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GEOL7323 Borehole Geophysics - Day3 02-24-2023
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00:00 Oh good. So there, great . Stephanie was just trying to see
00:15 where we left off last time. think we did the soil stuff that
00:19 diagrams. I think so too, like a quick review. I didn't
00:38 didn't do the musical stuff. That's kind of the fun thing if you're
00:48 interested is to take these well logs put them to music. I don't
00:52 do have a bit of a musical at all actually. Oh great.
01:07 know, if you're ever interested in and you're multiple things to do,
01:10 is something I did a long time we took these well, log sweets
01:14 then we map them through a midi to a voice. And so basically
01:21 can it's just a string of It's a well log and you can
01:24 those through midi from 0 to 1 or the number of keys on the
01:28 or whatever and then um and then them and play them together. So
01:33 sounds kind of interesting but. Yeah, so let's uh go on
01:42 next one. Uh I trust that turn off sometime. Okay.
02:12 so there were a few things that up last time and I thought we'd
02:18 , I've got three or four things came up in our last meeting.
02:23 so just remembering about temperatures, the uh temperatures and pressures. Oh great
02:30 , you too. Yeah that would very helpful. You know, these
02:34 like they were actually bottled at high . Seriously? Yeah so back had
02:46 quick reminder because in all these well there's we look at a variety as
02:53 remember a variety of units and The U. S. Is one
02:56 the few places. But for example doing a project of the India right
02:59 it's in metric. You know we're about the Canadian oil, sands
03:04 So we just want to remember that conversions, the ones I always like
03:09 -40 C. You can see here how it all got started. Which
03:15 all really interesting. There was no before really before Fahrenheit stuff froze and
03:21 just hard to imagine that people didn't numbers on stuff but they didn't hey
03:24 really cold out. Guess what? he was actually a glass blowing vase
03:30 kinda guy. But he he was these glass blown tubes putting alcohol and
03:38 all kinds of stuff and then gradually just adds scales on them to say
03:43 is this is freezing, this is gave rise to a standard which is
03:48 key. And so he originally said zero degree zero the number zero was
03:55 of a saline solution, a briny originally and that he pegged at 90
04:02 going to be the number for the of the human body. Anyway that
04:06 that worked out a little bit and changed it but way back then so
04:10 where the scale came from the Fahrenheit and then uh that the numbers are
04:16 of funky, so you know that's what we do here. But
04:25 Celsius said, nah let's go from to 100 and just put which makes
04:31 . And so he developed that other and then you can see the
04:35 So it's good to be able to that for quick purposes. I always
04:42 that minus 40 F is minus 40 . I don't know whether you've ever
04:47 that cold before, but regardless of it's cold. And then of course
04:54 is freezing 32 f. The other I remember is again 28 C is
05:00 F and then of course 100 Is 2, 12 F. So
05:05 there's a conversion. So you wanna able to do that because a lot
05:09 the times around here, of course the recordings enough, but everywhere else
05:13 can see. So if you're working other provinces or states, you have
05:19 know once again, so that was original, the french originally put together
05:25 standardization because it was mainly for length you go from one village to the
05:30 and they had no standard for how your property was. So there are
05:34 kinds of disagreements, you know, guy used a french foot, the
05:37 guy used an Egyptian foot, who ? But it was all screwed
05:43 So during the french revolution, once they said we've got to have a
05:47 for length and they made it the which was something like 1 10 thousands
05:54 the circumference of the earth for a . But so then they developed this
05:59 . K. S. System, kilogram second and then of course they
06:03 have electricity back then. So they need a unit. Uh not morphed
06:09 the system, each of the I. System, which is what
06:16 of the world uses and all of uses. So again it's M.
06:20 . S meter kilogram second, but with current with a vampire's degrees,
06:29 kelvin, it's the same size as subsystem of course it starts at absolute
06:35 and then uh Greatness and the So those are the units that you're
06:42 going to see in all the scientific . Another coworker who just moved here
06:49 Albania in november. And she's always you americans, you don't know how
06:55 measure here. And I said we she always gets like with degrees and
07:01 is funny, she gets confused. and on her part she's got to
07:06 a new system, sorry you're living . So but when I was in
07:13 when they changed the system. So were we were imperial and like the
07:18 . And then there was a decree came down that changed the whole country
07:22 metric and most people hated it, didn't want to do it because all
07:26 a sudden you're going to buy a of butter at the grocery store and
07:30 .4 Kg. And what the hell that? So most people didn't like
07:35 , but you learn to live with . Um, eventually the US probably
07:43 . I mean the hospitals and they don't give you an ounce of
07:47 . You know, it's going to in CCS. So it'll change.
07:58 . They always tell us her. . Because they've got to keep
08:04 especially with the child if it says , what the hell is 10.
08:11 , you know, you got to these standards. So these are the
08:13 and well logging. It's really critical the well logs are all in different
08:18 . We have messed it up sometimes the well log the well might be
08:22 depth, but the units are in , So you might have a well
08:28 in depth and then microseconds per So it's good to just be alert
08:35 that. You were talking about H S. So I went back and
08:39 at this a little bit as you know, hydrogen sulfide, your sour
08:48 and sour. Actually has a definition the oil field And it's uh,
08:55 than .5% by weight. Um, that's actually the sulfur content. So
09:06 should be S. 02. It be sulfur dioxide. It could be
09:10 Could be uh, something hydro hydro acid. There's lots of things that
09:16 be. But as you were the 500 parts per million is probably
09:25 to be fatal and much above it's almost instantaneous. This is a
09:30 , really toxic gas. So now can also see various various kinds of
09:46 sort of sour crude is, in sense. Doubly bad because it's typically
09:51 , it's typically got very very long chains. And so it's dense and
09:57 also somewhat toxic. So when you up to the west texas intermediate,
10:04 the stuff that's coming out of the basin right now is very light around
10:10 degrees A. P. I. it's very sweet point 25 or something
10:19 percent. So it's W. I. West texas intermediate crude is
10:25 , really a good good oil. you can see some of that
10:33 Now, interestingly, I was one my students, I met with her
10:36 morning, she's working for one of companies in west texas and they're drilling
10:42 kinds of holes in west texas and two of us is a really big
10:46 for them. And so finally she brought it up, it's gonna
10:50 that it's gonna be a chapter. said, I want to I want
10:52 look at this, She's leading a for the company on H. two
10:58 . Kind of from the production of things because when it gets into the
11:03 and pipelines it corrodes and so it erodes and corrodes and eats, eats
11:09 steel. So she said that H S was a big problem for
11:14 And she wants to find a way explore for it like gas. So
11:22 I said, well, you never , It might be that we can
11:27 seismic, we can do an do A. B. O.
