| 00:00 | Did it in class. You got grade for the quiz that had class |
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| 00:09 | and three where we had to OK. I took a point off |
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| 00:14 | class three was not as flat as wanted it to, to show, |
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| 00:18 | emphasize. Unfortunately, it was not my notes the way I thought it |
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| 00:25 | , it's in the notes. It's the class that I'm giving today. |
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| 00:31 | classes I gave this, I gave lecture and then gave him the quiz |
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| 00:37 | again. But you were, you have benefits of this lecture. So |
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| 00:42 | gave everybody a point for the class , flattening that I took off |
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| 00:48 | So give it that, that makes a plus so far. OK. |
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| 00:55 | . Ready. Oh, yeah. . Is there any questions you might |
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| 01:00 | ? Right? Is that a somebody OK. Ready. And any |
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| 01:09 | participation questions in here? Oh, got uh everybody in the audience. |
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| 01:19 | . I have seven here but I have six. Yeah, but they |
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| 01:28 | giving Stephanie, she won't be So is that the only person we |
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| 01:34 | missing then Stephanie in here? I think he's, he's gone to |
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| 01:44 | day. Yeah, because they asked the quizzes beforehand. Ok. |
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| 01:50 | uh, let's see how disastrous I be in trying to get this slide |
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| 01:58 | . Huh? We're gonna try. , ok. Let me see, |
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| 02:34 | , back to the Zoom and I to go to share it, share |
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| 02:39 | screen. So. Oh, I see. Ok. Can you |
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| 02:48 | the slides out there in Wonderland? . OK. Classification of Avion anomalies |
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| 03:12 | 19 seventies, we had a technology bright spots. Does that relate to |
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| 03:16 | VO are common midpoint gathers necessary for spot regimes? Should we request asses |
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| 03:25 | to depth for new seismic acquisition is easy to determine for a particular A |
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| 03:34 | class. Oh We're skipping over 35 that's the same as 23. It |
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| 03:47 | uh I wanted to have the amplitudes both places and I did not give |
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| 03:56 | section either. I skipped over it . Uh 35 is a lot of |
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| 04:03 | and as I said, just showing equations for the anisotropy. Basically just |
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| 04:10 | of it this way. When you anisotropy, you have different equations for |
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| 04:14 | A bo it means that whatever angle shooting. If you're shooting, if |
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| 04:21 | reflection angle changes, then so does amplitude that no longer obeys Zage, |
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| 04:30 | obeys it halfway and you have to another term to the equation. And |
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| 04:36 | if the asthma enters in it In words, if you're source and receiver |
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| 04:42 | both in a north plain, a south plain, that's gonna be different |
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| 04:49 | if your source and receiver are in east west plane vertical plane. So |
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| 04:56 | adds another term to the reflection And it introduces 2 to 4 more |
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| 05:07 | besides velocities. WW. When you done it, it, it, |
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| 05:13 | all the anisotropy, there is nine you have right now. we think |
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| 05:21 | P wave velocity, shear wave velocity density as the parameters that describe the |
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| 05:28 | . But when you put in a M, you have to have two |
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| 05:32 | wave velocities, two shear wave It adds up to be nine different |
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| 05:39 | and only a few people really work that because the processing is exceptionally difficult |
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| 05:53 | it's also very noisy. You have have exceptionally good quality data where you |
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| 06:01 | it. It's usually the poorest data might need it in Saudi Arabia or |
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| 06:07 | like that. And you got the seismic data you can imagine West Texas |
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| 06:11 | it badly and they have awful seismic because up shallow in West Texas, |
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| 06:19 | have the castile evaporates and then they into a really soft section and because |
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| 06:27 | that large velocity inversion of shallow, got noise coming everywhere. OK. |
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| 06:37 | look at a VO cla classification just show you that I like to be |
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| 06:44 | hoarder of all things. This is book that was given everybody in 1973 |
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| 06:53 | was held at Exxon's Auditorium and it's lithology and direct detection of hydrocarbons using |
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| 07:02 | methods. 1973. Well, this also called the Bright Spot here. |
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| 07:11 | the DD I direct detection indicator. was at Mobile and in 1969 this |
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| 07:22 | came to Mobile and I don't know exactly at Mobile did it uh brought |
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| 07:28 | over, but shell said they had in the 19 sixties, 1966 they |
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| 07:35 | using it. It's a pretty significant basically what it is in the Gulf |
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| 07:46 | Mexico. Let's take there when you're for gas reserves, you get a |
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| 07:52 | big high amplitude. I mean, , it's gonna rip right through your |
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| 07:56 | section. That was the bright spot so bright spots became synonymous with gas |
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| 08:06 | . I was at Mobile and so had it for about three years and |
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| 08:14 | thought, well, I'll go to symposium but I know everything. All |
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| 08:19 | . I mean, we have one of the first ones and I |
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| 08:24 | to the symposium and lo and I thought we were above most of |
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| 08:29 | folks surely in the United States. we found out that Russia had done |
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| 08:37 | years before us, there were seven that were translated, there's six of |
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| 08:45 | and it shows that they had to it at least five or six years |
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| 08:50 | these published papers. And us, published anything yet. Then I got |
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| 08:56 | thinking, yeah, but we have called four D. You ever hear |
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| 09:02 | expression four D, four D means , you go out and shoot a |
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| 09:08 | survey. You're successful, you get big field and it's big and |
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| 09:15 | you start training it. Then after six years you wanna know, |
