wedges that we saw for northern Bahamas, Trade ones seem to
48:04 play a role here in terms of the stronger trade one systems tend to
48:10 a greater degree of evaporation. So might have a better chance of of
48:14 some isolated settings for evaporate deposition like coastal Selena's we talked about.
48:21 And conversely, you know, some the bigger platforms that don't have the
48:26 trade winds, sometimes there's a little more freshwater associated with them.
48:31 something to think about. All Alright, so let's get into this
48:38 formal classification of carbonate plays and what going to try to do here is
48:43 reservoir distribution and geometry to the source seal faces. But do it in
48:49 context of fizzy graphic setting, fizzy setting at a local scale. All
48:55 . So in other words relate these types back to a position along a
48:59 or steeper margin platform setting. All . But what do you always have
49:05 do? You always have to factor your geological age because that controls who
49:09 players were. And some of these types don't exist in different geological time
49:16 . Okay. Because the organisms didn't . Alright. And probably the most
49:21 example that will be the pinnacle reefs I just alluded to for the michigan
49:27 . Right. They only occur in select few geological time periods. Because
49:35 when those organisms that could make could those clinical reads existed. Alright.
49:39 , obviously that's an important consideration from standpoint of sediment composition and the starting
49:48 . Okay, so these are the are the play types. And we're
49:52 going to go through all of these the in the in our discussion here
49:57 and tomorrow. But we're going to go through the conventional play types.
50:02 what do I mean by conventional play ? I mean, and I was
50:07 this approach. Well, before companies talking about unconventional shale or carbonate
50:13 For me, a conventional play type has been one that companies historically chased
50:19 because of their seismic expression or because their setting. Alright. Setting along
50:27 deposition profile. Right. So, can see how I'm trying to relate
50:32 back to a deposition setting here. platform margin or ramp crest related grain
50:38 would be one of the conventional play . Platform margin reefs. Okay,
50:45 we don't get linear reef systems developed a ramp. Alright, so it's
50:49 limited to these platform margin settings. platform margin settings. Platform mound
50:56 These are buildups that occur up on drowned carbonate platform. Their lower relief
51:01 up historically because you're up on a . You don't have the subsidies to
51:06 great vertical thickness is usually all Platform interior or ramp related form.
51:13 critic wacky stone paxton plays by its . You don't expect there to be
51:18 good reservoir quality associated with a critic . Whether they're pack stones or wacky
51:24 or lying but stones. So part the story here is you've got to
51:28 what you gotta have favorable die genesis create reservoir quality. Okay, so
51:34 is historically where you have to factor the die genesis, right? And
51:40 basing all down ramp mound carbonates. are the buildups that occur down the
51:47 into a basin. Alright. That the classical pinnacle reefs to get up
51:52 over 1000 ft thick. But it includes the low relief buildups that we
51:58 . We didn't really talk about yet the rock record perspective, but these
52:03 the so called baffle stone deposits. ? The build ups that are created
52:07 more delicate branching organisms like dry zones cry noise and uh things like that
52:15 algae. They can't they don't live high energy shallower deepwater settings.
52:21 But they trapped suspended mike. And they built topography through time.
52:26 historically these things can't get thicker than 100 m. Okay, In contrast
52:33 the pinnacle reefs, that might be or 400 m thick. Right,
52:39 , we're gonna go through those. , from a conventional standpoint, the
52:44 is to get through the platform and this afternoon. All right. And
52:50 we'll pick these two up tomorrow And then the unconventional plays are the
52:54 that for me, historically, companies chase either because of their unique de
52:59 setting or because of their lack of response or because of their unique di
53:07 attributes. Okay. And so that include the four slope carbonate deposits.
53:13 are the things that are shut off the platform and again principally off the
53:18 margin. Right. And then the all de positional chalks. So that
53:24 be things like the austin chalk here texas, eagle furred Niobrara chalk in
53:29 western U. S. The famous Sea chalks off of Norway.
53:36 And then I'm going to get into are called fall control digest plays because
53:41 want you to appreciate the role that seated structure plays not only in attracting
53:48 , but favorably driving. Excuse me driving dia genesis and creating secondary porosity
53:57 depth. Okay, and the examples go through are going to be one
54:03 these other play types modified by this seated vaulting. Alright. And I
54:09 you to appreciate the role of structure I think I mentioned this when we
54:14 our die genesis discussion. You we used to look at faulting mainly
54:19 the standpoint of entrapping hydrocarbon, but seated false. And what do we
54:25 by that? We mean things are in basement, right, frenetic
54:30 These are wrench and strike slip Right? So things that have this
54:34 of movement or this kind of movement there's a vertical component. Right?
54:38 wrench ball, those kinds of false hotter fluids from frenetic basement rock and
54:45 fluids that come out of frenetic basement ? Historically, acidic. Okay,
54:52 the ones that precipitate the base metal and things like that from acidic
54:57 Right? So what what asset fluids to carbonates? They dissolve?
55:03 They create secondary prostate potentially. I want you to appreciate that
55:09 And I'll drive that theme home with number of examples. All right now
55:14 listed some of conformity cars. Place listed fractured carbonates, fractured carbonates.
55:20 a misnomer. Alright. We talked about fractures, I guess last
55:29 Right? Or maybe the weekend before we talked about ferocity fractures don't add
55:36 volume of holes to solely be the why you get a reservoir.
55:45 In other words, they can't hold oil and gas to account for all
55:48 production for some of these so called reservoirs. So, what are people
55:53 fractured reservoirs? They're calling one of other play types that have an over
55:57 fractures to improve the permeability. so fractured, fractured. The role
56:03 fractures is to prove the permeability by to 10 times. But historically they
56:08 add more than one or two prostate to that reservoir. Okay, so
56:15 carbon is usually one of these other modified by fractures. So, where
56:20 the case, I'll talk about that for these conventional or unconventional place.
56:26 . The same with sub conformity All right. This is this is
56:32 a play type modified by Karst. ? And historically most people relate this
56:38 to several exposure. Right? But showed you another way to do this
56:45 ? In the depth, right, . Remember that concept that we talked
56:52 , right? You can dissolve on grand scale in the near surface
56:56 right? To make Carlsbad caverns, you can also dissolve in a big
57:02 . And in the subsurface, it's enough to get solution collapse. And
57:06 , Alright. And that can create quality. Alright, So, we'll
57:10 about that as well. Right? it comes into play here for these
57:14 play types. And then I'm not to talk about the custom carbonates.
57:18 not going to talk about microbial This is sort of the buzz right
57:22 for some of these sequences where people think they're seeing the influence of cyanobacteria
57:28 driving precipitation, creating crossing things like . And I listed church reservoirs
57:36 I mean, church is a silicon . Right? It's this court's micro
57:42 . Micro crystalline quartz. And reservoirs because you create secondary prostate micro cords
57:50 . Alright, so there's a die over print here as well. And
57:54 listed them here because historically the church are associated with carbonate succession.
58:00 Where does most of the silica come ? To begin with. It comes
58:03 salacious sponges. Where do they normally in a carbonate profile? The deeper
58:09 parts of the carbonate profile. But so Poland silica, which is very
58:14 . So, during shallow burials dissolves migrates. Right. And that's what
58:19 you the church nodules or the more church deposits, but that's still not
58:25 to give you reservoir quality. You have to create some porosity. And
58:29 do that through later die genesis. right, we're not gonna talk about
58:33 of that. All right. you'll notice I loaded the bibliography on
58:39 for carbonate plays. The bibliography is out in this order here.
58:47 And so you'll see bibliography for somebody cars or like Custer and carbonates.
58:55 right, But I'm not gonna formally about those play types in this
58:59 I'm going to stick to the ones you more typically are likely to encounter
59:03 the subsurface. Okay. Alright. let's let's work our way through
59:10 This is my attempt to relate play geometry to de positional setting for the
59:19 end member models. Okay. And here's that term geometry again,
59:25 That everybody seems to struggle with. uh you're gonna you're gonna see geometry
59:31 to play for the final exam. guarantee you. All right, just
59:35 drive home this relationship. So, have geometry internally. Right? For
59:41 body. Right? So build ups build up geometry, Right? That's
59:48 geometry. And then we then we about the geometry that occurs with carbon
59:54 trying to pro grade or grade Right? If they pro grade,
59:57 a program. Additional internal geometry. they can't pro grade laterally, they
60:01 vertically. That's aggregation all geometry. ? And then we talked about geometry
60:08 the cycles. The staff. That's back stepping and four stepping.
60:13 aggregation stacking geometry. Okay, So we're talking about here is really the
60:19 geometry. Okay, So she like refers to the pro gradation. All
60:25 . Right? As the system Progres develops this more sheet. Like internal
60:31 . What is ribbon geometry referred to to reefs that occur along state margin
60:38 where they can't pro grade. because the hole is too deep.
60:43 how do you build your geometry? build it vertically or aggregation?
60:48 so ribbon like geometry is aggregation. geometry that runs along the strike of
60:54 platform margin. Okay. Right. a barrier reef. Right, barrier
60:59 . Can't pro grade a lot like talked about in the modern. So
61:02 going to build this linear ribbon like along the strike of the platform.
61:09 . And then mount like geometry just to build up topography, recognizing that
61:15 reefs are going to be really like the pinnacle reefs, right to
61:19 over 1000 ft thick versus some of low relief buildups that might be 100
61:24 or a couple 100 ft thick. , Alright, everybody appreciate what I'm
61:31 . And then then you want to about how the play types and their
61:38 tie back to position along the deposition . Alright, so this cartoon has
61:44 one that's evolved over all the years been teaching off of this diagram
61:50 I just had this upper part of diagram here. Alright, that I
61:54 everything with respect to the classical platform base in transition. Right? The
61:59 margin right here, right. That be the focus of high energy where
62:05 currents or tidal currents and pinched right restricted platform interior and then progressively deeper
62:12 into the basin to the right. right. So, factoring in time
62:17 . Graphic age, right. If in a platform to base and transition
62:23 you're out in the basin, what the play type that develops out
62:26 The deepwater de positional chalks, But limited to what basically cretaceous and younger
62:35 . Right. The proto chalk start during the upper Jurassic. But the
62:40 chalk deposits really don't start evolving until time and they still exist today.
62:46 . That's the age control. And their geometry likely to be? It's
62:50 to be a wide spread sheet like right down in deeper water. All
62:55 stuff living the upper part of the column, dying, selling down,
62:59 a Sheila geometry. Okay. And you move up onto the force
63:05 We talked about how important the orientation here, because where's most of the
63:10 on the four slope? It's on leeward side of the platform is not
63:13 open ocean when we're facing sides. , So the material that shut off
63:21 is gonna be what it's going to re deposited as an on lapping wedge
63:26 that for so upsetting. Right? , I use the term sheet like
63:33 more appropriately, it's a non lapping , right, for this unique
63:37 All right. And then you come onto the margin. This is as
63:41 saw, is the focus of high related to oceanic swells or tidal currents
63:48 accentuated by the trade winds. But this is where we talked about
63:52 reefs or high energy carbonate sands developed they're going to tend to do what
63:57 going to tend to build up. they can't pro grade. Right?
64:03 they can pro grade, it's going be a sheet like geometry.
64:06 So it all depends on the slope here, and if it's a lower
64:11 angle, you get that sheet, geometry developed for both the sands and
64:14 reefs. But if it's a steeper , everything goes vertically, then your
64:20 would have more of a ribbon like . Okay. And then the platform
64:25 , whether it's carbonate sand or carbonate depends on the strength of the of
64:29 trade winds. Right? So if more MMA critic, it's going to
64:34 more sheet like geometry, it's more sand. It's going to be still
64:38 like geometry and a platform material And then a modification of this would
64:43 the title flat. That might occur here. Right? And if it
64:47 grades, it's still going to develop sheet like geometry. Right? Everybody
64:53 the approach I'm trying to use We're trying to explain the likely geometries
64:58 gonna get in these different settings. also uh but you also have to
65:02 in the age control here because some these things don't develop depending on the
65:07 time period. No contrast that with ramp, right? The little bump
65:14 you get on a ramp is what called the ramp crest, right.
65:19 was the focus of high energy closest the shore line. That's where you
65:24 development of mostly carbonate sands, reefs are not normally associated with the
65:30 model. And certainly linear barrier reefs never associated with the ramp model.
65:36 the bump here would be generally where get your grain stone developed.
65:41 And again, what kind of geometry end up with depends on the amount
65:45 pro gradation. But I think remember definition of ramp, it's on your
65:51 . Right. Did you guys get right? One degree slope angle or
65:55 ? Right, So it's very easy program that stuff. Okay, so
66:01 typically see a lot more pro gravitational associated with the ramp model?