11:31 can certainly see gas and maybe there be a certain association, we probably
11:39 see H two S directly, but can probably see that there's high gas
11:43 here. And if we know that in this rock at this depth corresponds
11:49 H two S, then we can proxies. So, you know
11:52 this is the H two S prone . And so that is very,
11:57 practical, they might want to completely it. So, you know
12:01 we don't want to deal with that of hydrogen sulfide. So that was
12:06 the thing that came out this morning will probably start looking for. How
12:11 we somehow predict what might be high to us in the shales. So
12:20 kind of interesting. Uh we had a little bit about other other materials
12:27 the in the reservoir fluids. And once again here, you can see
12:33 typically in the reservoir, the water brine and it's very saline Uh
12:48 as you can see is maybe a percent salt. Use about 3.5%
12:58 And of course we can't drink seawater that puts ions in us and our
13:06 have a certain amount of fresh And so drinking salt water, your
13:12 tries to equip vibrate and get the concentration down that dehydrates your cells and
13:19 cells don't like that. And then course your nervous system is firing on
13:24 that are very delicate balance to conduct back and forth. And if you
13:29 that up with other ions, that's bad for your body. So we
13:35 drink seawater. Fresh water, as can see is less than .05 or
13:48 parts per 1000. And of in in seawater, that's mainly sodium
13:55 , rock, dissolved rock salt. , I was curious uh about the
14:06 kind of, the relationship. Salt to brine as sugar is to
14:14 And you can see that extreme brine about as salty as ice wine is
14:24 . So just as an idea how brine is and how sweet ice wine
14:31 . So here we go with different , you can see that very dry
14:35 zero measured grams per 100 millimeters. you can see that this is,
14:42 is actually 500, believe it or , Does't look like 500, That's
14:53 500 miles. Um so a dry . Somewhere around here would be one
15:03 per 100 mils. So there would five g of salt. These five
15:08 of sugar in that that's kind of . Yeah. So when you get
15:15 to wines that probably more people like a 2345. Um and that corresponds
15:24 something like five g of sugar per mils. So this guy would have
15:30 g of sugar in it. That's sweeter. Then when you get the
15:34 wine there are 25 g per 100 . So this would have a 2525
15:41 cubes to salt in it. And really good. But you just how
15:52 sure you're eating is unbelievable. So a bit of an idea from something
15:56 we can taste too. Also saltiness various fluids. Sea water is seawater
16:06 something like a medium sweet wine. salt, it's a medium salty fluid
16:15 to a medium sweet wine. But the time we're getting to brian in
16:18 formation it's extremely salty. And it's even more salty than ice wine is
16:28 . Then we talked a little bit just about where about us production,
16:31 are just kind of cleaning up from we talked about last time. And
16:43 can see that the U. Is the biggest oil producer in the
16:46 right now which is great Pushing 12 barrels of oil per day. And
16:56 what what's the price of oil today . Yeah. Beautiful. I'm glad
17:13 hear that. No. Well it so much of what's happening around here
17:23 around the world. So I've just the I just have the apple stock
17:32 and you can it's did you see ? What who's what's the name of
17:50 what are we looking for? Um just I've got it on the stock
17:56 so the apples there's a list. not sure what. Yeah. Well
18:06 actually should be crude oil and and annotation is C. L. Equals
18:10 . For some reason 1 29. you add stocks on that where you
18:26 ? Yeah. Um I see new see maybe just see. Yeah
19:43 Yeah. So there you go. you can do the quick multiplication,
19:54 a barrel and 12 million barrels a . How much money is that bringing
20:01 per day for the US? Yeah so a billion a day and
20:16 you can kind of double that with gas but so you've got that's why
20:22 just fabulously important for the U. . Economy. And not to mention
20:28 texas, it's not to mention in because texas produces about half that.
20:36 the numbers for we'll get to that west texas But just so you've got
20:41 in your back pocket that that the produces about 12 million barrels per
20:48 The next two biggest producers. Saudi somewhere around 10 or 11. And
20:54 Russia is around the same around 10 11 million barrels per day. So
21:01 are the big the three biggest producers far and then there are fairly big
21:08 . Canada Iraq Nigeria china are all , moderate producers. But you can
21:24 see that this is mainly Permian west and it's it's light and this is
21:35 , great oil. I just added here the what's happening right now.
21:43 um you know the biggest the biggest in U. S. History was
21:50 a couple of years ago. Then course with Covid it all fell down
21:53 now it's been increasing. So here got that peak and now we're increasing
21:58 . So the fact of the matter in the U. S. Production
22:01 increasing. People are going for There were of course in this period
22:10 very many jobs, this is starting get a little bit better than we
22:15 the crash that there weren't many But now with the price of oil
22:20 there's just so much money in oil , so things are changing. Uh
22:28 gas down here, you can see effect of geography. So US natural
22:33 is lots of natural gas in the , some of it's coming out of
22:38 marcellus shale, some of that of Permian lots of places, gas doesn't
22:47 trade with an international price because you ship it very easily. So there's
22:52 lot of gas in the U. . Good for the U.
22:55 Industry. And so it's cheap, a lot of it. And you
23:00 get it out very easily. But big industry now is lng liquified natural
23:09 . So if you cool and pressurize natural gas, you can ship it
23:17 . And there's some of the biggest in the world right here. Saving
23:21 with senior saving past huge facility just of Beaumont. So, not far
23:27 here. And, but to move gas, you have to get it
23:41 a part. You have to compress , cool it, clean it,
23:44 all that stuff, then you gotta ships built, it'll take pressurized natural
23:48 and you've got to ship it and you got to get it someplace they
23:51 to have the decompression facilities. So bottom line is that it's expanding the
23:57 . S. Changed its, its laws to allow hydrocarbon exports a
24:03 years ago, which was great. opposed by some of the chemical manufacturers
24:09 , why would the petrochemical guys oppose exports? Mm hmm. Because 20
24:32 , It just means that people are to compete and pay more for
24:35 They say, I don't, I want anybody. I want, if
24:40 trying to produce, make something here needs natural gas coming in. I
24:44 cheap gas. If I've got cops somebody else is willing to pay for
24:48 , then I have to pay more it. It's pretty simple. So
24:51 can see what happened, uh, course, during, during conflicts or
25:01 when the, when the price of goes down or or porch shot or
25:05 else like that. It's not a deal for here as much. But
25:11 you're in Korea or europe then they have their own natural gas they desperately
25:15 . And so you can see that price would go up to 35 bucks
25:18 M. C. F. When typically trading for three bucks here.
25:23 Korea and Japan and Rotterdam and Germany stuck paying a lot. So once
25:36 , This is the Permian basin. can see that the premium base is
25:39 about 5.5 million barrels of oil a . Just massive amounts. So
25:43 $400 million dollars a day coming out the Permian. And then normally we
25:53 of the Permian being in two there's the Delaware basin separated by high
26:01 then the midland basin, all that the Permian basin. And you can
26:07 that we've talked a little bit about . T. I. West texas
26:11 versus Brent Brent is from the North . It's also a good oil.
26:17 not quite as beautiful as W. . I. It's a little bit
26:24 and it's got a little bit more . The good news, why Brent
26:32 trades for more then W. I. Is that energy is expensive
26:38 over in europe. Plus people like because it's easily accessible. It's on
26:47 ocean already, you don't have to it. So they're willing to pay
26:52 for it because it's, it's more and it's ready, it's being produced
26:59 offshore platforms already, so bring a up, have an FPs so floating
27:06 production and storage and offloading ship that refines it right there, puts it
27:12 another, take it anywhere in the europe is good at that. Then
27:25 talked a little bit about just where lot of the west texas crude
27:30 it goes to cushing Oklahoma because they huge storage there and a distribution network
27:37 this is actually where oil is So if I buy oil on the
27:45 market or something, it's for delivery cushing and so the way the market
27:52 is that there are all kinds of that go to cushing Oklahoma, the
27:57 go there and effectively by the oil there and then they ship it to
28:00 they need to. But the price quoted is west texas crude at cushing
28:16 of course their traders all over the who are, who are trading but
28:19 is actually physical delivery of the oil and that's why that time a couple
28:23 ago when oil went to negative Yeah, that was at that
28:29 it was just bizarre. I have I didn't even know what it
28:36 I remember because we had a group on and I was like dr Stewart's
28:40 freak out today. Say it was was bizarre, bizarre. Okay so
28:55 the other, another example that just remember about fluids, you can see
29:01 brand on this graph is just more . W. T. I.
29:05 a little bit less Western. Canadian comes from the largely from the oil
29:10 up here. The biggest deposit of on earth is about a trillion
29:14 Actually there uh over the area of like probably the size of massachusetts,
29:27 huge but it's it's uh as you see it's high viscosity, its heavy
29:31 and so it um you have to it or dilute it, its hydrocarbon
29:38 it's heavy hydrocarbon. So This produces three million barrels a day. It's
29:42 very productive but it's a bit more . Yeah I've probably gone over this
29:50 class but I don't remember um what like Canada versus like Saudi like geologically
29:59 why is the oil like like it's oil that Canadian was just like so
30:06 and it was like what about geological makes it so different. Yeah the
30:17 about Saudi, it's a number one the source rock so they had a
30:21 marine shale so that's number one, wasn't a carriage iness, sorry.
30:29 um and then it was buried and it was appropriately cooked and then it
30:47 it didn't migrate it was kept so was kept in the oven kept kept
30:56 deep and then not degraded So in Venezuela as well as Canada. This
31:15 two ideas probably was pretty good. then it basically spilled, it's
31:24 It's only at some of it's right the surface. So in fact it's
31:31 , it's not even for a lot it is actually just scooped up.