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| 09:22 | how much is left in there. you shoot another 3d survey and you |
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| 09:30 | your current 3D to the previous which was your baseline that's called four |
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| 09:38 | because you had that. So, I, I thought us was the |
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| 09:43 | one to do that. And in was a Russian paper in his |
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| 09:48 | how they used it every year, they did as they had salt dos |
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| 09:55 | they filled the salt domes full of during the summer. And then during |
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| 10:00 | winter, they go ahead and drain salt domes to use as, as |
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| 10:06 | as they needed. In about they would shoot a two D line |
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| 10:13 | the Saldo to see what was the of the gas remaining in the sal |
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| 10:19 | . And so every year they did . And I thought my gosh, |
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| 10:23 | pure application of four D, it was a two D series but |
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| 10:30 | a beautiful application way before the United . So Russia had a lot, |
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| 10:37 | brilliant technology. They just didn't have equipment to go along with it |
|
| 10:43 | to give you an idea. Has been here of logging? Logging a |
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| 10:48 | , is everybody ever been associated with ? Any mud loggers in the group |
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| 10:54 | , somebody collects samples. One of problems that Russia had for a long |
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| 11:01 | is determining the stretch that was on cable that they put into the |
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| 11:07 | If they have something that's 4 m , that's a big damn cable. |
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| 11:12 | gonna stretch the wire. How much it stretch? Well, it could |
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| 11:17 | 30 ft, you know, something that. Well, you're, if |
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| 11:22 | trying to predict what depths the drill that, you gotta know close to |
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| 11:28 | plus run is 30 ft. So is where something can be that you |
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| 11:33 | believe, to make sure they didn't a target. They cleared the, |
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| 11:39 | , sometimes the whole, well, would core, that's what Hungary did |
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| 11:44 | years because the Russian technology was in . But computer room, their computer |
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| 11:53 | were terrible compared to what United States in very small counties. But the |
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| 11:59 | were educated beyond. Ok. Enough Great Russia. Here's the birth of |
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| 12:05 | bright spot here. You see a section and they have on it, |
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| 12:10 | called an automatic gain control, a where they bring in the seismic duration |
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| 12:16 | try to make the amplitude average over certain window the same, take the |
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| 12:22 | MS value and just keep on making . So every window has the same |
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| 12:27 | this is what you get with a automatic gain control. Now you take |
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| 12:33 | off and you process the seismic you get this. Now, where |
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| 12:38 | you drill? Well, obviously this where you would drill. It |
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| 12:45 | Now companies, when they recorded when he first started analog, they |
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| 12:52 | an automatic gain control. Remember all had is paper records. They didn't |
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| 12:58 | have tape. So what they put that paper record and it was a |
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| 13:04 | record. These had a light beam across it and that's all how you |
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| 13:08 | your seismic trace. They had eight beams going across wiggling as the electricity |
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| 13:16 | in. So they had to have A GC auto game control. Then |
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| 13:23 | start getting tapes, magnetic tapes, digital, still a animal. They |
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| 13:31 | what they call program game. they could predict the gain that they |
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| 13:35 | on there. OK. Enough of . So what was the technology? |
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| 13:44 | spot technology, hydrocarbon indicators, We call them Hcis hydrocarbon HC indicator |
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| 13:53 | brought the technology direct detection indicators. I and those of us who uh |
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| 14:00 | had had the bright spot thesis oh, this is just the BS |
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| 14:05 | . OK. I saw one Yeah. All right. Leave it |
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| 14:18 | that. And to an extent it the presence of gas and to a |
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| 14:23 | extent oil, oil with a high , oil ratio will change the reflection |
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| 14:30 | significantly how the carbon indicators are lateral vertical changes in reflection continuity. There |
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| 14:40 | auxiliary measurements or observations that indicate the or absence of hydro drugs. They're |
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| 14:48 | only they're not absolute proof significant when several indicators are present. So for |
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| 14:58 | , if you got a bright spot your seismic data, how about the |
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| 15:03 | beneath it? Should they be a dimmer? And what if you had |
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| 15:07 | flat reflection, you know, it's all over the place and you get |
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| 15:12 | bright spot above it. Why is bright spot? Oh The velocity got |
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| 15:16 | because you put gas instead of But what would that do? It |
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| 15:21 | the reflectors beneath it down a little ? So you see a little |
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| 15:26 | a little, I should say a , a little small section that became |
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| 15:33 | down underneath. Here's the bright If you look at this right |
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| 15:43 | that's something you could see. it's an anomaly. That's an |
|
| 15:49 | Now, if you come up here put your nose to the screen and |
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| 15:53 | look sideways down the screen, you see that right here pretty flat. |
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| 16:02 | fact, this, this almost intersects top. So there are two |
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| 16:09 | two peaks, 12 and the bottom tends to come across an intersect way |
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| 16:18 | here. This bottom limb is a face. It's a gas to water |
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| 16:28 | . It's not a boundary from sand shale. It's a fluid upon fluid |
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| 16:33 | is a big seismic indicator. Also hydrocarbons. It says you got a |
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| 16:40 | surface. Why do you got a surface? Because gas and water have |
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| 16:45 | different density gravity will make them settle to one flat surface. Gas above |
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| 16:52 | below water below one or the Notice right underneath here, this right |