66:08 high energy focus is going to be here. All right, lower and
66:11 energy, deeper water as you go to the right here. What you
66:15 out here in the basin again is to depend on whether you're in Mesozoic
66:19 younger systems. That's gonna be the deposits out here with. She'd like
66:24 . Remember we talked about examples I you an example from the Triassic in
66:31 , the where you shed those things into deeper water. So you can
66:35 the tempest tights. Will she like out here down the ramp and the
66:39 model. And if they amalgamate into thicker enough thick enough sequence, then
66:44 can get good reservoir quality there. . And then the ramp interior,
66:48 tend to write off its low energy the critic including the tidal flats back
66:54 to get reservoir quality back here, usually have to do something favorably from
66:58 diabetic standpoint. Okay. All So that's that's the framework that I
67:04 to be catching. I want to this discussion in for the conventional play
67:09 and some of the unconventional stuff like four soap and chalk deposits also fit
67:14 this profile as well. Okay, let's just get right into this and
67:20 gonna take breaks as we go along , we'll start all the five conventional
67:25 types. I'm going to present you a little cartoon like this that tries
67:30 relate relate the reservoir, the grain to the seal faces and the nearby
67:37 rock faces. Alright, so everything is dependent for the grain
67:43 Everything is dependent on the slope Obviously, if you're dealing with a
67:48 crest with a lower slope angle, things are going to procreate and what's
67:52 to provide the top seal, it's to be the back show. Laguna
67:57 marma critic, subtitle carbonates. if you're dealing with more of a
68:02 style, a deposition with a steeper , which fortunately is not that common
68:07 the rock record, you may not able to pro grade. Right?
68:12 you might have an issue. They're to provide a top seal and then
68:17 both settings, where would your source likely be? Be the offshore
68:22 All environment where if you could create oxy on the sea floor, you
68:27 you'd have a potential offshore environment for that hydrocarbon. Okay, so there
68:36 a couple first principles of geology we to talk about here with respect to
68:42 play type. And the first principle paleo highs began paleo highs Alright.
68:51 talked about how reefs like to take high ground corals like to take the
68:54 ground, sometimes a foot or two than everybody else in that environment.
69:00 get started. And the same thing to some of these high energy carbonate
69:05 bodies. And to illustrate that here's example from the cretaceous in south
69:12 We're going to talk about this area south texas. See where we're at
69:17 texas and the play here, or setting here is a steep margin platform
69:25 the in the lower to middle cretaceous you get brief deposition along the edges
69:33 the ancestral gulf of Mexico. And then behind it, you have
69:38 broad shallow water carbonate environment that gets and more restricted in terms of water
69:45 and energy as you go further Right, remember all the oceanic condition
69:52 entitled currents dissipate very quickly as you away from that platform and margin and
69:58 go towards the platform interior. So if you look at if you
70:03 at the this Edwards trend in south , right? It's high energy right
70:08 the margin where you get the good developed. But when you start getting
70:13 back inboard on the platform, it's dominated by these low energy. Um
70:17 critic wacky stones and paxton's, that's green and light brown colored material until
70:23 come back up onto the subtle paleo called the belt and high, which
70:28 a structural extension off of a frenetic , a lift called the llano
70:33 And maybe some of you have hiked enchanted rock right outside of fredericksburg.
70:41 the that's the surface expression of the uplift. Right? It was a
70:45 feature in the subsurface all the way to the camera in central texas.
70:52 right. And look what happens we change from. These would look
70:56 should be low energy MMA critic We get into this high energy thick
71:02 of bulleted grain stuff. Alright, , this never made any sense based
71:07 what I showed you for the northern , right? Where tidal current energy
71:12 very quickly as you go further up the platform. Nobody could ever explain
71:17 you get these analytics sands over 100 in from the open ocean. But
71:23 it makes sense if you think about trade rights, right? So if
71:27 look at the paleo geography for this , in the cretaceous, your 15
71:31 north of the equator. That's in heart of the strong easterly trade wind
71:36 . And so it's the combined effect the paleo topography and the strong trade
71:41 that allow you to generate this 100 thick For more grain Stone 100 km
71:48 from the open ocean. Okay, in part this is the trade wind
71:54 , but in part this is what advantage of subtle paleo topography.
71:59 Paleo highs beget paleo highs. That's key principle of carbonate geology.
72:06 and then what was the other relationship talked about for the modern grain stone
72:10 sand body systems? Every grain stone the modern whether it's analytic or skeletal
72:17 two components the active. Right, then the stable. Right. And
72:27 was on the quiz today. What's the difference between the active and
72:32 ? Right, in terms of sedimentary ? Right. This this is the
72:37 , persistently agitated stuff. This is burrowed stuff, right. It never
72:42 on a day to day basis. due to tidal currents or wind wave
72:48 . And then the texture, grain . Right? More of a pack
72:52 texture here and then reservoir potential. . Right. Poor. Okay.
73:01 as I said the other day, . Historically we chase the active grain
73:06 . Right. We're hoping either to on to that reservoir quality long enough
73:11 entrap the hydrocarbons or we're hoping that crossing perm becomes allows some later fluids
73:19 that enhance that reservoir quality. And we look at the stabilized stuff being
73:27 side or top sealed two reservoirs made of these active grain stacks.
73:33 Okay. So let's just get right some of these play types and and
73:40 I think I told you the first we started sometimes you're gonna see me
73:47 slides. Okay. Either because they just there for background information.
73:53 So it might be a strata graphic or it might be a map for
73:57 or it might be a map or diagram that shows you production data or
74:01 like that. You're also going to me in the interest of time skip
74:05 of these play type examples. so I'm gonna mention this again.
74:11 gonna give you the guidelines for the exam here before we break today.
74:18 if I don't cover a play type this lecture, if I skip over
74:22 , then I'm not gonna test you it. Okay? So, so
74:26 just throwing it in there for your here later. If you come back
74:31 get into the oil and gas business you come back and I want to
74:35 some of these slides for play Play types will be there. But
74:39 won't talk about it. Okay. right. So we're gonna And then
74:44 I'm going to go through for these types is I'm picking play types that
74:48 think are pretty common expressions of these plays in terms of the attributes.
74:54 I also want to stress some of different pathways for creating reservoir quality.
74:59 ? Either preserving ferocity or creating favorable process development. So I'm gonna show
75:05 different ways to modify porosity and perm these different play types. Okay,
75:11 let's start first with the Jurassic and back over formation. This this is
75:16 very common grain stone bearing sequence around northern gulf rim. It actually has
75:23 age sequences in Mexico that are Alright. And you can see where
75:29 fits here. It's not the uppermost falls into this category right here.
75:37 right. And the graphic smack over is under lane and around the
75:43 S. Gulf coast by blue and . Right. The salted form during
75:47 initial rifting of the ancestral gulf of basin. And then that shifts to
75:52 Norfolk classic deposits And some of the is made up of stuff that's eroded
76:00 the old Appalachian mountains that re deposited the shorelines. Some of this gets
76:05 alluvial fans, some of this is into alien deposits. Most of the
76:12 north of production is alien sand Okay, and then that gets drowned
76:20 by relative rise of sea level, rapid rise of sea level creates a
76:24 accommodation. Right? And then what we do we fill it in?
76:28 , We create an upward shoaling succession carbonates to start off with deep water
76:34 on carbonates at the at the And this is locally called the
76:37 dense. And then that grades up uh deposits closer to the shore
76:43 You're gonna see there's an active and component associated with that. And then
76:48 you build up above sea level to linear barrier barrier islands of bulleted grain
76:55 , what do you create behind You create a restricted shoal, I'm
77:00 , restricted Laguna environment of low energy carbonate. And then on the other
77:05 , what do you get you get beach or you get an error entitled
77:08 with evaporates. Okay. And that's so called Buckner. Alright, so
77:13 Buckner formation is actually part of the sequence. Right. People break it
77:18 I said last weekend because of the in mythology, but it's still part
77:23 still time equivalent part of the supper sequence. Okay, so here's the
77:30 that we see in the northern gulf , right, This would have been
77:33 deepwater ancestral gulf of Mexico out here the south. The initial discoveries were
77:40 made in southern Arkansas. There's a town in southern Arkansas called smack over
77:46 that's where the formation name comes All right, and this was
77:52 Most of these shallow reservoirs were discovered surface seats and everybody developed this back
78:00 the twenties. Right because it was , most of the reservoirs are a
78:04 1000 ft to generally no more than or 10,000 ft of burial.
78:10 Oil and Gas province right here, province right here. And then by
78:17 by people just pushing the trend. pushed it to the west in the
78:24 texas and they're the smack over is deeply buried. The reservoirs are um
78:31 12 13 14,000 ft of burial there they're deeper, it's not an oil
78:38 anymore, It's gas and condensate. , so it's deeper, hotter part
78:43 the trend. And here most of reservoirs have to be demonetized that reservoir
78:49 . And then what happened is companies the trend To the east and
78:56 There's more deeply buried reservoirs are on scale of 12-20,000 ft of burial and
79:03 could be lime stones or or typically are duller stones in order to hold
79:08 to that reservoir quality. Remember the about burial right? Once you get
79:12 deep, even the limestone, reservoir starts to give. So the
79:19 deeper buried reservoirs here tend to be stones where you form that ferocity relatively
79:24 and hold onto that ferocity long enough trap the hydrocarbon. Okay, all
79:30 . Most of the, most of oil pools associated with the smack over
79:36 Arkansas Louisiana are ones that developed close the shore line. They're basically a
79:42 of the Arabian gulf model we talked last weekend. And so because they
79:47 close to the shore line and their relief right ramp like topography, what
79:53 they gonna do? They're gonna pro . Okay. And they're gonna pro
79:57 tens of miles out into the deeper . So part of the consideration here
80:04 when you look at the zulu grain , part of the consideration is you
80:08 to be thinking about, well, far down dip did these things pro
80:12 . Right, because part of the here is the later die genesis of
80:18 carbonates. Okay, so the smack again, it's this classical leopard chilling
80:26 . The laminated nick wright lime mud down here are the source rock 1
80:33 2% T. O. C. , and then that comes up the
80:38 , you get out of those anoxic basil carbonates, you get into more
80:44 the up ramp biter baited skeletal political stones and pack stones with no reservoir
80:50 . And then that grades up into politic grain stone complexes with the active
80:56 stable components and then everything is over by the Buckner red beds and
81:00 That's the effective top seal for these stones. Okay, now you can
81:06 analytics, sands developed further offshore in smack over, but you have to
81:11 pre existing topography. Okay, so is where the structural topography comes into
81:17 . Sometimes it's basement blocks moving to topography. Sometimes the salt tectonics offshore
81:25 create paleo eyes. Okay, but you're playing the shore line, you
81:34 grain stones. If you're too far dip, there's a one style of
81:39 genesis that comes into play. And you're further down dip, there's a
81:43 different style. Okay. And so can see what's been mapped here regionally
81:48 the companies that have Chase's trend now 60 or 70 years. And you
81:56 , you can see the blue is northern zone characterized by one style of
82:01 genesis. There's not a lot of pools developed up here where most of
82:05 pools is down here in the in the southern zone for reasons will
82:09 obvious. And then you see there's transitional zone here where some of the
82:18 like McKamey Patton for Mount vernon have digest aspects of like the northern
82:25 but aspects that are like the southern as well. Okay, so what's
82:30 on here? All the big pools in the southern zone here. And
82:35 going on here is that sometime in cretaceous, the update part of the
82:42 sequence appears to have been influenced by freshwater aquifer system coming down from the
82:49 . So the up dip part of trend and yellow saw the effects of
82:56 early freshwater die genesis. The down part in blue never saw the effects
83:03 then some of the transitional reservoirs like vernon field, you see some of
83:10 fresh water over print for part of field and some of it is
83:15 Okay, so the up dip stuff like this. Remember this fabric,
83:21 is that classical Parisian version fabric? talked about where the original grains that
83:30 regulated goods were leached out. That's molded porosity fabric, selective
83:36 That's great. Okay to to create proxy for storage. But what is
83:42 downside of too much secondary porosity You generate the early pre compaction
83:49 which is good because it freezes that . Right? That's the way to
83:54 porosity. But if it goes too , what happens to your permeability?
84:00 kill it. Right? Remember our . If you go too far,
84:05 choke off all that primary porosity where have the permeability. Okay. And
84:11 what's happened to a lot of the part of the smack over has great
84:15 . I told you that's what the loggers call heartbreak ferocity. Right?
84:19 logs read really good ferocity, but no permeability because you choked off all
84:26 you killed all the pore throats. fill them in with counseling event.