31:37 should I should have brought that Um I've got some in my
31:41 just oil sand. It's just like to Galveston's on and dumping on the
31:48 or bitumen on the beach. It nature's spilt. And so a lot
31:54 this soil migrated. Some people think it may have migrated hundreds of miles
31:58 being good oil and then it migrated the surface and then it gets
32:11 So that's one thing that can And in Canada, this is,
32:18 is all shallow. If, if been a cap rock, like Saudi
32:21 has a big cap rock and it's kept kept the cooker on
32:24 cooked it to uh to certain temperatures then it kept it there and there
32:30 no degradation of the oil and, that had been cooked perfectly. So
32:42 is shallow again. So it gets when it gets shallow and it may
32:47 not have been cooked enough. You , there's a couple things happen.
32:54 like if you were saying baking muffins something and you've got the dough and
33:02 it bake it until it was all and fluffy and a nice card muffin
33:07 something. But if you didn't bake enough, it would still be a
33:10 bit gooey. So that's one Or if you took that muffin and
33:16 left it outside for a couple of , it's probably gonna be hard.
33:23 there are a couple of things that happen. Both them probably happened
33:27 So the oil is degraded. It's bad. It's like I told
33:30 the guy who was one of my in grad school, john Hunt,
33:35 wrote the textbook of petroleum geochemistry and were in his class like you were
33:40 he went to Venezuela and Venezuela is same thing, huge shoots similar of
33:44 deposit like this. But it The service degraded became heavy. And
33:48 just wrote us a postcard and he on the postcard and you can almost
33:53 his tears old for a cap In other words, if that stuff
33:58 made it to the surface and have cooked a bit more and stored,
34:02 would have had by far the biggest in the world. Likewise here,
34:08 this stuff had met a cap rock the Saudi Arabia Saudi Arabia had a
34:15 rock, it didn't spew to the and it kept very nice crude.
34:22 , so we've been through Gavin Rae . Um I think one thing that
34:27 might not have discussed last time was when we start to move a little
34:32 more toward quantitative analysis. Um the just wanted to mention that we established
34:43 the sand line or the minimum gamma and we'll look at this in one
34:50 your cases and then typically you established maximum value of the gap Marie and
34:58 the spread. Then you just take the log, whatever it is.
35:03 got our log coming down like The fraction of basically the fraction of
35:09 the logs reading between minimum and That's just our fraction. So
35:15 we've got a minimum here. Sad , shale line, the logs like
35:19 and then that's just percentage saM going . So that becomes our gamma ray
35:28 . And basically you kind of call a volume of shale or be
35:35 So we talked about the gallery last , but this is the calculation.
35:41 once again, uh our basic gamma gives us everything that's radioactive, but
35:54 can be a bit more selective. a more sophisticated log is called the
35:59 gamma ray log. And it has filter because potassium has energy of gamma
36:06 , uranium has slightly different energy of rays and the thorium has slightly
36:10 So we can filter for those and make three tracks. And that would
36:14 if we were lucky if we really to know the details here.
36:20 normally in conventional reservoirs, we don't care because I just hate shales.
36:27 so in the conventional reservoir, we want shells in an unconventional reservoir,
36:32 love shells because we're gonna break them get there. But in the in
36:47 organics, the organics might be more by the uranium track than,
36:53 the thorium track. So if we're to tease out exactly what's attached to
37:00 oil and not the matrix the I might want to know, especially
37:04 the shale, just exactly what's in shale. And so I want more
37:09 just total radio activity. I want know where is the radio activity coming
37:12 And that's going to be a total content indicator. A toc indicator,
37:19 it might be that its potassium might more attacks strictly to the matrix uranium
37:26 be more of an organic indicator. we might want to separate them.
37:30 just a bit more sophisticated. So again at our field camp, when
37:37 looked at this as an example, might call this the sand, that's
37:41 minimum on the gamma ray, So we might call this the sand
37:49 and then the maximum I may be that the shale. So if we
38:00 to do that, the sand of case, what's the value there,
38:04 , can you see here's the scale . This is gonna be the
38:25 25. Yeah, so this is . That's 100. The divisions are
38:31 each. So 0, 2040. in there you would yeah, let's
38:42 it 25 or 30. Okay, we're gonna pay that, this is
38:49 minimum. So we're going to call our sand. And then if I
38:53 at the maximum excursion here, it's okay, say 100. So that's
39:07 excursion from 30 to say 100. , I'm gonna say that's pure
39:13 that's pure shale. And then whatever numbers are, I'm going to subtract
39:22 minimum and do the ratio and that's to give me a fraction of sand
39:29 1 - that is the fraction assuming that this is a classic sand
39:36 system, which around here is so let's do a quick calculation. Say
39:47 took the depth right here. What's value? 40 right there. Time
40:15 using the numbers up here and So I said right, where was
40:25 ? I was right there. I on my iPad 60. Okay,
40:39 . Yeah, it's okay, that's . Let's compute the percentage.
40:53 So, we're gonna take basically 60 the minimum, which we said was
40:59 friends, 30. And then the was a 100 -30. So that's
41:06 70 seven. So 2 points. .42. Yeah, so 3/7,
41:35 will be about .42. Okay. , is that what is that?
41:40 that the sand or the shale? that's right, so that's 42% shale
41:48 how much sand? Yeah. So gonna say that's 58 at that particular
42:01 , We're looking at 58% sand six that's that's the most simple lethality log
42:14 got. And when we look at how they've done it, that's more
42:19 less how they they've done their mythology , they're just gonna say,
42:26 assume it's sand shell, guess what got uh 58% sand there. I
42:34 when it's a blog and like some of log equation, not just thinking
42:43 yeah so it it is the depth but but this, oh where was
42:54 ? This is just the value out given these are all given depths but
43:00 gonna take the gr log is the ray log and that's just the log
43:05 a function of depth. So this the gamma ray value at that
43:09 So these other values these guy and guy we take we look at the
43:16 log and what's the minimum of the log or this whole this whole
43:21 what's the maximum over the whole And now we're looking at my log
43:26 going like this for every every depth that log, what does that mean
43:31 terms of with ology? So this just a real way to convert that
43:40 into something kind of quantitative and with logically meaning if let's let's look at
43:54 of your Yeah, she would so if you can it was
44:51 So here This is 75 sorry. simple Teresa. Okay, camera
45:27 And then you can look at your that 75. So that should be
45:46 say so Your gamma ray is excursion from 50 to 90. That's the
45:58 . We're gonna say rage. Now have an exercise right now. Oh
46:09 , engineer here. So do Yeah. Okay, great,
46:25 Good. So that's that's just a on the gamma ray, what is
46:34 us and then how to make it bit more quantitative. And again the
46:39 in the in the log analysis package do basically exactly that, take a
46:45 of maximum, then look everywhere in , it's sand and shale and then
46:49 out nice pretty colors and charging. . We we had we talked a
47:00 bit more about the but the acoustic too. And and mentioned that this
47:11 just uh in the simplest form the time of sound waves or sonic value
47:18 a given interval. So here it be just how fast it takes sound
47:23 travel across a foot. And then is your measurement, it's the microsecond
47:30 the transit time across the foot. here's the basic idea that we have
47:41 little chirp for that's just a little unit, it sends out a little
47:45 , you can actually hear it and that goes through the fluid hits the
47:50 wall and vibrates the borehole wall sends wave and then we recorded a receiver
47:58 . So the simplest thing is just go from the source to the
48:02 And if they were separated by about foot that gives you a microsecond transit
48:07 per foot that be your output. it turns out that's okay but if
48:12 tool is tilted or the formation of or the logos or rough or something
48:18 it doesn't work as well. So course being a geophysicist we want more
48:24 . So the way to correct this to have an upper transmitter that transmits
48:29 we receive it a lower transmitter, receive it and we basically just subtract
48:34 guys and so we get an interval this interior one ft. And it
48:40 depend as much on the fluid and borehole wall and the tilt and all
48:45 errors. So this is a called B. H. C. Or
48:52 whole corrected sonic log. And it one of the first ways to get
48:57 little bit better reading because now instead just trying to pick this first arrival
49:12 can actually correlate the arrival here in rival here and look for the move
49:18 . So when you think of processing , if I gotta pick this first
49:22 , I have to do it So I need to know what's the
49:24 that I have to have a pulse . And then there are all kinds
49:28 bad things that can happen. But I've got two measurements, I can
49:31 cross correlate these guys and look for leg so I can bring a lot
49:36 data into it in the cross It's a bit more tolerant of errors
49:41 noise. And I can just look the leg here and that gives me
49:46 microseconds per foot between those two So it's a more robust noise,
49:55 measurement. And we do that. find that a lot of rocks have
50:02 characteristic times. And so you can some of the times here. It's
50:09 to take 55 microseconds to go across foot of sandstone. Uh dolla mates
50:16 faster or slower. They would yeah, it's taking less time to
50:27 across them and salts are slower. , so that's that's one thing.