|
| 17:01 | there is the double depositional model. in the Gulf of Mexico. Anybody |
|
| 17:11 | cinema in college here, anybody took sections? Nobody, Tessa can I |
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| 17:19 | you? We, we keep we keep our face on so we |
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| 17:25 | sure everybody's still awake. See if , I have to scream and we |
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| 17:31 | it likewise. Also, please. you. Has anybody taken cinema |
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| 17:38 | Tessa has, she's Tessa has taken the courses in college. You know |
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| 17:43 | the only anyone, everybody else is hide their face because they don't wanna |
|
| 17:47 | asked. OK. What is the depositional model and sediment sema? Isn't |
|
| 17:53 | one where if you have a gas , you always have another sand just |
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| 17:57 | the, the same size. It's double depositional model. You always have |
|
| 18:03 | G in it. Didn't you ever that or is this another one of |
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| 18:10 | black magic tricks that Fred's played? think it's a black magic trick then |
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| 18:17 | is this? Because you see this and over again from the seismic data |
|
| 18:22 | the 19 sixties and 19 seventies. it is? It's a function of |
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| 18:31 | air gun going off and leaving a , an air gun when it is |
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| 18:42 | as a big pulse and then the starts to grow and then the bubble |
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| 18:51 | and there's another pulse, the distance the original explosion to where the bubble |
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| 18:58 | up and collapses. That's a function how much pressure you have in the |
|
| 19:04 | . When the air gun goes it's a function of how deep the |
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| 19:08 | gun is, is flowing. How they get rid of it? |
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| 19:15 | this has 200 cubic inches in but they also have another air gun |
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| 19:22 | goes off and it only has 50 inches. So its bubble does not |
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| 19:30 | in at the same time, but original shot comes in at the same |
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| 19:35 | . And when you add all those guns together, it kind of gets |
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| 19:39 | of the bubble right here. that was a later type of |
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| 19:47 | various size of chambers. So the come in differently and you know, |
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| 19:53 | 20 air guns maybe being out That's a lot of air guns. |
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| 19:58 | originally those air guns were very expensive only one person had them bull and |
|
| 20:04 | charged an arm and a leg and sued you in court if you try |
|
| 20:09 | make, make any. They also , I think I showed you one |
|
| 20:17 | cages where you could explode gas inside metal cage. And it would have |
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| 20:25 | bubble as the explosions going off. the cage, which had a lot |
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| 20:30 | holes in it who let the air but dispersed it. So it never |
|
| 20:36 | a bubble. And that was one . But at the same time, |
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| 20:41 | heard many stories about the cage, get away from the, the Gulf |
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| 20:46 | Mexico going across, say the Atlantic their site and all of a sudden |
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| 20:52 | can't get any reflections, the amount energy just seemed to decrease. What |
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| 20:58 | they do? They said bring that gun, bring that cage back, |
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| 21:03 | it on board the ship, take cage off, just explode it. |
|
| 21:06 | leave it live with the bubble. gotta have some energy out there and |
|
| 21:11 | of a sudden you get reflections but get the bubble when you see the |
|
| 21:16 | down here, look up here. right there. There's another bubble a |
|
| 21:21 | smaller though, have to, that's bright spots you would notice that. |
|
| 21:27 | when you're interpreting the data, then of a sudden they find out |
|
| 21:33 | there were bright spots where they were to come. Here's a well that |
|
| 21:38 | driven and the amplitude decreases. What that? That's a carbonate play and |
|
| 21:44 | get fractured and the velocity get gets little lower and all of a sudden |
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| 21:50 | velocity between slow here to the fast gets even slower. So you don't |
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| 21:58 | as big as a plus reflection. decreases here. That was the |
|
| 22:04 | And then there were, there were areas where I'm thankful that the author |
|
| 22:11 | I copied this from, put a around this because if you look very |
|
| 22:17 | , you'll see the peak just above rib goes into a trough over |
|
| 22:26 | It's a phase reversal where here's the response and here's the gas, this |
|
| 22:35 | called the phase reversal. And then course, this is a beautiful one |
|
| 22:39 | had to put in literature. It a gas signature and you can see |
|
| 22:46 | interface between gas above and water below look how comes straight over and where |
|
| 22:53 | stops. That's kind of where the amplitude stops also. Now, that |
|
| 23:05 | 1973. And in that discussion, was a gentleman by the name of |
|
| 23:14 | forget is his name Paige. page showed these two sections and he |
|
| 23:24 | , why? And basically it was the audience, why is it that |
|
| 23:30 | noticed on my far offset sections, can see the gas a lot better |
|
| 23:37 | I can on my near offset. never gave an answer that related |
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| 23:45 | Yes, he related it to, , there's a bigger array effect and |
|
| 23:51 | smoothing the response more on the far and that's why the amplitude decayed. |
|
| 23:57 | it really was the first I can in literature showing a vo that on |
|
| 24:03 | far offsets big angles of incidents, gonna get a writer's amplitude. So |
|
| 24:19 | seventies that was the bright spot And geophysicists always like to be quantitative |
|
| 24:29 | here's the way they went ahead and , categorized and classified their amplitude |
|
| 24:37 | This is an axis or plus as . This is the normal incidence, |
|
| 24:42 | dash line that doesn't divide us into quadrants, that dash line. It's |
|
| 24:49 | to show you this is zero We'll start up at the top when |
|
| 24:56 | blue, that indicates a water When you have paint, the gas |
|
| 25:03 | the size of it indicates the So we start off with a limestone |
|
| 25:13 | it has a fast velocity compared to shell right up. So when you |
|
| 25:20 | a little bit of gas in, a limestone velocity decreases. But it's |
|
| 25:27 | when you have shell over limestone, if you put gas in this right |
|
| 25:34 | , this acoustic competes is still gonna greater than this shield. So your |
|
| 25:39 | decreases, but it's still a plus . So we're above zero. It's |
|
| 25:44 | plus ample. Then I'm gonna get here at the bottom and then we'll |
|
| 25:48 | the middle. Then there's the bright . You have a plastic rock and |
|
| 25:54 | might be positive when you're wet, might be slightly negative when you're |
|
| 26:02 | Brine Phil. But you add gas kazoo, your amplitude goes way down |
|
| 26:10 | becomes bright, unconsolidated sands. When put gas in them, you really |
|
| 26:17 | their velocity depending upon, of your depth as we learned. |
|
| 26:24 | there's those that you put gas in , it's positive it becomes negative or |
|
| 26:34 | could be slightly positive. You put in it, it's still negative, |
|
| 26:39 | it isn't a bright spot. It very far on the far traces. |
|
| 26:44 | gets a high amplitude. So we're have to take a look at those |
|
| 26:49 | the high amplitude is a negative I got, I had a question |
|
| 26:56 | that. Uh Can you go back a second? So yeah, I |
|
| 27:02 | a little confused by this. I this is from your your paper and |
|
| 27:07 | was confused based off of this compared Rutherford's paper where I thought he was |
|
| 27:14 | the dim out was when a phase happens because basically you have the positive |
|
| 27:22 | that get erased by the negative amplitudes you have the phase reversal and you |
|
