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GEOL 6381 Petroleum Geology - Feb 27 2023
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00:08 Didn't say anything. Did it where do you see that? You
00:32 up here somewhere. Yeah, it . It's, it's tragic.
00:39 Awesome. It didn't matter. Should be working. Ok. That's
01:11 stop video. Ok. So it's . Ok. So, anyway,
01:15 , today I'll just go through this quickly and it's another fun thing with
01:23 . Sometimes the up and down buttons sometimes they don't. So here we
01:31 . Uh, it could, it all have and I hate the fact
01:35 this is in your way. Let's then out of the way it'll help
02:00 , um, for the logging These are the colors to use if
02:04 have, uh, pencils. I go through this every time I
02:11 like I'm wasting my time. But the same time, You know,
02:16 I have 10 people in a class of them use different colors and I'm
02:21 sure why, I guess every, , uh oil companies will have their
02:25 uh color schemes, but the colors I have here are kind of what
02:30 sort of the industry standard so you know, anybody going, looking
02:34 a log from a partner or going a partner meeting or, uh,
02:39 to a farm in or a farm . You know, when you look
02:43 them, when you see something yellow the log, it's a sand.
02:45 you see something brown, it's a . Ok? If you see something
02:50 , it's oil. Uh, gas red and blue is water. Although
02:57 fluids are gonna be on the right , mythology is gonna be on the
03:01 side. Sometimes on the left they'll use blue for carbonates. Uh
03:07 don't have any carbonate in this. I didn't put that on there to
03:11 , but you have a fluid side oxide. Again, that kind of
03:15 the logic for dividing up uh logs rock tools and fluid tools because the
03:22 tools are on the right uh rock are on the left. When you
03:28 stuff like that, it makes it whole lot easier for. I
03:32 I can you imagine if you changed , you know, you're allowed to
03:37 most uh systems to put whatever you to plot in the left side,
03:42 you want to plot in the right , call them channels. But it's
03:45 to have consistency. So that every log in your collection in a
03:51 , we have exactly the same So you'll look for the same
03:54 So you can see these things with eyes rather than having to have an
03:59 . Sp something out and tell you what it should be even though it
04:02 not be. Ok. So, one of things with uh sand
04:11 you know, they have this uh of sand versus shale. So they
04:17 a thing called alpha, uh which calculated through the uh a potential of
04:22 porosity. So, it, what means is it's the sandstones acting the
04:27 they expect it to work with the balance of uh mud versus salinity and
04:33 proper balance of uh the poor throat that allow this uh current to
04:40 So, uh the thing is is um There's sort of an alpha,
04:46 you know, 100% alpha is gonna uh absolute or um static P they
04:55 and that would be what they would in a, in a typical porus
05:03 with decent size pore throats and the balance between the mud, the mud
05:09 and the formation salinity things a little different if you change those things.
05:15 . With the gamma log, uh have a thing that's called B shell
05:18 there's a way to calculate it. , you know, for the purposes
05:22 this, I'm thinking just kind of at the gamma log almost like it's
05:25 S P log and we're kind of instead of B shale, you kind
05:28 do something that's similar to alpha. other words, here's my maximum sand
05:33 and a good sand. Uh that's of my alpha. Um And then
05:40 between there is my shale line and of split it up that way.
05:47 . And so here is, here's an, a really good example and
05:50 showed you this earlier. Here's the S P here. This should be
05:56 maximum you'd ever see in the sand . And that just means there's a
06:00 of porosity. Uh Here, you have a clean sandstone and uh you
06:06 see here it's a little bit su from this one. There's several things
06:12 can cause this to happen. Does remember what they are? Do
06:22 To a resolution? Yeah. And uh because this bed is a little
06:26 thinner than that bed, it might have reached the static S P.
06:30 words, it started to go up then it came back down before because
06:34 was right away. Uh Normally you that in a bed um Like,
06:38 see, like here, this, is a really good example of uh
06:43 good clean sandstone that doesn't get the S P. But here this is
06:47 pretty good sized sandstone. It still get there. So what, what
06:51 you think could have an impact on sandstone? Like for example, if
06:56 isn't uh thick a thickness impact rather that, it's something else. What
07:03 that something else be? Oh Uh porosity is part of it,
07:14 probably more important than anything is the throats could be smaller or the,
07:20 it could be finer grain sand stuff , or it could be,
07:27 uh, because permeability is what really , affects that flow because the,
07:31 know, the, the size of , it's like having a, a
07:34 wire to, uh, to pick the uh flow. And so,
07:39 , that's one part of it. , uh, the other thing is
07:42 could be shales, a little bit the, the sorting could be weaker
07:47 there could be some smaller particles blocking some of the four throats. And
07:51 could be some, um, it even be some clay particles in there
07:55 are having an impact on getting the static S P. In other
07:58 the clay could be blocking it and could even be what else? Little
08:04 of cement like cement rims or something that. So there's all sorts of
08:07 that could make that happen, but is the good clean one. And
08:11 when you co it, you're hoping gonna see something there. And of
08:13 , this is the one that's got in it, this has gas in
08:18 . Uh What do you think gas do to uh S P, it
08:29 offset some of the fluid in, the, in the poor throats and
08:33 , uh affect the response. Ok. So there, there's a
08:39 of things that can cause problems but you know, it's clear, I
08:45 to get an idea of what this S P is so that you can
08:49 of start to think about what's going over here. And of course,
08:53 oil over here is gonna include some those poor throats too. And
08:57 and if this sand had no oil it, uh my guess is the
09:04 S P for this log would be . Yeah. OK. So this
09:14 similar to the log that you're gonna looking at. So one of the
09:18 that I'm gonna want everyone to do they do this, the first,
09:21 gonna be two logs to this exercise this is exercise number two and exercise
09:27 two has two parts to it. , you know, two different locks
09:32 , and, um, when when you turn it into me,
09:35 , try to make sure that, , let's get ready to do this
09:39 see if I could get that a bit higher. Yeah. But
09:44 um, when you turn it make sure that your name's on the
09:48 somewhere because if I get, eight, answers from people in the
09:55 , it exercise too, you on who's who on the, on
09:58 file. So it just makes it for me to manage this.
