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00:36 | Ok. Um, can everybody see slides or is, is there a |
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00:42 | right here? Yeah, we can this, like, ok. |
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00:49 | I'm very sorry, I had to this again, but I'm not feeling |
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00:52 | and I'm more than anything. I'm about, uh, passing something on |
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00:56 | any somebody else know when we, , when we're doing social distancing, |
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01:02 | didn't catch anything but, uh, been picking up all kinds of bugs |
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01:08 | then. So, um, and would like to point out, Been |
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01:16 | here for 20 years and this is first semester I've missed a class in |
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01:22 | when it was scheduled to be in . And, uh, I think |
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01:27 | really irritating to me that, uh, that I'm getting sick. |
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01:32 | hope that, uh, you, folks as students, whenever you get |
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01:37 | that's a little nasty, you stay too. And, uh, and |
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01:42 | me know because I can stream while lecturing from the lecture hall if, |
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01:46 | it's necessary. So, I, don't know who I caught this |
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01:51 | but, uh, when my wife quite often I would catch things from |
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01:55 | that she caught from students and she's . So, uh, I'm guessing |
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02:01 | probably caught something here on campus Um, all of that aside, |
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02:09 | , we left off here and, , I may take a drink of |
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02:15 | every now and then. Um, to make sure I don't overwork |
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02:23 | uh, vocal chords here, which tend to do. Uh, |
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02:27 | we got to the point of, , Turbidity currents and of course, |
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02:33 | is 1, 1 looks like in tank. And um the key is |
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02:40 | to, to, to any turbid , whether it's a current or an |
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02:47 | mass, like you might see with avalanche, it's that the, the |
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02:52 | lines cross each other. Um here you're seeing um laminar flow, |
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03:00 | call it. And even if things like this, as long as they're |
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03:06 | of sub parallel, the flow lines parallel, that's still laminar flow. |
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03:11 | that's what you see before you get the turbine flow. Uh Once you |
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03:16 | to the turbine, the, the has gotten to the point where things |
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03:20 | to roll over and mix. Uh like breaking waves in the ocean |
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03:26 | And uh it causes uh a considerable amount of cross cutting of flows |
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03:35 | and uh and so it's just a of water that's tumultuous and just churning |
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03:41 | this rather than stuff that's rolling like like down the side of the |
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03:46 | Uh like we might see uh when have uh the debris flow itself, |
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03:52 | getting uh dynamic dila see going on the particles are getting farther apart, |
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03:58 | in with more water. Here, have things bending over, but it's |
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04:02 | laminar flow uh uh with limited uh invasion and um dynamic di latency. |
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04:13 | here you're getting some good dynamic di . So the, the mass itself |
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04:17 | becoming less dense but it's still very when it gets down here in turbid |
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04:21 | because it's uh particles that have specific over two, mixing with things that |
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04:27 | a specific gravity of one. And the uh famous Boma sequence is |
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04:36 | . And uh When this uh first into being in the 60s, |
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04:44 | it was a little bit before I in classes. And uh in |
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04:50 | I was in uh wasn't even in high yet. But anyway, the |
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04:57 | uh the sequences, this uh graded , which is high energy energy uh |
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05:04 | . Uh And you get these um things they call standing waves which actually |
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05:11 | it doesn't really show you this, you can get Andy Dune standing |
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05:15 | The standing waves of course are uh sign of uh anti dunes when |
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05:22 | when you see those things moving up hill and uh sometimes they just, |
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05:27 | reach a point where they're just stable the flow is still going out but |
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05:31 | not moving. And uh and then get to uh plain bed with the |
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05:37 | grain movement where it's just kind of everything out but dropping the sediment and |
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05:42 | have a lot of sediment that's uh traction. And um and then you |
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05:48 | getting these dunes uh and uh uh can kind of lump this into three |
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05:56 | uh crosscut beds and dunes. And and then you reach a point where |
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06:04 | you have an upper division where it's that energy is slowed down. And |
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06:09 | is uh uh sort of like just sediment settling out and falling like Laina |
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06:16 | lake. And then uh then you this poetic. So a lot of |
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06:23 | , fecal pellets and stuff like that this in. And uh if it |
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06:28 | relatively low oxygen level, it, uh won't get breed. If it's |
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06:33 | higher oxygen level, it will get and you'll, you'll miss, you'll |
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06:37 | the lamination all disrupted by uh that biotic activity. So this is |
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06:43 | sort of the uh the sequence that expect to see pretty much at the |
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06:50 | end of a submarine fan. And depending on where you're at within a |
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06:57 | fan overall architecture, which we haven't about yet, we have uh um |
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07:06 | channels and then as it starts to out, it has distributors to the |
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07:11 | channel. And as it fans out , all you have are uh things |
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07:15 | look like this sequences that come out this shape because it's the high energy |
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07:20 | down uh and sort of being buffered it falls uh farther and farther into |
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07:25 | basin. And this is um uh of early on what everybody thought we |
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07:33 | see for all turbos, we didn't the complexity of a submarine fan |
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07:38 | Uh But we, we were applying things in sequences and our crops and |
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07:44 | course, realized that it was uh deposition uh after Arnold Ba and some |
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07:50 | folks at L S U sorted out uh what, what the character of |
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07:57 | deep water sediments looked like. And they hadn't come to grips with, |
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08:04 | the full three dimensional complexity of a fan at that point in time. |
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08:10 | as you might suspect, uh there our crops around the world that went |
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08:16 | very shallow water interpretations to uh uh , they all, most of them |
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08:23 | started out as interpretations of some sort fluvial alluvial system. Then uh many |
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08:30 | out crops were interpreted by the experts the time as being uh short face |
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08:37 | . And then later on, uh they ventured further out into the |
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08:41 | they realized there were uh bars below base, sand bars below wave |
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08:48 | And uh eventually they started seeing these and recognizing them for what they were |
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08:53 | make a long story short as uh , ologists were able to get deeper |
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09:00 | deeper water examples of sedimentation through And uh then relating that back to |
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09:09 | crops that we've seen lots of There are, there are many |
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09:13 | especially on the coast of England where has been done for a long |
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09:19 | Uh There are places where the, same, the exact same outcrop uh |
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09:26 | interpreted over the years uh from anywhere uh uh pluvial uh sediments to near |
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09:35 | to offshore bars. Uh just and finally to something that looked like a |
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09:42 | fans, this of course, is in the distal part of the fan |
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09:46 | you get more approximate or closer to source of the sediment. Uh You |
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09:52 | up seeing uh more and more uh the coarser grain stuff and less and |
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09:59 | of this because it keeps getting cut with uh with a higher energy uh |
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10:06 | until you finally get uh way offshore it's distal. Uh do you guys |
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10:12 | ? Didn't, did I tell everyone depositional dip is in this class? |
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10:16 | I'm pretty sure I did. Yes. Yeah. Anybody want to |
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10:27 | me what depositional dip is. Nobody's enough to tell me. Huh. |
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10:39 | was uh sort of it related to proximity of the source. That's exactly |
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10:51 | . So, uh so when you of a delta, for example, |
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10:57 | see the river that's forming the delta , is the source. And as |
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11:02 | get farther away from that um initial into the uh in the in the |
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11:11 | mass that it's building out into, , you're getting farther and farther away |
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11:18 | it. So the faces have lower lower energy. In other words, |
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11:21 | have that jet flow, it's coming fast with a turbo. You have |
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11:27 | , um, you have something that's down a hill and picking up |
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11:31 | So, uh, in most it's not always that case, but |
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11:36 | it's that case or sometimes it's an in size valley that things are rumbling |