| 27:28 | it is it might thinking about right? Or good, good point |
|
| 27:34 | , good point. This is the normal incidents. Ah So yeah, |
|
| 27:40 | not shifting in incidents, you Yeah, you see on we had |
|
| 27:51 | but here we had the angle theta talking about only on this axis right |
|
| 27:59 | normal. So you start positive, can go like this. That's Rutherford |
|
| 28:05 | Williams, this is the negative the reversal. But ours, if I |
|
| 28:12 | , if I become gas charged, gonna move down, right? |
|
| 28:18 | Yeah. So incidence isn't changing at . It's just the fluid that is |
|
| 28:22 | , it's just the fluid right Yes. OK. Thank you. |
|
| 28:26 | question. So that was the 19 class that was a 1970 classification. |
|
| 28:35 | come to the 19 nineties and here the Rutherford Williams paper and in |
|
| 28:42 | they showed class one, class two class three. Class one. They |
|
| 28:49 | with a high impede in the When they put gas in it, |
|
| 28:54 | went toward negative plus two. Your incidence is right around zero small amplitude |
|
| 29:05 | it decreases also when you put gas it. In class three, it |
|
| 29:12 | a big negative on the normal incidence it decreases also when you add gas |
|
| 29:20 | it. Now, one of the that was kind of uh interesting uh |
|
| 29:29 | , Steve Rutherford uh was a well use in Geophysical Society and he actually |
|
| 29:36 | , I didn't call that class He said, I told, I |
|
| 29:40 | , and this is section one of paper. This is section two of |
|
| 29:43 | paper. This is section three. blames that on me now. But |
|
| 29:49 | will stick with in class 12 of ex excellent paper. I loved |
|
| 29:54 | No, this is great. And see on the x axis it has |
|
| 30:01 | angle except once again, geophysicists are . They don't tell you what is |
|
| 30:10 | wet response. What if the wet lied right on top of the gas |
|
| 30:17 | wouldn't give you any help. So always wanna know what happens. Oh |
|
| 30:22 | four also by uh Ag and So here are classes 12 and |
|
| 30:37 | Mm. And this time I have it's wet and also when it's gas |
|
| 30:47 | , wet and gas charge for class . And finally class three. |
|
| 30:55 | it's a little bit too much is here. So let's only go out |
|
| 31:00 | about 30 degrees and summer right around . This is where offset between the |
|
| 31:08 | and receiver equals depth. So let's that back like that and analyze |
|
| 31:17 | And this right here is gonna be the quiz. I could tell you |
|
| 31:25 | it's look at class 12 and The black is class one. The |
|
| 31:34 | curve is gas, the lower excuse me, the upper curve is |
|
| 31:40 | . The lower curve is gas on these. You always go lower |
|
| 31:48 | No, remember the word amplitude means or minus magnitude is plus. So |
|
| 32:00 | said when you go from what? high to carbon charge, you always |
|
| 32:07 | more negative amplitude. Good quiz But magnitude might change magnitude might increase |
|
| 32:19 | offset when you add gas because we going always downward on this chart. |
|
| 32:34 | do you notice that's different between all ? Tell me something that is |
|
| 32:41 | that shit different but obvious. There's lot of things in here that's very |
|
| 32:48 | . The first thing you, you had, you had an experience |
|
| 32:55 | this when I gave you a wet and gas. And I told you |
|
| 33:02 | the simple Avio equation and compute the is four or five offsets every five |
|
| 33:11 | 10 degrees and draw, draw the and you did that day one. |
|
| 33:16 | , and what did you get? , here's what I found out, |
|
| 33:20 | , I found out the wet response always above the gas. Yeah. |
|
| 33:26 | else did you see? Oh, zero, right around a normal |
|
| 33:31 | It's a flat curve on everything. coefficient doesn't change quickly around theta equals |
|
| 33:39 | . That means something. I when you're analyzing the data, oh |
|
| 33:46 | gosh, the wet and a they have parallel shapes. I bet |
|
| 33:54 | gonna be worth 10 points on the . I bet it is too because |
|
| 34:00 | about it if I gave you the shape for what? Listen carefully. |
|
| 34:08 | gave you the A O shape for and I says now here's the gas |
|
| 34:14 | but I don't give you a of . I just give you the normal |
|
| 34:18 | value. All of a sudden you draw the A vo for the gas |
|
| 34:25 | . Why? Because it's same as we, you just have to shift |
|
| 34:29 | down. That's very important cause a of times you don't have a, |
|
| 34:37 | lot of information, especially if you out to evaluate a prospect and somebody |
|
| 34:43 | showing you something, you can quickly at that as curs see if they're |
|
| 34:49 | and if they're not, something's wrong , what you're trying to tell me |
|
| 34:55 | not correct. This is not a prospect. Well, the first thing |
|
| 35:00 | gonna see is this, the gas is the same as the wet, |
|
| 35:06 | it's more negative. The difference between gas and the wet. See that |
|
| 35:16 | right there. Now, look at same difference between the blue, the |
|
| 35:23 | between the wet at the top and gas at the bottom. It's bigger |
|
| 35:29 | class two. Then class one, you get to class three. That's |
|
| 35:35 | biggest. So you have more separation wet and gas as you go from |
|
| 35:42 | one to class three. What does tell you? I don't like class |
|
| 35:47 | . It's gonna be hard to see class three is gonna be easy to |
|
| 35:51 | because there's a big difference between wet gas makes it easy to see. |
|
| 36:00 | , that's nice. The A VO becomes flatter from class 1 to |
|
| 36:08 | So class one up here, you're dipping but look down here at class |
|
| 36:15 | , you're kind of flat sitting in . Ok, let me, let |
|
| 36:21 | write this down. I add three to somebody's great. I add three |
|
| 36:31 | right now. You make sure I it all you gotta tell me is |
|
| 36:37 | all the curves in class three flatter nose in class one. Who wants |
|
| 36:44 | get three points. Raise your Oh, we got somebody's hand up |
|
| 36:59 | in the audience. Can you see ? No, we don't have anybody's |
|
| 37:05 | . I just said that to get excited. Sometimes somebody of the audience |
|
| 37:11 | raised their hand. OK. Not going for three. I got |
|
| 37:22 | operating and they were going through, through going number. Oh, take |
|
| 37:24 | for four. Anybody want to go four. Anybody want four points. |
|
| 37:27 | want to challenge it. Four points I go five. What if I |
|
| 37:30 | give you an a no, I'm gonna do that. Anybody want to |
|
| 37:35 | it. Newton says he's gonna try and he says the hell, I |
|
| 37:40 | I didn't say that. Ok, can offer some suggestion. Anybody. |
|
| 37:50 | . Let me lead a little Then which one of these has the |
|
| 37:58 | velocity? Which one of these 12 or three involve larger velocities plus |
|
| 38:10 | class? That's good. Class Uh I said three. So maybe |
|
| 38:16 | was wrong. That's OK. I one. Why? Why? |
|
| 38:25 | let's, let's think about it. during the rock physics, I said |
|
| 38:31 | you had a class, if you a rock that's around 8000 ft per |
|
| 38:38 | and you put gas in it, velocity drops. That was during the |
|
| 38:44 | an experiment, we said you add little bit of gas to unconsolidated rock |
|
| 38:51 | drops. But if you have a 18,000 ft per second and you had |
|
| 38:55 | to it, it just a, a little bit of draw, just |
|
| 38:58 | little bit. So the harder, consolidated the rock, the less it |
|
| 39:06 | on the poor float to change its . Consolidated hard rocks. They changed |
|
| 39:14 | velocity due to porosity fractures. It's unconsolidated rock that depends heavily on what's |
|
| 39:23 | the pores. So, up here class one, we have the consolidated |
|
| 39:31 | and they're a high velocity. Why is this dipping more? What |
|
| 39:45 | the dip? Well, Fred, a dip. So you ought to |
|
| 39:49 | everything. OK. I'll think of Reinhard Borel. Good old Reinhardt. |
|
| 39:58 | sat and we talked about him a bit and say what is so significant |
|
| 40:04 | Reinhardt's proxim Reinhardt? When you looked his approximation in amplitude section, his |
|
| 40:13 | term concerned fluids and only responded to . However, when we looked at |
|
| 40:22 | , the second term, it only to sheer away velocity. It says |
|
| 40:29 | larger the sheer wave velocity difference, larger the sheer wave velocity difference, |
|
| 40:37 | more you're going to change, the offset, the more that second term |
|
| 40:41 | gonna add. Now, what was sheer wave velocity of the shallow |
|
| 40:49 | Remember when we start looking at we said, hm, look at |
|
| 40:55 | , this sh this class three. we're looking at it, I said |
|
| 41:01 | looks like a fluid. It reacts a fluid, it has a low |
|
| 41:07 | wave velocity. There's not a large . So Don here we said those |
|
| 41:15 | , they act like a fluid, rocks do they have a low shear |
|
| 41:21 | velocity and therefore the differences in the wave blasi are gonna be small and |
|
| 41:28 | gonna have a flat curve. So have the high acoustic appearances below acoustic |
|
| 41:38 | on our curve ra where they fall flu discrimination resides in the normal |