50:40 Now that was kind of a compression wave, but but we can also
50:46 shear wave that propagates along the whole to to get a shear wave
50:51 And that's done by having a di or a piston source here that pushes
50:59 fluid. And then that causes sort ground roll to go along. Or
51:03 surface wave to go along the border which is attached to the shear wave
51:07 . So we can get a shear velocity that way. And oops,
51:13 slides kind of messed up the uh , here's just a little bit more
51:17 the mechanics of, of an actual . This is a little bit more
51:29 but basically we like to measure both compression wave velocity and the shear wave
51:34 . And we do that. We start to separate the rock type.
51:42 once again we just make a raw . Wave measurement, a shear wave
51:47 for a given place and the ratio the cross plot of those guys starts
51:53 separate and we can determine what kind rock it is and sometimes what kind
51:56 ferocity from just these two measurements then an actual tool, what it looks
52:12 . We have a source here and receivers receivers and a source and so
52:20 just gonna put this in the well then measure the time through the formation
52:23 here to hear that blast. This measure the time two here and two
52:32 and then really average all those and the time across this area in the
52:38 and that's R. D. Or our time of transmission across that
52:45 interval. And then this is moving measurements done really fast as the tool
52:52 up the whole and it's only taking few some dozens of microseconds to travel
53:00 that because sound travels really fast then the tool that maybe a meter per
53:07 . But the sound is propagating at m per second. So you can
53:12 this measurement while logging so once again a couple more when we're in all
53:26 logging instruments, we have to worry how big they are. Really embarrassing
53:32 you've got a a smaller well and two of us too big, it
53:36 fit. So we worry about that little bit because when we're drilling water
53:42 or something, they're, they're not big and the instrument has to be
53:46 to fit inside. So simple things in the oil field, if you've
53:51 a particularly hot well, then you to make sure that the tool will
53:58 that. Or if it's a deep , can it go that deep?
54:01 those are all things that we would to consider in a well logging
54:08 And for us, if we've got array sonic or multiple receivers, you
54:11 see that across the array of the , the sound wave goes through the
54:16 propagates back in the borehole and we look at the, the move out
54:22 or the slope and you can see we can extract that slope by just
54:28 a cross correlation between all these guys that's how we automatically determine the
54:53 So the result of that is I've this tool and I'm logging and I
54:59 the slope one over the slope is velocity. So the slowness, whatever
55:05 slowness is, the transit time for or that's just one over the
55:11 And so normally the well logs are plotted in Sonus or transit time because
55:16 how they're measured. But as geophysicist usually think of velocities. So we
55:25 take one over. Just take the and then ultimately we see classic figures
55:31 this. So the log is in and velocity and we've got a p
55:37 value and share way value. And can see that for this area.
55:45 was kind of Shelly up here and this is sandy and then this is
55:52 . The P wave doesn't see too difference between the sand and the
55:58 But the shear wave sees a big between the sand in the shell because
56:07 sand is very rigid and the shale very malleable. So the sand shows
56:16 as a high shear wave velocity which a high rigidity. The shell shows
56:30 as a relatively low shear wave velocity it's not very rigid. The P
56:36 is telling us more about compressibility and both kind of equally compressible. So
56:41 doesn't seem much different. Okay. you can see that this is
56:57 you know what O. W. . Stands for the oil water
57:04 So once again the oil is floating top of the water because it's .85
57:13 per cc. And the water is 1.1 g per cc. And then
57:19 can see that this is all interpreted as sand but there's a bit of
57:28 kick here and that's probably because there's some dia genesis. This is
57:39 it's probably been briny first 50 million . And so there's a slightly different
57:45 type that's been generated because of dia because going from oil to water,
58:08 is slightly more dense. So in the the shear wave velocity would normally
58:16 a little bit, but it's not increasing and the people have increased a
58:22 . So you'd have to guess that some rock type change, not just
58:30 fluid. And then there were a of different values. And you start
58:39 get to know these guys sandstone has high shear wave velocity, so a
58:44 ratio. And then as we get some of these other units, they
58:49 variable amounts. Okay, we're going get this guy and had a look
59:01 that before. But this is just once again make sure that we can
59:04 all this stuff and and work through . And so let's take a little
59:08 those stuff. Not we start cross . Thank you. So we can
59:23 those two numbers. And at any or we start plotting V. S
59:30 Vp. And you can see when when we do that, the
59:35 numbers start to separate into clusters at different depths. And you can see
59:42 the say the limestone is fast Vp fast V. S. Is fast
59:53 that's an indicator that this this is limestone. You can see way down
59:59 , the shells are slower. All . And so when we've got these
60:09 pure units, they separate. So I have an area that on the
60:18 and the VP is 5000 and the . S. Is 3000. Can
60:22 tell me what kind of rock it ? V. P. 5000.
60:27 . S. Is. 3000? Well 3000 slower. Oh wait he's
60:40 VPN um V. P. 5000 V. S. 3000.
60:54 kind of rock is it? You don't have to overthink this.
61:05 read the graph. Yes. VPs V. S. Is 3000.
61:21 . Yes. Yeah but you don't have to do that. 3000
61:33 Guess what it's it's right there. . So. No it's just getting
61:39 but so the point here is that just made two measurements and for this
61:48 area, those two measurements tell me kind of rock it is. So
62:01 the really key concept here is that making just a property measurement, just
62:10 transit time of wave through it. can actually tell you what kind of
62:15 it is for these simple cases this real data but for for simple geology
62:20 I could tell you likewise if if said oh I looked at this area
62:26 is 4000 V. S. Is that is that a dolomite?
62:32 I don't have dollar mine. So don't know is a limestone. So
62:37 . P. S. 4000 S. Is 2000. What is
62:44 ? Sure? Yeah. V. . Over V. S. Is
62:50 around too. So you're thinking could just from V. P. Over
62:55 . S. It could be this this. That's the that's the two
62:59 . But the velocities are really So it has to be down
63:02 So guess what? That's a shell that's the that's the kind of Fernie
63:15 . So likewise we can make a of density. This is a bit
63:20 complicated. I can make a measurement density with a log And we'll talk
63:24 that smart. And then I can that V. P. V.
63:27 . Value and just do the very thing have all my logs. And
63:32 for every depth, pick the pick the V. S. Pick
63:36 density and then cross plot those. that's what people do A lot log
63:41 and industry people do a lot of cross plots. When I cross plot
63:47 get all this garbage and I think I don't understand that. But if
63:51 had a third log the gamma ray and I plot that in color
63:57 Then all of a sudden I start see something coherent. So how we
64:04 this is as the material at any . Get shay earlier and shay earlier
64:10 can see that I start to get here. So B. P.
64:15 B. S. Gets bigger. gets higher. But if I picked
64:22 I had density of 2.25 And the . p. v. s ratio
64:27 2.7. I'd be out here. radioactive is that rock likely be
64:41 So say from seismic measurements I could density and velocity. I can't get
64:49 activity from the surface. It's too away. But if I've got density
64:55 VPs they cross plot and that's pretty . So if you've got a fairly
65:00 density rock and a high B. . P. S ratio, I
65:04 almost guarantee you it's radioactive. So concept here is that I can make
65:12 measurements or three and by correlation and lots of Work, I can actually
65:23 a 4th one in this case radio . Which is very valuable because I'll
65:28 these measurements. I don't know what is. It's just got the
65:31 It's got this philosophy. Well, what? It's a shame. So
65:41 we look on further we can often the P wave velocity. The shear
65:47 velocity of seismic. I can often something of density out of seismic.
65:52 I can get that, then I actually infer how radioactive the rockets.
65:59 so that's important. I get to things and I in for a very
66:06 thing. So that's that's really the . And that's the idea with seismic
66:12 . I make these measurements. The . I get seismic. I do
66:15 the processing inversion. I come up these beautiful seismic inversions for density.
66:20 . P. V. S. , nobody cares about VPN Bs.