10:03 So here we have, uh, , what you've done at the person's
10:08 up with a shale line and the line can shift because, because the
10:15 , um, grain size and whatnot shift through time as well as you're
10:21 up and down a log. But you're working within a given area,
10:24 gonna have, you know, a shale line. And, uh,
10:27 there's something wrong with the tool and can see here this And this would
10:32 sort of 100%, we're gonna assume is 100% permeability or 100% sand.
10:37 this is 0% sand. But we know for sure. Uh You
10:42 maybe the static S P should actually higher, higher than that right
10:47 But you just uh calibrate it as as this would be 100 and this
10:52 be zero down here. And what gonna ask you to do is to
10:58 , Pick your pay, your net on the 50% mark that you figure
11:03 . And of course, this is to 100 when it's the first time
11:10 does some things. It's difficult. It doesn't matter how far that is
11:15 between would be 50%. OK. uh so this won't look exactly like
11:22 log, but, but then it nothing to do with, with the
11:26 up here, but it does have do with um um the distance between
11:33 maximum and the minimum. And with assumption that this is 100% sand and
11:39 is 0% sand. Where is it be 50% and that would be your
11:43 pay cut off. Ok? You make it different if you want
11:49 Now, another thing that happens, when you're doing real developmental geology,
11:56 you might Go so far as to this is 100% net and this might
12:01 a little bit less net just because , it's on the, it's on
12:06 shoulder and not at the feet. again, this is obviously pouring
12:13 The tool came down here, saw sharp, a sharp boundary went way
12:18 here all the way to there and slowly coming down to this. So
12:21 is probably a real, a real finding downwards trend. We normally do
12:27 upwards because sediments are deposited on top each other. So when we think
12:32 the geological sequences, we think of the bottom up. OK. And
12:39 just a, an example I put here, this was from uh what
12:43 had before and these are the kinds responses you're gonna get. And um
12:49 you can see um uh resistivity going in some of these things. So
12:56 actually seeing the possibility of pay over and water over here. So,
13:01 you know, the water, here's water line over here for the
13:06 Here's the shale line here and your your maximum sand is out here.
13:12 again, over here, you see resistivity resistivity. And um here's sort
13:19 uh they're calling this a transition Sometimes you'll have U 400% watered
13:26 100% oil from here up and somewhere here you have less, right?
13:33 . So it's really important to remember thing when you're looking at these
13:38 uh the, the deep tools are out here, the shallow tools are
13:42 in here, the shallow tools, , oftentimes we'll be seeing,
13:50 the flush zone and the transition zone this, this, by the way
13:54 a different transition zone. Then this zone we're talking about as I'm
14:00 we have uh hydrocarbon. So as move from the board, I'm gonna
14:07 um the invaded zone that invaded zone gonna be mostly mud cake and it
14:13 be very thick. Then I'm gonna into a transition zone and then I'm
14:17 have a logging tool that's measuring the way out here somewhere uh in the
14:23 . And if it's got no oil gas in it, it's gonna be
14:30 water. So the resistivity will be low. OK. But if the
14:36 is high, it's because it's So that's over here. We got
14:40 here and the true uh un invaded . This is true rock uh signal
14:49 out here. Same thing out Um That's how, that's uh that's
14:55 that's trying to show you. It's important to have this diagram in the
14:59 of your head whenever you're doing, at logs. And, uh,
15:04 you look at the, the gamma , is it really controlled by as
15:08 things, uh that can affect it E S P law. And uh
15:12 fact that oil and gas will suppress S P log is a good way
15:18 compare a gamma. If you see suppression where you have a good strong
15:23 , you know, you probably have in the system. And,
15:26 and so that's, in other if I had a S P log
15:29 and it might do something like this of its response time and it'd be
15:34 late here like this. And then , if the oil and gas is
15:38 here, it would start bending over this a little bit, it'd still
15:42 high and it would be above alpha , but it would still be a
15:46 bit higher at the same time that uh hydrocarbon eludes the, uh
15:54 millivolts for flow through the, to for throats because the saline water is
16:00 by uh hydro boats and gas can very dramatic though. And uh so
16:10 I, what I really want you see and uh kind of want to
16:13 up on the board and show But, but um if I had
16:17 log here that just went like this as an arrow like this yellow
16:27 so this is like this is like S P almost that kind of broke
16:32 in here. You can see the gamma tool responded to the shale
16:38 the middle. So, you you have a shale break there.
16:42 not way over here like you get these uh very radioactive shales.
16:48 But you can see there's a So um I might draw a shale
16:54 , something like this. Through this . You can see here there's an
16:58 lower in the well, but through you might drill it, uh draw
17:01 like this. And so this would 100%. Um This would be less
17:08 100%. But again, this is really thin interval in here. This
17:14 in feet. So, uh even it's from the North Sea, this
17:19 in feet and uh that's a small there, it's from, you
17:23 12,000, 250. So each one these things is uh is about 10
17:29 ft. So, uh you that's just a, that's a really
17:33 stringer, but it's good to see is that this thin stringer even
17:39 and even though this is a, quick tool response that thin stringer is
17:43 this thing over here. So if was trying to figure out how much
17:47 I had in this total section, would you think I should do
17:52 Say this whole thing is, it like it's close to, to 50
17:56 thick If I'm reading this, No, excuse me, 250 ft
18:02 . I'm sorry, it's 250 ft . And each one of these things
18:07 , uh, 50 ft actually. so we have five of them.