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11:40 | . And uh but anyway, uh sources uh landward and uh and so |
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11:50 | is away from the land in depositional . And um and then of |
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11:58 | if you're up dip up depositional you're gonna be approximate to the coast |
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12:03 | or the source. And so, what I'm trying to tell you is |
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12:08 | you understand these words, then, this, this is without drawing you |
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12:13 | fan, this would be in the portions of the fan, you |
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12:16 | the fan sticks out into the water this and it has, you |
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12:21 | a nice crescent shape to it. this is the distal part, this |
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12:25 | be where um uh you would see aboma sequences as you come farther |
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12:33 | they get truncated, the upper parts get truncated because it's still high energy |
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12:38 | as we come closer and closer to shoreline on my, on my hand |
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12:42 | get more uh proximate to the And of course, uh this sequence |
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12:49 | fining upwards. But as the delta out each sequence that stacks on top |
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12:57 | this one is gonna be coarser grain the previous one. And so the |
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13:02 | submarine fan is coarsening upwards, but coursing upwards with uh depositional events which |
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13:12 | call episodes sometimes. But that a event is uh putting this out as |
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13:20 | upward sequences. But as the thing up, if it's, this becomes |
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13:25 | spot becomes more and more proximal as builds up because the whole thing is |
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13:30 | out into the basin. OK. it's really important to kind of understand |
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13:37 | . Um when we talk about sequence , if you don't know uh up |
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13:42 | and down dip deposition, you're, kind of missing a lot of uh |
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13:46 | the key implications and interpretations. Um inferences that you can make from various |
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13:54 | patterns of lap out, which we'll about when we talk about sequence stratigraphy |
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13:59 | a little bit. OK. So other things that happen is you have |
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14:03 | structures. And of course, uh is this is from a basic sediment |
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14:11 | . Um I could show you a from uh um technology which uh shows |
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14:21 | lot of uh different types of uh biogenic structures. Uh This is kind |
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14:32 | showing you ones that sort of have structure to them and they maintain that |
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14:36 | . But there's a lot of grazing burrowing uh that just simply turns this |
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14:41 | one thing you don't see in this is a lot of lamination you can |
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14:45 | here where this particular animal is, backing out and moving upwards uh in |
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14:52 | , in his, uh his living , so to speak. And, |
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14:57 | , but, but that's it, don't see the lamination and, and |
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15:00 | a lot of times when you look this area that they don't show anything |
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15:05 | oftentimes this is politic and there's a uh tic and they, uh, |
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15:12 | course, there's lots of organisms living the bottom that feed from the fecal |
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15:16 | that drop from above from uh all invertebrates and vertebrates, uh uh either |
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15:24 | the water column or uh crawling across surface. In some cases, swimming |
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15:29 | it, they could be neck, time or um, things that |
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15:33 | uh can swim. Ok. And is, uh just an example from |
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15:40 | rock record showing you, uh the of a lot of these things. |
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15:46 | this is, this is actually the side of a bed that's been burrowed |
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15:52 | the surface. And the, the tracks and tunnels that were being |
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15:58 | were preserved. Uh Sometimes when you at a shale that's been heavily |
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16:06 | you don't see these structures but you'll see shadows and stuff like, |
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16:10 | if you do a thin section through , you might see a slightly off |
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16:14 | for a tubular thing that was coming it in this direction. Of |
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16:18 | the thin section, it was uh to this face. In other |
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16:24 | perpendicular to it, uh you would something that would be close to uh |
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16:31 | uh burrow that uh that you could just from changes in the color because |
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16:37 | gonna have sediment here. The burrow be full of sediment but uh uh |
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16:43 | the process of ingestion, digestion and , uh some of the minerals are |
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16:51 | concentrated, some of them are uh and therefore you see sort of slightly |
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16:55 | colors. And here's something I did fun. And I, and when |
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17:01 | did it, I didn't think that would be so incredible. But um |
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17:08 | is uh a micro C T A cat scan. Um the software and |
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17:14 | machine together cost about a million This was at Shell lab, which |
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17:19 | now in the petroleum engineering department because shut down that lab. Mike Myers |
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17:25 | the one that ran this lab and had a, a student doing a |
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17:30 | on this. But uh this particular is interesting because, you know, |
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17:35 | talk about porosity and permeability and uh know, this is a core from |
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17:44 | recent beach sand that if you're not careful with it, it would just |
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17:51 | . The sand was not cemented together anything, but we were really careful |
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17:56 | it and we left it in the and a half tube. And um |
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18:03 | of the things that you do to rid of the tube. Uh It's |
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18:05 | plastic tube. You, uh, the cat scan, it has |
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18:08 | a thing where you can pet out and not look at things of a |
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18:13 | density. And, uh, you , with a regular x-ray, uh |
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18:20 | this was a regular x-ray, these might be bones, uh, |
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18:24 | bones or something in the middle of soft mudd but, but this was |
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18:32 | almost a pure sandstone and you wonder the the poor channels look like, |
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18:39 | poor throats might look like. Uh I did was decided to, to |
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18:46 | everything between almost no density at at all to zero density. So |
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18:53 | in fact, is an image of all the rock away and allowing you |
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18:59 | see the framework of all these interconnected pores and poor throats. And it's |
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19:07 | bio turb that's done it. This probably a burrow uh that's opened up |
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19:14 | a real fluffy zone in this uh this thing where it's almost, it's |
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19:19 | all air and uh and same And first thing you notice about these |
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19:26 | is they look exactly like algal rhizomes something of that nature. Uh There's |
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19:32 | plants that have roots. Some of bigger ones are could possibly be |
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19:37 | Uh This could be where it was and it's was very recent. I |
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19:42 | it's a Yucca pudge or something like . Fiddler. Crab. But |
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19:49 | this is, was probably a bigger . Now, I, I sliced |
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19:53 | too like this, but you are seeing through a good bit of |
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19:58 | If I was to slice it much , uh, in, in the |
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20:03 | like this, there would have been few of these things and you could |
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20:08 | which ones might be interconnected except that minute it would go into another |
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20:13 | you would lose it. In other , this burrow probably goes into uh |
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20:17 | probably comes out at you in the because this is the front face |
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20:22 | of that core. It was a core like this, we cut it |
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20:25 | that. So we're looking at the that would be right here. So |
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20:32 | these are traces of rhizomes and filamentous and also probably some significant roots. |
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20:39 | I think because of where it it was up beyond the dunes, |
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20:43 | think this is all uh for the part vegetative activity, there could be |
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20:48 | uh small vertebrates uh that did some the burrowing up in here. One |
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20:54 | the things is uh it does look there might have been some sort of |
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20:58 | here. But again, this could be the bro has come out of |
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21:01 | plane of the core and uh we see it continuing. And um I |
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21:09 | if you're doing anything with uh it would be really useful to do |
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21:16 | , which by the way was the they got this thing and I don't |
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21:19 | how the research advanced or if anybody was doing this, but um anywhere |
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21:25 | you have uh micro perros, micro uh and you have uh natural fracture |
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21:34 | your trying to fracture, uh this be a good tool to actually uh |
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21:40 | that in a core uh because you be able to remove the rock and |
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21:46 | look and see what the uh fracture were, uh what the pore throat |
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21:52 | looked like and, and that sort thing. So this is an extremely |
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21:56 | thing uh for anybody that would be advanced reservoir characterization. And uh I |