66:24 do care about whether it's shale or . And so that's the first,
66:29 I take my picture, that's PVS density. I convert it into
66:34 shell in this image. So that's we're going with why we do a
66:38 of this stuff. Okay, so do another little exercise. Um now
66:59 this case we we've talked about this of making the measurement of the transit
67:09 through a material. This could be core plug, it could be a
67:13 or anything. And because we're we're simple people. We imagine that
67:21 rock is really this simple. It's matrix and ferocity that's full of
67:30 of a water or water or a or a gas. So when we
67:38 a vibration out here and it goes , we imagine that that travel time
67:42 just going through the matrix and the . I mean obviously this is
67:46 really simple, but we're going to if it works, it works.
67:49 here's and if that's our concept, is our concept, it's going through
67:56 matrix, then going through the Then you can see that the travel
68:01 through the rock is the travel time the matrix. Travel time through the
68:12 . So I just replaced travel time the rock with the distance, the
68:17 of the rock and the travel time the matrix is just one minus the
68:24 . That's that length. Then through process it's just the percentage of the
68:28 length. Then if I just saw simple equation, I get the porosity
68:36 the transit time or the slowness. this is exactly like the equation for
68:47 percentage shale. So we've made this log measurement, but now I could
69:17 a porosity which is getting closer to I want. So we're gonna use
69:22 sonic log for two things. The thing is just like those cross plots
69:26 determine mythology. The second thing is extract an estimate of ferocity. So
69:33 what we're gonna use the sonic log . So let's do it. So
69:41 another little calculation for you. So we looked at the nordic, let's
69:54 the calculation for the nordic. The transit time or slowness. The P
70:03 was 200. Okay, So measured of the P wave is 200.
70:24 was the unit? Yeah. Then going to assume that it was a
70:37 because that's more or less what all numbers gave us. So now we
70:42 to we're going to assume we have make an assumption. We're going to
70:46 that it's a sandstone. So now need to know the matrix slowness of
70:51 and we had that 1.6. but we also know that it was
71:16 cemented. Right? So, among , why don't we just say 50
71:23 per foot? So immediately we run a unit's problem but I would just
71:31 it all down because we're gonna fix . So the Sandstone Matrix is say
71:38 microseconds per foot. Then we've got find the slowness of brain. And
71:56 we we looked that up and the of Brian, they tell us is
72:00 190 microseconds per foot. Well 190 per foot. That actually that's the
72:11 sort of the mud velocity because we're that it's invaded the formation.
72:20 so now you've got the fluid slowness now you just need to plug.
72:30 know the matrix. We said the was 50 microseconds per but the fluid
72:39 1 90. Yeah, the matrix a game 50. But you're going
72:52 have to convert this? Two microseconds foot 7, 3. That one
73:11 can look up. I'll take So, you know more or
73:19 And it's good to have a basic to me, it's like using google
73:23 when driving. I want to know or less where I'm going because every
73:27 in a while, the google map is wrong, 3.28. Right?
73:35 and so A meter, as you imagine it is about three ft a
73:40 more than three ft. So if my slowness is 200 microseconds per meter
73:57 takes it takes 200 microseconds to go ft. So how many, how
74:02 microseconds to go? one ft? . Okay, so this is why
74:25 want to do it by hand. so there's nothing wrong with this.
74:29 want to work through my hands. it's taking 200 microseconds to go 3.28
74:35 . So Tony Go, one it's gonna take about a third of
74:39 . So it's 200 divided by which gave you Yeah. So what's
74:47 porosity? Right, so that is to be and that you can use
75:06 your calculator. So to the of rock, which is going to be
75:26 . The matrix. Yeah, So what's what's that in percentage.
76:34 , so now you think about does, is that about what you
76:39 expect? Is that in the game talked about a maximum porosity rock,
76:50 ? Which was extreme ferocity might Was it 150? Did you just
77:02 this is ferocity extreme, extremely porous ? I don't Well, extremely
77:16 might be up to say almost half rock is airing. So be something
77:21 45% is extremely porous. We typically see that. So what a porous
77:28 might be something like 25%. That'd very good ferocity. A porous carbonate
77:33 be 10%. So this looks like pretty somewhat low porosity sandstone, but
77:42 in the game. So you calculate . Well, that's in the
77:48 I believe it. It makes sense the rock is very high velocity and
77:55 a sandstone. So we know it's very high velocity sandstone and we know
77:58 got carbonate cement. So how much is left? Well, Not that
78:06 . And so 9% says, there's not that much. So that
78:10 calculation because in the ballpark, so kind of believe it, but it's
78:18 through the calculation yourself tells you, first of all, this is the
78:23 the computer is going to do So if you're gonna write some
78:27 you would do exactly that. good. Okay. Um so that's
78:37 how from this raw measurement, the sonic measurement, we're going to
78:43 I would put a sonic track a track. So that's how it's
78:53 Okay, let's move on to catch on the density log. And this
79:05 another big important detail. We've got know the density of the rock and
79:10 want to know the density of the as again, the mythology indicator we
79:16 process is the same way to get out of it. So I'm gonna
79:19 ferocity out of this. Then when make synthetic size programs, we know
79:26 seismic waves are sensitive to the density the rock, especially the density
79:37 So this is another very standard log you can see the way it
79:49 it goes into the formation again and a radioactive source. Now, the
79:56 ray tools remember it was just a detector, it was sodium iodide crystals
80:02 something. It's just measuring the natural activity coming into it. This is
80:06 active source. So this is generating own radio activity and shooting gamma rays
80:11 the formation. And what it does it's going to look for the attenuation
80:16 gamma rays and that's going to tell what the bulk density of the
80:24 Okay, good physics here. And going to look at the basically attenuation
80:30 gamma rays between the short detector and long detector. And this presses against
80:38 borehole wall because we want to get radio activity right into the formation and
80:44 have it go through the fluid because fluid attenuated. And I want to
80:48 a measurement just of the rock. once again, we've got a source
80:57 irradiating the formation and we're receiving here receiving energy here. And we're gonna
81:03 at what's the decrease in gamma radiation here. And from that, we
81:11 determine something about the bulk density of rock. So we kind of get
81:27 the physics of we shoot gamma rays And depending on the electronic structure will
81:35 us um the amount of attenuation or for our purposes. The photon goes
81:45 , it gets scattered or absorbed and we measure how much the absorption is
81:54 there's physics stretch in the physics, for us practical purposes, we've got
82:00 radioactive source here, it gets the photons it emits gets scattered absorbed
82:05 we measure them and look at the . And uh in the in the
82:14 gamma radiation. As you can see , the the intensity that received is
82:23 to the atomic number or the or element that's scattering. The atomic number
82:29 related to the bulk density. And number one from this is just the
82:33 density line. This gives us just the density of the formation.
82:42 I'm gonna quickly go on here for second. What does that manifest itself
83:02 ? So here's here's the Yeah school can stop for a sec. Usually
83:34 meeting is being recorded. So once we've got that density is being is
83:43 weekly to velocity, velocity is related typically the age of the rock,
83:50 depth of burial, how old it . Just because as we bury a
83:55 and compress it and let it It just gets brittle and rickety and
84:01 and Bridget. And then there's relations mud rock line or the Castano
84:09 which just says that shear wave velocity typically linearly related to p wave
84:16 These are all empirical background relationships that just generally true. What we're often
84:25 for is actually when they're not true excursions or anomalies that we're often looking
84:35 . In other words, I'm often looking for average or background. I'm
84:40 for an accumulation. I'm looking for that's different than average, a little
84:45 different than average. But these averages us a ballpark cast. Okay,
84:52 plug some numbers in the game to a little exercise. So we said
85:02 Gardner's relationship from a lot of cross , just logs that were from the
85:07 , coast velocity, log a p log, a dead sea log.
85:14 cross plotted all those and came up this relationship. So we can say
85:27 according to the relationship Dere is .31 philosophy. The quarter power.
85:35 Suppose we made a measurement on the and it was 3000 m/s and we
85:42 have a density like. So I'm gonna look at What does Gardner
85:47 So if we plug 3000 m per and that, what does gardeners say
85:52 the density should be that get to a calculator in this one too?