84:31 so all the big fields, all good big field produced from fabric that
84:36 like this. Alright, walker creek the biggest, I think there's some
84:41 for walker creek in your in your . But look at the difference
84:45 the U. S. Are not dissolved out. Right? They've been
84:51 together, which tells you there's no dissolution, no early pre compaction calcite
84:57 . But you started off with a effective porosity perm system. You're able
85:02 hold onto enough porosity and perm long to entrap the hydrocarbons and you end
85:07 with the best reservoir quality. so all the good fields in Arkansas
85:12 Louisiana producer and fabric that looks like . Okay, so walker creek,
85:19 most famous example. Alright, what happens when you carry this trend
85:26 east texas? You have essentially the de positional system, the same shoreline
85:34 analytics and body systems that pro grade into the basin. They get the
85:39 stones get over lane by the red beds and evaporates. But what
85:44 to come into play here is the stones have to be delimited.
85:49 Okay. If they're not dilemma they don't have any reservoir quality Because
85:55 they're too deeply buried in 12, of burial. And so the models
86:01 have been published on for east texas attribute the demonization effect to the reflex
86:10 where people say that Buckner pushes those rich brian's into the grain stones and
86:17 to the dolomite. Okay, why it happen in Arkansas and Louisiana?
86:23 there's no delay immunization there, same , graphic relationship. So maybe that's
86:29 the right model, but that's the that everybody invokes wherever you get juxtaposition
86:34 evaporates and dolomite. Right? The . The other story for making dolomite
86:40 be the faulting. Alright, we'll about later. So you can see
86:48 again. There's a hybrid here in of what controls play type distribution.
86:53 update fields like brantley Jackson up here more of the classical shore line related
87:01 politic grain stones and appropriated us some . Okay. But look where the
87:06 pools are there more down dip and of these down dip pools are down
87:12 because of the influence of salt These are local isolated grain stone bodies
87:18 on top of a a leo structure the sea floor. Created the salt
87:24 . Right, okay. That's one the influences potentially assault. You can
87:32 punch of structures on the sea get shallow enough that can be agitated
87:36 either currents or by wind wave And you can put wood grain stones
87:41 top of that. All right. that's what these samples these reservoirs reflect
87:46 here and then some of these other like bryan mills are influenced by a
87:52 fault trend. There's a fall trend runs through this part of northeast texas
87:57 the Mahia Taco fault trend. And they These on echelon fault system
88:04 from the southwest up to the And so that's the other part of
88:09 story or potentially is the faults are accessing some of these deep seated fluids
88:15 we talked about. The dry, demonization. Okay. So I think
88:21 mentioned, you know, we were about the influence of progressive development.
88:26 on process development. We start with grain stone for example and we start
88:30 delimit ties it. What do we up with towards that 7080% by lime
88:36 . We end up with fabric like where you leech out the remaining calcium
88:41 . You plug a lot of that porosity with dolomite, cement overgrowth.
88:46 if you can hold onto some of permeability or you can enhance it with
88:51 then these rocks end up with decent quality. Okay. And that's pretty
88:57 the story for these rocks. In words it's the active bulleted grain stones
89:03 this trend that end up with the reservoir quality. Alright but there is
89:08 local stabilized wood production where you get that looks like this where the member
89:17 equivalent the U. S. That there to form their, they got
89:21 in by storms, they're mixed in more MMA critic political fabric. And
89:26 if you have big brains floating in muddy matrix, right? What gets
89:31 first? It's the muddy matrix. this stuff here because it's stolen ties
89:38 . And then what happens later? talked about how the remaining calcification
89:43 reach out to give you that secondary . Alright so what saves this rock
89:50 a probability standpoint is the dolomite is and it's going to fracture. And
89:56 you can tie this stuff together. plus east texas, we're talking gas
90:01 condensate if you don't need a lot permeability to get that stuff out of
90:05 rock, right? There's oil that an issue. But gas and
90:11 uh, fractures are enough to give that permeability. Okay. Everybody understand
90:17 we're talking about. And then the types here. Clyde more was a
90:25 at L. S. U. in the seventies and eighties. And
90:30 , did a industry consortium study on smack over. And this is some
90:35 the trap types that he documented. you can see some of the examples
90:39 we've talked about. All right. of the traps, as you would
90:42 a combination have a structural and a graphic component. All right,
90:49 And then the famous example from uh Arabia, Right? The giant oil
90:55 , Dewar we talked a little bit gore, Right? It's a ramp
91:01 . Pro grades back steps, programs steps. But then it's a big
91:04 structure With 1500 ft of structural Look at the scale here. That's
91:11 km right? I told you the structure here, the length of
91:15 structure is like driving from Houston to . Okay. Just to give you
91:19 feel for the scale and we talked the stuff that occurs in and
91:25 Remember I showed you the due to oil field that occurs over here.
91:30 basically the same structural trend that you in Saudi Arabia ramp ramp like carbonates
91:38 easy for this stuff to pro grade step, pro grade back step and
91:42 most of the production occurs from the lime stones. The grain
91:47 These are political skeletal, sometimes a with a lot of primary porosity but
91:54 dramatized. Okay. And I think had this discussion the other day last
92:03 about the you see how everybody calls people idle pack stones or something like
92:09 because of the cloudy centers of the crystals. And I caution you that
92:15 not necessarily the case. Right. think a lot of these dolar stones
92:20 grain stones that have been replaced by dolomite. Alright. They're not
92:26 low energy democratic political carbonates. And then this is what the ceiling
92:33 looks like, right? Classical modular hydrate that we talked about forming today
92:39 of on the tidal flats of abu . This is essentially what the Buckner
92:46 look like. Except they have more a red bed fabric here. The
92:50 would be more red bed than you here. Okay, yeah, we're
92:58 talking about the platform margin or ramp brain stones. Okay, we're still
93:03 that same plane toe. I'm just you through different examples to give you
93:08 for what these things look like and some of the ceiling faces are.
93:12 of the digest pathways. Okay, example to show you the role that
93:22 winds play and localizing this kind of type. The example I'm going to
93:27 about is called Vivian field in the cretaceous. Alright. The lower cretaceous
93:34 the northern gulf frame is called the formation. Alright. And the Sligo
93:43 a platform barrier reef developed in this right here. Okay. The blue
93:52 deep for production and then look at little field called Vivian field that
93:58 That's about 240 km in from the ocean. Okay, and again,
94:04 never made any sense based on the northern Bahamas models that are ingrained in
94:09 literature. Alright, but where does field sit? It sits on the
94:15 with respect to the trade winds of structure called the cattle pine island
94:22 Remember when I showed you on keiko's you have island topography and the trade
94:26 are moving, moving wind waves this . And what happens when they hit
94:33 exposed topography? The Pfeiffer que come , that's that time below effect.
94:38 , I sort of find this interesting the living field is developed essentially on
94:43 leeward side of this pine island Okay, and why do we know
94:49 trade winds are part of the story ? Because of the development of the
94:53 stone way? Way too far inboard be driven by tidal currents.
95:00 but I appreciate what I'm saying. . Trade winds can't tidal currents can't
95:04 this far inboard, this has to trade with. Okay, and then
95:08 think it's I don't think it's fortuitous you've got this structural effect. The
95:14 pine island paleo high sitting there with grain stones developed on the back
95:19 Right? That's where you get the polo effect. All right. And
95:23 the further line of evidence that you're agitated in the platform interior setting is
95:30 scale of the cyclist city here. got these repetitive upward showing sequences that
95:36 analytic or mixed skeletal grain stone. these these things are on the scale
95:41 10 or 15 ft thick. That's scale cyclist city, which is normally
95:47 you develop in a more platform material . Right? You don't develop these
95:51 thick cycles that's limited to the Okay, so the scale of cyclist
95:56 is consistent with a platform material All right. You can see again
96:03 grading back stepping, pro grading classical of cyclist city and it's producing from
96:10 that looks like this. These are brain stones. Okay. But there's
96:17 interesting die genic over print here. that has to do with the development
96:22 the micro porosity. The zoo it's riddled with secondary micro porosity. And
96:29 talked a little bit about this last . What happens when you have a
96:33 mobile pour system where you have effective inter particle ferocity. Well connected.
96:41 . And then you have isolated secondary molded porosity within the U.
96:45 And P. Lloyds. Where do trap your water by capillary force.
96:50 in the in these grains. Where's oil? It's in this porosity.
96:57 . We talked about what happens when run a resistive the log,
97:01 It picks up on the water in micro porosity And it leads you to
97:08 high water saturation. But these are famous examples that produced oil water free
97:15 though they had water saturation of 60 80% so this is a famous example
97:22 that. Okay. And then another would be Alabama ferry field that occurs
97:28 east texas. Again a field. how far back from the platform margin
97:34 occurs during the middle part of the . That's 10 miles. That's 10
97:40 miles in from the open ocean. . And then look at look at
97:45 lobes with this orientation. See how line up from the southeast to
97:51 Remember we talked about prevailing wind coming of the eastern quadrant. It doesn't
97:55 everything's just out of due east. can also be out of the southeast
98:00 at southeastern quadrant. Right? That's what I showed you for keiko's.
98:05 either due east or southeast. And the combination of these elastic and scalable
98:11 stones, 30 miles inboard from the ocean and the orientation of the sand
98:15 again is to me it's geological evidence the trade, the strong trade
98:20 Strong trade wind effects. Okay so really key to see the U.
98:26 . Okay. You know what it to make us now. Right.
98:31 water, persistent agitation. Something I to code. Right, There are
98:37 two ways to do this tidal currents wind wave agitation. The tidal currents
98:42 operate 30 miles in on an open . Okay. That energy gets dissipated
98:50 quickly. Okay, Alright. And example from west texas central basin platform
98:59 the Permian. This is a structural surrounded by deep water, shallow interpret
99:06 basins, the midland and Delaware I'm gonna show you some grain stone
99:10 up on the central basin platform or the southern part of this northwestern
99:17 Okay. And if you look at paleo geography here, it's sort of
99:21 that during this time in the early middle to late Permian look where this
99:29 was, it's nestled right close to paleo equator. Okay. And so
99:35 some question about whether these reservoirs, , this is my computer acting up
99:42 its own here. There's some question whether you would have been in a
99:47 suitable to be influenced by strong trade agitation. Okay, because you're close
99:53 the you're within that five degree Okay, so that begs the
100:00 right, If you don't have trade to drive, making new it's what
100:03 you left with just title parents. , So there's a couple of different
100:11 views to show you this field, ? Which is called vacuum field.
100:16 is called northwest shelf up here And field. Some some maps show central
100:23 platform tied directly into the uh north shelf. But other maps like this
100:30 show that there's actually a channel in . All right. And I think
100:34 people, I think most people now that there's probably a channel that cuts
100:39 here and here's vacuum field. And field produces from these demonetized analytic grain
100:46 . So, the question is no we're not at the right paleo latitude
100:53 trade win agitation. Maybe this is by tidal currents. Right? Taking
100:58 of that channel. Because what happens you try to move water back and
101:02 with normal title exchange between the middle basin and the Delaware basin.
101:08 You try to squeeze water through these , you increase the tidal current
101:13 Alright, So that might be the why vacuum field exists where it
101:18 All right. But it's a ramp . The wood grain stones are at
101:24 ramp crest, right? That little right here, That would be close
101:28 the high energy part of the part the profile. Right? Low energy
101:36 a critic carbonates behind it. Deeper faces. You go off to the
101:42 , Alright. And why does vacuum work? It works because of
101:45 Alright, politic scalable grain stones have dramatized? All right. It's a
101:52 profile. It's basically the Arabian gulf that I showed you from the
101:58 And you have stratification associated with these dualistic grain stones. And then what
102:06 do you see you see this classical like geometry. This is that pro
102:12 all back stepping. Pro gradation back profile which is more commonly associated with
102:20 low angle ramp settings. Okay, it all fits together here in terms
102:26 deposition on setting. The big question , what was the driver?
102:29 Was it trade winds or was it cards? Right. And I
102:38 I think the only way maybe to that question would be to try to
102:41 a pack some of the sand bodies see if there's a preferred orientation that
102:46 reflect one or the other. Remember how we talked about the same
102:50 orientations are different between the trade winds And what the title parents did.
102:57 . And then one last example here another field called bulletin field still on
103:02 central basin platform. Alright, similar positional model here ramp crust is where
103:09 get the high energy politic phases. relationship here, procreation back stepping,
103:19 back stepping, sale the tidal Pro grade out along with the grain
103:23 . And then you back step build , you pro grade out, you
103:27 step, you pro grade out. are you creating here again, multiple
103:32 reservoir units. Again. Okay, ferocity is mostly associated with the grain
103:40 and the best reservoir quality is in grain stones. And of course,
103:46 it's because of favorable limestone die genesis you reach out to you, it's
103:52 these cross stratified units, but sometimes a dolomite over print that comes into
103:57 here as well. Alright, One last example here, Mississippian,
104:07 that time period. If you had guess two things about the Mississippian,
104:12 would guess you should guess Quran Lloyd's , tons of crying noise in the
104:19 . And and then what else? of boots. Right. And uh
104:25 don't you get into Mississippi? You get any classical high energy shallow water
104:29 because you didn't have the right kind organisms to make those reefs.