|
| 41:49 | normal incident difference. Why do I that? How much is this upper |
|
| 41:57 | different from the lower curve? So I gave you the slope at any |
|
| 42:05 | towards you, just a slope, example, but the slope itself, |
|
| 42:11 | said you couldn't tell me if if it's a what or guess the |
|
| 42:16 | are the same. So that means slope doesn't give you, it's this |
|
| 42:22 | right up here where it's attached to normal in instances that tells us if |
|
| 42:28 | gas or if it's wet, that's big discriminator right there. The largest |
|
| 42:37 | that you're gonna get is on a three and I should say magnitude. |
|
| 42:45 | class three or two. What has largest magnitude? Uh which absolute value |
|
| 42:55 | gonna be the largest? It's gonna way out here for class two. |
|
| 43:00 | you're in an area that's class You see a big amplitude on the |
|
| 43:05 | offsets a big magnitude. I think most likely a hydro crop like that |
|
| 43:13 | here. You gonna say, oh , I'm gonna look for the slope |
|
| 43:21 | right here now. Oh, you're look at the difference between this and |
|
| 43:28 | fact is last night you remember that you read Michelle called stacked. That |
|
| 43:35 | one of the outputs that they They said look at the stack |
|
| 43:40 | That'll tell you what the fluid content . If you're in a class three |
|
| 43:47 | . How do we tell that? the interval? A lawsuit? I'll |
|
| 43:51 | you the range and I'll tell you you're in class three, here's the |
|
| 44:00 | . I, I have a quick going back to that last one. |
|
| 44:07 | class three, it looks like the and gas curves are not parallel. |
|
| 44:14 | that the case? Uh piggy picky? Yes. OK. But |
|
| 44:19 | , it's, they're not far OK. It's, if I, |
|
| 44:24 | you drew this, this is 2.6 that's three, you know that |
|
| 44:31 | you're not gonna really see it on data because you're within the air |
|
| 44:36 | Uh But see up here, there a big difference. Well, it's |
|
| 44:42 | related, always related to what happens the near trace. You're looking at |
|
| 44:50 | common midpoint gather and you're gonna see bright amplitude and this bright one not |
|
| 44:57 | , but you're not really. Oh , I got a big slope |
|
| 45:01 | A change it. No, you're big. You're big. But right |
|
| 45:07 | , that big is big because you're it against the trace that is at |
|
| 45:11 | offset and it's five times bigger. , that's what your eye sees |
|
| 45:18 | I look. Oh, I'm 4% . Uh That just doesn't click to |
|
| 45:24 | eye. All right. No, , thanks. Yeah, that's a |
|
| 45:28 | question about this. So you mentioned here uh but and is controlled by |
|
| 45:39 | source, right? So this, you say amplitude and if I tell |
|
| 45:50 | this, you're not gonna hold it be arrogant over anybody else now because |
|
| 45:54 | know more than they do. Just tease it, you can correct |
|
| 46:00 | . But when you say amplitude, means plus and minus exist, you |
|
| 46:07 | have a minus two and the plus , that's an amplitude difference. But |
|
| 46:13 | is the absolute value mag magnitude is an absolute value. So when you |
|
| 46:23 | you have a big magnitude on the of your data, it could be |
|
| 46:28 | negative reflection or it could be a reflection. But when you say a |
|
| 46:33 | amplitude, you're normally talking about a reflection, you're talking about being done |
|
| 46:41 | in a gas zone. OK? is the source energy, right? |
|
| 46:51 | OK, your amplitude comes from OK? It also comes from all |
|
| 47:02 | attenuation has to go through to reduce amplitude or magnitude amplitude is just a |
|
| 47:18 | that doesn't have to be related to . It could be an oscillation. |
|
| 47:27 | When you say that's a big that wave has a large amplitude, |
|
| 47:34 | actually you're going between trough and That's a magnitude. The amplitude would |
|
| 47:44 | . If you say that's a big , you don't say that in the |
|
| 47:48 | because you, you don't know where zero line is. But here on |
|
| 47:54 | data, we know where the zero is. You see this right |
|
| 48:05 | That's a big magnitude. Big Both. I mean that it's most |
|
| 48:16 | two oh OK. Over here, a plus value. That's a big |
|
| 48:37 | etude. That's a big magnitude over . You have a big magnitude but |
|
| 48:50 | smallest amplitude, that's the smallest amplitude you have because it's minus 0.3. |
|
| 49:03 | is only minus point 01, something that. If it is negative, |
|
| 49:15 | red lines are 1020 30 40 50 degrees. OK? Because why do |
|
| 49:28 | have notches in those angles? If have a velocity of 10 here and |
|
| 49:40 | velocity of seven here you come to boundary and you Google in like this |
|
| 49:48 | art like that. So the angle is 20. The angle here in |
|
| 49:58 | low velocity is five. If I back the angle here, what's it |
|
| 50:14 | ? Your angle was 20. But you get in the middle, it's |
|
| 50:19 | this right here, this right That's 0 1020. This is only |
|
| 50:30 | . The actual seismic you see the that you get right here is a |
|
| 50:38 | 1020 30 degrees, 30 degrees is the heck out there on that |
|
| 50:52 | This trace in here above you might 30 degrees. This is only gonna |
|
| 50:59 | 15 degrees. These are contour lines what they are. Oh my |
|
| 51:14 | Uh, you missed your break. go ahead. Take a break, |
|
| 51:18 | . About 10 minutes. I got minutes after nine. Let's come back |
|
| 51:23 | 25 minutes. Jo 10 those of that are in the same time |
|
| 51:39 | you probably didn't hear that because well, that's hard to see. |
|
| 51:56 | . It's time to start again. . I thought for sure Taylor was |
|
| 52:08 | to quiz me again and say you it wrong again. Fred. |
|
| 52:12 | I hate to have to correct you the time. Fred. OK. |
|
| 52:18 | did I get it wrong this Well, you taught us something about |
|
| 52:28 | black curves being parallel. Look at blue. You said these are |
|
| 52:34 | that's the class two, right? then I come on to the next |
|
| 52:40 | and I'm tell I'm telling you that curves have the same slope also and |
|
| 52:49 | seem seem right. Does it going to, to this curve, the |
|
| 52:57 | between the upper and the lower kind remains the same? And yet when |
|
| 53:06 | look here, uh the amplitudes are S oh my God, Fred. |
|
| 53:11 | crazy man here. It looks like , they're the same right amplitude there |
|
| 53:16 | it is much different there. So wrong because I was wrong. They're |
|
| 53:22 | same magnitude, but they're not the amplitude. You see this is plus |
|
| 53:35 | right there. Take the peak here not the peak, it's the |
|
| 53:42 | That's the first gimme that's minus two a magnitude of four here at the |
|
| 53:50 | , far, this is zero, this is minus four. They have |
|
| 53:57 | same magnitude but the amplitude is OK. So when somebody says, |
|
| 54:11 | , this is the biggest amplitude, was it turns out that's the smallest |
|
| 54:18 | amplitude has a sign. But don't with them because we'll have a hard |
|
| 54:22 | discussing magnitude versus amplitude. But we to know the difference when we were |
|
| 54:30 | to say the difference. And these amplitudes is the same as the difference |
|
| 54:36 | the two amplitudes over here small point you happen to have a gas, |
|
| 54:48 | contact. So you have the same and the gas is lower velocity and |
|
| 55:01 | density, the that water sand. what does it say? It tells |
|
| 55:07 | the reflection coefficient and positive and it an increased of amplitude with offset. |
|
| 55:15 | other words, its slope is gonna up like that. Like this |
|
| 55:29 | this is the one of the better interfaces, fluid contact that you'll see |
|
| 55:39 | Sea nice flat event there. That's positive reflection. An example. |
|
| 56:00 | I'm gonna give you my definition of do you quantify class 12 and |
|
| 56:09 | How do you quantify that? And this is my attempt to show you |
|
| 56:16 | you quantify it? For instance, told me this seismic data that she |
|
| 56:23 | last week, most of most of zone of interest was a class |
|
| 56:32 | What does a class two look like it? Maybe your class two is |
|
| 56:40 | bright spot for me or maybe your two as a class one from |
|
| 56:47 | How can we be? Sure? we're gonna go ahead and look for |
|
| 56:52 | method to quantify the amplitudes that we . I'm gonna take a far offset |
|
| 57:03 | call it 30 degrees and I'm gonna notice this, I'm taking the absolute |
|
| 57:12 | of what I find on the amplitudes the far offset. And I'm gonna |
|
| 57:20 | that I want, I'm gonna call K times the normal incident. So |
|
| 57:27 | class two is now defined as take far offset if it is two times |
|
| 57:37 | than the normal incident. That's a two. No, if you |
|
| 57:45 | that's all, that's the only definition would really need there. So we're |
|
| 57:53 | look at the class two at 30 . This is the green, it's |
|
| 58:01 | degrees right here. You got an of minus two. Your normal incidents |
|
| 58:11 | one. So on your favorite one of your equations minus two is |
|
| 58:19 | to the normal incident, which happens be one plus 0.25 times the B |