18:13 , uh, this is less than ft. So, what do you
18:16 would be, uh, the, , amount of net pay right in
18:26 . It might be around 50%. , uh, what, what we
18:29 to do with logs is uh and is how I got in trouble but
18:34 get in trouble. But when um when you see this, it
18:40 means there's shale partings and there's shale here, there's probably some shale partings
18:46 here. This is what I would um sort of a subtle response to
18:52 . Same over here. This is of a, a subtle response to
18:57 being in it. And uh you , it looks like a good
19:01 This looks like a good stand. one though is really obvious right
19:05 See that one. And so uh , if you were trying to figure
19:10 net pay, you would try to out what this thickness is right about
19:14 here and just completely zero that It's not Up here, it's a
19:18 bit more subtle, but again, also a thin bed. This is
19:21 thin bed, but it made it the way over there. So maybe
19:24 something like what you said, cut back by 50%. In other
19:27 when you're doing pay, you you kind of look at these,
19:31 at the character of it and basically straighter, the line, the more
19:36 it is and more likely the cleaner is. If I get stuff wiggling
19:42 in this direction, it's getting it's getting, it's getting in.
19:47 . And so you have to remove little bit, uh, if in
19:52 Marsala 128 when I was doing I didn't have any logs that looked
19:56 that. They were more like And so there was a lot of
19:58 to get out of it. uh, that's how we lost 75
20:03 barrels. But, uh, uh, and like I said,
20:08 , uh, when it was I, I turned out to be
20:10 optimistic, the auditors took even more away from it or, you
20:15 using it as a, you you can use that capital as,
20:19 a, as a token to, borrow money to. Ok. And
20:25 this is where it starts and this the first log and, um,
20:35 increment left to right is 10 That's 20 right there. Um,
20:40 lot of times when they do these , uh when they do that,
20:44 means each one of these little things , is 20. But,
20:50 I don't know why people have to their logs in the way we do
20:53 , but they, they do all time. But uh for the purpose
20:56 this exercise, each one of these 10 millivolts. So two of them
21:00 20 and it lines up perfectly with . Here, here we have an
21:06 P log here. Uh We have out here which is a reflection of
21:14 it's the inverse of resistivity. It's a uh um a slightly uh subtle
21:22 so that you don't see this big back here. And uh and you
21:28 uh you have something that's steep and have something that's shallow on the resistivity
21:36 . And um this is uh actually is, is going, is going
21:45 in this direction, it's going up that direction. So it's kind of
21:49 like resistivity. OK? It it's the same, it looks like
21:53 same response. It's actually a reverse , but it's plotted that way.
21:58 your eye catches it, there was purpose to all of this when I
22:01 stuff going to the right. It resistivity. In this case, it
22:07 less, less connectivity which is equal resist. And here's some uh
22:15 I've tried to be very explicit in questions and every time I read
22:19 I wish I'd written in a different and I'm just, I've given up
22:22 to change it but read it If uh if it confuses you,
22:26 me know, but I'm trying to you to do uh something quite
22:32 Such that on this side, I'll yellow in here and maybe you don't
22:37 you want to, you can just things yellow. There's no point in
22:39 the whole brown. But let me where you think the sand is.
22:43 want you to come up with uh predicted alpha 100 alpha and a zero
22:52 at the same time. This is thin bed, there's a thin bed
22:55 and one of the questions is adjust to the thin bed effect.
22:59 Don't change, don't change your, impression of the amount of net
23:05 Just know that it's, it's not it as fully. Uh How can
23:11 say this? This probably is clean it looks less clean than, than
23:15 static S P because, because uh a short, it's a short uh
23:19 know, OK. The tool response fast enough to show you the pull
23:26 . OK. Here we have a log over here and it's really
23:29 And one of the critical things in one is I want you to note
23:33 uh you know, you're gonna have shale line over here and I,
23:37 call this 78 50 Sandstone. So do you think that might be?
23:51 . One of the things that I , that you always do uh when
23:56 um well, God knows what people doing now, now that they can
24:00 a million colors, but uh typically happens uh is that you draw a
24:07 on the top of the sand that think is important. Now, a
24:10 of times you might wanna pick uh up an inflection. So if you
24:15 this is the inflection and that's the halfway up would be right about
24:20 But you can see here, there's little nick here. And so maybe
24:24 sand starts about halfway up here between Nick and that Nick. And it
24:29 is represented here by the resistivity log being the top of the sand.
24:34 the sand isn't quite at uh at 79 50. And uh
24:41 uh if you look at this where would you think The base of
24:45 79 50 Sandstone would be? Because is something, almost half the class
24:50 gets wrong. Where do you think base of that sandstone is 79 20
25:10 here? No, I can see you, I can, I know
25:16 you said it. But uh that's it, but we'll, we'll get
25:21 that. What did you say? , the base of this sand?
25:31 , how many feet is the base the sand at I uh right about
25:44 . Just So maybe 79, OK. And, and I,
25:53 think you're right and see you got down here, this is a shali
25:57 than that. Uh But you this is probably one sandstone unit.
26:04 is a sandstone stringer here and uh another one and maybe this is
26:11 a little bigger sandstone. So if , if I was picking two sands
26:15 , I might pick one right here uh 8100 and 10, Which is
26:21 that is where that little dot that's 80 10. And um,
26:28 up here, it's pretty much the of this one somewhere. Either here
26:34 here. I would probably pick it just because, because this goes to
26:39 that just doesn't look right. And here on this side, what do
26:44 see over here? Ok. we see really high resistivity and,
26:54 , I labeled the shallow, Which is more resistive then the
27:05 But it's kind of a quick Right? But what's going on right
27:10 ? If the deep, if the is less resistive right here, what
27:16 that mean for the, for the the True Rock? We're looking at
27:24 True Rock here? It's got good , low resistivity. What does that
27:31 is going on away from the well at this point in this log?
27:42 . What's going on here then? do this. Excuse me?
27:52 Yes. Sorry. I, I listen for sale, but Brian's with
27:56 lot of people. You so, , the water is sailing. So
28:01 point right here goes from, you know, some people get in
28:06 and look and they'll try to figure that it's the same problem over
28:10 but it isn't um this scale, can't see it and, and you've
28:14 stuff in here that's actually when you to the edge, this is conductivity
28:19 here. So when you get to edge of this, it cycles back
28:23 here and when you get to the of it over here, it
28:25 So some of these little lines in relate to the peaks that couldn't get
28:31 over here because the scale ended right . And it's, it's not the
28:37 uh image in the world, but went flying to the right.