86:10 , Okay. And so this question a little bit of a tricky
86:15 So Gardner says 2.3 and then we a measurement, we took a core
86:25 or We sniffed around and we actually a densely log later on. And
86:30 said 2.5 then what was our So 23 five. Yeah, I
86:49 remember. Well, in fact you do it either way really, you
86:55 say the error from actual or the from approximated. So you could pick
87:04 two. So yeah. So Gardner this case gave 2.3. The error
87:27 about .2 And that's just under So this is just really to to
87:37 the mechanics again and twist it slightly . So, and you might say
87:42 this case Gardner was an empirical I didn't know anything about density when
87:46 started, but I had velocity, predicted the density, guess what it
87:49 within 10%. Then I went out I Did some more work and I
87:54 a density log and it was not , but it was wrong by 8%
87:59 9%. So that's one of the that we would do with the empirical
88:09 . And then another thing that we're just again, if I had the
88:13 time here at a certain level and density here and I cross plot
88:21 Then I can determine what kind of it is and maybe even what porosity
88:26 is. And this is what all the application codes would do with
88:35 J if you said, look, gonna pay for my little log.
88:40 you made all these measurements you've logged , but I'm really lazy this
88:44 So you guys figured out and tell what kind of rock it is and
88:47 its porosity is, then it will plotted out and it's going to use
88:51 like this to do that. so now we know a little bit
89:02 about the density log and there's another that's derived from this and this came
89:13 the physics, depending on how energetic gamma rays are. They have these
89:21 processes. We talked about compton scattering a little bit of the photo electric
89:25 , so if they're really, really , they're gonna scatter if they're not
89:28 energetic, they might get absorbed. it depends a little bit this log
89:33 uses both. It uses both mechanisms so when we look at absorption we
89:43 calculate something and it's called a photo effect log and it depends on the
89:49 type. And so from that gamma injection, the density tool we get
90:00 numbers, we get the bulk density we just get this photo electric factor
90:06 maps to rock tape. So photo factor is just another gamma ray absorption
90:13 but we can make a log out it. And so that's done.
90:16 called the pf log. The photo factor log and it maps to certain
90:21 tapes origin role B Yeah, that's . Okay, so but it it
90:40 at a good point all the logging use some kind of acronym or short
90:47 . So roby is typically row b buck density but you've got to write
90:53 out because most of the, most the systems aren't going to have that
90:59 , that's a row font. So just write it out in english.
91:04 roby is just both density. That's it. Yeah. But incidentally the
91:12 these acronyms Pf, what's P. . You know, it's a I
91:18 know what it is but so you're actually look it up. And the
91:22 companies have pages of short farms and . So some of the ones that
91:28 obvious PF is not obvious but it's photoelectric effect. Uh D.
91:35 Cole delta T compression. But each might have a slightly different. They
91:42 some might call it D. P. Or whatever. So you
91:46 have to look it up. Well that's a quick aspect of the
91:55 we can get out of the gamma or density log. It's called gamma
92:01 because I'm going to inject the gamma and I'm going to record a gamma
92:05 gamma gamma And depending on the energy the gamma ray that comes from different
92:18 effects. And those different physics are on different aspects of the atom or
92:23 element. And so I can get map of that element to what I'm
92:30 and then that's the law. All logs have to be interpreted somehow.
92:36 . Okay, so the other really standard log is the neutron log and
92:42 is using another kind of physics. this gets another active source and instead
92:47 cesium. Now we're using hammer worrisome and this guy radiates neutrons. He
92:57 neutrons. And so the neutrons propagates the formation and they bash into the
93:05 and the rock emits gamma rays and we count the gamma rays a
93:13 So how does this work? You remember from first year physics if we
93:15 two billiard balls that are about the size and they collide, there's a
93:19 of transfer and energy. That's the transfer from 1 to the other.
93:25 they're the same size, if one huge and others not, it's just
93:30 bounce off. There isn't much energy or if one is enormous then ones
93:35 . It's just gonna walk right Not much energy. So it's the
93:40 kind of model when you put a through. What's the atom That's about
93:45 size of a neutron? Like So if I'm gonna if I've got a
93:57 here, which is pretty small, what element or what adam is about
94:04 size of just a neutron? like yeah. And what's what's a
94:14 proton? What's the name of a proton? What element is a single
94:21 hydrogen? Yeah. So if I'm neutrons through formation, the biggest energy
94:32 is when I hit hydrogen. So log is looking at the decrease in
95:00 , that's right. So if I've a lot of hydrogen between me and
95:07 detector, it's going to scatter all neutrons and I just don't get as
95:10 neutrons. So I don't count as gamma rays. So when I get
95:14 gamma ray council, when I get neutrons, it seems the interpretation here
95:20 that I've got a lot of So Okay. Yeah. Yeah.
95:41 when you think about hydrogen and you about simple compounds, what has hydrogen
95:47 it? Simple simple hates to it's got a lot of hydrogen in
95:58 . And what else has hydrogen? other simple thing of gas?
96:11 No. Well, we talked about gasses that have different amounts of
96:17 Different amounts of hydrogen, Like Methane is just CH four. So
96:24 has hydrogen then, you know, some other materials that have a little
96:38 of hydrogen in it. But If think of water, water is a
96:46 and so there's a lot of H20 that fluid. Methane has hydrogen in
96:54 , but it's a gas. So has if I've got a water here
97:00 then methane here. Who has more ? Yeah, by far because it's
97:08 fluid. So methane does have hydrogen it's very, very sparse. It's
97:14 gas. So the neutron logging tool counts neutron loss, which we infer
97:33 based on hydrogen content, which we is coming from water, which we
97:39 is filling the ferocity. So, I get very low neutron counts,
97:49 does that mean? Very low neutron a lot of hydrogen. I have
98:04 I have a lot of water, have a lot of porosity. So
98:09 is a straight map from neutron arrivals for all. So that's how it
98:37 Now. Um, if you were kind of an entry technician, you
98:47 say, I don't care. Just me the prostate lock. But you
98:52 , we want to know more than and we can actually use it because
98:57 give you a sonic calculation for We can do a density calculation for
99:04 . And now we've got a neutron for porosity and they're all going to
99:08 different. And so we have to why they're different. And then we
99:13 want to use that difference to for own benefit, for the benefit of
99:19 interpretation. Good. So, um one of the ways that we're gonna
99:33 that, this is jumping a bit . But let's let's look at this
99:43 , we can look at our classic . So the gamma ray is the
99:56 line. And now there's there's a here that goes from 0 to 1
100:07 . So that means that this line zero and this line is 1
100:11 That's where the plot is. sometimes if the radio activity got really
100:17 would go off the plot. So the way that they handle that
100:21 to have a wraparound. In other , if I see this, that
100:26 gamma ray is here and suppose it going off the plot, I could
100:31 it around and then I would go 1 25 to 50. This is
100:35 just another way to put more data one graph. So let's interpret this
100:54 . So we've got the gamma we're up here and the gamma rays
100:59 down. Okay, okay. The somewhat big. So this is kind
101:13 moderate gamma ray. I'm coming down and then all of a sudden it
101:19 big time. So we expect that you can see the interpretation here.
101:26 we've got sandstone goes back up once again you can actually see that
101:32 caliper gets less in the sandstone. was that again? Because yeah,
102:01 interpretation is that the wells like the fluid is going into a permeable
102:09 , its permeability. It's yeah, depositing including mud cake which actually makes
102:19 formation the the diameter of the world . Okay, so we're gonna have
102:41 talk about one other thing though before get this, Take a break.
102:54 , exercise time, take a little . So this is this meeting is
103:06 recorded. This is a fair amount stuff too to look at. So
103:17 good to just practice it. So let's do another case and we haven't
103:27 about all this but it's going to us into it. So if we
103:33 up here at this example. So is down 10,000 ft. So first
103:39 all we're gonna look at the units 10,004. Okay. So we go
103:50 to our trusted gamma ray, the line that and we can see the
103:58 ray is here here. So in this log analysis, one of the
104:11 things that we're looking for character and again this there are all these different
104:16 , but there's only it's only one . So when you look through this
104:21 if we were in the conventional we're typically looking for something that's
104:30 We're not looking for a shell. you want something clean. So is
104:38 you've got a little bit of help . But if you're looking down
104:40 what intervals are you going to Yeah. And like this is all
104:58 . And then down here at this this is all clean. Right?
105:08 in the way that we're gonna do analysis is again you this is already
105:13 for you. But the idea is pick the top and the base of
105:17 unit of interest. So were immediately in this guy because it's clean.