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22:02 | have time to, to keep working it. And uh I know at |
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22:06 | time the people to show up thought was crazy, but I, they |
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22:10 | talked to me about it for a . So I think they're probably doing |
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22:15 | . OK. Anyway. Um And this is, uh you know, |
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22:22 | of the, uh one of the uh structured things is uh betting and |
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22:29 | and of course, it kind of to uh from where we were |
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22:34 | uh where we're looking at things that like this or things that look like |
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22:39 | . So it's still kind of on higher end type of stuff. But |
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22:43 | also, as we know from the sequence, we get the same structures |
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22:49 | from high energy and low energy, is low energy, this is really |
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22:54 | level. And so none of these structures by themselves or can always be |
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23:04 | the indicator of what it is. the three dimensional relationship to it and |
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23:09 | relationship to other faces. For in the Boma sequence, you have |
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23:16 | faces, you have that faces, you have this one and then you |
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23:22 | uh the smaller rippled beds and then get this. So, you |
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23:27 | it's slowing down as it comes up way. So, you know, |
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23:30 | is this is between this high this high energy and it looks exactly |
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23:35 | where it should be and so on so forth. So again, this |
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23:39 | only a two dimensional diagram and you're looking at it in a sequence as |
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23:44 | one single dimension, that single dimension you interpret uh these two two sets |
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23:51 | structures that look quite similar. Um would expect that the grain sizes down |
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23:57 | would be greater than the grain sizes here as well. OK. Uh |
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24:05 | anyway, laminate usually less than a centimeter beds can be greater than a |
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24:11 | and attain great thickness like meters And uh trying to explain to an |
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24:20 | . Uh one of the hardest things is is to explain to him what |
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24:25 | bed is because it's, it kind uh goes beyond scale. But, |
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24:31 | uh the biggest lumps of things that see in an out crop often are |
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24:35 | we're gonna call a bed. uh, the laminate are gonna be |
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24:39 | fine grain, uh smaller uh Uh You would get lemonade though in |
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24:46 | of these course grain things if it's . Uh, here is, |
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24:55 | beach slip face. Um, I know exactly where this picture came |
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25:00 | Again, this is out of but this looks very similar to a |
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25:04 | of the trenches that I did on South Carolina coast and uh in the |
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25:08 | Carolina coast and the Virginia coast. and that's because you get heavy minerals |
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25:14 | the heavy minerals help you see a between the uh lighter colored quartz grains |
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25:21 | the heavy minerals. And you can all sorts of little, uh Here's |
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25:25 | a little erosional surface in here, sorts of uh little structures and um |
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25:32 | uh dewatering fractures, probably all sorts things are going on in this. |
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25:37 | And here this is a beach, is high energy, but it's coarser |
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25:42 | than over here over here is deep . And um and basically, uh |
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25:51 | a lot of places, uh we things called varves where you can see |
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25:55 | of these, which one is one be in the spring and uh one |
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25:59 | be in the summer or the, the fall. Uh And it's kind |
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26:03 | usually related to overturn if you have Diy lake, what's called a Dim |
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26:08 | that overturns twice. Ok. And of to pulling that all together. |
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26:16 | There's a lot of lemonade, finer lemonade and these shales in here. |
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26:20 | this, this is an ancient lake . Then we get some of these |
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26:26 | coarser grain thicker uh units that are much bed size. But within |
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26:32 | but within here between this carbonate rich in this carbonate rich bed, you |
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26:38 | a bed of shales in here that's of laminate. So you can get |
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26:42 | in this bed. But sometimes we have a massive bed where you don't |
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26:46 | see any of the laminate uh like thick sandstone, for example. And |
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26:53 | just looking here and you, and can see if you look at |
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26:56 | the resistance To erosion profile here a bit, you can see that this |
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27:03 | cemented up more and it's a little more uh resistant to erosion and sort |
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27:08 | kind of go in here again and pops back out at the next bed |
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27:12 | that's really what a bed is on scale that uh uh from, from |
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27:17 | here to about there is probably uh ft. And uh so uh this |
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27:25 | right here is probably on the order a, a yard or a meter |
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27:29 | . This might be a little bit than a meter and these are getting |
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27:33 | here and then you get some bigger back up here. But then |
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27:35 | you can see Laina in between. uh these are the uh organic rich |
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27:43 | shales in the Uinta basin uh that quite famous uh for their high |
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27:50 | greater than 25% in some places. . So that's the end of that |
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28:00 | . Let me just make sure. . Yep, we're recording. Is |
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28:09 | here today, doctor? I I just uh wanted to let you |
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28:18 | that I didn't receive the email Last night, Mohammed just sent me |
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28:23 | link but just for you to know maybe I can send you an email |
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28:26 | my, with my email just for to double check if maybe there was |
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28:30 | mistake there or something. Ok. , this is uh this is |
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28:37 | Yes. Ok. Yeah, I'm about that. I, you didn't |
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28:41 | trouble getting the last one, did ? No, I didn't. |
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28:45 | That's weird. I didn't use a email, I don't think. But |
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28:48 | knows? Ok, my apologies, I'm glad you're here. Yes. |
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28:54 | . No, no problems. Ok. It's not important to you |
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29:15 | , I love it when my escape doesn't work. OK. The next |
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29:36 | is, um, this is sort , uh, you know, because |
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29:40 | is a class that covers a lot topics. We uh and because traps |
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29:46 | often are related to structure and almost always related to basin development, |
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29:55 | kind of have to talk a little about sedimentary basins and uh this is |
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30:01 | a course in structural geology. Um I do remember when I did my |
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30:08 | G R E s in geology, of my highest grades was in structure |
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30:11 | I have no idea why. But I think it had a lot to |
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30:16 | with the, the folks at Wits uh came down and visited us. |
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30:22 | We had guest lectures for our structural from the people that were actually uh |
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30:28 | the work to uh to pretty much the fact that plate tectonics actually |
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30:35 | And uh they were working on sea spreading. So we got a, |
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30:39 | got a lot of lectures on that since that was an up and coming |
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30:42 | and it was being taught in the , even though I went to school |
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30:45 | the Southeast, uh uh it was heavily imprinted in uh in the G |
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30:51 | E test. And uh and I getting trained, at least in that |
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30:56 | from professors that uh that taught in northeast. So, uh you folks |
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31:02 | don't, I don't know if everybody the G R E because we don't |
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31:05 | it anymore. But, but for very long time, the G R |
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31:09 | s were uh very provincial. They , they're really geared and calibrated to |
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31:15 | any school in the northeast. They have, they might have gone out |
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31:19 | Stanford to get a couple of questions something like that or CAL tech. |
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31:24 | , uh, basically, um, , it's, it was really straightforward |
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31:30 | geology, you know, in the we didn't really talk about uh, |
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31:35 | , uh, deposits as much as would have expected. Or actually it |
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31:40 | like it was normal. Uh, spent a lot of time talking about |
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31:44 | planes because we had coastal planes. , uh, if you went to |
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31:48 | in the northeast, there's not much a coastal plane. So those people |
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31:53 | were to on anything that had to with the coastal plane. But at |
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31:56 | same time, um, um that in the test. So, uh |
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32:04 | test was really focused on the universities the northeast and uh through the |
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32:10 | uh, of the G R E , it got better and better. |
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32:12 | mean, people started screaming, scratching and kicking and whatnot and they |
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32:16 | to, uh, get a lot at it. And then I think |
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32:20 | most, uh geoscience departments decided not use that test. But anyway, |