28:43 That means high resistivity. What's the resistivity that you can think of as
28:47 fluid? Yes. So, um matter what kind of overlap you're seeing
28:53 here, some people would have in , in the class have thought,
28:57 know, maybe it's, it's even though the resistivity is high,
29:01 still looks like it's um the overlap you would see for uh uh brine
29:11 uh salt water in the formation. , but that's not what it
29:14 It's just totally, it goes off like that and the tool almost looks
29:19 it's malfunctioning. It's natural gas or else could it be? And it
29:30 won't be that far, but it be very tight rock. OK.
29:35 what you're seeing in some of these shrink stringers here, you might see
29:40 occasionally see tightness. I don't see of this But, uh, but
29:44 here, if you come across you picking up a little bit of
29:48 , you're picking up even more resistivity , uh which suggests that there's some
29:53 in that, in that shale. there's, there's a lot of things
29:57 on here. But basically, you a sandstone from about right in here
30:04 you're gonna have a hydrocarbon leg and gonna have a water wet leg.
30:10 I'm gonna ask you to tell me the net pay is. And I'm
30:14 ask you to tell me what the how much, how much of this
30:19 , what's the net? How much sandstone can you see um a water
30:25 ? Ok. And it's good if start with this is the base and
30:31 up here across from this resistivity kick the top right there, right?
30:38 you know, it's so close in . It's hard to, it's hard
30:40 eyeball it. He is a Ok? Then log # two has
30:49 whole set of questions. And uh these are the questions for log number
30:55 , which are right there and I of went through what you needed and
30:59 I have blanks and the reason I blanks is so you can print them
31:03 and uh and play with them without up the things. So, you
31:07 , I can print out two or copies. Little red dot won't be
31:10 them. Yeah. And uh and should be that for the,
31:35 Um, now that the recorder is , still on, I'll say it
31:42 more time when we, uh, many people noticed a date mistake on
31:51 , uh, syllabus. Yeah, midterm was on the 9th. It's
31:56 be on the 8th, but we're do it the next Monday. So
32:01 we'll, we'll get all the way the logging exercises and the test will
32:04 that. Well, the, the was supposed to be on the eighth
32:10 though it said the 9th. But we missed a day, I wanna
32:13 , I wanna get this half of class out and then we'll make up
32:16 extra time in the, in the section. And, uh, and
32:22 , it's a more fun part of , but I hope, I hope
32:28 find it as much fun as I . Um, I enjoy all this
32:32 but, you know, a lot this basic stuff we kind of have
32:35 go through just to make sure everybody the classroom is, is,
32:38 is up to speed on it because of the problems with petroleum geologies,
32:42 use lots and lots of tools and can't use them all here. And
32:47 , um, and we interpret all of types of basins, but we
32:53 interpret all of them for one You know, it's just, it's
32:57 , uh, a really broad based of information that I'm trying to convey
33:01 you and trying to go through the I kind of looked at it when
33:05 was a development geologist because I think the best way to, to handle
33:09 . In other words, the, focus from start to finish is the
33:14 . OK. How did the reservoir there? How did it get
33:17 How big is it? How much can I? OK. So uh
33:22 already looked at the rock mythology We looked at ferocity and permeability
33:26 fluid identification tools. Now, I'm gonna go through uh just mentioning some
33:31 the pressure tools. Um the one the interesting things about uh all these
33:38 pressure tools. Uh And when we into the second half, we'll talk
33:43 it one block in the same formation a different pressure. Well, you
33:50 a well here and a well here they have different uh boil water
33:56 for example, that tells you they're separated if, if there's different pressures
34:01 them that could tell you they're separated . You have the same oil water
34:05 . The pressure is different. There's different about those units. There's,
34:09 a pressure seal like another fault that can't see in seismic and sometimes not
34:14 in the well data because you haven't it with your wells. OK.
34:20 these, these can be really important for compartmentalization problems. And again,
34:28 you know, when, when you a well a reservoir engineer can calculate
34:32 spread uh or the draw in terms a volume in an an approximate area
34:39 that well board. And if you a small compartment, you might be
34:43 to drain it with one well. you have a larger twice the size
34:46 wells, three times the size three , uh they do these calculations,
34:50 want to put in as many straws they need but not too many.
34:54 uh and then again, a lot times now they're drilling appraisal wells early
35:00 which they could use for injection uh that are down dip uh while
35:04 trying to find exactly where the oil contact is. But uh I would
35:09 recommend doing that myself just thinking of economics and the efficiency of making sure
35:16 up dip of the oil water, oil water contact or the gas water
35:21 , whatever it is and down depth any fault plane that might be uh
35:29 that reservoir. You know, you don't want to drill into uh a
35:34 plane and you don't want to drill right at the oil water contact because
35:38 you miss, if you miss the , it might be one of the
35:41 wells that made you miss the whole the entire reservoir even though there's one
35:49 . OK. This is in the book. And um the way he
35:54 it makes, makes, uh you , it makes a lot of sense
35:57 here's what's going on. He shows uh the water gradient it's steeper for
36:06 than it is for his oil And um why do you think uh
36:14 water would be steeper than the In other words, this, this
36:22 isn't changing at all. This one changing a lot and it, I
36:27 it sounds, this is a shallower but it looks, but it's actually
36:32 higher gradient. It's changing faster. other words, it's right,
36:38 this this distance in this direction is a lot more than from here to
36:45 because the oil, no, it's it's it all. Well, here's
37:01 deal. It's really has to do density and the water is denser than
37:08 wood. So uh if you stack water, The number of atmosphere like
37:16 ft of uh water depth is an of pressure. OK. And you
37:22 keep adding that up. If uh it's oil, it's gonna be less
37:26 33 ft. I mean, it's be, it's gonna be, it'll
37:30 more than 33 ft to, to a whole atmosphere of pressure. And
37:36 , you know, it's one of things that looks backwards but it's
37:40 And uh and, but the the really is how much I'm changing over
37:46 thickness and it's, it's much more . The gradient is much more rapid
37:50 uh than it is here. And because this, this fluid is denser
37:56 that fluid. OK. That just now that you have that sort of
38:00 your head, uh as we produce , the free water level is gonna
38:05 up, right? But also the , the pressure in the uh oil
38:12 gonna shift, right. It's gonna . Um But it doesn't really change
38:18 way he's drawn it. Um At I can't figure that out. Uh
38:23 anyway, the oil gradient, the gradient is still gonna be there.