104:35 so the famous area of Mississippi sand deposition with well established oil and
104:44 production is the yucatan involvement in the the in the central US.
104:53 This is in Kansas, you get isolated, intricate tonic basins with sand
105:01 . And again, everybody historically related zoo. It stands to what tidal
105:08 Back in the 60s, 70s and , because that was the only model
105:11 had back then. But if you about it, this really doesn't make
105:16 sense, right? You're in an basin, you're not connected to the
105:20 ocean. You don't have any oceanic like tidal currents. So this is
105:26 I think needs to be reevaluated in of the trade wind models.
105:30 you're at the right paleo geography for wind effects. But somebody needs to
105:36 this stuff again. But the It's remember I showed you how the
105:40 . It's there's really no difference between that are formed by trade winds and
105:45 ones that are formed by tidal Alright, You have to look at
105:48 geometries of the sand bodies and and about that. And I'm I'm working
105:54 some people in Oklahoma city. This one of them john brad who's Bendy
106:00 and he's he's seen the trade wind on sand deposition. He's taking those
106:06 and now he's starting to apply it some of his prospects and he's seeing
106:10 orientation effect come into play here. , trying to exploit that.
106:17 Alright, one last comment here and we're gonna take a break. One
106:22 sequence, I want to show you the the US gulf, northern gulf
106:27 of the ancestral gulf of Mexico is sequence called the Haynesville limestone or locally
106:33 called the Gilmore limestone. And I to show you the sequence because I
106:38 you to appreciate there's another way to a parable die genesis and thats burial
106:45 to great ferocity. Okay, Most what I've showed you here is either
106:49 primary porosity or it's early form ferocity to favorable limestone die genesis or early
106:58 . Okay, so this sequence occurs east texas. All right. And
107:04 is uh, the basin is called Texan salt basin. And you can
107:09 there are two flanks here that have deposition. The eastern flank is the
107:16 famous with the bigger gas fields. sorry, there is there is isolated
107:25 and oil production on the western side , but all these yellow dots you
107:29 here are driven by salt tectonics. , so salt punch up structures that
107:36 little isolated with sand body systems or happened the salt withdrew. So what
107:43 to the salt that actually occurs in lows now? Alright, so sometimes
107:48 play the highs, sometimes they actually the lows looking for what used to
107:53 I right where the salt withdrew, you had that sand deposition.
108:01 now everybody thinks this is the more side and it is from assault tectonic
108:07 . But actually there's some major uh reactivated basement fault systems that run through
108:15 that are part of the die genesis , I think. Okay, so
108:19 , the Haynesville or what people call Gilmer limestone is actually very similar to
108:26 similar to the smack over that. just talked about, okay, a
108:32 100 ft thick, deeper water at base, right? You come out
108:34 the Buckner, you deepen the Buckner and red beds, you create new
108:39 and you shallow up and you shall on the eastern flank into these high
108:43 utility grain stones. And because there's little sub basin off to the right
108:49 not a steep margin. The sand what pro grades. Okay. And
108:53 it pro grades, it shoots those deposits out in front of it.
108:58 , remember we talked about this the big storms will pull stuff offshore
109:06 that stuff can amalgamate into thicker Greenstone . Okay, so all of these
109:12 and And uh this part of east are gas productive except for one prospect
109:19 that pioneer drill back in the late , they found the ferocity they
109:25 but they probably found a breach trap one of the false systems breached and
109:30 gas leaked out. Alright. But that you see here in red produces
109:36 the zulu grain stones. Okay, includes the main goal, which is
109:41 up here at the top and these tights that occur out in front of
109:45 . All right. And I talked why these are storm deposits. Remember
109:52 gonna show you the core for this a minute, but I want you
109:55 appreciate the sequence here. The showing that culminates in an act of shoal
110:01 the back shoulder goon behind it is out by the Bossier shale. The
110:07 shale is also the source rock for gas. Okay, so that's a
110:12 , that's what we call a drowning conformity. But the old literature and
110:17 the excellent sea level curve treats us what a type one on conformity.
110:23 claim it's a major severe real exposure . Alright. And that's based on
110:27 strata geometries. It's not based on physical rock data because when you look
110:33 the court contacts right there, if a true several exposure surface, what
110:39 we see? We should see things cursed reddish soil profiles. Right?
110:47 dissolution, early semente shin. We see a reddish color, right?
110:53 to oxygen, oxygenation by oxidation by water. Right? We shouldn't see
111:02 like pyrite. Right? Which is reduced variety of iron sulfide.
111:07 here's what the court contact looks It's sharp as you'd expect because it's
111:13 major deepening on top. But the stones here are replaced by pyrite.
111:19 no cursed. There's no soil Okay. There's no exposure.
111:26 This whole system was drowned out. right. And the active show looks
111:31 this in core with a high degree preserve stratification, which is what you
111:36 expect, right? Because you maintain through time and high energy environments.
111:41 produced preserved a lot of that primary . And then the Tempest sites I
111:50 you they were probably stratified when they deposited. But then they get reworked
111:54 the contacts get reworked. Okay. that's down ramp sediment. But this
112:01 is gas productive because it develops the type of ferocity. And the proxy
112:08 is interesting because most of the Painesville is dry gas. But there are
112:16 couple of oil fields on the western and they look like this. And
112:21 section this looks just like some of down dip smack over. I showed
112:25 from Arkansas and Louisiana where it's You see the grain sutured, high
112:32 of primary prostate. No secondary microprocessing . It's okay. So, when
112:37 in the oil window, you don't that secondary microprocessor development, when you
112:42 into the gas window. Alright, develop that high amount of micro porosity
112:47 the Eu IDs unless you somehow in those grains and oil. Dead
112:54 All right. See what I'm So the microprocessor developed came from fluids
112:59 the cracking of oil to gas. , so the Haynesville produces from this
113:07 . We talked a little bit about last week. Right? And it's
113:12 high amount of secondary microprocessing. It's it's preserved up to and around
113:16 style lights. It's preserved along the to grain future context. There's no
113:23 cement. Okay, There's leaching of tick grains like oysters. The process
113:32 after the fractures have been cemented, of this process forming during barrel.
113:38 , so, I want you to that some for this play type there
113:42 that potential to develop the reservoir quality during burial. And I'm gonna argue
113:47 a minute that that's where the structural comes into play. All right,
113:52 , you've got these diagrams in your , but basically we start with
113:57 There's no early die genesis. We the rocks. Get the pressure solution
114:03 . Right. That generates some of pore filling barrel cal sites. Remember
114:09 they're distributed away from the future? contacts. Oil comes in right,
114:16 got an oil field on the west when it's still in the oil
114:19 But what happens is these carbonates continue get more deeply buried. The oil
114:25 or cracks, right? Oil leaves you still have some reservoir quality.
114:34 second fluid comes in, drives that leeches the calcite grains. So,
114:39 know, these are acid fluids. , that's going to generate a little
114:43 more of this poor filling calcite Alright, so you end up with
114:48 that looks like this today. Mostly secondary micro molding ferocity, one
114:54 two primary prostate units. These are reservoirs. The permeability is not a
115:00 control here. These don't have to fractured to be productive. Alright,
115:05 appreciate the timing relationship here. And the porosity always shows this bell
115:15 distribution highest at the center of the , lower and lower as you go
115:19 the go towards the edges. Because continued burial, you actually bleed in
115:26 cement from the critic beds on both of that grain stone to give you
115:31 bell shaped ferocity. And then the that this is also a fault controlled
115:37 play is the fact that we have these exotic non carbonate minerals associated with
115:44 Haynesville. And it's not just right the top. It's all through the
115:48 . Alright so we haven't talked about significance of these minerals yet Really.
115:55 my ride is iron sulfide. And Marcus site is it's this is
116:02 mineral. It has the same mineral but a different structure. Okay.
116:10 what is significant about Marcus side Market only precipitates for massive fluids.
116:17 As does Ortho genic courts as does And mega courts, where do these
116:23 come from? They come from deep frenetic basement rock. Okay. Now
116:30 is one of these A C. . C minerals. It can precipitate
116:34 acid fluids. It can precipitate from fluids. So by itself it doesn't
116:38 anything about the chemistry of the poor . The market side does.
116:44 And market sites distributed all through here the sequence. As is quartz,
116:49 fluoride. Okay everybody appreciate what I'm here. We're using these exotic non
116:56 minerals to figure out where the fluids coming from. Okay, so that's
117:01 I'm arguing that this is a fall digest play as well as a ramp
117:08 brain stone play. Okay and then I'm biased here in terms of of
117:16 up some of the production associated with parts of the of these fields.
117:21 you sort of see a linear trend which I think is what you would
117:25 to see when you do see this other sequences where there's underlying fall control
117:29 the on the better reservoir quality. , so food for thought. And
117:37 a paper on your travel drive that a lot of these relationships.
117:41 for this field. Alright, so summarize And then we'll take a 10
117:47 break here. Platform margin ramp, grain stones, Pre existing topographic highs
117:53 usually localized these carbonate sand bodies. , subtle topographic highs are very important
118:02 . Okay, you're gonna see this for all five conventional plays. Depth
118:06 burial digest history controls reservoir quality. , the best reservoirs are those that
118:12 partially cemented early in grain stones are delimited or dramatized early where you hold
118:20 to that process depth. The fizzy setting controls the stacking of the
118:27 Ramps, as you've seen, pro back step, pro grade back step
118:32 margin profile. What are you gonna a grade right ribbon like morphology along
118:38 platform margin. Alright, sometimes you structuring to entrap the hydrocarbons, but
118:44 think strata, graphic digest traps are more common in the subsurface than companies
118:50 been willing to admit. The seals time equivalent. The critic or evaporated
118:55 show faces. Source rocks are usually a problem there offshore nearby. Based
119:01 shale or limestone. Okay. And are some of the examples. All
119:07 . So in the future you have bibliography that you can rely on
119:13 you know if you get involved in kinds of plays later. Okay.
119:19 questions or comments about this first, play? All right, let's take
119:25 10 minute break and then we'll come and talk about the 2nd style.
119:29 platform margin briefs. Okay, so let's move on to the
119:37 what I call conventional play type. that's the platform margin reefs and two
119:44 here show you the difference in the of the reef geometry to slope angle
119:51 what sea level is doing through Okay, so the upper cartoon is
119:57 of the northern Bahamas example today where have a reef develop along the ST
120:03 profile. Right? Remember these reefs to form where open ocean sides of
120:09 these platforms where they catch the oceanic if they also face into the prevailing
120:15 , that's even better. Okay, and this this example here, they
120:21 really appropriate, right? Because the is really deep in front, so
120:24 forced to build vertically through time. is the ribbon geometry that I was
120:28 about. Okay, so you the issue here is how do we
120:33 seal this potential reservoir? Right. can't use the platform interior lagoon sediment
120:42 the top seal because it can't pro out over that brief through time because
120:46 not programming. Okay, so in model, you top seal it by
120:52 out the reef sea level comes up such a rate that the reef can't
120:57 to grow. You drown it out you put deep water carbonate or deep
121:01 shale on top. Okay. And are lots of examples like that in
121:05 rock record. Okay. But you the slope angle, like having the
121:10 diagram here where this system can pro . And I showed you this
121:16 an outcrop reef like this. An from Mexico. Last weekend we talked
121:21 the torpedo formation. Remember the big ? Don't remember the big shirt on
121:29 diagram. All right, lateral procreation 100 km for this reef system.
121:36 , that's a lower slope angle. . And in that case, what
121:41 piggyback on top of that through time subsidence is the time equivalent more um
121:47 critic back reef again. Okay. so in this model, you're effective
121:52 seal would be the time equivalent back again. Okay. And there are
121:56 of examples of that in the rock , right? No, there's a
122:02 an industry that carbonates are not good faces, right? Because they're carbonated
122:10 they're gonna fracture, right? And gonna leak. But that's not supported
122:16 the observations, right. If you a thick enough lagoon, als muddy
122:20 sitting on top of the reef that be an effective effective top seal.
122:26 . A lot of companies think the way to effectively top ceiling carbonates with
122:29 shale. Alright, And that's that's not true. All right. Source
122:35 in this model would be offshore nearby carbonate or basin oil shale.
122:41 And then last weekend we spent time about the barrier reef model. I
122:47 you to appreciate any one point in to basically to sub faces the re
122:53 . The factory relatively narrow, A few 100 m across for
123:00 And then time equivalent to that is lagoon behind it, right? Or
123:07 slope in front of it. But shedding is not this way on open
123:11 reefs, It is back behind it make the battery flat. So the
123:17 flat ends up being 10 or 20 wider than the re front.
123:22 But the whole system can do what time pro grade if it's the slope
123:28 is not too high and the whole front is not too high.