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32:25 | an aside that, uh, just a little bit of our time |
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32:28 | Um So we're gonna go into this of course, one of the reasons |
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32:32 | , uh uh we really want to this is because, uh, is |
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32:41 | anything that says screen sharing that's blocking title up there? No. |
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32:48 | it's, it's amazing you guys see whole picture. I see all this |
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32:52 | hanging down in the wake. Um So anyway, um uh, |
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33:03 | know, the, the most, simplest thing, of course, in |
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33:06 | of structures would be an Anne And of course, uh, quite |
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33:11 | when you had an Anne client, , everywhere in the world, it |
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33:15 | Pena plane like this. In other , it wasn't eroded and scoured |
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33:20 | we call that Pena plan. uh, but anyway, the, |
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33:27 | , you normally would get like a high and, uh, farmer over |
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33:32 | could see that structural high and that's they went after. And that's uh |
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33:35 | they went after Pierce Junction, I I mentioned that uh the um this |
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33:42 | kind of the uh the exploration Um I don't know what book I |
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33:49 | this out of. It's really unfortunate uh but I would never uh color |
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33:56 | blue even though it's a lighter blue the water. And uh you |
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34:02 | this should be red for gas and for oil. Uh But that's the |
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34:06 | it is. Uh But I'm just you so that, you know that |
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34:09 | here it's the same thing. This oil, this is gas. Uh |
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34:14 | this was the primary structure when uh exploration started. This was, this |
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34:19 | the go get it model. And everybody wanted to get on top of |
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34:23 | structure so they could get this big down here. And uh and of |
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34:29 | , uh as it turns out, the structure, the top of the |
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34:35 | would be like here in Pierce everything right underneath it was, was |
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34:42 | . But the beds that kind of into that on the sides of the |
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34:46 | around the edges is where it So it kind of looked like this |
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34:52 | uh there was a, an there uh straddle terminations running into that anticline |
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34:58 | this. It was a Pierce dome was breaking through the strategic. |
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35:05 | So, uh and so that's the thing then, of course, um |
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35:10 | I worked offshore, this was um of what I saw. Um a |
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35:21 | of, a lot of people that up working in um uh the Denver |
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35:26 | of, of almost any oil company some places out in the west, |
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35:30 | course, where there's active uh rusting , you'd saw see this kind of |
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35:36 | . But a lot of my experience been in the uh the Annie Klein |
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35:42 | fault uh situation. And uh and might say a lot of normal |
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35:47 | Uh and of course, uh down Venezuela, you have uh some things |
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35:52 | this, there's a lot of places the world where the tectonics uh uh |
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35:58 | thrust faults and other complicated types of . Uh So this is also an |
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36:02 | thing to know. Um But it's, it has a lot to |
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36:07 | with, with the development of that in the, in the underlying uh |
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36:13 | tectonics. In other words, why that big basin sinking. Why are |
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36:18 | sides lifting up? Uh what's going ? Is it just a platform like |
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36:23 | coastal plane that's loading sediment on top something? And, and you're getting |
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36:28 | weakness underneath that coastal plane uh to these kinds of things that are tension |
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36:34 | um as opposed to where you've got , a nearby collision, the boundary |
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36:40 | terms of plate tectonics that's causing uh rather dramatic type of uh faulting and |
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36:47 | and overturn. And this is uh is a uh seismic interpretation up |
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36:57 | And this is a plaster slash clay uh where they try to mimic the |
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37:05 | of tension going on with uh with uplift of uh of this structure. |
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37:12 | then later uh settling back down with uh you had thermal dumbing to |
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37:18 | it, you had a surface that picked up like this. And so |
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37:23 | short like this when it's flat, when it's lifted up, it's getting |
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37:27 | out. And so you have to normal faults just fill in the |
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37:36 | And I'm not sure if I'm gonna it through this whole hour and a |
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37:38 | , but I'll, I'm gonna keep . Um Uh when I was going |
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37:45 | the first slide, I realized I feeling 100%. So I'm glad I'm |
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37:50 | in class with you anyway. Um So this is sort of the plaster |
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37:58 | which, which, which kind of you see that, you know, |
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38:01 | is all grounded in, in Um You know, you push, |
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38:06 | something up here, it causes the surface to have to stretch out. |
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38:11 | get these tension features known as normal . And um when we uh We |
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38:23 | at something like this, this might normally what we see in an area |
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38:27 | two km um With 20 m of or more. Uh but then when |
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38:34 | uh look a little bit closer uh maybe we have well logged data and |
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38:41 | we're starting to get uh three dimensional and looking at some uh uh amplitude |
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38:47 | to help us uh see some of things. And sometimes you can see |
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38:51 | patterns like this and uh gravity, data too to help you see |
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38:57 | you know, you may have these faults, but there's a lot of |
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39:00 | smaller fractures and compartments that are being at a smaller scale that's often hard |
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39:05 | see by uh reflection, seismic and and uh and single component seismic. |
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39:15 | you'd go to multi component, of , uh you'd get a bit a |
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39:18 | of an enhancement as well. And and of course, uh might as |
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39:25 | go back to this if you're um you're looking in the chalks, for |
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39:30 | , in the North Sea and sometimes places uh uh for unconventional which is |
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39:37 | uh because they have the gas cloud single um component uh seismic just doing |
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39:47 | wave seismic. Uh sometimes uh these be faults that were, were uh |
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39:52 | greater, definitely greater than 20 And at the same time with, |
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39:57 | well data, uh there were places we were picking um uh 30 ft |
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40:05 | , not 30 m faults, but 30 ft faults and uh Something you |
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40:12 | , less than 10 m. OK . Um I always put this in |
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40:21 | just so people are aware of common , uh map symbols and that kind |
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40:26 | thing. Um When we used to things by hand, uh there were |
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40:32 | lot of uh conventions that people followed that everything, a lot of things |
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40:36 | done on the computer. Um I um which, which you really need |
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40:47 | uh much out for is using this for anything but a thrust. And |
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40:53 | but, but I think a lot times people do here's a hanging |
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40:59 | Uh This is up and that's down uh and uh it kind of points |
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41:06 | dip of the fault. So this would have to be um this |
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41:11 | be a normal or reverse fault And um you can see um excuse |
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41:24 | , this, this is, this obviously a reverse fold, I'm |
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41:27 | And uh anyway, the uh you see here even when it's just a |
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41:34 | fault and not a thrust fault. You can see that the hanging wall |
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41:38 | here, this is pointing in the of the dip, the dip is |
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41:43 | this way. So, uh this right here would probably uh cut right |
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41:48 | like this. And uh and uh would get that configuration there. Um |
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41:57 | uh when we have a, this also uh out of, actually, |
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42:02 | think it's out of your book. And I, I hate this, |
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42:07 | is, this is the way I normal normally do it. Uh But |
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42:13 | we have the foot walls up but hanging wall is down. And uh |
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42:20 | so uh this would be uh a fault and it looks like this. |
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42:28 | ? And uh leave it to me try to confuse you. But |
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42:32 | this is the kind of symbol uh I would uh would use most of |
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42:37 | time uh when I was drawing maps hand. Oh Was uh it was |
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42:44 | time when uh one of the most useful things about drawing your own maps |
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42:52 | , as opposed to having a computer , to draw one, you have |
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42:56 | understand it. You can't, you draw a line unless you understand |
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43:00 | A computer can take data and create map. But in that process, |
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43:05 | haven't done anything to understand that, actual structure. And uh and it's |
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43:11 | real short coming I think of uh things by computer all the time because |