38:27 not gonna go when you start, you start replacing uh hydrocarbon with uh
38:34 know, you do, you do this ship to the left. But
38:38 really happens is it looks more like . Yes, the oil water contact
38:44 up and this gradient shifts over and oil shifts over with it.
38:51 Um You know, unless you have really tight transition zone and it's all
38:58 , you might not see it. uh but there would be, if
39:02 had a thick transition zone, there be a pressure gradient that's different in
39:06 zone versus the oil lake by itself versus the water. So it would
39:12 look more like this. And so he's trying to show you with this
39:15 is that um if we uh if produce the uh oil, it's gonna
39:25 over here. But, but you , the, the water line didn't
39:30 up, the water line has to up because the water line has to
39:33 to a lower pressure by becoming uh in the well, you know,
39:39 water doesn't disappear. You know, not like like the pressure in the
39:44 is not gonna shift over here like just because you're depleting the residue.
39:50 . It's still gonna be water and still gonna be heavier than this.
39:56 it, it should really uh look like that. In other words,
40:01 water gradient goes up, the oil goes lit and this will go as
40:08 get to further depletion, this whole right here will shift over and the
40:13 gradient will be in front of OK? But you'll still have,
40:17 still have water coming down here like . And of course, you can
40:25 the pressure of the water is being as it is as it raises
40:30 you know, but it doesn't, not disconnected, you know, you
40:35 disconnect it the system. OK. what he's trying to show with you
40:43 is if you had um if you this leg, uh that was more
40:50 and you were producing more out of , you had a permeability layer in
40:54 . In other words, you're producing a rate in here and a rate
40:57 there. And uh all of a uh you run out of oil in
41:06 bottom leg, then this thing would be shifted over like that. But
41:11 might shift over faster than the other . In other words, if,
41:14 I have more perf up here than have down here, you might see
41:19 , a real line that looks like . Ok? Because, because he's
41:25 you have a permeable barrier here that it, but it doesn't make the
41:31 thing move over, you know, per the permeable, uh, impermeable
41:37 , truncate it, uh, in this case, but not in
41:43 no impermeable barrier here. So you truncate it like it's done there.
41:49 know, you can't really just shoot here from that you have, it
41:52 to be a continuation. In other , the oil leg is gonna shift
41:57 the left gradually as the gradient of water moves to the left with
42:05 Everybody see that, you know, was drawn right in the first
42:08 I wouldn't have to explain it to . But, but it's in
42:11 a really good book and I don't why people do stuff like that.
42:15 um OK. And here is uh an example of a type of flow
42:22 . And uh uh the whole point this though is we have tools that
42:25 can measure these pressures and we can what's going on. We can see
42:28 one leg is faster than the Again, the first thing I pointed
42:32 is if they're in different compartments from different compartment and you just have one
42:36 leg uh in each of those and pressures change on either side, you
42:40 , once producing in a volume that's from the other one. In other
42:45 , if I'm draining a volume over , that's smaller than the volume over
42:50 , the other, well, this gonna lose pressure quicker and quicker and
42:56 water gradient is gonna just come it's gonna come up this section,
42:59 not gonna swing to the right. know, once, once the pressure
43:06 there, it doesn't, it, know, you'll get some reduction,
43:09 you get reduction primarily because it's, becoming higher and higher and the water
43:14 is getting weaker. OK. And uh here we've got a flow meter
43:25 uh uh I invite you and hope you will read this. I don't
43:30 to read it out, but I just want you to see that
43:33 the flow meter. Uh using these , they create a thing called sigma
43:38 the gamma response um from the uh neutrons hitting the chlorine ions. And
43:48 it helps them distinguish between a lot uh um a lot of water over
43:55 to a little bit of water over . And this is showing you how
44:00 got swept and this is filled in water. This was in uh Here's
44:07 2007 line, here's the 2004 Uh here. You had oil down here
44:15 uh by 2007, this has become . In other words, this has
44:20 , it was like this and it shipped over into this direction. So
44:23 is showing you more water, this showing you more oil over here.
44:29 oil water contact originally was down here water and then we get more and
44:33 water, more and more water through . And it reaches up here in
44:38 . So this is the 2007, get that. OK. Then there's
44:49 other types of tools uh that are and sediment tools and uh to some
44:57 , um in terms of the you would include sidewalk cores and other
45:03 of cores. But uh but uh courses and other courses are actually a
45:09 of rock. And uh I made point of this at one in the
45:14 is that some geophysicists think tying the um rocks to the seismic is tying
45:27 rock as an indirect measure to the , which is a direct because that's
45:33 way they think that the seismic is direct tool. The only direct tool
45:38 here is when you pull a chunk rock out of the ground, that's
45:41 . I mean, you get to what it is, you know,
45:44 not, it's not an algorithm trying figure out, you know,
45:48 With this gamma response, it should this given these conditions, it's,
45:53 , it's the rock, you it's the real thing. So,
45:57 deal with the real thing. Geophysicists doing remote sensing and uh it's not
46:03 remote sensing. It's fantastic remote But it's still, it's re,
46:08 , it's sometimes I use passive sometimes I use active sources but it's
46:14 not directly measured. They're measuring something indicates what that real rocket is.
46:21 you pull a rock out of the , that's it. You don't get
46:23 change it, you know, you live with it. And so these
46:27 really the direct tools down here. , and the thing that I always
46:32 strange in, in industry was you know, we have a lot
46:35 geologists with a lot of great ideas their head. But most of the
46:39 we're looking at indirect evidence to try come up with a real model.