123:34 You expect these reefs have good scientific because you're building that vertical aggregation profile
123:42 the reef starts to pro grade. then most reefs that build the sea
123:48 , want to do what they want build it. They want to build
123:54 and then do what pro grade out seaward direction. Right. This creates
123:57 we call the mature barrier reef Right. The definition of the mature
124:03 reef model was you built up the level with a good re flat.
124:08 , Okay. And this this is produced by showing up. But then
124:14 right in order to get the debris thrown back and filling the old reef
124:20 hill reef margin was here and built seaward direction like that. Right.
124:25 I took you guys through a couple modern analog, the police barrier reef
124:29 the caribbean. And then I contrasted with the the great barrier reef system
124:34 Australia. Alright. Any one point time, the system looks like
124:39 Re front out here, bakrie flat with excellent reservoir potential. Right?
124:47 remember with respect to marines imitation, where do you get marines imitation in
124:51 profile out here in front, where you get marines imitation anywhere back
124:57 Okay, and so the brief the of the reef flat is really your
125:05 reservoir interval, Right? If you to, you have to guess where
125:11 best reservoir quality is gonna be in model, You're always gonna pick the
125:16 flat. Okay, the debris. right, the course of rubble or
125:20 finer grained stone material. Right? then remember all of these reef systems
125:26 cut by channels. You need channels get water on and off the
125:30 But think about this in the right? When you bury your
125:35 write your linear prostate trend. If any structural tilting, you gotta do
125:41 you gotta seal it right to keep oil from leaking out, right going
125:46 dip. So one way to do is to take advantage of these channels
125:51 cut the reef. If they get in with deep water carbonate or
125:55 they provide a nice up dip seal that linear porosity trend. Okay,
126:02 you gotta hope for their fault or like that to cut through there to
126:06 that that seal. Okay, so just jump right into some examples here
126:13 we'll just move through geological time We'll start in the lower paleozoic with
126:18 devonian and the devonian reefs were mostly by Strome atop roids, not
126:27 And this is a complicated map because comparing apples and oranges with respect to
126:33 types. All I want you to on for this diagram is this part
126:38 the map right here? What's called shell basin is a horrible term.
126:45 should be called cooking like platform. , It's not a deep water
126:50 It's a drowned carbonate platform. And that platform are isolated reefs of a
126:56 play type. Like we're going to about next, but right along the
127:01 , right here are linear reefs, , margin reefs dominated by Strome atop
127:08 . Okay, They're mature reefs. built up the sea level with a
127:11 flat. Most of them are delimited , so they have that over print
127:17 create secondary process, but a couple still limestone. And what's the orientation
127:23 respect to the trade winds. This actually the leeward side of the
127:28 Okay, so this is western This is Alberta. Okay. And
127:35 paleo geography during this time of the was for 15 degrees south of the
127:41 . All right. The prevailing winds out of the east Northeast quadrant.
127:46 . And we still develop these reefs the leeward March. So, why
127:51 we do that? We blocked off sediment transportation. Alright, What's one
127:58 the ways to do that to have platform deep enough to inhibit off bank
128:04 ? Right, so the trade winds agitation along this margin, but the
128:09 winds are not able to put fine carbonate material and suspension here and persistently
128:15 those reefs. Okay, so these always consist of the two components that
128:24 just talked about from the modern, the re front looks like this in
128:32 thick tabular strom atop roids. These thought to be in clusters.
128:36 So this is part of that shallow front or the C. Word part
128:42 the of the reef flat with coarse . This is that root stone and
128:48 stone fabric. Excellent primary porosity. , so in this, in these
128:54 systems you get that are not delimit yet. This has this is still
128:59 . That's what controls the processing Right. It's that fabric. But
129:03 better processing perm occur in the debris behind this. Okay. And that
129:09 looks like this. The broken up of strom atop roids. These are
129:13 roots stones and float stones with a storm at operator skeletal grain stone
129:21 Ok. But sometimes hundreds of military of permeability because you've got good,
129:27 connection of poor threats. Okay, talk about the demonization effect here in
129:33 minute. All right. But just a limestone perspective, right. This
129:37 what some of the, some of devonian pools look like. Alright,
129:42 just jump back up into the Remember, this is another variation on
129:48 map I showed you for the grain development in west texas. This is
129:52 northwestern shelf that we talked about. is a central basin platform. There's
129:57 channel called the san Simon channel. . And I'm going to talk about
130:01 reefs that occur along this margin right . Okay, On the northern end
130:06 what is the Delaware basin in west . These are lower Permian aged
130:12 oldest permian aged reefs. The trend called a bow. Okay. And
130:18 of the famous fields is called Empire field. You can see the reserves
130:26 . You know what a giant oil is In terms of oil in place
130:31 million is a giant oil field. , so this is not quite a
130:36 oil field, but it's pretty Alright. And this stuff works because
130:42 reef is Delaema ties. These are is Permian age. So the Permian
130:46 a time where you have corals. weird cal correa sponges, other cal
130:51 algae and then you have debris associated it. And all of this stuff
130:56 to be Delaema ties to be Okay, so it's not an incredibly
131:02 platform margin. Alright. There's a bit of procreation that you see here
131:07 with that refill system. Okay, you come out into the Delaware
131:14 this is what the refill rock looks . These are the cal curious
131:18 I don't know if you remember to feeds. I talked briefly about tube
131:23 that's an encrusted in the permian that to some of the re framework
131:28 It's an organism that nobody knows really it is. Okay. And you
131:33 see some of the porosity and also some of the late stage and
131:39 Remember the common theme that we developed weekend was we have late stage and
131:43 coming into Dulles stone, we start some secondary leaching of that fabric,
131:49 exactly what you see here. so the re front is productive because
131:55 the secondary process development. The debris that occur on both sides of that
132:00 front look like this in core. . Remember the fuselage needs are the
132:06 benthic. Foraminifera Krih noise. Those the Quran IDes of the light colored
132:12 right there, You can see All right, high degree of secondary
132:17 development. And then of course the benefit of dilemma ties in the reef
132:21 you get fractures and the fractures help some of that secondary porosity and then
132:28 is over land or top sealed by green shales. Alright, so that's
132:32 effective top seal for that reservoir. . Platform margin, but this case
132:40 to have favorable reservoir quality. and let's move up into the cretaceous
132:50 we're gonna talk about the middle part the cretaceous. I talked about south
132:57 when I was I started this discussion talking about the paleo highs beget paleo
133:02 , right, that was the Edwards cretaceous trend that occurs in south
133:07 We're gonna talk about that trend it's a marginal economic gas trend.
133:13 gas trend that occurs in south That trend extends all the way around
133:18 gulf rim to florida comes down here Mexico and we'll talk about the equivalent
133:25 in Mexico. That is a oil called uh Golden lane. Okay,
133:36 strata graphically. This is where we're . We're in the Albion age.
133:42 of the trend basically middle cretaceous part the trend. We're gonna be talking
133:46 the Edwards, which in the subsurface broken out into a zone and a
133:51 . This is essentially two cycles of related sedimentation. Okay, the trend
133:59 south texas runs from the northeast down the southwest and the It's interesting remember
134:13 llano uplift that I talked about the extension off the landau uplift. It's
134:18 the san Marcus platform here in south . The san Marcus platform is going
134:23 come into play for our discussion about Austin chalk. Tomorrow. That's
134:28 basement rock. Okay. Which is the landau uplift is up to the
134:33 west. There's an older cretaceous platform called the Sligo that we talked about
134:42 Louisiana that I said was too deep be productive. It's marginally gas productive
134:48 in south texas. And then look when you come into the next three
134:54 , The younger re sequence, which the Edwards. Look how it
134:57 one on top of the other when sits on frenetic basement rock. But
135:04 trends actually bifurcate when they go to Northeast and when they go to the
135:09 and nobody really knows why they Okay, but the logical influence probably
135:17 salt tectonics because there's active salt movement the northeast of that sand Marcus arch
135:23 there's active salt tectonics to the south . Okay, And then you see
135:29 red line here in this lower map the Edwards reef trend. And I
135:34 you to appreciate that While it looks all of these reservoirs that are listed
135:38 are aligned with that platform margin The 22 of the bigger gas
135:44 Dilworth and word field actually are different type. They produce from back
135:51 lagoon carbonates. Okay, that's a play type. The one that falls
135:56 this category for discussion is pawnee. , so Ponti is a good example
136:01 the platform margin Edwards reef trend. right, so what's unique about the
136:07 of cretaceous? This is that geological period where the corals and storm atop
136:15 droid sort of die off. You see them as much in the middle
136:19 upper cretaceous. You see this change a these marginal reefs that are dominated
136:24 rudest. Remember rudest were mollusk. . And there are basically five types
136:34 molluscs, rudest that are associated with of these reef complexes. And I
136:41 I briefly mentioned this the other Right? Uh A couple of them
136:48 horn shaped like you see here. some of them are were as big
136:52 my leg and outcrop. Alright. lot of internal porosity, which means
136:57 they're easily broken down into debris. we mentioned the mineralogy summer Iraq
137:04 And then some like the two It's are schizophrenic. They have one
137:08 of this calcite, one layer. Iraq genetic. Okay. And then
137:12 monopoly boards are cal citic, but occur in these low energy batteries behind
137:18 reef margin. Okay, so the for making rudest reefs is different than
137:26 we talked about for the classical barrier . Classical barrier reef. We saw
137:31 , high energy reef along the Right, rudest or not like the
137:38 day barrier reefs. They occurred as pat reefs and some groups some of
137:47 rudest grew like this upright trapping sediment then they die and fall over where
137:53 lived horizontally on the surface of trapped . Okay, then they would get
137:59 up by major storm activity. All , so these reefs are put together
138:04 these mixtures of reef cores which never thicker than about 25 m surrounded by
138:13 debris. Okay. And one's a stone, Right? So stuff trapping
138:21 mud matrix and then grain stone debris it generated by the storms. And
138:26 what happens through time is all of coalesces along the margin. Okay.
138:31 so that's why people map this linear trend, but it wasn't a classical
138:36 reef, like it is like we today. Everybody understand it was a
138:40 of little patch trees, it got over periodically by storms. Regroup shed
138:46 , coalesced. Okay, so that's this diagram is trying to show.
138:53 , And Edwards is made up of 2 2 sequences of deposition. The
138:59 Edwards B, which is historically not productive and then what they call the
139:03 . D. M. B, is regional dense member. This is
139:07 a reflection of a new cycle where deepened, drowned out the reef.
139:12 started up again and then the bottom out of here on the gamma.
139:17 can see this is the Georgetown, is a deep water pelagic carbonate that
139:22 out the reef. Okay, so me show you the outcrop equivalent
139:27 So you appreciate what it looks like the field. This is from Mexico
139:31 one of the, what we call reef core. All those holes you
139:35 there used to be pieces of the , the magnetic. And what's in
139:41 is the mud matrix that was trapped those roots before they died and got
139:46 . Okay, so that's the outcrop . Here's the subsurface equivalent. You
139:52 see the rudest pieces with the internal . You can see there's a schizophrenic
139:58 that I talked about that has the calcification A. Er and the re
140:02 white former magnetic layer. But look in between the critic colloidal mud.
140:10 , there's no porosity in the There's no perm. But the reef
140:16 have ferocity. Alright. People have 1520% porosity for these reefs. But
140:23 are they? The mold? The , The mold, the mold.
140:27 . Not connected, no permeability. historically this kind of stuff never
140:33 Alright, the productive faces is the sheets in between. So here's another
140:40 in central texas. That's a patch where you see the bigger pieces.
140:45 , the baffle stone texture. There's over here and then look at what's
140:49 between these rippled asymmetrical ripple, That's one wave oscillation, ripples of
140:55 stone debris. That's the stuff soft the patrick by major storm activity.
141:01 the equivalent in the subsurface. That's the basically the re flat degree
141:08 up by major storm activity. That's most of the Edwards produces from.
141:13 , it looks like this infant you can see some of the primary
141:17 of the rudest fragments. That's primary particle ferocity, partial multi porosity
141:25 Mostly secondary porosity with calcite sedimentation, some of that original porosity. And
141:34 You can see the sample here. is 10,360 ft. This is from
141:40 NMR study I think I talked about weekend that I did for Anadarko where
141:45 try to use the NMR tools two expiration. So this is a plug
141:51 9% porosity, 2.4 million Darcy's Alright, this would be gas
141:57 Alright, because you don't need a of perm for for dry gas.
142:04 . And then I mentioned Ponti field , Ponti is an old shell field
142:09 they shall discover this back in I guess the 60's and their development
142:15 all vertical drilling. Okay. And could see their history up until 1985
142:24 vertical wells producing field wide 8.5 million billion cubic feet of gas today.