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43:16 | don't, doesn't uh force you to Think in three dimensions. And you |
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43:23 | to constantly think in three dimensions. , uh, it's, uh, |
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43:29 | , it has a lot to do , uh, your ability to |
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43:33 | uh, uh, appreciate when a is done really well and not a |
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43:37 | , uh, or, uh, even recognize that there's some major problems |
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43:41 | a map. Uh, here's here's a typical map, uh, |
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43:48 | the Shepherd book. And, and this is the Brent group and |
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43:52 | , uh I don't think he's a Sea person, but here he's got |
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43:55 | North Sea example. And uh you can see uh these are all |
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44:02 | faults. And uh can somebody tell uh right off the bat how I |
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44:10 | this is a normal phone? There's minuses on this, but I can |
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44:21 | you that all of these are These are all sub C numbers you |
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44:27 | tell using the symbology key. Well, that the symbols look like |
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44:35 | says it is. But, you , and there's a declaration change, |
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44:40 | me, does the elevation change or contours? And that's exactly what you |
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44:46 | to do. And if you're not a map, you often don't catch |
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44:50 | . And uh and, but sometimes you draw maps, you, you |
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44:53 | uh make mistakes too. But as uh as you come across here |
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45:01 | that's 4100, if I go over , what would this line be if |
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45:05 | one was 4400, 40, 43, 20, right? So |
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45:21 | is deeper. And of course, we draw a map like this, |
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45:25 | drawing it on a surface and uh cross cutting relationships become a little bit |
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45:33 | when you're just doing a surface. when you do field work, you're |
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45:36 | at a plane surface that's, that's I can like we're looking at a |
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45:44 | , when we look here, we're at a layer and what's happened is |
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45:47 | we know the dip is in that and we know this bed's moved |
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45:53 | right? It's deeper and that's how know that it's a normal fault just |
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45:58 | across the line. Also, if gonna draw a map and we |
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46:03 | we're playing around and doing our contours here. Um The contours over |
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46:09 | if we know there's a normal fault , because we made a fault plane |
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46:13 | , we have to make sure that contours on the other side show the |
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46:17 | uh offset. So if I have data here and well data here and |
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46:21 | this sort of thing, and I up with this and I also have |
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46:25 | cuts and I know what the throw this fault cut is. If, |
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46:30 | I make my interpretation that looks like , I automatically know that what, |
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46:35 | across here has to be offset by fault plane map. In other |
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46:41 | I know what's going on over I've got some wells that cut into |
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46:48 | fault, for example, this where is this, where is that |
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46:52 | gonna be in this? Well, it gonna be below that surface or |
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46:55 | that surface? Other words, this a map of a surface. |
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47:06 | is right around 4050 ft at this . And this is the same surface |
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47:15 | in another area. But again, know, it's not like a bulldozer |
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47:21 | in and flattened it and you got fault cut that's on a flat surface |
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47:25 | you see in our crops or uh a, on a, on a |
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47:29 | surface of a fault exposed. But , but they're actually things that were |
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47:35 | at the same time and one's moved , you know, one's one's moved |
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47:42 | and it's across from older beds now that it's moved down, so |
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47:48 | , its position is opposite older So, you know what the angle |
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47:55 | , you know, roughly what what the dip of this bed is |
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47:59 | these things, right? This fat , and that fault is dipping down |
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48:04 | way. So where would that fault this? Well, would it hit |
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48:09 | below the surface or above the And this is what I mean by |
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48:14 | to be able to think in three would be below the surface, wouldn't |
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48:22 | ? No, it wouldn't. Uh you for trying. Um, |
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48:29 | it's, it's really hard to. , so anyway, we have this |
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48:35 | and I have a surface here, . It's up and I have a |
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48:41 | down here and, uh, and see the fault but the boundary, |
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48:47 | surface is hitting the fault here. , uh, you can see the |
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48:53 | of my nose. Uh, if nose was, say where the well |
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48:58 | up, if the well comes straight here, it's not gonna hit the |
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49:02 | until it gets right about there. other words, here's the, |
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49:08 | the well board goes like that and what I mean by being able to |
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49:12 | in three dimensions. And it, seems stupid maybe. But it's, |
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49:17 | has a lot to do with the that figure out where the oil is |
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49:20 | the people that don't. And, , because the oils in layers too |
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49:28 | it's offset by faults as well. , um, it's, it's deadly |
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49:36 | in some ways, in other it's extremely complicated because it's in three |
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49:40 | and you, and you have to able to, um, you |
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49:44 | when you're looking at things, you to expect it. In other |
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49:48 | Oh, If all of my wells to 5000 ft and it was, |
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49:53 | wanted to get another fault cut, wouldn't, wouldn't go over here because |
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49:56 | might get too deep. Wouldn't see fa cup. Uh, I have |
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50:01 | come over here to get my fault . Just a simple little decision like |
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50:06 | important. Work a lot faster. here's here's kind of a thing |
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50:11 | um, I don't know how many do this. Um, when I |
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50:16 | to go to joint interest meetings uh people that didn't have the mentoring that |
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50:21 | had. Uh when I was uh I saw a lot of strange |
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50:26 | on map. I never saw one this bad but, but uh, |
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50:30 | often, um when you, when get to the, uh when you |
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50:37 | get to falls, things like this happen. And um depending on the |
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50:47 | of the fault and the orientation of bed that doesn't always happen. |
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50:53 | um, and certainly if you have oil water contact, um uh you're |
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51:00 | see something that looks maybe more like , it gets steeper over here. |
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51:04 | This is getting shallow, but this a map where somebody carefully contoured |
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51:11 | And I believe uh it's still possible a computer um app to have it |
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51:18 | map a compartment uh where everything looks it's just fine and it's working out |
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51:24 | . In other words, it's focused what it sees in here. And |
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51:30 | most mapping routines focus on the Well, so uh you could get |
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51:35 | that happens like this. And then here it's contoured based on some other |
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51:40 | . And over here completely separate data over here completely separated, but here |
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51:46 | have a normal fault and so the on this side should be what larger |
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51:52 | smaller when the contours are wider, should be bigger. Can you say |
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52:07 | a little bit louder? I didn't hear it. I said when, |
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52:10 | the are wider. So it should a bigger, uh, a bigger |
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52:16 | . Yeah, it's a bigger area here's a fault. It's a normal |
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52:21 | . So the contour numbers should be down here or they should be larger |
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52:28 | here. Remember? The fog goes the, if this Yeah, like |
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52:37 | this uh uh related to the So the is in the down |
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52:42 | sorry. OK. So the down side or the uh which would be |
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52:53 | , the hanging wall for a normal is gonna be deeper, right? |
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53:00 | this should all be deeper. So, ok, so look and |
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53:05 | if that's true. Is this always than over here, November 10th 50 |
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53:14 | mark or no? Sorry. Ignore . It, it looks like we |
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53:24 | a general dip towards the east because southeastern Brook is the, the most |
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53:30 | the, the most deep one in southeast. So the general dip is |
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53:36 | going from west to east and the to deepest one is in the |
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53:42 | OK. Ok. But we have fault. So if you see anything |
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53:47 | looks weird. Yeah, on the , like if you follow the country |
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53:52 | says 5, 5800 to the left to the left and you follow that |
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53:59 | , you will see that on on the food wall, it says |
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54:05 | . So that's, that's wrong. if you have the hanging wall there |
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54:08 | the south, those values should be than the values that you have on |