105:21 we'll pick the top and the base that's done in a then we come
105:25 . Okay, this all looks Oh, I like this. I'll
105:30 that as B then we're still coming and that looks pretty good. I'll
105:36 that whole thing and see and then further just in the base of the
105:41 ray, I'll pick all that So strictly on the basis of the
105:47 ray log we've picked some intervals of . Then we talked a little bit
105:58 the sp log, right about current and and so all these areas here
106:04 will come up the S. Is the solid line. So the
106:12 is there there so the sp. kind of mirroring what the gamma ray
106:26 has said. So why do you that is because hasn't been Garrels?
107:06 remember the sp log is really our log. So it's the voltage that
107:12 and the voltage develops because the brain the formation is different than the fresh
107:17 and the in the mud. So trying to equip great we've got a
107:23 salty formation, we've got a very water in the mud. So it's
107:27 to equal a break the salt and causes that's current flow so that's a
107:38 . It's like philosophy forward. So for right now we're just trying
107:46 really pick where their excursions are because trying to divide, we're trying to
107:54 the levels at this stage. But looking at the sp log we like
107:58 area. So I like A. that this log is helping me pick
108:02 . Because I'm saying there's an excursion there's permeability and then down at
108:08 Do I like be on the basis the sp log. Yeah I like
108:13 . And then this whole C. . Do I like it?
108:20 I guess I'm starting off because we and we like because like they're not
108:25 the line like all of a sudden see is like hugging it now.
108:30 it's because these are completely different This is gamma ray and this is
108:35 . So the and there's a little more here too. But this is
108:44 kicking hard but we like that because means that there's a very strong current
108:53 . There's a very strong voltage drop we interpreted as being very permeable.
109:07 we go down a bit further and get in D and we've got to
109:12 very nice current flow, very nice kick. So we like that unit
109:23 . So now the the gamma ray told us what low radio activity and
109:35 sp has told us that slower that is permeability. Okay, so we
109:45 all that. So both those curves into why we picked these areas of
109:50 . There were two drivers for, interested in a were interested in
109:56 We're interested to see and where it's to be. Why am I not
110:00 in this area? This is this not like big chunks. Yeah.
110:12 there's no there's some but there's no interval in here that's sandy and
110:18 So I'm just not as crazy about . It's not that interesting. So
110:27 we've talked a little bit about the and N. five. What's that
110:34 ? This gets back to your roby robe And five. What's 5?
110:48 . So this. Yeah. So fair enough. So that's the
110:52 porosity calculated. And here's the neutron and we get a little indicator of
111:00 these guys think they calibrated those logs remember they had, we had to
111:08 what kind of rock it was. what did they tell you what it
111:12 ? And then what's 2.65? Why that there? That's right,
111:18 that's the density of court. So could have said sad, but they
111:22 said this is the number we put there. Okay, and that goes
111:28 zero porosity to 50% porosity from So now assuming that it is a
111:40 and assuming that it's brian saturated, logs should agree with each other.
111:49 in a lot of areas there, sort of do agree with each
111:54 But let's look at a the density is a little bit lower than the
112:04 porosity. So is that gas density lower. No, we said that
112:15 was the other way around. We . So this porosity is low,
112:26 can see it's pretty low porosity. this interval is low porosity. So
112:39 we interested low porosity not we're not interested because we want volumes. Now
113:10 come down here and we were interested this area. But now I see
113:17 the neutron says really low porosity, the density, This is very high
113:28 . Yeah. So you can see we went from the neutron porosity being
113:40 bit higher than the density porosity, is kind of normal. We went
113:46 the other way And this isn't a a little bit. You can see
113:50 , you can see the neutron porosity and the density porosity is here.
113:55 is these are 30% different. So did we say would cause that?
114:11 , let's see who's picking up on , gas. So the neutron is
114:25 , hey, I don't see much because I'm not seeing much hydrogen.
114:30 density is saying in the bulk Hey, this thing is getting really
114:34 density. So this is a huge . So that is our flag that
114:41 could be gas. Now, we talked about it yet. But here
114:49 the resistive. Itty logs on this . So we can see that the
114:57 . Itty goes crazy. The resistance getting extremely high. So from what
115:03 know, what did we say about is brian resistive. Yeah, brian
115:10 very conductive. Okay, so it's resistant. It's organic, there's nothing
115:19 about it. It's very resistant. when I saturate a formation with
115:23 does it become resistive extremely. When saturated with gas, does it become
115:32 ? Why not? Three? wait, it's um sometimes this is
115:51 sound good, but sometimes I mix gas because I think of gasoline.
115:58 I don't think of it as like gas? That's fair enough. Call
116:06 methane. But the thing is it's than methane. Yeah, yeah.
116:14 don't think of gasoline. Let me it this way. So natural
116:20 so it is natural gas, no natural gas, there's nothing
116:32 there's nothing electrical of natural gas. if I put natural gas in the
116:39 , do I expect the formation to resistive? Yes, very. So
116:45 you go. We had clean we had permeable, we have a
116:59 major difference which is our gas indicator huge resistive itty in this permeable
117:07 So what do you think? yeah, big time. So
117:16 very, very very gassy. Okay, so let's go down here
117:28 we're getting good at this stuff. let's look at C and C
117:34 So do we like this interval just these guys, do we like the
117:37 to start off with? Yeah, like it, it's clean and it's
117:45 . So I go over here and see this is kind of weird because
117:50 this whole formation, it looks kind uniform, but if I go over
117:56 there's a crossover in the top and overlay of the log across the logs
118:01 the bottom. So what do you ? Perfect overlay here. What's that
118:19 ? It means that all the assumptions made with these prostate locks are
118:24 And what did we assume, What the assumption number one that it was
118:30 and numbered. Foots the saturation. via the assumption that it's bright.
118:42 that's the assumption. So our proxy being bang on that is an indicator
118:48 us that these logs agree and they because it's sand and brian saturated because
118:56 how I did it. So it to me like this is a brian
119:00 sand but this is weird. There's cross over here. And what's the
119:08 an indicator of? Yeah, of kind in particular? No, this
119:17 the same as that. Oh so yeah. So does it make sense
119:27 have gas on top of brian? , gas is gonna float. So
119:47 interpretation here. So that's that's some the porosity logs. Now we haven't
119:52 about this yet but here's a resistive log. And this resisted the logs
120:01 deep into the formation. So when look deep into the formation down here
120:06 resistive. Itty is extremely low and the resistive it is very low.
120:11 do I think the saturation is? well low resistive. Itty city is
120:42 what's resistive et game, this is . Remember it's conductive. Oh that's
120:50 actually let's see yeah. So this low resistive Itty or high conductivity.
120:57 this means if it's low resistive. high conductivity, it means it's
121:02 It's conducted. But then I've got unit again and I go up and
121:08 of a sudden it becomes high Itty same unit. What's that?
121:15 I had low resistive it and then went into high resistive. Itty
121:27 Yeah right here gas. Oh this gas too. So our interpretation of
121:34 is really simple. We've got this sandstone, it's permeable. The bottom
121:38 is full of brine. And then got gas sitting on top of
121:43 So that's classic. This is the example of a gas reservoir. Gas
121:53 sitting on top of brian in a sandstorm. Then let's look at this
122:21 . So we saw that the gamma has a nice excursion, the sp
122:31 some excursion. So it looks like little bit of permeability. But when
122:39 look over here, what does this me about the porosity. Very very
122:45 porosity. So that's there. So we like d probably not. It's
122:55 low porosity. So even if I some hydrocarbon, there's not much of
122:59 and it doesn't doesn't look very So then I come down to deep
123:07 and the porosity ease agree. So does that look like? It looks
123:17 brian saturation. And if I look the deep resistive. Itty the deep
123:24 . Itty for that whole unit is low. So does that conflict or
123:30 that confirm our interpretation. It does resistive. Itty here means that I've
123:38 brian and it's conductive, it's low . Itty. So we don't like
123:43 . We're looking for high register. that that's sort of where I wanted
123:53 get you in terms of this basic analysis. Because if you understand
124:01 then you kind of understand all the log analysis. These are basic logs
124:07 kind of reservoirs were looking for and you can pick them and then go
124:12 there. Now we just to finish , we didn't, I jumped you
124:17 resistive it because it's just kind of to look ahead and eat dessert
124:20 But yeah, that's a lot of . So that is that's pretty much
124:29 you need, the basics of everything need to know in conventional log
124:34 one more question. One more why do we not like ferocity?