142:33 . And then pioneer natural resources out Dallas before they became a shale
142:40 we're pretty active with carbonates that they this field and redeveloped it with horizontal
142:46 because the other concept was people thought the low matrix perm these these reefs
142:52 to be fractured to be productive. so the strategy was to come in
142:57 . Okay. And even without the just coming in horizontally, you're obviously
143:04 a lot more porosity. Right? they got the production up, I
143:08 , look at the change in production field wide up to 50 million cubic
143:14 of gas that they of course they a lot more wells too,
143:17 but I know that their production increased . Right? These wells would produce
143:24 or two million cubic feet of gas day with a vertical well, these
143:27 were producing 8 to 10 million cubic of gas today, horizontally.
143:33 so horizontal wells improve your produce Right, Alright, so that's a
143:39 study from south texas. Alright, gas. We're talking barrel depths of
143:45 little over 10 to over 13,000 ft burial. Alright, and so one
143:51 the critical considerations is holding on to process long enough to entrapped. Excuse
143:59 long enough to attract the gas. , now let me bring you down
144:04 to Mexico Golden Lane platform is has production associated with it. It's the
144:11 age as the rock that occurs in texas. But this is a classical
144:17 oil field. Alright, It's an structure. It's basically an offshore
144:26 Alright, sitting on a granite basement . So that's the pink that you
144:30 in this diagram right here and then top of it, is this widespread
144:36 platform called a labra platform. And , paleo geographically, we were 15
144:42 north of the equator. So we're the strong easterly trade wind belt,
144:46 means that this was the windward This is the leeward side. There's
144:51 developed on both sides, but in tertiary, later structural tilting up to
144:57 northwest. So where's most of the ? It's on this side.
145:03 And Pemex has pretty much given up given up on this margin here that
145:08 can see there are some purple areas production here. They've pretty much given
145:14 on this side because they think most it is below the oil water
145:18 But I think they actually missed the here. But you can see where
145:23 of the production is on the western . So all of these strings of
145:29 that you see here in purple define people call Golden Lane field Discovered in
145:35 early early 1990, Sorry, They it was discovered in the early 1990s
145:44 . Okay. And of course these discovered by surface seats and this is
145:53 not only a leeward platform margin reef . Okay, by definition ist leeward
146:00 . So that begs the question, did you get reefs on the leeward
146:04 ? Why didn't they get smothered by bank transportation. That's the first
146:10 And then the second interesting thing about is there's superposition of tertiary car certification
146:17 top of these briefs. Okay, created arguably cavernous porosity. Okay,
146:26 you see the reserves are greater than billion barrels of oil in place.
146:31 expression suggests some sort of car certification at the top here. That's confirmed
146:37 the production, uh, this field these fields. This leeward margin field
146:45 holds the record for the highest initial from a carbonate reservoir 260,000 barrels a
146:54 . Okay. And this is described the literature, stalactites blew out of
147:01 whole stalagmites blew out of the Okay. That's related to the cavernous
147:08 due to classification. Okay. And there's hearsay in Pemex and actually learned
147:17 as a grad student. When I a grad student Rice, my,
147:21 advisor was James Lee Wilson, one the famous older earlier carbonate greats already
147:27 a book on carbonate faces through geological . And he was, he was
147:33 in spanish and he had a long of working the outcrops in northern Mexico
147:40 he had a close relationship with Pemex he told me as a grad student
147:45 in Pemex that the hearsay is that only does stalactites and stalagmites blow out
147:52 the hole, but 60ft of drill broke off, turned upside down and
148:01 out the whole like that. 60 ft. So you need enough
148:08 in that cavern to rotate the drill and blow it out upside down.
148:14 , so that's the hearsay. That's in the literature. I actually taught
148:19 course for Pemex about 10 years I went to Mexico and taught of
148:23 . When we got to this I had to ask these guys,
148:28 that they were around in the early hundreds. But I said if you
148:31 heard this is this carried through Pemex I said yes, this is what
148:36 always been told that the drill string off came out the whole upside
148:41 So that gives you a feel for effect of the cavernous porosity.
148:44 So this is a platform margin reef , but it's also a cars modified
148:51 margin reef. Okay, so appreciate . Alright, now, the bigger
148:57 is, why do you get reefs both sides? You can appreciate why
149:01 get a reef on this side. , That's the open ocean side with
149:05 to the ancestral gulf of Mexico and windward margin. Okay, but this
149:11 is I showed you for the northern or keiko should be what sediment
149:16 But we got good reefs all along margin, right from north to
149:20 So what's going on there? I think two things, first of
149:25 , why do you get reefs on leeward side? Right, that's not
149:28 side where you get oceanic swells. what has to be the driver?
149:35 is the this is where the trade would operate provide the agitation.
149:40 and the evidence for that is the that the back reef debris back here
149:46 , sorry, politic brain stone. is a picture I lifted from a
149:51 in 1972 where they described a little stone behind the reef Again, that
149:58 back in 72 we only had the Bahamas model. Right. And I
150:02 it was reefs or you? but not the two together. One
150:07 the other. Yet, here's that's they're describing right here. And that
150:11 made any sense until the trade wind came into play. Now, it
150:15 sense. Right? So the reefs agitated by the trade winds. That's
150:20 provides the day to day agitation. also makes the U. It's in
150:25 finer debris. Okay. But the is not generated by the trade winds
150:30 by hurricanes. Right, Hurricanes would up briefs. Okay. So the
150:36 is, why didn't this stuff get by off bank transportation? Well,
150:40 think the answer is back here. lagoon had to be deep enough to
150:45 off bank transportation. Okay. See I'm saying. So, in
150:51 you know, I showed on Keiko's platform materials only about 2025 ft and
150:56 strong trade winds can push mud and sand to the edge and over.
151:02 you deepen it maybe the 30 or ft. That might be enough to
151:05 that off bank transportation. Okay. there's some suggestion on the newer seismic
151:11 that was like a bucket. This is like an eight. All
151:15 . A tall morphology with a deeper and that would serve the purpose right
151:21 inhibiting off bank transportation. Okay. lot of these old plays just never
151:28 any sense based on the northern Bahamas . Right. When you start thinking
151:32 the trade winds changes the story, ? And I think it gives
151:38 there's food for thought to think about new opportunities and places that historically we
151:43 have written off based on the northern . Okay, Alright. So let's
151:48 this up and let me make one about steep margin reef systems here.
151:54 , again, with respect to the imitation effect reefs build their own
152:01 Right? And they build their own . And they just sit there getting
152:05 by oceanic swells every 10, 15 . Right? And so you're pumping
152:11 lot of marine fluid through that reef . And so what's one of the
152:15 here? One of the risk is you can cement up the reef and
152:20 a lot of that reservoir potential on sea floor by marine sedimentation.
152:27 We had that discussion about how quickly cement precipitate out. I showed you
152:32 police example where the, those fan crystals were growing at rates of 8-25
152:39 per 100 years. Okay. And this is one of the risk.
152:46 , this is one of the questions . And the exam today,
152:49 Where you're gonna get marine sedimentation. just going to get it on the
152:52 side of the reef, the reef and the upper four. So,
152:56 don't you get the reef, marine ? You don't get it in the
153:00 reef flat, You don't get it in the lagoon. Alright, So
153:04 see one of the risk here, reef itself could be cemented and companies
153:10 drilled into that, they see that what do they do? Adios?
153:15 ? They walk away. They think whole reef is tight. When what
153:20 they do? They should drill like . So that's tight reef. They
153:24 the front of the reef is what should they do? They should
153:26 back and they should they call it stocking. Alright, Should go horizontal
153:31 drill into the debris. They're gonna porosity. Okay, if you understand
153:38 carbonate system. Alright, So that's the issue. All right, so
153:43 is the famous example where the reef least an outcrop, 90% of that
153:49 was destroyed on the sea floor by radial fiber cement. Right? That
153:55 marine cement, Right? But you see this in the back reef.
154:04 reef is a little bit different, in most in other reef complexes,
154:09 don't see this breeds imitation effect in debris. Okay. And the right
154:12 flat. Okay, everybody appreciate Okay. And then one comment here
154:20 demonization of reefs? We talked about of the popular models for making
154:26 And remember one of the models was a carbonate platform with a reef margin
154:31 ? A basin filled with shale or . What's one model that can operate
154:38 on the watering where you can squeeze up out of that shell basin.
154:44 the gray here represents the shale There's your carbonate platform in blue.
154:49 have reefs along the edge here. could be preferentially delaema ties like you
154:53 here in purple. And two things happen when you dilemma ties that
154:59 And the first is you get an degree of fracturing because dolomite obviously is
155:04 brittle, but more importantly, what happen to that reef fabric, especially
155:09 degree. This is where you can that super permeable reservoir rock In the
155:16 stones especially. Right. Remember the of root stone. The big grains
155:20 touching in three D. You got finer sand matrix in between that gets
155:26 monetized first. Then we talked about happens during the advanced stages of the
155:31 . We leach out the remaining calcium to create this porosity. But that
155:37 is touching in three D. So at the permeability you get here
155:41 5 Darcy's. Right. Normally you're to get a few 100 millibar seas
155:48 ferocity from a reservoir in the Okay, alright, so always something
155:56 think about your general fizzy graphic What's filling the basin. Right,
156:02 your time period that controls the Right. But most of these reef
156:07 always have those two components the reef reef core and then the debris sheet
156:13 it. Okay, so summary here we'll take a little break here in
156:20 minute. Platform margin reefs. they like to take the paleo
156:27 Right there, influenced by paleo All right. So that paleo hizbut
156:31 paleo highs not only applies to the stone situation obviously extends to the
156:38 Okay. And sometimes these these paleo are so subtle. You really have
156:43 hard time even mapping. Okay. influences the digest pathways. This is
156:50 we pay attention to the age of reef organisms. Okay, what's the
156:56 rule of thumb? Lower paleozoic reefs mostly cal citic. Upper paleozoic briefs
157:04 a mixture of calcite and Dragon Mesozoic and younger reef systems. Mostly
157:10 genetic. Okay, So as you've , right, the board, Dragon
157:15 we have in the system the more for a limestone, we're gonna get
157:18 lot more secondary process. Right. things are more stable calcite, we
157:23 not to see that unless you dolma some of that brief material. All
157:29 . Same point about reservoir quality governed depth of burial di genetic history I
157:34 sometimes you need structuring to seal off linear reef trend. But you can
157:39 advantage of those channels in a case a deepwater shale and carbonate. The
157:45 seals obviously are deep marine carbonate or , but you can't have more MMA
157:50 back reef carbonates doing the same Source rocks are usually not a
157:54 Okay. And that's couple of Okay, any questions about this play
158:04 ? The good thing about this play is good seismic expression. Right,
158:08 are normally new, created along that point on margin. So it's easy
158:14 image. Remember we talked about it's enough just to image this. You
158:19 to know what your orientation is. ? Does it face away from the
158:23 ocean? Does it face towards the ocean? Okay. Alright, let's
158:28 take about a five minute break until 15 and then we'll finish up with
158:34 last play type for the day. , okay. The third conventional play
158:46 is what I call a platform mound . Okay, so you can see
158:50 the schematic cartoon, we are dealing a platform to base and transition where
158:58 we had platform margin reef development along edge in this position right here.
159:05 . And then what happened to that ? It got drowned out.
159:10 so we have a major relatively rapid in sea level that kills your platform
159:15 reef. What are you gonna do those refill organisms? They're gonna shift
159:20 dip right, those coral polyps are want to go somewhere up dip the
159:25 water and they're going to take advantage paleo topography up on that drowned carbonate
159:31 . Okay, so every little paleo becomes a potential site for an isolated
159:37 deposit. So, the geometry these is completely different than what we just
159:42 about on the margin. Okay, I call these platform mound carbonates,
159:47 Mount. Is that nebulous term for build up? Alright. And some
159:53 these build ups are going to be energy and they're gonna be like many
160:00 of the barrier reef, right? gonna have a reef margin, a
160:03 flat. But some of these other are going to be lower energy.
160:07 ? So, they could be They could be carbonate mud banks and
160:11 like that. So, there's a of different potential here for different styles
160:15 brief deposition, but everybody appreciate what dealing with here. We're dealing with
160:19 we call a back step effect where drown out our marginal reefs and we
160:24 our focus of reef deposition somewhere up that drown carbonate platform to a paleo
160:30 . Okay, And so you build build up. Typically these build ups
160:35 not that thick, they don't usually thicker than a few 100 ft thick
160:39 the most. All right, there's exceptions, but because we're up on
160:44 platform historically, our rates of subsidence not as great as they would be
160:49 in the basin. Right? you can't build great vertical thickness.