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54:12 | food wall to the north. So something wrong there with that fault with |
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54:17 | normal fault. Yeah, exactly. . If you follow that contour, |
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54:20 | says 5000, 800 if you go the north of the fold, it |
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54:24 | 6000 and it doesn't make sense for normal fault to have those values. |
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54:29 | . So, so somebody had some and they were doing this kind of |
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54:33 | and they, and why, why they want to make? Um |
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54:40 | you know, you're gonna expect a to come up here, you would |
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54:43 | it to and you want the structure come up here. But what you |
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54:47 | buy it is it's uh it's called twist fault or something goofy like |
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54:52 | And um our screw fault and the reversed on this on this fall based |
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55:00 | the contour lines. Uh If somebody a fault plane map and they figured |
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55:05 | out what it means is that with same data, uh someone was able |
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55:12 | draw it the wrong way because they thinking about. And this is showing |
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55:16 | the offsets and uh so this is you dip in this direction, this |
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55:21 | showing you dip in that direction. , uh, and you can't do |
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55:26 | . Now, um, if, the computer is just mapping stuff in |
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55:30 | and you have one, well, here it's very likely that it could |
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55:34 | do that. And, uh, , I think, I think this |
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55:38 | name is Dave Shoup. I, don't remember exactly but I think it's |
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55:41 | Sheep and he's been teaching people a time. And, uh, but |
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55:46 | , he, he pointed that I've never, I've never seen anybody |
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55:50 | this mistake myself, but I worked Mobile and, uh, I won't |
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55:55 | you what companies made that mistake, , uh, apparently frequently. |
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56:02 | uh, but anyway, uh, one of the reasons why you have |
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56:07 | be able to think in three dimensions , you know, that the map |
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56:12 | data points and it has very few points and it doesn't have a brain |
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56:16 | you do. The computer doesn't really like you do. And, |
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56:21 | uh, and even if you have , I, it's not gonna do |
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56:23 | whole lot with one will. uh, you know, it's, |
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56:29 | can't do that but as a human , um, and I'm sure we're |
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56:35 | try to get a I to do . You know, this, the |
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56:38 | relationship of these faults is important to before you start mapping, you don't |
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56:45 | the fault patterns, you're gonna make mistakes like this. In other |
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56:50 | if you put the faults in, you start drawing the lines, uh |
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56:55 | lines might be wrong in the first and you would, you never would |
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56:58 | seen this fault. And uh but , you need to, uh one |
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57:03 | the first steps in making a map to sort out where the major faults |
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57:07 | for sure. Uh If you can any little ones that's even better. |
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57:12 | , finding fault cuts in wells is important and uh I have an exercise |
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57:18 | do that. Most of the students up hating it. Uh The better |
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57:22 | really love it because um uh it them that, you know, |
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57:27 | there's work that geologists can do. interpretations that we can do as geologists |
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57:33 | can see resolution at a, at um higher precision level Uh than you |
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57:41 | with most seize even with 0D seism . Ok. So structure and petroleum |
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57:51 | , um you know, in the frontier scale understanding, you know, |
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58:00 | type of basin it is, is give you an understanding of, of |
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58:07 | possibility of the possibility, the uh and type of trap styles that you |
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58:15 | see in that basin. So it's, it's absolutely vital information that |
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58:21 | understand that that basin and how it's it's uh developed. And, and |
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58:28 | course, you know, the very slides I showed you in the beginning |
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58:33 | with anticlines and sin Clines, what's cause that uh normal faults versus reverse |
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58:41 | thrust faults, what's gonna cause that the frequency of that. And, |
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58:46 | of course, if you have a that's had some sort of uh base |
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58:50 | reversal where the, where, what going up at one point in time |
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58:55 | down in other times, it creates lot of complexities and perhaps a lot |
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58:59 | fractures. So it's always important to this thing from the frontier scale. |
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59:06 | And of course, when you're doing uh the basin that these unconventional shells |
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59:12 | deposited in, it's really important to the timing and the critical mo |
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59:18 | uh tectonic movements of that basin and it may have impacted tractor. |
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59:25 | Um Major and re major or regional and blocks play, have a big |
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59:31 | thing on play and play, fairway . And we're talking about like the |
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59:36 | , like the trend, somebody uh may be a whole stretch of oil |
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59:41 | along a major fault that go on miles to the northeast and the southwest |
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59:47 | the uh on the coastal plain of of uh Texas. And uh and |
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59:54 | the same would be true in, Louisiana and Mississippi and Alabama, not |
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60:00 | much on the east coast. Uh of that would be farther offshore, |
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60:07 | uh and folds and faults uh obviously generate and create traps and therefore they |
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60:16 | and generate fault uh prospects and the is. So when you've got the |
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60:23 | the elements of what a play is a trap and that makes it a |
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60:31 | . And then of course, uh fracturing part that I mentioned is all |
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60:36 | reservoir enhancement. OK. So, again, this is not an exhaustive |
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60:43 | , but I wanna make sure everybody we have um two major types of |
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60:51 | and uh they relate to plate but uh extensional basins are gonna tend |
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60:57 | have more of the normal fault type , uh compression and extensional basins uh |
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61:08 | gonna have more of the thrusting type and over uh overthrown uh beds |
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61:17 | and that sort of thing or And uh then transform settings are things |
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61:23 | are trans tension compression or rotational and are like uh strike slip faults and |
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61:32 | and often are transformed settings. But do get uh some of these things |
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61:38 | from uh the spreading ridge and it it never goes away, it's still |
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61:43 | . And so you have to watch for that. And of course, |
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61:46 | the northern part of uh South the Caribbean, we've got lots of |
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61:52 | things of this nature. There are uh uh of course, in California |
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61:59 | uh relate to this. Uh But and large, a lot of the |
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62:03 | plains are this. So that's an lot of what we explore. Uh |
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62:09 | when we have uh other areas that much more complicated, uh they can |
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62:15 | uh oftentimes very large reservoirs and, of course, uh many smaller reservoirs |
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62:23 | in these compression and extensional basins. so it always helps to know where |
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62:29 | working. And uh in my I've pretty much hung around in this |
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62:34 | , the most of uh most of career because there's an awful lot of |
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62:38 | estate that falls under the realm of uh settings. OK. So, |
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62:48 | most of the things that we see things that are called uh rift |
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62:53 | Uh The North Sea is an example will hound on all the time. |
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62:57 | But there's uh other ones, um Bohai basin is uh somewhat of a |
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63:04 | basin. Uh There's other uh there certain rip features, of course, |
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63:12 | uh here in the Gulf of And um and then of course, |
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63:18 | we have these things that are called protonic basins which are sags. And |
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63:23 | of the time, these sags uh , like the Bohai basin was really |
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63:27 | that, but it's, it's uh really a rift basin, uh a |
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63:32 | rift basin that's uh that went into uh thermal cooling and uh collapse underneath |
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63:42 | . And uh the Michigan Basin would into this aspect and some of the |
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63:48 | rifting uh because of its age and everything that went on on top |
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63:53 | it. Uh A lot of times don't notice uh that it was actually |
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63:58 | features uh that we had a hard uh uh interpreting or, or uh |
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64:05 | and, and we just would call sex. Then of course, we |
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64:08 | passive margins. Uh, once you past, uh, the remnants of |
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64:15 | um uh Riff Basin, you're gonna a passive margin building out in front |
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64:21 | us. And, uh of you know, on the uh coast |
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64:29 | uh West Africa and eastern Brazil, have the remnants of the rift basin |