|
| 58:29 | slope. Now 25 is the sine to 30 degrees sine of 30 degrees |
|
| 58:36 | 0.5 square, that is 0.25. that's gonna give us B solve for |
|
| 58:42 | and it becomes minus 12. So and here is minus 12. Now |
|
| 58:50 | go for the other one. Let's the red curve right here. The |
|
| 58:56 | O is minus amplitude at the far is minus two. The normal incidence |
|
| 59:03 | minus one. So you have a B of minus four. Here's what |
|
| 59:12 | means. We plot normally plot the incident on the X axis in the |
|
| 59:20 | . On the why this green 0.1 more incidence than B that is this |
|
| 59:29 | right here. This point of minus and minus one is this value |
|
| 59:39 | Draw a line through this right in . And that happens to be one |
|
| 59:46 | the far absolute value is greater than times the absolute value of the normal |
|
| 59:54 | , everything within these bonds right So if you get a normal incidence |
|
| 60:01 | and you get a slope value and one value falls right here, you're |
|
| 60:07 | be a class two. If you're this side, it's a class three |
|
| 60:12 | this side, class one. And finally, this is something that has |
|
| 60:17 | slope that's positive. Most slopes on CD P gather that et slope is |
|
| 60:26 | be negative very few class fours. when we look at this data |
|
| 60:39 | we see that this is a class , this magnitude there is greater than |
|
| 60:52 | times that magnitude right there and so . Here's a little exercise that you |
|
| 61:06 | put on your computer. How many a Mac? How many, how |
|
| 61:13 | have a Windows ss start again How many have tips running? Who |
|
| 61:19 | tips running? One Jessica? Do have tips running? I don't, |
|
| 61:29 | I can move to a computer that , ok. Can you get, |
|
| 61:34 | you get to it on, P day? No. Carlos. |
|
| 61:40 | you have tips running for some I can't hear you. Carlos. |
|
| 61:51 | doesn't look like you're muted. Just your head. You have tips running |
|
| 62:04 | no, it's not, it's not properly. It's like there are some |
|
| 62:09 | . I don't know why is it windows environment? No, no, |
|
| 62:13 | in, it's in a Mac. on the Mac. Yeah. Do |
|
| 62:18 | have avail, do you have windows for the tips? You don't have |
|
| 62:24 | bill? No, no, sir. Ok. Where do you |
|
| 62:28 | ? Houston? No, sir. Colombia? You're in Colombia now? |
|
| 62:33 | , sir. Ok, I'm gonna you a plane ticket to come up |
|
| 62:36 | expensive cash. Ok, let's I can make it. Yeah. |
|
| 62:43 | . Would you like that to be class? Yeah. Yeah, that |
|
| 62:47 | be good too. Ok. I'm missing somebody here. Aren't. |
|
| 62:52 | , there's only four live. Yeah. Ok. Who in this |
|
| 62:58 | does not have tips on a You don't and you don't and you |
|
| 63:09 | three well, that kind of sty . The idea of having a, |
|
| 63:21 | all day type of, uh, think, uh, or ok, |
|
| 63:34 | have to change, change the game . What I was gonna say, |
|
| 63:42 | is a nice exercise to do to how you go from class 123 and |
|
| 63:52 | . What are points hot if you a class one anomaly. And you |
|
| 63:58 | if I give it a little bit gas, I'll get a class |
|
| 64:03 | Well, surprised you gotta go through two first. As it, as |
|
| 64:07 | increase the that amount of gas or lower the velocity, it doesn't jump |
|
| 64:13 | 1 to 3 or 1 to And this little exercise shows that |
|
| 64:24 | So real data, class 123, is a show, this is two |
|
| 64:37 | data didn't have 3D. They I did uh you're looking at a |
|
| 64:48 | blue, the color bar, red negative, blue is positive. So |
|
| 64:55 | is a negative, positive. That that you have a negative, positive |
|
| 65:03 | acoustic impens means you're negative coming down like this. That happens to be |
|
| 65:13 | lower acoustic and bees than the surrounding trough peak. Likewise down here, |
|
| 65:23 | bright amplitudes sitting in there. These class three bright spots, deep water |
|
| 65:29 | of Mexico. Let's take a look the dotted rectangle and see how that |
|
| 65:36 | with incident angle, all the angles the amplitude changes 0 to 12 degrees |
|
| 65:44 | to 24 to 36 when I looked at the bottom and compare that to |
|
| 65:52 | immediately. You wanna say Fred, got bigger amplitude on the far |
|
| 65:59 | And Fred has to complain that Fred too smart when he did this because |
|
| 66:06 | is the company's software wasn't developed for VO And so when I brought this |
|
| 66:15 | section of the block, the program computes the background amplitude, the R |
|
| 66:24 | background. And then plus at 0.7 when it gets down here, the |
|
| 66:33 | amplitude is very low. So it you're gonna need a higher gain to |
|
| 66:38 | . And so it's hard to but this amplitude is the same as |
|
| 66:46 | if I apply the same gain Now, you can see that by |
|
| 66:52 | at the CD P gather right here is the CD P gather at the |
|
| 67:00 | site. Look right here near look at the trough almost the same |
|
| 67:08 | all the way across. Now, know what you're saying. Ah Look |
|
| 67:13 | this right here, Fred, that's the same amplitude. Well, what |
|
| 67:18 | got there is something that Fred wish there this data as what's called a |
|
| 67:31 | multiple suppression. And after you do move up, if you have |
|
| 67:41 | normally they are a slower velocity so when you normally move or correct a |
|
| 67:47 | using primary velocity, you normally have event that is parabolic like this. |
|
| 67:57 | So you search that isn't right, like it, you search for Parabolas |
|
| 68:10 | program or actually find that multiple and will design an operator that looks like |
|
| 68:19 | multiple and subtract it off, but subtracted it off at the zero offset |
|
| 68:31 | took the amplitude away and we don't that. So that's originally one of |
|
| 68:37 | downfalls of the original, the multiple radar is if you did have a |
|
| 68:44 | multiple there and there was a, another reflector like this, right? |
|
| 68:50 | just wipe it out at the near . And that's what happens over here |
|
| 68:57 | . Current processing doesn't do that. yes, the class three did have |
|
| 69:01 | aptitude that's consistent. I go don who will make the assumption that this |
|
| 69:08 | here is wet and I look at amplitude and I can see it, |
|
| 69:13 | amplitude is being compared to this amplitude depth. Is it direction zero? |
|
| 69:26 | what does the well cite if I a welder, I can make an |
|
| 69:31 | vo response for wet and gas at location, a tip type of a |
|
| 69:38 | . And we see the gas and wet both are essentially flat out to |
|
| 69:45 | 40 degrees and the gas as about one to about three times bigger than |
|
| 69:56 | web. And that might be what seeing here, that amplitude is about |
|
| 70:01 | times bigger than that. So that's class three. And if we look |
|
| 70:09 | the summary gas zones or oil. you have a high G gas, |
|
| 70:17 | ratio, gas zones are bright on stack and all angle limited stacks, |
|
| 70:25 | angles. When I looked at this here, that was angles between zero |
|
| 70:33 | 12 degrees, they were stacked Amplitude, gas, amplitude is constant |
|
| 70:45 | increases slightly with offset if you have great big change in amplitude with offset |
|
| 70:57 | you can't relate it to radon. that's another anomaly. It might be |
|
| 71:02 | limestone or a volcanic sitting there. wavelet is a trough peak on all |
|
| 71:11 | stacks. Hydrocarbon prediction is possible from stat. You can actually say, |
|
| 71:19 | that an oil, is it wet is it gas Peggy? How do |
|
| 71:28 | know you're in class three and bark the background interval velocity between 14,000 ft |
|
| 71:35 | second? Who's gonna work for oil gas exploration? Anybody in here wanted |
|
| 71:45 | get oil and gas? You all to be environmental. Judge J |
|
| 71:52 | is anybody else out in the other ? There gonna be uh oil and |
|
| 71:57 | industry? OK. The reason I'm that even if you think you're a |
|
| 72:10 | and won't get involved uh wrong because gonna be looking at seismic data more |
|
| 72:17 | the geophysicist is gonna be looking and gonna come back and have a responsibility |
|
| 72:26 | your data is gonna get processed. , they're gonna ask you what do |
|
| 72:30 | want and you're gonna have to tell what you want. You're gonna |
|
| 72:37 | well, I want the data process not enough. No, you have |
|
| 72:43 | say I want a stack and I want these angle stacks. And I |
|
| 72:54 | want the CDP gathers themselves right before stacked. But the biggie is in |
|
| 73:02 | red diner. You have to I want the background velocity field every |
|
| 73:11 | cds, they do at least a analysis. And you want that velocity |
|
| 73:19 | because you wanna know what is the , velocity in my zone of |
|
| 73:26 | Because it's, if it's 50 to , 50,000, what 5000 to 9000 |
|
| 73:33 | per second, you're gonna say I be in bright spot regime and you're |
|
| 73:38 | expect to see all of these. have a question. We have, |
|
| 73:45 | have, can you hear me? have what a question? Uh |
|
| 73:52 | we have seen everything here that is . It's the seismic is intact, |