160:53 , you're lucky to make something with few 100 ft of vertical thickness and
160:58 what happens to that build up? gets encased in its own debris
161:03 which is yellow and then it gets out by deep water carbonates or deep
161:08 shells. And so this creates what call excellent strata, graphic trapping potential
161:15 good four way closure. Right? closure. Just means all the way
161:19 that build up. You've effectively trapped ferocity. Okay, So that's the
161:25 thing about this kind of the play is you end up with this excellent
161:30 , graphic trapping potential. All And look at the scale of these
161:34 are typically a few to tens of across at the most. Okay,
161:41 they're not very thick, they get , if they get more than a
161:45 100 ft thick, that's pretty You expect. Again, relative to
161:50 trade winds, there's gonna be a side and the leeward side and here's
161:55 the strength of the trade winds is important. Again, for influencing what
162:00 on the reef and we'll get shut of the reef. Okay, And
162:06 could see again, just like I about for Golden Lane on a bigger
162:10 , right? You could have like double edged reef, right? Could
162:13 reef on one side reef on the side. If your central lagoon is
162:17 deep and inhibits Halkbank transportation. we expect the complex to evolve to
162:25 that looks like this where the best development is on the windward facing
162:33 The leeward facing side is patchy because the off bank sediment stress.
162:39 again, the composition lagoon sediment depends how deep the lagoon is and also
162:46 strength of the trade winds. And we actually talked about this in
162:51 modern, I contrasted uh the police here, right where the lagoon was
163:01 deep, 30 40 ft of water . And where's your high energy
163:07 The reef and debris is around the . Laguna's tight would be tight in
163:11 critic. Okay, then I showed the example from Australia similar position,
163:19 much more energetic. Right? It just the trade winds is also that
163:24 that 10 to 12 ft title range produces a strong tidal current. And
163:30 did we see in Australia? High reef margin and carbonate sand in the
163:37 . Because you stripped out all the . Right, because of that more
163:41 setting. Alright, so that's something want to factor into your evaluation in
163:45 rock record. All right. So most famous example of of this is
163:53 reservoir in western Canada called judy It's devonian aged and here's the
163:59 The pink is a broad shallow water platform. The green represents the deep
164:06 basin. Okay, so these are deeper water burrow, lime mud stones
164:12 wacky stones. Okay, no prior the development of these blue features
164:20 every one of which is a Mountain carbonate reservoir. There used to
164:27 marginal reef developed on this side here is the eastern windward side of the
164:33 there to producing reefs. Trans here mountain and deer mountain. Okay.
164:40 got drowned out. Ok. Sea came up you killed off that
164:44 Set up a really nice play there you encased in deep water carbonate.
164:49 drowned the platform. And where did shift your reef deposition to? A
164:54 of very subtle and I mean really you can barely map these out with
165:00 well controlled and there's a ton of controlled. All right, very subtle
165:05 highs that that initiates these reefs. one of these blue blobs is productive
165:11 judy creek is the most famous because all the rock data that went into
165:16 development and evaluation. Alright. And the case study. I'm gonna take
165:21 through tomorrow. Alright. To show how esso resources modeled this reservoir,
165:28 they use that simple cycle contact relationship build this detailed faces strata, graphic
165:36 to milk more oil and gas out that reservoir. Okay. And I'll
165:41 you some cross sections of judy I mean they're already on I've already
165:46 on blackboard. So if you can't you can go look at them but
165:50 go through those tomorrow. Okay, I'm not gonna spend a lot of
165:53 talking about judy creek cause I'm going go through this in a lot of
165:57 , show you the rock data and you some of the cross sections that
166:00 built And more importantly show you With simple approach, how they got almost
166:07 million extra barrels of oil out of reservoir. Okay, so here's the
166:14 relationship though, shows you why you this excellent geographic trapping right? House
166:19 and Deer Mountain were along the platform . You drown them out back
166:23 you create these isolated reef complexes. they get surrounded and and and and
166:30 by the deepwater waterways. Carbonates. , these are basically based on carbonates
166:36 drowned out the swan hills, Okay, alright, so let me
166:41 show you some examples here. We'll back, we'll do the Devonian example
166:46 . Here's an example from the permian earlier I talked about the abo empire
166:54 brief trend that occurs in this position here along the margin as a platform
166:59 reef. Right, demonetized equivalent to or slightly after that is another isolated
167:07 complex back here called North Anderson And if you look at the scale
167:11 , you're about 10 miles back in the open ocean. Right. And
167:16 you've got two issues here. The issue is you got to have something
167:20 which the back step to right, paleo topography, but you still need
167:24 you need a driver for deposition. not gonna get oceanic conditions here because
167:29 too far back. So what becomes driver again? The trade winds
167:34 Trade winds provide that persistent agitation. most of these platform mound carbonates are
167:39 by trade wind influences. All And this is, this is North
167:45 Ranch. Just to give you a for the setting and um not trying
167:50 impress you. This is not a field, but I want you to
167:54 that this is a comparable setting. we just talked about like for judy
167:58 . Okay, now let's move into cretaceous. The lower cretaceous is a
168:06 around the world where you get this a very common play type developed.
168:11 , and I'm gonna show you two from the ancestral gulf of Mexico during
168:16 lower cretaceous. Uh, and Appreciate setting. Again that these paleo geographic
168:24 suggest we're about 15° north of the . Right? And that puts us
168:32 the heart of the strong easterly trade belt. So just keep that in
168:37 . Alright. And the first sequence gonna look at is related to the
168:42 . I showed you a Sligo grain play type that was Vivian field that
168:47 240 kilometers in board. So I I've already convinced you trade winds were
168:52 of that story. Okay, well field I'm going to talk about is
168:57 Black Lake and this sits even closer the margin. Remember Vivian field was
169:02 here in the north. Okay, Lakefield sits, look at the scale
169:08 here, that's 8200 kilometers in from open ocean. It's taking advantage of
169:14 salt related structure. Alright, so is part of the story for the
169:19 , but again, its presence here made any sense based on what I
169:23 you for the northern Bahamas way too inboard to be driven by oceanic swells
169:32 tidal currents don't make good reefs but tidal currents wouldn't operate 80 kilometers
169:37 on an open platform. Okay, here's an older map published back in
169:44 . Uh, Leo Herman was a at uh, La Tech outside of
169:50 Louisiana. And I never met Leo . So I don't know the basis
169:57 for this map, but I can of surmise what he was struggling
170:01 All right, here's the main reef that we just talked about earlier.
170:04 said, this is too deeply right? This is a classical barrier
170:09 complex of corals and Strome atop But its 16-18,000 ft of burial and
170:15 limestone, there's no porosity. so it's never produced down here.
170:22 then here's Black Lake field that they by accident. Okay. And I
170:29 his, his answer was in order explain why you get this high energy
170:33 and also sand complex. This far up from the margin. He just
170:40 the margin, take a left hand and then come on back out like
170:44 . Right, Which I've talked to who discovered Black Lakefield. They don't
170:49 where this map came from. They there's no evidence on seismic for
170:52 Okay, I think he was just to conceptually understand how you could get
170:58 high energy reef that far in from open ocean. Alright, so what's
171:03 key observation in Black Lake field? is not a. Which is a
171:06 little field. Right. 160 million oil field produced almost a TCF of
171:12 . All right. And the key is to recognize that not only is
171:17 a brief complex dominated by rudest Okay, so as you've learned,
171:23 rudest brief complexes are made up of . Right? The grain stone
171:27 which is the blue. Alright, some of that is converted to elliptic
171:33 . So, reefs and kids together . Okay. Which bucks the northern
171:40 model. Right. It doesn't make based on the northern Bahamas model.
171:44 , this is another example that bugged lot of us for for a long
171:48 . Right? How could you get far import? And then when you
171:53 at the distribution of the reef, is it? It's nestled along the
171:57 margin of that salt related structure and debris is all back to the west
172:03 northwest. Okay, so again, think about the prevailing wind direction
172:08 Okay, east and southeast quadrants so it makes perfect sense.
172:13 if you think about what I showed on keiko's the trade winds provide
172:19 Well up onto the platform. And you shed debris and then what
172:26 to that finer debris that gets pushed by storms? It gets converted to
172:31 write. And I showed you how trade ones actually moved carbonate sand.
172:35 , So the risk get broken up big storms, but then that sand
172:39 gets moved progressively downwind by the trade . When it becomes fine enough to
172:45 moved persistently by the trade winds, gets converted to a light and that
172:51 to refuel light relationship. Okay, this map from keiko's, I showed
172:56 these isolated reef complex as well up carbonate platform. Made no sense based
173:02 the northern Bahamas, but that's the win agitation driving the reef deposition and
173:08 converting some of that. Fine, I showed you this map, I
173:12 you some of that Sediment that makes the halo around the reefs in
173:17 30 ft of water is being converted to who is the scale of materials
173:23 on the Olympic coatings. Okay, , so, the argument here would
173:29 the geology proves the trade wind effect geology is the fact that you've got
173:34 reefs and you it's so far Too far in board to be driven
173:40 oceanic swells. Okay, Trade winds more sense. Okay, and then
173:48 second example here in east texas is , what's called the James limestone are
173:56 of the Pearsall formation in the northern rim. James limestone is, is
174:02 and gas productive around other parts of , of the northern gulf rim from
174:09 through offshore florida. Okay. And major field that occurs in northeast texas
174:17 that field is called Fairway field. look at the fizzy graphic setting.
174:22 , there's the basin margin. too deep for any kind of reef
174:28 . Okay, And appreciate the scale . That's 20 miles. So that's
174:35 100 miles inboard Fairway fields, it's miles inboard from the open ocean.
174:42 a strip. It's comprised of these storm atop the grief complexes and
174:46 Okay, and again, why does field exist here? The foundation is
174:54 salt related structure. Okay. There's turtle structure related to salt tectonics.
175:00 a couple of diagrams in your I'm skipping that. Show that I
175:04 . And then look at the other of the story. Fairway field is
175:08 atoll reef complex. All right. . Start yelling at my computer for
175:17 . Stop advancing on its own uh, a tall reef complex.
175:26 , and then look at this impressive off of it to the northwest.
175:31 then what do you come up too to the shoreline shoreline, parallel grain
175:36 . Okay. And you see the on this map, 1985, We
175:43 know yet. That could be made trade ones. Okay. The only
175:51 we knew to make its back then by tidal currents. But the fairway
175:58 100 miles inboard then the wood grain are. What? Another 40 or
176:03 miles even further inboard. 150 miles from the open ocean. You're gonna
176:08 goods by tidal currents? No, no way. Okay, so this
176:14 made any sense. So, Pretty good size field here, 400
176:22 barrel oil field. What's going on ? Well, if you look at
176:28 reef itself, most reefs, as said, I have the better production
176:32 the grain stones. Okay. And true here the red red is the
176:37 stones yellow or the reef cores, better productions associated with the grain
176:42 Okay. And if you ice a , some of the grain stone intervals
176:48 don't see here. Right. Which from this debris. Alright, so
176:57 can see what the reefs look like are coral storm atop rides in growth
177:01 here, there's a there's the debris up by storms. And then what
177:06 to that degree is it gets organized uh sand bodies within the lagoon and
177:14 it gets pushed off the back to this impressive tailors that you see
177:19 All right. And this is some the mapping a pack mapping,
177:25 Just looking at the thicknesses of the bodies and their orientation for some of
177:30 grain stone debris in that atoll reef . And look at the same.
177:34 at the orientation here, it's identical that big taylor slope off of the
177:39 side. Okay, You understand what saying? This is locally within the
177:44 reef complex. The grain stones line with this southeast northwest orientation. All
177:53 , So in Trade wind systems subtitled do what they line up parallel to
177:59 strong easterly trade wind effect. Except , the strong trade wind effect was
178:06 out of the southeast quadrant. Could be either one, sometimes
178:11 But here everything lines up southeast to orientation. Isn't that what I showed
178:17 for keiko's platform? Remember those big ? Sand bodies here and here line
178:21 parallel to the prevailing trade winds. then what happened over here on this
178:27 ? West Caicos, where the older faces into the trade winds, we
178:32 the shore line parallel to grain Okay, so subtitle with this orientation
178:40 with disorientation. Trade wins. See I'm talking about the geology I think
178:47 consistent with the trade wind effect. , alright, so the difference is
178:53 trade winds were out of the southeast . They account for the orientation of
178:57 sand bodies in the lagoon for this . All right. And again,
179:01 shedding would be both storms and the trade winds. I showed you from
179:05 modern how they boost sediments. I you they moved 80 m over a
179:09 year period on that big shoal from . And then up up up against
179:16 shoreline shoreline parallel, we'll let the starts. Okay. And then one
179:26 on the theme here, come up the tertiary of Southeast Asia. We
179:31 these platform mound carbonates developed up on drowned Miocene platform. The red is
179:38 productive. The oil is shown with green blobs. Okay, so you
179:43 see how we're coming up onto the here. And the point I want
179:47 make here is that It's a similar to what we've been talking about.