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64:35 | form the Atlantic. And of you have passive margins that have built |
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64:40 | into shelves, uh seaward or down dip from those features. OK. |
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64:49 | is um and just to show you how very simplistically how uh valley |
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64:58 | There's some kind of thermal uplift and thermal uplift creates a stretch. You |
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65:03 | , in other words, it, you have a flat, if you |
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65:10 | a flat surface like this and you it like that, uh I think |
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65:16 | you notice is when I do my hands go up because because the |
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65:22 | is shortening, the, the crust to shorten to do this. And |
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65:25 | it shortens, it has to break here because because it's not flexible, |
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65:30 | a piece of uh paper. And you get this starting out in the |
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65:36 | . Uh Here's a part of what see in the basin and range |
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65:40 | is uh got some of that where a thermal stress, thermal uplift from |
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65:48 | . And uh some of the most ones, of course, to the |
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65:52 | Sea, which is a failed rift , uh West African pre salt |
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65:58 | Uh and um and also uh eventually uh as that basin got bigger, |
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66:11 | filled in with water, it filled with salt water. And so that |
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66:15 | was the breakup of the continents. Eastern Brazil is the same thing. |
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66:20 | then of course, uh there's similar like the Bohai basin and ones that |
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66:24 | offshore uh Southeast China that relate to uh that rifting uh offshore. And |
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66:33 | just kind of uh looking at a junction, the Red Sea, the |
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66:38 | of Acaba and the Gulf of And of course, these are rift |
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66:42 | features here uh on either side of Sinai and uh Peninsula. And here |
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66:49 | have uh uh other things uh going in the Red Sea too, but |
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66:54 | get this, this uh normal fault , going on again. It's, |
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67:01 | starts out like this, it lifts and these blocks are falling down while |
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67:06 | whole thing is actually kind of raising . And uh oftentimes uh the peaks |
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67:15 | these things become mountains and when, you see a rip out and |
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67:21 | of course, you know, I talked about the basin and |
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67:23 | This is what it looks like from . Here's a little bit more of |
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67:28 | that looks like. And uh uh stretching the crust and of course, |
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67:36 | even with block diagrams or blocks of you can tell that when, |
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67:41 | uh, when you, uh, you have a normal fall, you |
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67:48 | , if you cut a piece of , the, the thicker parts of |
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67:51 | side of that block of wood are closer and closer to each other as |
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67:56 | go down. You know, when here, you got a fault like |
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67:59 | . But then when, so this my thumb here will be the longer |
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68:03 | on the, the block to uh left probably it might be uh it |
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68:09 | like it's my left on the screen . Uh And then um uh as |
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68:15 | comes down like this, uh as goes like this, this is the |
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68:19 | one on this side because the cut like that. So the longer side |
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68:22 | the block gets there. So you to stretch, it has to be |
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68:25 | result of the stretching of the crust the lengthening of the crust. |
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68:32 | And this is just showing you when get these kinds of configurations, you |
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68:36 | the possibility of an awful lot of prospects. You know, these traps |
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68:42 | this, uh where you have a . Oh, it's got a seal |
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68:48 | , dip up, dip on the into the uh into the hanging |
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68:54 | And uh and again here, uh would be sealed up against younger, |
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68:59 | units than this one and this would sealed against younger units still against that |
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69:09 | . But uh one of the things , uh, they've seen with the |
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69:12 | African Rift and some of the other that are harder to examine, |
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69:20 | is that you get these ramp relays of, um, the blocks being |
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69:30 | like this all the time. You , you, you saw it on |
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69:36 | over here. But what's happening sometimes one side falls down a little bit |
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69:41 | than the other side and this side down a little bit farther from here |
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69:45 | here. But there's sort of a ramp uh where it's kind of |
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69:50 | It's, it's going down, but part goes down a little faster than |
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69:54 | other part and it rips and it's I think it's consistent with nature that |
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69:59 | and nothing is ever exactly equal. uh even um except uh except some |
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70:08 | in uh in igneous rocks, of . So here we have uh an |
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70:15 | uh picture of a half grabbing like fault block or list or spoon shaped |
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70:22 | and RIC means spoon shaped. And and that's kind of what this looks |
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70:27 | a spoon. And uh and you see that, yeah, as there's |
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70:36 | going this way, you have rotation the strata this way and there's sort |
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70:44 | a block over here kind of holding up. And what you see in |
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70:50 | here here, you see a bunch layers that are relatively thin, those |
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70:54 | layers over here are much thicker. can see there's cycles of rotation uh |
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71:02 | here's one and here's another mega And another me, you know, |
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71:06 | see lots of uh multiple uh stack in this. But what is one |
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71:13 | the most obvious things that you see through here? Terms of sediment accumulation |
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71:22 | over here? OK. We, is, you know, a, |
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71:41 | nice regional line, but it's, uh basically showing you something that |
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71:51 | a lot of geologists weren't aware of the oil industry started coming up with |
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71:56 | these uh big regional lines, offshore engine, the petroleum industry really uh |
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72:06 | a lot of money into trying to out what was going on. So |
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72:15 | I have beds over here, I beds over here. What is dramatically |
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72:21 | between this section in that section, interval between events that thickness, I |
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72:32 | you would call the net thickness is greater, right? Let let me |
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72:43 | put it to you this way, gross, the gross thickness is much |
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72:46 | , right? Yes. Yes. . This line right here that I |
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72:52 | drew but it, well, let draw a line. I can do |
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73:00 | . OK. So I'm just kind drawing something that's perpendicular. My apple |
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73:18 | are pretty weak. OK? That right there not to be confused with |
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73:27 | fault is a lot longer then this is kind of perpendicular to the the |
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73:39 | . So from here, from so this this is pretty close to |
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73:49 | timeline right in here. And there's one pretty somewhere around in here like |
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73:57 | . Look at all this sediment oh my gosh, look at how |
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74:01 | more it is over here. So one closer to the fourth or in |
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74:06 | position, their wa sin depositional. , of course. I mean, |
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74:14 | is basically sin depositional but uh what what it's showing you is uh we |
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74:21 | call this um a sin depositional In other words, the fault is |
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74:27 | while depo deposition is occurring. And it's not like a fault happened and |
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74:34 | it filled in with sediment. It's this is a major fault that's been |
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74:42 | over millions of years, more or down this sliding ever so carefully down |
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74:49 | . Uh While there's a high over , which is kind of slowing it |
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74:54 | . But as as such, the of rotation is it point of the |
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75:00 | point of rotation changes through time, it's somewhere over here. Nevertheless. |
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75:05 | there's a point of rotation like the points here. And so this |
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75:14 | down to here. So there's an , you know, so you have |
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75:19 | the layers actually, you know, a point of rotation that's moving through |
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75:25 | and it's, and of course, is sin depositional. Uh The lack |
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75:29 | motion over here is also sin but it's not moving. Uh it's |
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75:34 | , it's not the motion of the . So that's why this would be |
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75:38 | sin depositional uh faulting over here. what is so wonderful about this? |
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75:46 | If I'm an oil person, there go. It looks like you, |
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76:01 | will always have an uh accommodation to more sediment, then you can have |
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76:06 | multi level, you can have multi ? Multi world? Yes. |
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76:15 | So, absolutely. So what you was a good answer to a test |
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76:21 | . I'd like to ask. And and this, this rotating nature is |
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76:31 | uh it's a half groin like fault list or spoon shaped with growth. |
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76:38 | growth is depositional growth. In other , it's, it's, it's uh |