|
| 73:57 | ? But can we do the same depth? Absolutely. When they, |
|
| 74:06 | they do this in depth, they to make a velocity model a 3d |
|
| 74:13 | model. And you want that because want to know what was the interval |
|
| 74:19 | in your target interval? That's even because it's it is more accurately computed |
|
| 74:27 | they do a depth model. So . And you want the CD PS |
|
| 74:37 | time, I prefer time because if process isn't very good, the depth |
|
| 74:43 | look screwed up, but time is forgiving to the beginning processor. |
|
| 75:00 | Class two Avios. I really, wish I could take that little blue |
|
| 75:10 | and get rid of it right by . Well, because then I could |
|
| 75:15 | you, do you see any hydrocarbons this seismic se in other words, |
|
| 75:22 | don't see hydro carbs on a stack if it's class two and we need |
|
| 75:30 | know what velocity range it might be we'll, we'll give you that. |
|
| 75:36 | that tells you if you have class , you better have some type of |
|
| 75:42 | vo discriminator. What would that Just having three different offset ranges allows |
|
| 75:49 | to examine what the avia would So that's the minimum that you |
|
| 75:56 | Minimum. These are gas, let's at. So this whole section |
|
| 76:05 | I'm going to squeeze sideways. Remember you wanna get a good interpretation of |
|
| 76:12 | structure and you're having a diff difficult , squeeze it together, make it |
|
| 76:18 | horizontally. It helps your interpretation. , when I did that, we |
|
| 76:24 | down by the well, and we this is blue red, that's positive |
|
| 76:31 | negative. I didn't want that. thought that should be negative. |
|
| 76:36 | that hurts. OK. I have arrow for some reason pointing there. |
|
| 76:44 | would I put that there? I know. Let's look at the next |
|
| 76:47 | range right beside it. 00 Look iphone all of a sudden with |
|
| 76:57 | That blue, red is now a , blue and look beneath it. |
|
| 77:03 | multi red, blue, red, sitting down there ears. Oh. |
|
| 77:09 | , remember this? You didn't know we picked it. Look at it |
|
| 77:13 | . It has an amplitude. Let's right here. Oh, it's picking |
|
| 77:22 | an amplitude now, wasn't there? , let's go really far. I |
|
| 77:30 | hydrocarbons everywhere. Oh, my Bosses are gonna be so exciting. |
|
| 77:36 | even had hydrocarbons migrating down de no in the other world except on my |
|
| 77:42 | . Does the hydrocarbons go down dep . This makes it suspect Fred. |
|
| 77:49 | . Look at this. No, II I, any place that I |
|
| 77:55 | , I'm gonna find hydro cars. is just tremendous except for one thing |
|
| 78:01 | not gonna trust this. This is and normally that is one of the |
|
| 78:12 | risks in the Gulf of Mexico, water. And how was that? |
|
| 78:20 | 100 companies list this as one of biggest risks. This is a clean |
|
| 78:26 | , a very clean sand and it I pros but the main thing is |
|
| 78:33 | clean and what happens then it can like a gas s what does the |
|
| 78:39 | see? Have a very high sheer velocity and it's going to give it |
|
| 78:47 | big poison ratio difference. So this here, Ashley is a clean |
|
| 78:59 | Let's look at someplace else that arrow we go to officer, it's |
|
| 79:07 | This right in here looks like the wasn't showing up on the normal |
|
| 79:15 | but it's getting bigger. It has amplitude increasing magnitude increasing. I come |
|
| 79:24 | here in the red zone and look it and say, hm, as |
|
| 79:33 | go from far, which has very reflections in there, the near, |
|
| 79:39 | get all kind of good reflections. . So what is this telling |
|
| 79:46 | Big hint, geologist geo scientist, hint going from here to here to |
|
| 79:54 | , we got a will. There's sand in here. There's no sense |
|
| 80:03 | all shall how does it, how it show itself? Look at the |
|
| 80:07 | offset, it loses amplitude with Oh my gosh. Does that may |
|
| 80:14 | ? I look at all those reflections there. Yeah, all of this |
|
| 80:20 | of looks like massive shall sitting in and you can draw it just by |
|
| 80:27 | fact look how the amplitude decreased with . Big clue. Remember on Ruther |
|
| 80:38 | William's chart, the slope was negative everything except one class war. That |
|
| 80:48 | the magnitude no has or has a of getting smaller it off. And |
|
| 80:55 | what you're seeing right in here. chill a sand starting operating here. |
|
| 81:09 | help. Really big help. If look at the stack section here is |
|
| 81:19 | where the reservoirs might have been. look at the CDP gathers this is |
|
| 81:29 | the field, this is off the over here. See that blue line |
|
| 81:39 | blue line is normally offset as equal depth. Normally, you don't see |
|
| 81:48 | data. Normally, you don't see . Normally you don't see that we're |
|
| 82:00 | out very far and we'll show you reason why. So that's a |
|
| 82:06 | that's a gas down there. I at the amplitude versus offset how it |
|
| 82:15 | and the wet sand ick is over it dies so you can start off |
|
| 82:25 | it does. The, yes, it starts off small. But when |
|
| 82:34 | gets way, way out here, is a monster. You compare this |
|
| 82:41 | that and it's so much bigger. you're seeing right here going across this |
|
| 82:53 | right here. Is that a gas ? Yeah. Well, look at |
|
| 82:59 | . Does it make it to the ? But there's nothing else, nothing |
|
| 83:04 | . But really this thing right Sean got a little another one down |
|
| 83:09 | . This is your clean sand. clean sand doesn't have anything on the |
|
| 83:14 | offset. Now, the biggie don't down here. Some of you are |
|
| 83:26 | as it don't look. Ok. is a very special volume special because |
|
| 83:33 | has something very unusual. This is is equal to depth. Notice how |
|
| 83:39 | events are flat here and then they upward. In other words, the |
|
| 83:47 | our correction was wrong. We over . That is known as the hockey |
|
| 83:54 | effect. It looks like a hockey . You hit the puck with this |
|
| 84:00 | right here and so you don't like , you rather that they be flat |
|
| 84:11 | this prior to 1991. This is we lived with actually a little earlier |
|
| 84:21 | that, but around that time and this. No leaning back and let |
|
| 84:33 | tell you about a young phd by name of Brian Duvall. And around |
|
| 84:42 | Brian was getting his phd at Colorado of Mines and he gave me a |
|
| 84:48 | call. His dad is a well Geophysics in Houston. It says, |
|
| 84:54 | , can I come down to your and process some seismic data? He |
|
| 84:59 | I have nine components. I have phones too. A vertical phone. |
|
| 85:06 | had vibrators that came out shook horizontally two directions and vertically. That's nine |
|
| 85:13 | now. And we don't have enough power for me to process it here |
|
| 85:18 | the school of mines. I OK, bring it down. So |
|
| 85:26 | brought it down to Houston. He , well, I'm here, |
|
| 85:30 | I'd like to do some interpretation because processing takes a fairly large time and |
|
| 85:37 | only run it when it's none of year jobs. The company G is |
|
| 85:42 | Corporation was running jobs is OK. said you're just lucky. We got |
|
| 85:49 | , a 3D volume that's nine square . It's an offshore block and we're |
|
| 85:58 | it for free because we don't have 3D that we can show people that |
|
| 86:04 | can process it. We don't own . And I, I can't get |
|
| 86:08 | off the company that's shooting it. he says I found a count in |
|
| 86:12 | oryx that said, yes, they'll it. And I told him |
|
| 86:15 | I'll show him everything. I won't back. I said, II, |
|
| 86:18 | don't think it's right. You're taking and I'm gonna wanna release some of |
|
| 86:24 | . So we start processing for them I want to show you something we |
|
| 86:32 | for Brian F. He, we down to the work room and there |
|
| 86:37 | 13 piles. Each one of them a different wall location. We had |
|
| 86:43 | the modeling done, all the processing stack sections, the CD P gatherers |
|
| 86:50 | angle stacks. And he comes down says, Fred, we're gonna have |
|
| 86:55 | get these normal move by corrections. gonna have to correct for them. |
|
| 87:00 | just, oh I says, I says, well, why? |
|
| 87:04 | said this is the sign of hydrocarbons you go ahead and you get those |
|
| 87:14 | , which is thing here. He , look at the far offset. |
|
| 87:19 | do you, if you stack what's gonna happen, you're gonna get |
|
| 87:23 | stack here here and down here, get something to stack here here and |
|
| 87:31 | . Every one of these that I drew, but that's the only energy |
|
| 87:35 | gonna get from the far offsets to right of the red line. They're |
|
| 87:41 | hydrocarbon reserves. This is the the only events on this far offset |
|
| 87:49 | the hydrocarbons. Whoa. So I we better go ahead and look in |
|
| 87:55 | literature and find out how to do is. Oh no. He says |
|
| 87:59 | is due to anisotropy as it will that, that was published by Leon |
|
| 88:06 | . Professor Eric Mines the most read paper in the SCG history by the |
|
| 88:15 | . And I said, well, we better go find out how to |