46:43 that's why we model a lot. of the reasons why geologists have to
46:47 is most of the time we're using tools to help us figure out.
46:52 this a delta? Is it a channel? What is it um is
46:57 , is it a homogeneous sandstone or a heterogeneous sandstone? Is it laminated
47:02 is it not laminated has been All these different things, we can
47:05 them when we have the actual we can't, we can't always see
47:09 that stuff and we don't know exactly anything is from an algorithm, but
47:13 know what it should be OK. um for structural features dip is really
47:21 . And one of the next things gonna talk about after we look at
47:24 few uh geophysical tools quickly in the lecture, we'll be looking at
47:29 And of course, correlation is also important tool for helping us sort out
47:34 . In other words, if we tops moving up and down from one
47:37 to the next, we automatically see and the base is important too.
47:43 as it turns out in, in my mixed up world where I've done
47:48 lot of uh prorate through bio and done a lot of sediment technology uh
47:54 looking at sand masses and stuff like in the recent. Uh I've always
48:01 that the top and the bottom of poorest unit is one of the most
48:04 things. So, one of the important things in reservoir characterization is gonna
48:10 clearly identifying the base on the top that reservoir. Because if the base
48:14 the top of that reservoir are different the base on the top of this
48:19 over here, they don't correlate, know, they, you know,
48:22 somehow they have to be correlated to other. Uh And it can't be
48:26 because you draw a line between the wells. OK. So um a
48:34 of these different uh regional features you know, regional dip and regional
48:38 , a really important thing. Um lot of, uh, textbooks on
48:43 , put a lot of energy into . But regional dip kind of,
48:47 , tells you right away. Do have? I have, uh,
48:50 sandstone and it's dipping, say, , let's see, which way would
48:55 south be about like that? if it's dipping to the south,
48:59 know if I drill for that same to the north, it's gonna be
49:04 and if I go that way, gonna be deeper. And uh you
49:07 , that's a really was really important they first started drilling. There's other
49:14 uh that are important to know is because as we've already mentioned, and
49:18 of you probably know faults can be up to boundaries for a tilted formation
49:26 they can have different types of roller are also important and uh some poles
49:31 create an anti. OK. uh and at any time is where
49:36 get a lot of trap development. There's other depositional features that we can
49:42 uh with dip meters and uh and kind of what this is talking
49:46 But again, it relates to the process of correlation too. Uh You
49:52 , we can see depositional features uh certain patterns in a dip meter.
49:59 Sometimes we can uh determine uh paleo direction. I know when I was
50:05 with Mobile, uh we're on the River and they pointed out that uh
50:09 done a really big study and to get what the current, the true
50:15 direction is, you need almost 1500 within a short distance to figure out
50:21 the regional uh flow is. In words, it actually is telling you
50:26 depositional dip and a lot of times you see publications, I'll have a
50:30 rose diagram and uh and you can there's one little bit of it that's
50:36 mostly in one direction and that's probably regional tip. And uh but it
50:40 a lot of data points to do . Uh just looking at one or
50:44 logs uh can give you some indication it may not be the right
50:51 OK? OK. And uh there's lot of other things here. Um
50:59 obviously lack, often lack dip is they like a basin floor. Where
51:03 it? It's just shooting straight out the basin for. And uh and
51:08 when you have the levees on a lot of times if you get
51:12 little bit off the levee, uh know, there may be tiny,
51:15 bit of dip but it's pretty flat even off to the off in the
51:19 . If you call it, I'm call it off of the levies of
51:23 uh submarine channel. And of uh when you have salt intrusions and
51:29 , you can get all sorts of things happening in your um and your
51:33 meter, including the dip just goes . OK. Um And dip meters
51:44 trans transformed into image logs. Is uh working on logs right now,
51:49 you've actually had dip meters or, image logs? I see you've seen
51:55 before. Yeah. Yeah. uh, they're, they're expensive tools
52:00 they, and they, they hang and so they're really easy to get
52:05 up when you drop them down a board, they, they kind of
52:08 and then they come out when you to the bottom, but they can
52:11 up on things. Um I don't what kind of dip meter tools they
52:18 now for uh horizontal wells, but guessing they have something but it's probably
52:24 um not exactly what we're gonna be here and it, it would have
52:29 um um it be more like an log where, where you don't have
52:35 things hanging out where you have lots micro channels to try to try to
52:39 it out. But again, that's . If you're trying to stay in
52:43 bed bed, you're trying to avoid by all, by all means.
52:49 the image log rather than having these that stick out like the old
52:53 uh they basically have a lot of channels and nodes on the tool.