179:53 what's different here is the thickness of buildups is not just a few 100
179:58 , it's over 1000 ft thick. , because this part of South East
180:03 is much more highly subsiding. and it's a greater subsidence that gives
180:10 a little bit more accommodation to make greater vertical build up. And
180:16 look at these build ups are comparable to the kinds of stuff we've been
180:20 about. But look at the seismic , right? The typical seismic expressions
180:26 platform mound carbonate, like judy creek like what I showed you for fairway
180:32 pancake like, Right, very subtle relief structure. But here, this
180:37 looks like a pinnacle reef. But it's up on it's not a
180:42 pinnacle reef because it's not down into basin. That's up on a drowned
180:46 platform. Okay. And These things up 2000 ft thick. And
180:53 like I showed you for Keiko's, things start out as little isolated
180:58 but they shed debris and they coalesce a bigger structures and you sort of
181:03 the same sort of thing for these here. Right. Probably a couple
181:07 different reef complexes coalescing together to give that that thickness and seismic expression.
181:17 . And then we haven't talked about carbonate mud banks, but the modern
181:23 mud banks would be I showed you first day underwater photograph of seagrass.
181:30 that with the barracuda swimming over the grass. And and I talked about
181:36 role that seagrass plays and trapping sediment actually creating mounds on the sea
181:42 believe it or not, these things be transformed into reservoirs. And here's
181:47 couple of examples from um Southeast Asia the tertiary. Alright, so even
181:53 even in a shallow water lower energy . If you could build topography with
181:58 , these kinds of isolated build you have potential. Again, you
182:02 favorable die genesis obviously if it's muddy convert it to secondary porosity.
182:09 And here it's these are cal citic limestone buildups but they developed a high
182:15 of secondary porosity because it's originally a sediments is very prone to dissolution and
182:24 crystallization. Okay, alright, so summarize platform, mound carbonates. These
182:30 generally small scale buildups on drowned carbonate that usually possess great aerial extent and
182:40 a lot of vertical thickness. That's we refer to it as pancake
182:45 The exception would be highly subsiding areas I showed you for Southeast asia.
182:50 point about meteorology and age because that who the organisms were. And they're
182:56 meteorology. Same point about reservoir Always being dependent on depth of barrel
183:02 history. Historically, the best reservoir are confined to the margins of the
183:07 up. And historically, that would which side when we're facing science.
183:14 , okay. So, I was , keep that in mind.
183:19 Strong graphic trapping potential seeming faces usually up being uh the critics are based
183:26 lime stones that drown out these buildups encase them in deeper water. Carbonate
183:32 rock could be an issue here, on how far back you are from
183:35 open ocean. If that's where your is. Uh, I know one
183:39 in Western Canada where in some of restricted lagoons and he's a tall reef
183:45 , they're able to preserve some organic and squirt a little bit of hydrocarbon
183:49 . But that's not going to be major carbonate source. Right,
183:55 Those are some of the examples. . All right. Any questions about
184:10 play? We can do two things . We can go to six.
184:20 could start in on the next play or we can put it off the
184:23 morning. You get finished earlier theoretically unless I talk too much.
184:37 all right, let me make This sort of an interesting play and there's
184:43 lot of variability on the plate type here. So let's let's jump to
184:48 fourth, so called conventional play. these were platform interior or rap
184:54 wacky stones and Pakistan's. Okay, this is a this diagram. You
185:02 to look at it differently depending on you think you're dealing with a platform
185:07 or a ramp model. Okay, if you're dealing with a platform model
185:12 this this situation, you have to the platform margin to be off the
185:18 to the right, Alright, 10s km, tens of miles. In
185:23 words, your way back on the part of the state margin platform.
185:28 . And so it's low energy and critic back here because you're in a
185:32 Bahamas situation where tidal currents and oceanic have dissipated, you've got sluggish
185:39 quiet water, you get a critic subtitle carbonates and then sometimes it feeds
185:46 title flat. Okay, so that's you would have to look at this
185:49 if you're dealing with a platform. . If you're dealing with a
185:54 then the ramp crest is probably closer the edge of this diagram.
185:59 We've built a shoulder a skeletal grain shoal. Right? And then we
186:05 to build up above above sea level make a little barrier island and then
186:09 it would be the back show lagoon with the critic burrow carbonate feeding a
186:17 or tidal flat back here. so and then what's the other part
186:22 the story related to the ramp? your here's your ramp crest,
186:27 ramp crest back and restricted lagoon behind . But then what what do you
186:32 out front? You ramp down into and deeper water as you go
186:37 you get into the critic carbonates there . Right? So the front side
186:41 the ramp. Alright, this is people call the outer ramp for down
186:45 setting also has the potential for wacky paxton deposition. But you see the
186:52 here for this play type. If want reservoir quality. Almost always you
186:57 to do what you have to create dia genesis to get reservoir quality.
187:03 only exception would be what tidal flats finesse troll ferocity. Remember the remember
187:11 title flats with the holes, primary levy. Right? Only on the
187:20 , you can produce oil out of prosperity and tomorrow you'll see that at
187:24 creek. Okay, otherwise for the platform interior ramp related wacky stones and
187:32 stones, you've got to do something genetically. Alright, so we talked
187:37 the difference between the restricted subtitle and title flat. Remember we use that
187:44 Perry title, which is that's one the bonus. Is that one of
187:49 bonus questions today. Terry title. . So perry titles? This nebulous
187:55 . I know I'm in a restricted , but I know exactly where I'm
187:59 . It could be the shallow It could be part of the title
188:02 . Okay. We talked about all attributes that we want to see in
188:07 rock record to you know, identify flats or restricted subtitle. But historically
188:13 don't view these environments as being great . We view them being a ceiling
188:19 , right? We expect them to up like this type colloidal wacky stones
188:25 paxton's no reservoir quality. We're gonna at it as a ceiling faces for
188:31 offshore. Right? Title fight's gonna over a grain stone and provide a
188:36 seal. So to get reservoir quality of this stuff. With the exception
188:42 the financial porosity, you have to what you have to create favorable die
188:49 . And historically everybody thinks you have do what you have to do.
188:53 , right? And they think you to dilemma ties early because these are
188:58 critic carbonates and you need Torossian perm get the fluid in. Right?
189:03 everybody thinks that has to happen before get too deeply buried. All
189:07 So that's the that's the challenge. right. So let's just jump into
189:13 of these examples here and we'll start with the sole Orian, which is
189:22 the Williston basin. Alright. See know where the Williston basin is?
189:28 up there around North Dakota Montana South , that, that part of the
189:34 . Right. So, it's one these interco tonic basins. Right?
189:37 basal sags. Alright. Not connected the open ocean. Yeah, This
189:44 a Cabin Creek field is an old discovery back in the 50s, Shell
189:49 and you can see how it's put . All right. It's a a
189:55 of these repetitive stack cycles of restricted to tidal flat that repeat over and
190:02 again. So, a series of little upper chilling sequences that go from
190:07 loyal Pakistan's and Pakistan's restricted subtitle component into the tidal flat. So there's
190:15 super title stuff. Right? And you drown it out. Minor
190:20 right? You drown it out with minor sea level change, you go
190:23 to the subtitle, repeat over and again. Right? The reservoir is
190:27 in green are the parts of the flat that were favorably delay,
190:34 The top seal or tighter stuff. either the subtitle carbonate that didn't get
190:39 or it's evaporates. Okay, so of the super title stuff has evaporates
190:44 that provides the top seal for these . Okay. And the scale of
190:49 city, 10, 15, 20 cycles right? Small scale cycles.
190:55 that's consistent with the platform interior Right? You're not going to get
190:59 100 or 200-foot tech cycles in a material setting. They're all going to
191:04 the small scale repetitive cycles. so the good news is I've got
191:10 stacked reservoir units. Okay. The news is they're not very thick.
191:19 . But the good news is I do what I can extend that thickness
191:25 . We'll go to the title flat through time. What's the word?
191:31 grade? Right. You pro grade . Okay. So you can expand
191:35 reservoir by pro gradation. Okay. that that could be the good
191:40 Right. Again, what does every flat need to start? You need
191:45 older backstop. Right? Either older topography or you create topography during a
191:51 and you plaster it up by Then you do what you pro grade
191:56 . Okay. So, so there's good points to this. There's some
192:01 points and you look at the reserves 75 million barrels of oil. That's
192:06 major oil company. They wouldn't, wouldn't touch this stuff. Okay.
192:11 for an independent independent make a lot money off of something like this.
192:15 right. And then what's the other here? You can see how you
192:21 up reservoir. You can see how set up a trap. Where's your
192:25 rock? Source rock could be 100 out in the base somewhere.
192:34 So one of the evaluations of the rock migration pathway distance. Right?
192:44 something you want to be thinking about your kitchen is way out in the
192:48 . Okay. So, sorry, don't, I don't know what,
193:00 just think that's an arbitrary uh, for some of the layers or
193:07 Um, I don't recall. I don't remember to be honest. You
193:12 , I never paid attention to You're the first person never asked.
193:15 . I'm curious. I'll go back look at his paper. But
193:20 if I do that before we're I'll tell you we're finished with this
193:25 . Um, I don't know. just thinking this probably has something to
193:29 with the just an arbitrary number of beds or faces or something.
193:37 so there are good points to this type and the fact that you can
193:41 multiple stacked reservoirs that the the downside again, as the thickness or aerial
193:47 of your ferocity. The other downside be how far away your kitchen or
193:52 rock is. All right. So example of this would be a little
193:59 field in Montana. It's also in Williston basin and you can see it's
194:04 numbers associated with this. I it's not, it's much better in
194:09 of reserves here. And it sits again by regional paleo. High
194:15 you need a backstop. All tidal require backstop to plaster that settlement against
194:21 . Right? Because I told you flats are mostly storm flats where winter
194:26 or hurricanes push this stuff up. , you can feed it with day
194:30 day trade winds and stuff like But you need to get it going
194:34 the storms. Okay. And this the model. It's a wrap
194:41 This model really is weird. Ramp don't really look like this.
194:47 but the the story is that the and it is a time for ramp
194:54 because I told you there's no platform reefs in the Mississippi and there's no
194:58 to create steep margin platforms in the and everything is low relief going out
195:04 deep water. And so you expect to be up to tidal flats.
195:09 . And then they're gonna pro Alright. And then this is just
195:14 of the process works because of the again. Okay, so appreciate
195:21 And then let me take you through example from the Permian in west
195:27 Again, up on the central basin that we talked about earlier for the
195:33 stone deposition. The analytic and scholar stone deposition. The inner parts of
195:39 ramp profiles have a critic carbonate accumulating some of that's organized in the tidal
195:45 again. And if that stuff gets altered, die genetically, you can
195:51 reservoir potential. And so this is field where you get production pretty substantial
195:58 out of that fabric. All So, we talked earlier about the
196:02 crest where you get grain stones and isolated reefs. Alright, that would
196:08 right here. But then behind it the restricted lagoons and tidal flat.
196:13 this is the part of the deposition for for this field where you produce
196:19 kinds of fabrics here. Right. a critic carbonate burrowed color. Did
196:25 fabric. Alright. But Dolma ties to give you that secondary porosity.
196:32 right. And this is what most that field produces from. All
196:38 But similar stacking relationships to the right, bunch of thin, repetitive
196:44 . Again, due to procreation back , procreation back stepping. So,
196:49 , that's the good news for this of setting, right? Because you're
196:51 a you're in a low angle, angle slope ramp environment. It doesn't
196:57 much of a sea level change to down your title flat. Go back
197:02 subtitle conditions build out again. Back , pro grade out. Okay.
197:11 . I think we'll stop right Okay, So when we come
197:15 we're gonna jump up into the And I'm going to show you a
197:18 of different ways to make reservoir And is a critic cretaceous deposits.
197:25 . And uh and we'll just keep on the story. All right.
197:32 , you missed the first part. actually jumped to the fourth type
197:37 Okay, just to start to save time for tomorrow. So, we've
197:41 through platform margin or ramp crust related stones. Okay. And different geometries
197:50 on the slope angle platform margin Right? You don't get platform margin
197:55 and a ramp models on the steep platform ribbon like they can't pro grade
198:02 relational internal geometry if it can pro . Alright. And that determines
198:09 What's the top seal? Whether it to be deep water carbonates or whether
198:14 can do it with your back reef , all carbonates. And then we
198:18 about the platform mounds right where we step our reef margin up on the
198:23 paleo highs on the ground. platform pancake like geometry, usually
198:29 just a few 100 ft vertical but kilometers across for scale.
198:38 And then we just started in on four type, which is What are
198:42 ? The critic deposits related either to parts of platforms, so restricted subtitle
198:47 title flat or ramp related the critic which could be behind the ramp crest
198:54 down the slope. And we're gonna to some of those examples later down
198:59 slope. Okay. All right. got a handout for you. Might
199:06 well give this to you now. also email this to you if you
199:10 . Just in case you lose These are You might as well start
199:16 about the
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