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76:46 | thicker over here because this is falling and of course, up dip, |
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76:50 | up, dip, what's up, dip? Come on. You, |
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76:59 | guys already know this is it the , the source, yes, the |
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77:04 | is up there. So the source up here. It comes rolling down |
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77:08 | hill and there's more space. It's accommodation space and it fills it |
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77:13 | then it slips some more. It some more and it fills it in |
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77:16 | and it rotates some more and it it in again. So this uh |
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77:23 | plane here that is rotating through time it, and it, and it |
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77:28 | by the way at one point it here, then it's here, then |
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77:31 | point of rotation is here. So shifting a little bit through time. |
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77:36 | it's still basically somewhere over here. It's rotating and uh and you're getting |
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77:42 | of the sediment. So the sediment column gets thicker because there's more, |
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77:47 | more accommodation space because of that uh subsidence of this surface. It keeps |
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77:54 | down and it fills in, it down more and it fills in more |
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77:58 | to some extent, the, the sediment load or burden may actually help |
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78:03 | . But you, you're getting these that are full of uh water and |
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78:08 | uh that are pushing down on a zone of weakness, which is |
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78:12 | major rotational block. And uh this that this might uh through time, |
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78:18 | know, through the next 25 million , this might become a big major |
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78:22 | . And uh this is kind of you uh over here that the point |
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78:28 | rotation is dancing in this direction and that direction, but it's dancing this |
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78:33 | through time. And uh and this rotating more and more as you go |
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78:39 | time. And as that point of changes, this fault may be abandoned |
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78:44 | you might start to develop another bigger over here. And so you're creating |
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78:49 | rock and while you're creating reservoir you're creating additional due to the |
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78:56 | you're creating additional uh zones of weaknesses , and necessity to because it's |
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79:02 | it's bending, it's uh necessitate stretching the crust and therefore you get more |
|
|
79:09 | . So not only do you get sediments that can do two things, |
|
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79:13 | source rocks and reservoir rocks. Uh it can also uh create these structures |
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79:21 | can, can help at least uh one side of a of a |
|
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79:26 | um triple closure of fault. So is um what else is, what |
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|
79:34 | is this when it's getting buried the over here of this age or somewhere |
|
|
79:40 | here of that age? What's another about a petroleum system that's being benefited |
|
|
79:46 | this, this difference between rocks of age being here and that same age |
|
|
79:52 | up here. It's a contribution to petroleum system. Specant one. By |
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80:03 | way, could it be a anti trap? Ok. Um We, |
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80:11 | already talked about the petroleum system. . We've talked about here how this |
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80:17 | more sedimentation which creates um sands and , uh sands create for sure good |
|
|
80:29 | , shales create source rocks, which also be unconventional reservoirs. Uh The |
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80:36 | is creating more faulting and trapping opportunities of it's uh it's further enhancing the |
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80:44 | feature. And uh and on top that, if I have a rock |
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80:53 | , it's organic rich and I have rock here of the same age. |
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|
80:58 | organic rich. What's that other word we're thinking about in the uh petroleum |
|
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81:08 | ? Migration, maybe what comes before ? Thank you. Yes, |
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81:23 | OK. As, as we go in a well bore from here to |
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81:27 | it gets hotter and hotter and hotter hotter and hotter. Uh There are |
|
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81:31 | that can change heat flow dramatically, like a salt bed or something like |
|
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81:37 | . But at the same time in , if you see a section like |
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81:41 | , it's a good chance that this immature, there's also a good chance |
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81:45 | this is already mature. Uh It's same age, for example, if |
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81:49 | was a Jurassic bed and it was Ridge in age, uh I, |
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81:56 | ventured against maybe up to here that mature. But as you get a |
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82:01 | bit higher, it's gonna be uh low grade maturity to not mature at |
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82:08 | , might be getting some early uh evolution out of it and, and |
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82:12 | course, up in here, you get some biogenic gas, but most |
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82:16 | that goes to the sky anyway. this particular structure in itself is, |
|
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82:23 | something that every petroleum geologist should understand uh these uh growth faults are um |
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|
82:34 | kings of if you, if you or queens, whatever you wanna call |
|
|
82:38 | uh at creating petroleum systems. And why we drill so many of |
|
|
82:45 | That's why there's so many wells in North Sea. That's why there's so |
|
|
82:50 | wells offshore uh West Africa, offshore uh certain parts of the Gulf of |
|
|
83:01 | and uh and uh and the coast Brazil and whatnot. Now, um |
|
|
83:08 | not gonna talk about Guyana yet. I'm gonna try to save that for |
|
|
83:12 | we get the frontier uh and give some more insights into what's going on |
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|
83:20 | . OK. And here is, is another one that's the reverse of |
|
|
83:25 | picture in terms of the orientation. uh it's just showing you uh kind |
|
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83:32 | what you can see in here. showing you at a smaller scale uh |
|
|
83:37 | we have a growth fault here. uh uh this one stopped growing |
|
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83:44 | And uh and you've got thick sediments . Thinner. 2nd, this is |
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83:48 | a reverse, basically a reverse image that. And uh and you can |
|
|
83:56 | uh why it's called a growth fault uh this bed or these units that |
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|
84:03 | make up uh is going to be thicker and thicker. I'm not exactly |
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84:09 | this is uh 700 m. This a, a small scale growth |
|
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84:14 | This one right here is huge. don't have a scale on it, |
|
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84:17 | this is huge. This is millions years right there. OK. So |
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84:28 | we're getting near the end here but growth fault uh also uh can do |
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|
84:34 | things with beds just because of the , the fact that there is a |
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|
84:39 | flexure and that you have uh you have uh things that drag and things |
|
|
84:46 | don't drag along a fault plane. uh so here you can kind of |
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|
84:53 | what we call us convex rollover where , it's bending over as this growth |
|
|
85:04 | . Uh The um the motion of is quicker than the build up the |
|
|
85:11 | . So it rolls over this And that's convex rollover. Whenever you |
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|
85:16 | with a growth fault, you can , you can, uh you can |
|
|
85:20 | things like this. Now, when it does that and gosh, |
|
|
85:24 | looks squiggly over here. I wonder that means. Uh When that |
|
|
85:27 | you end up getting traps that are anticlines, but it's convex rollover on |
|
|
85:31 | growth ball. Here's something that's completely and also quite uh um common. |
|
|
85:45 | uh this is concave rollover where um rate of motion on the uh along |
|
|
85:56 | fault is not that far ahead of uh deposition. And here you can |
|
|
86:05 | actually one of the complexities of you're starting to get a change in |
|
|
86:09 | rotation of the sur of these And uh it's almost complete. |
|
|
86:16 | it is the complete opposite of what just showed you in the uh convex |
|
|
86:21 | . And here you can see uh sort of a drag we call, |
|
|
86:26 | kind of call this uh typical Sometimes you get a typical drag that |
|
|
86:32 | like that with al almost looks like convex but not quite where it |
|
|
86:40 | it still starts to fall a little more closer to the fault. Uh |
|
|
86:45 | then, so here you can see nice thick section but it's kind of |
|
|
86:49 | uh you know, it's like there's slowing it down. So it's kind |
|
|
86:53 | creating uh this type of concave And here the faults are right, |
|
|
87:00 | uh the traps are right up against fault, they're right up against the |
|
|
87:04 | . Here, most of the traps in the uh rollover an cards. |
|
|
87:13 | uh this is kind of showing you details. Uh this is out of |
|
|
87:17 | A P G paper, uh which of goes into the phases of these |
|
|
87:22 | . And it also explains in great how the uh axis of rotation changes |
|
|
87:27 | time. Uh But we won't go that. You take uh Mike's advanced |
|
|
87:33 | , Mike Murphy's advanced structure. He explain that to you. I know |
|
|
87:36 | does when he teaches the course for petroleum geology because I gave him the |
|
|
87:42 | and he really loved it. And it's getting to be about 10 years |
|
|
87:46 | . So there may be some newer and uh and I'm gonna, |
|
|
87:51 | we're at the end of our So I'm gonna let you guys |
|
|
87:54 | So you don't get upset with me that. I wanna tell you um |
|
|
87:59 | the first five minutes I thought I gonna have to stop lecturing because I |
|
|
88:03 | felt bad. But uh I soldiered it and uh and I hope you |
|
|
88:09 | that even though we're not in class I'm trying to get this information to |
|
|
88:14 | but uh this is a series of uh down dip expansion faults that are |
|
|
88:21 | faults down to the southeast in the coastal plain which uh create an enormous |
|
|
88:29 | of uh uh potential traps reservoirs. There's definitely source rocks in this realm |
|
|
88:39 | are a little bit older and some them are actually involved in, in |
|
|
88:42 | part of the section. And uh we'll go into that in more |
|
|
88:47 | on Wednesday. And, uh, now I think it's about a 50% |
|
|
88:53 | I'll be showing up, uh, class on Wednesday. But, |
|
|
88:57 | I'm gonna leave the door open on one because, or maybe the door |
|
|
89:01 | , because uh, it really I don't want anybody to get sick |
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89:06 | because, um, I'm not, , clever enough to keep you away |
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89:12 | whatever bug it is. I have time. But, uh, |
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89:17 | that being said, uh, really you being here. I'm glad you're |
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89:21 | and this has been recorded for And, uh, here's what I |
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89:39 | do. I gotta do. it's not let me out of the |
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89:46 | . Let's see. There we I asked my wonderful escape |
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