53:03 here is a four pad one and can see here it kind of sticks
53:07 and um so it can go down up the hole at the same
53:14 Uh I, I don't think I did a, a dip meter because
53:22 , a lot of the information that need in terms of dip, you
53:25 see it with uh without a dip just by uh particularly in the and
53:33 you know, the Scott field where work, uh you probably would need
53:37 because you didn't have enough blogs that penetrated the sand. But in the
53:42 When I was working on it, in South Marsala one, we had
53:49 something close somewhere between 60 and 70 . So you had a lot to
53:53 lot of uh holes in the ground uh to figure out some of these
53:57 things in terms of regional depth and , but what it is is
54:01 it's got these, here's ABC D A again and it kind of uh
54:05 got four pads and you and some the uh in, in this particular
54:11 , but this is a three pad dip meter. And uh basically you
54:16 a North Southeast West and you were to figure out uh based on auto
54:22 . Now, you'll hear me say correlation is a joke. And uh
54:28 that here. So I don't forget . Auto correlation is a joke when
54:32 um when you're trying to do wells are far apart. If you're in
54:36 wellborn auto correlation works, it has work because it's a few inches away
54:42 the other one. You know, , you're basically measuring the same rock
54:47 very close in. And so if part of a bed is a
54:52 bit lower here and a little bit there, that's actually it, you
54:56 , it's not, um, it's not like a, I'm way
55:00 here and I'm trying to auto correlate ft of section with 350 ft of
55:07 and a 10,000 ft thing that I know what correlates to what that's when
55:11 correlation becomes really weird. And uh using gamma logs and carbonates is,
55:16 just these bizarre beyond, beyond But people do it anyway and they
55:22 up with these great papers that look good and all wrong. It's just
55:27 , it's just a shame. So , here's what a typical dip meter
55:32 looks like the plots would look And uh now to make it simpler
55:37 people, they might even just have curve and show you what the degrees
55:41 . And uh um but here's, a thing called the tadpole and uh
55:49 it looks like a tadpole and um, the round part of it
55:56 telling you what the angle is at point. If the dip meter determined
56:00 angle was at that, that Well, and uh and again,
56:05 really close. So if the bed's , this is just like you're on
56:09 crop almost. And uh, and can see it. So this is
56:12 , the degree and the little, tail to it is pointing to what
56:22 any. Right. And uh so everybody in here is everybody in
56:27 a geologist don't be ashamed if you're . But um, if you're uh
56:34 you're an engineer or geophysics, geologists put north at the top,
56:41 So notice here it doesn't say south east or west, but all
56:45 note north is up, of course the magic world of computers. Now
56:50 can twist things all around any way want. We don't copy maps that
56:54 made with that standard thing. And are all the time publishing maps that
56:59 twisted this way and twisted that It's really mind boggling that they have
57:03 do that. Uh I can get if an editor has something that's a
57:07 like this. But if I turn on the page, that's OK because
57:10 we can turn the book on the . But if they do it somewhere
57:13 between to make it fit, it no sense. But anyway, north
57:16 up east is over here. West over there and south is down that
57:21 . And so this tadpole right here pointing what, in what approximate
57:29 right? OK. And that's how read this. OK. And here
57:35 uh a sand body and it's showing look here, you can see,
57:38 know, you have a lot of to it and look at the directions
57:41 it. It's just gone all over place. Uh, here we're in
57:45 shale. What are we seeing with shale? It starts out shallow and
57:53 it gets, it starts to increase increase out this way. Right.
57:56 that's kind of what that's showing And you can see that it's not
58:00 . You know, you can see a lot of noise in it.
58:04 , everybody always asks this question, are the ones that are solid versus
58:08 ones that are? Uh, is it on there? Lower quality
58:22 is open? There you go. didn't want to read it but there
58:25 did, you read it very good you. Ok. So anyway,
58:31 we see different kinds of patterns on things. And, um,
58:41 a lot of times when people are the oil industry and I, and
58:45 was one of them when you start a world. A, well,
58:48 start to think of the world as the top and I'm going down into
58:54 but sediments get deposited this way all time. Unless it's an overturned
59:01 Ok. If it's an overturned you'll see lots of funny things that
59:03 you that it's an overturned bed And, uh, then you
59:09 unless you're near, uh, some of, uh, salt dome or
59:13 , some kind of pierce dome that have caused like an overlap. Uh
59:18 not gonna see that in a attentional is where I've spent most of my
59:22 . But here we have one that's called bag of nails. Here's one
59:28 upward increasing. Here's one that's excuse me, upward decreasing rather.
59:38 here's one that's fairly unable. And is the green pattern. This is
59:44 red, the blue and uh sometimes is a black pattern, but they
59:51 have a thing for black patterns But uh uh normally you just call
59:56 a random pattern. OK. And uh you can see this is over
60:05 trying to show you what the strata look like. And given if the
60:10 looked like that. In other this is a two dimensional representation of
60:14 bed that's dipping down to the west uh you'll never get it to the
60:22 . And then OK, it's dipping to the southwest. I'm sorry.
60:26 this one's dipping down to the up to the northeast and this will
60:31 you what you see in the OK. Here is another one where
60:37 see an increase in death. What that look like to you guys?
60:43 pattern right here could be, it be the flank of an A&E cline
60:50 as you get this greater steep uh Yeah. Yeah. But it
61:01 , it also looks a little bit growth. OK. And uh because
61:08 angle is getting wider, you it, it seems to be getting
61:12 little bit wider as we go in direction from here. But, you
61:16 , it's hard to draw these things realistic patterns. But, but what
61:20 is trying to show you is this uh decreasing upwards. So you could
61:29 , um, if you're looking at direction, could be on lap.
61:34 you're looking in this direction, you down lap. In other words,
61:37 could have pro gradation in this direction on lap in that direction. What's
61:43 on here? OK. So it's dip. It has structural dip,
61:59 it doesn't have sediment dip. This down here has some kind of sediment
62:03 to it because you're gone from a section to a thicker se you're going
62:09 like the edge of a uh depot to the middle of the depot.
62:14 one, this one is normally what see in a shale shells are normally
62:19 out. OK. What, what you see on a flood plain?
62:26 . The, the, the muds the floodplain are gonna be flat just
62:30 in the deep ocean, right? all gonna be flat. OK.
62:37 here's one that's uh upward increasing. is the blue and a lot of
62:45 things can be the same thing, the orientations change, don't it?
62:50 Here you, you actually see growth the left side, which is,
62:53 is unusual. But um here they that more often than not, this
62:58 gonna be what you see for fault and forces and all that sort of
63:03 . It's, you can look here see that. Um again, you're
63:06 a lot of the same things but orientations are different and it's happening in
63:10 different direction. So it's, it's that's uh straightforward. And um here's
63:19 you an un conformity. These are black patterns. uh where you just
63:24 everything is, this is like the , this is like a green
63:27 a green pattern but they ship, call that a black pattern.
63:34 OK. Here is um here is , here is green, but this
63:42 a black shift right here. And this is just showing you something
63:48 happened here. Uh What would what would something that looked like this
63:51 to be OK. And almost an and perform or two at that?