124:46 like, okay, so we're saying ferocity. Tell us again, well
124:51 tell me what what what does porosity ? That's right. So do you
124:58 $5 in your bank or 5000? . So if I've got low
125:06 it means I can't have very much in there. And if I've got
125:10 fluid, I've got low money, I've got big ferocity, then I
125:15 fill it up full of oil and got big volumes and volume times
125:24 times dollars. So when you're thinking this, I needed that make analogy
125:47 amount of money you have is directly to the ferocity ferocity is the price
125:52 oil per barrel. So mhm You think of that as straight
126:04 that's, I want big body. , it really is. It's like
126:13 I have $1 in the bank or . Yeah. So I want a
126:19 volume and if I've got a certain of rock and I've got 10%
126:29 Okay, that's a 30%. Always for that. Yeah, that's
126:46 Yeah, because now and that's great you want to slam dunk and whatever
126:51 is for your brain, like instead memorize stuff, remember rise, what
126:57 the most common elements in the earth's ? Well, wait, no,
127:05 most common elements in the earth's It's um it's a granite. Oh
127:22 God, I was literally just talking this with somebody the other day well
127:29 I wouldn't remember either, but uh elements, it's oxygen, silicon and
127:37 . So how do I say? as I said, I can't remember
127:41 normally. But as a kid, favorite lake for canoeing was the Ontario
127:48 of Artists. Like it was called . S. A lake. And
127:52 boom, I'll never forget os a . And that all I have to
127:56 is remember that. That's oxygen, and aluminum. And there you've got
128:02 obscure fact, those are the three elements to there's crust and it's like
128:09 or anything else. So whatever whatever need to do to attach something you
128:14 remember to something you're not gonna that's that's so if you've ever
128:19 I went once to a memory training and it was how to memorize people's
128:25 and they use a technique that's sort similar. It's not really a nice
128:30 , but you look at the they tell you their name and then
128:36 do what's called a psychological snap. attach something really bizarre to that person
128:42 the name and it helps you So Kevin has a giant nos que
129:00 , okay, the bad part about is is that you, that's how
129:05 do it. But then every time look at Kevin, I'm thinking,
129:07 my God, your nose and that's K. Knows and you know
129:12 I guess what it works and Kevin have to know what I'm thinking of
129:16 knows, you just remember, you remember my name, Thank
129:20 So, but it's it's kind of same thing right now, whatever you
129:24 for that snap and everybody understands money typically we want more of it.
129:32 it's it's a good snap and and that's perfect because ultimately why does the
129:38 care about porosity? That's the So, you know, especially the
129:48 , you're you're teaching this stuff and all these kind of things and people
129:51 kind of get away from why are doing this? Well somebody's got to
129:58 some money out of this somewhere or do you know what, maybe
130:05 maybe my daughter my niece is actually and It's $20,000 a year for the
130:13 that As one of my nieces So so you know what guess
130:19 I am motivated to make that $20,000 year more. That's the way it
130:27 . So yeah, I I Whatever, whatever the motivation is then
130:31 good. Okay, so these resisted logs. We just looked at
130:35 It's uh there's some nice physics they're in two ways. One of the
130:38 you can make your resisted the log it's unbelievable this even works. But
130:44 can have a transmitter. So this the end of the tool, this
130:47 in the well we can have the and we send an alternating current through
130:53 transmitter. And you probably remember from back if we've got an alternating current
131:00 a loop that generates a magnetic So that's what happens. So in
131:08 tool it has an alternating current in coil and that generates a magnetic field
131:14 oscillating in the formation. Now the thing happens. So now I've got
131:27 oscillating field magnetic field in the And so that induces I've got an
131:39 oscillating magnetic field and that induces a current in the formation, that loop
131:48 is feeling the resistive Itty of the . And that's where the measurements made
131:53 I've got a current going around in formation that is sensing how resistive the
132:01 is. You know, if it's it's in a brine then there's going
132:06 be a lot of current flowing If it's in a water saturated these
132:15 a non porous area, it's gonna resistant. But the bizarre thing
132:20 so now I've got this current that's around in the formation, but we
132:24 that if a current is oscillating in formation, what does it generate another
132:33 field? And it does. So loop current in the formation generates its
132:40 magnetic field and we're gonna sense that another coil, it's incredible that this
132:50 , but it does. So that's it's called a dual or a two
132:56 tool because we induce a magnetic field that causes a current. This current
133:03 a secondary magnetic field. That magnetic can cause a current in my receiving
133:11 and ultimately the size of the current here is related to the resistance of
133:19 formation. And so this is called dual induction resistive Itty tool. And
133:27 again, the ultimate output is just resistance of the formation. That's what
133:32 does. And so you can't see . But there are those coils inside
133:36 . This is my dual induction Okay, I'm gonna skip through
133:42 Um So ultimately this is what we now. I can I can space
133:53 coils apart a long way and that that the loop and the magnetic fields
134:01 deep inside the formation Or I could those coils really close together and that
134:07 that the resistive it is from very . So one is called a shallow
134:13 deep depending on how far apart the are and how deeply we go into
134:18 formation. So I've got the shallow the shallow focus log atmospherically focused log
134:26 is very very shallow like an inch two into the formation. And then
134:30 got the induction log deep I. . D. This is the deep
134:37 and you can see that they're often similar. Most well logging tools give
134:47 these three tracks. They give you very shallow track, shallow resistive.
134:51 right close to the border wall. usually going to have been invaded.
134:57 there's a medium one that might be two ft away and then there's a
135:01 one that might be a number of deep in the for information. So
135:06 interpret the deep log as the un virgin completely natural formation. The shallow
135:18 , we interpret it as having been with the drilling mud. It's pushed
135:27 out. So what we're measuring there really the drilling mud resistive. How
135:32 you feeling? Um Yeah just depending bit on how conductive the formations are
135:47 normally we would be thinking that the one is maybe I don't know five
135:50 six ft into the formation. The one. You're thinking an inch or
135:59 and then the medium one is is feet. So you can see that
136:05 . They agree. However, how the drilling mud gets into the formation
136:14 on its permeability and porosity. How fluid can I put in there?
136:18 you can see down here uh The ITty measured here in the shallow area
136:31 high in the deep area. The Itty is low. So what did
136:39 say? Low resistive Itty was And what did we say? Hi
136:46 Itty was oil or fresh water. we remember that the mud that we're
136:55 with on land is freshwater mud. it has a high resistive itty.
137:01 does this make sense that the shallow shallow rock should have high resistive
137:08 The deep rock has low resistive Yeah, this is a classic invaded
137:17 . So the invasion has gone a of inches. I measured that it's
137:22 mud. It's high resistive, be . I go into the formation deep
137:27 touched it, It's full of brine a little resistance. So here's the
137:33 signature. We have permeability. The log says we got its permeable.
137:41 sand drilling mud invaded. The deep is all bright. So if you
137:55 to look here for example and you see that there's sand. This is
138:06 this sp log as well as the . So we've got this interval right
138:13 is sandy. It's got a nice kick, We like that and both
138:23 show very high resistive itty. So interpretation is it's an oil saturated
138:37 Let's look up here. The P log is telling us that it's
138:44 . We've got a nice voltage Then we look over here the shallow
138:53 Itty is fairly high. Then the resistive itty is high, then goes
139:04 . Classic brian Haider. Okay, that's that's a fair amount for you
139:37 think about. So tomorrow. let's let's wrap it up. But
139:44 we can go into started on You can go through and just
139:59 just check that you understand. Just a little bit more about,
140:13 That's where I will go through this . Right? In terms of a
140:18 look before the same thing, how right sp gets So, Okay,
140:37 years. Any little any questions No, I just well, there's
140:54 really in all the well logs, 100 years of the physics because everything
141:01 used all the way from linear accelerators electrical methods to sonic. And then
141:07 applied, we're trying to get all very profound physics techniques and apply them
141:15 a very practical purpose. Finding some and there's a lot of that.
141:28 , good. Hello? Yeah. , well, yeah, we'll go
141:37 . What's the story If you have questions then uh let me know and
141:44 we'll go through the log analysis, how far we get tomorrow. And
141:52 in the VSP and a little bit
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