64:03 again, trying to, trying these images are a little bit hard
64:08 imagine in some ways. But uh know, you have this, we
64:13 what's happening in the Weber. Here is, here's that, you
64:21 , we go back to this this red pattern over here. There's
64:25 of growth. It looks just like , you know, you're moving some
64:32 of this weighs the edge, this deeper into the base and you're seeing
64:39 kind of. So it's starts out , it's a little steep and then
64:44 kind of stays the same thing, you're spreading it out and here's
64:48 the shells that don't change in terms the amount of dip. And that's
64:54 recording this section right in here and the limestones. And then when you
64:59 to this break, this truncation uh, it's shifted and it's in
65:04 to this depositional response is what's giving that response there. Ok.
65:12 here's a fault with some overturn and let you look at this yourselves.
65:16 again, here you're seeing, as you're coming through this part of
65:19 , well, uh you're seeing uh shales that haven't been affected and then
65:24 of a sudden you see shells that affected by a fault drag here.
65:29 is a normal fault drag and um, not roll over.
65:35 Sometimes you get it, you get either way. This is,
65:40 concave, uh, roll over and not convex, roll over.
65:48 This is showing you again a lot flat line beds, limestone shales.
65:53 all of a sudden you get this of nails and what causes this to
65:57 in a sandstone? Did you say betting? Like I didn't, wasn't
66:03 everybody heard that. But yeah, betting. Ok. And so,
66:15 , this is just an example of , an area where you have complex
66:20 patterns and a dip meter might help here because, um, you
66:25 you're not necessarily getting a clear picture here and it might be because,
66:32 , and it is in a list , and uh whenever you have one
66:36 these things where everything is just falling the edge of the, up off
66:40 edge of the scarf and falling into , you can see all sorts of
66:43 going on. But if you had dip meter in here, you might
66:46 a, you know, sometimes your may be the top of the whole
66:51 and uh there could be some stratification of it. You might be able
66:56 see with the dip meter that you see in the se it because you
66:59 this big thing on top of that of it. Uh this big,
67:04 me, everybody knows what, what's with it, right? It's like
67:11 a mass debris flow or something. just pours in over the edge.
67:17 uh could be a little bit like the bray sandstones and, and uh
67:23 places uh in the Tepe Basin in where you get different types of flows
67:31 sometimes it's just really massive and M mangled. And then we would call
67:35 on a list of it. But of the stuff that looks more like
67:38 , like a fluid flow or we would give it a different name
67:41 a look at the OK. And , here you see the image
67:48 they still have these pads but, um um when I last saw
67:56 they were retractable, I can't tell this. But uh but uh they
68:02 all these nodes on them. So have a lot of channels. So
68:05 , they're getting a signal. Um , here's a signal here. In
68:12 words, from this part of the pad to the next part of the
68:20 , these things you can see they're little bit offset. So you're getting
68:23 that duplicate each other and ones that in a different, in other
68:27 there's something like all the way across little path and then there's something aro
68:31 the way across from pad number four pad number two behind it. And
68:36 you're really getting um, high confidence , you know, it's not like
68:41 have one thing measuring the dip at one point. It's, it's all
68:45 that path. And, um, because of that, you have this
68:51 intensive fingerprint looking log over that And then you have another one,
68:56 other words, one's covering this another one's covering this area, another
69:01 covering that area and another one's covering area. And they kind of uh
69:05 on the size of the hole and , smaller the tool, the harder
69:09 is to move it. But Uh get pretty much 360° coverage almost in
69:15 cases and um, they end up kind of like this and then you
69:23 put the pieces together and it looks a court. And, uh,
69:27 so you get a really good log that and, um, and
69:33 there's all sorts of ways to interpret things and, uh, I think
69:38 , it's a lot like, a radiologist looking at x-rays or a
69:44 C T, it takes a lot , uh, education and,
69:48 uh, practice to figure out how , uh, sort this out because
69:53 you look at this log, the red lines are betting, in
69:58 words, they might be those green , uh, then sealed fractures or
70:03 green ones and open fractures are the ones. And, um, and
70:11 , I guess because, uh, open fractures, uh, they lack
70:16 response and so that lack of response up being blank space and that's why
70:21 an open fracture. So there's a of, a lot of detail that
70:25 into, uh, not only developing tools but also interpreting, you can
70:31 that, you know, the bigger hole is, the more likely you
70:35 four strips that aren't connected, but try to, uh, put the
70:39 together because they're looking, you you've got a pad over here and
70:42 pad over there. So, in ways, you know, if you
70:46 it all together, you got a that looks like this, but you
70:49 missing something and you can miss something between the smaller the hole, the
70:54 it is to move the tool. the closer it all gets to be
70:57 real uh, thing like an, , an actual core. Ok.
71:02 the last thing we want to look and this is, um, do
71:07 guys mind if we go a few or late? Yeah, but his
71:16 is really exciting. You don't wanna his stuff. Johnny is a great
71:25 and he has a great name. love his name. I think he
71:29 it, but I love his But, uh, Johnny. Woo
71:32 sounds really cool. Sounds like a superhero or something. And he's
71:39 pretty neat guy. But anyway, , we'll have to, I guess
71:43 better stop. But, uh, get into, uh, just a
71:46 more things and then on, Wednesday we'll finish up tools too.
71:49 think we'll finish this up and get tools, uh, too. And
71:54 we'll have the rest of the, , time with, uh, correlation
71:57 then, then we'll put off the by one day and, and,
72:00 , start working on sequence data. , uh, anyway, uh,
72:06 you for paying attention and, I hope, I hope some of
72:11 don't know all of this. no one's asking questions or answering them
72:19 quickly. So I'm guessing that some it's new to you. Oh,
72:24 , the exercise, uh, today's . Make it next Monday.
72:29 But if you get it done and to turn it in early. That's
72:34 . And I, and I'll get grades posted tomorrow or today for the
72:38 one. I'm sorry about that. just, I had more than,
72:42 , one distraction happening this past Thank you for that. I
72:55 uh, grades quite simply on, , on exercises. But again,
73:01 first one was an interesting one just see what people thought. Yeah.
73:05 . Like I know that, I didn't know you but I tried
73:17 , ok, I tried to, like I did so I tried to
73:22 it in a way that can
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