|
| 88:17 | that. He said that's ok. School of mines published an article about |
|
| 88:23 | to apply that. So don't people it? He says most people don't |
|
| 88:28 | the data that you have. You field data from Fairfield and this is |
|
| 88:34 | unusual data. Most people get seismic that goes to the offset is equal |
|
| 88:41 | the depth of interest. He says have offsets that are 15 miles away |
|
| 88:50 | Fairfield laid a line from the coast then go out 15 miles and then |
|
| 88:56 | shoot in between two lines, no . The cables are ocean bomb sensors |
|
| 89:02 | just so they got this tremendous offset you got all of them. So |
|
| 89:07 | able to go 2 to 34 times depth of your offset. It's |
|
| 89:13 | So we processed that we solve Brian did not. And when we |
|
| 89:18 | done, the data looked like this was that CD P gather and then |
|
| 89:26 | anisotropy as a new parameter, it very nicely. Look at the stretch |
|
| 89:32 | you see up here when you don't or correct them as much, they |
|
| 89:37 | have that stretch. This is a right here. Look at that. |
|
| 89:44 | is that this does a real good right in here. That's a pretty |
|
| 89:48 | match on the data. And sometimes go ahead and bring a overlay and |
|
| 90:00 | it on top of this. And you don't see this section and |
|
| 90:06 | where are the hydrocarbons? If you see them on this day, it's |
|
| 90:11 | . And I said, OK, , where, where are all the |
|
| 90:22 | ? Oh There are sands up Yeah, you can't see them all |
|
| 90:27 | you can see are the hydro chromes that's the resistivity sitting right there. |
|
| 90:33 | same with the field data. All see are the hydro carbs. |
|
| 90:40 | this leads to something that looks like . This is your conventional stack. |
|
| 90:47 | you find four hydrocarbon zones on Would you drill any of that? |
|
| 90:56 | , look at that. Would you any of that? Well, they |
|
| 91:01 | look good. Well, as it out each one of those locations here |
|
| 91:09 | , here, here all have No. What, what is the |
|
| 91:23 | between these? This is only the far traces only this data, only |
|
| 91:41 | data on A S was added together inside data right here that who's this |
|
| 91:54 | take? Only the very far? this is actually called officer, the |
|
| 92:01 | , the officer E equal twice the that's all harder comes in. Now |
|
| 92:13 | gonna watch for my audience participation. want you to look at this and |
|
| 92:21 | me reflectors. OK? You see that is. Let's go back. |
|
| 92:32 | kind of like right there. what's different one has reflectors? The |
|
| 92:45 | one doesn't one has reflectors and the one does it. These are the |
|
| 92:56 | far offsets. These are the near . Now, this is a class |
|
| 93:07 | . Remember what I said about shall shale. What happens when Shiel upon |
|
| 93:16 | , you go to the far off , shell on top of shell, |
|
| 93:23 | no reflections, shell upon shell on near offset. Ah But you got |
|
| 93:33 | . What the heck is all this ? This comes about by something in |
|
| 93:40 | photography. If you go back to 1976 Pete Vale at Exxon said seismic |
|
| 93:55 | come from Chrono Strat democratic boundaries. does that mean? Can a geologist |
|
| 94:02 | me what a Chrono stratigraphic boundary Halley said she cant Galley puts a |
|
| 94:09 | Stratigraphic boundary? Carlos I think he what it is. He's just keeping |
|
| 94:21 | . 00, we got an answer the audience. What is it |
|
| 94:27 | Yes. Chrono stratigraphic is a time boundary. What makes it significant? |
|
| 94:34 | a flooding surface. So what we're at are boundaries that are really quote |
|
| 94:43 | surfaces. That's what Deville had to . Now, remember something else that |
|
| 94:52 | about during the 19 sixties, that all very short offset type of |
|
| 95:01 | Now, they also said something They said something besides chrono stratigraphic |
|
| 95:08 | What were the other type of boundaries they talked about? Lithos, Strat |
|
| 95:14 | boundaries, lithos, Strat democratic boundaries those that occur because it's shall upon |
|
| 95:25 | interstate. Where do we see Mostly? Let me think, |
|
| 95:30 | let me think. I remember yesterday showed Ralph Chewy's plot, what which |
|
| 95:42 | was that you took? And you 0 to 15 degrees A CD P |
|
| 95:49 | and then 15 to 30 then 30 90. And in the middle, |
|
| 95:55 | he went 15 to 30 degrees, saw all these reflections but none |
|
| 96:01 | near offset just on the far in examine and lo and behold, they |
|
| 96:07 | all sand reflections and shale. So responded to voice songs ratio. Where |
|
| 96:18 | Poisson's ratio and the only equation, know, the farther offsets, |
|
| 96:25 | voice on ratios. Lithology and mythology in the father of them. So |
|
| 96:31 | have litho Strat Democratic reflections. Where the litho Strat Democratic reflections occur in |
|
| 96:39 | far offsets? So these are Chronos Democratic and they can include sand over |
|
| 96:47 | or shell upon shell, shell upon . You can have two different types |
|
| 96:51 | shell, but this one says it's shell. There's no change in |
|
| 97:01 | You can have all those different reflections the normal incident. But shell upon |
|
| 97:06 | is your litho strato? So here have now another feature, the litho |
|
| 97:12 | reflections that's coming up. So class , what does that give us? |
|
| 97:21 | we take a break at 10 I think we did, didn't |
|
| 97:25 | Oh, we'll do a break it around 1030 or so. Right. |
|
| 97:30 | think that was it. Um Let finish this and we'll take a |
|
| 97:34 | Ok. There's no indication of gas the near Englestad, very small normal |
|
| 97:45 | , reflection class two. Remember Rutherford Steinman gas amplitude increases with offset negative |
|
| 97:58 | event may or may not be event the stack section. Interesting. That |
|
| 98:04 | Rutherford Williams paper. What wavelet may may not be a trough peak on |
|
| 98:12 | stack section, but the waver is draft peak on the far angle stack |
|
| 98:19 | class two. Now the encouraging this is where interpreters take hold and |
|
| 98:27 | making a little advances. Inferences of are apparent when comparing near the far |
|
| 98:35 | stacks inferences such as what happens when go into overpressure and you get a |
|
| 98:44 | spot. Should you drill it? at the far off? Sets a |
|
| 98:50 | alone without calibration cannot distinguish a clean sand from a gas sand. Big |
|
| 99:00 | . This is why clean sands are as one of the biggest risks for |
|
| 99:07 | type of drilling. And if your interval velocity is between 23,000 ft per |
|
| 99:20 | , expect to be in class to . Somebody asked, well, how |
|
| 99:25 | if we have depth sections? if you have depth sections, the |
|
| 99:30 | beauty it is because you have a detailed interval velocity model that's required to |
|
| 99:37 | a depth migration. And you can where is the 9 to 14,000. |
|
| 99:42 | could say when I get at this , I'm in class two, pay |
|
| 99:46 | my different environment, different type of signature. A VO was invented for |
|
| 99:58 | two anomalies class three. We find look at the stack section, class |
|
| 100:10 | , we're going to have some type an Avio feature. We gotta have |
|
| 100:14 | different angle stacks to look at the P gathers something has to be |
|
| 100:22 | OK? I have a question real . I I don't quite understand how |
|
| 100:27 | distinguish that clean sand that starts you start to see those bright spots |
|
| 100:34 | increasing amplitude and it can be a sand and it can be a pitfall |
|
| 100:39 | how, how do you determine that is a clean sand? Um That's |
|
| 100:49 | this right here comes in Avio alone calibration cannot distinguish a clean sand from |
|
| 100:59 | gas sand, right? So what do you need to? We can |
|
| 101:03 | some inversion work. Look at see we see any significant difference in sheer |
|
| 101:09 | velocity from the o other ones because sheer wave velocity increases when you get |
|
| 101:15 | a limited uh clay content. Um songs ra or sheer wave used to |
|
| 101:28 | something that they would run in the for the petroleum engineers because it gave |
|
| 101:35 | an indication of the clay content. version. So anything that gives us |
|
| 101:41 | indication of the clay content and one be the sheer wave velocity. That's |
|
| 101:49 | uh we could put that into some then to see how that would go |
|
| 101:55 | a normal instance to the far But you need calibration, well controlled |
|
| 102:02 | to help. Maybe somebody else has magic wand. I don't have |
|
| 102:10 | You'll see that when I talk about analysis, this is Pete Rose in |
|
| 102:17 | consortium. I don't know how many they had probably over 100 1 |
|
| 102:22 | But have you gone through 203 100 prospects? And it keeps coming out |
|
| 102:29 | . Sin. Bit me. When drilled this, I can't give you |
|
| 102:36 | positive answer. I don't know who it. OK. Yeah. |
|
| 102:41 | fair enough. I just didn't know I missed it. Um So nothing |
|
| 102:54 | . Let's take about a 10 minute . I got uh 28 after let's |
|
| 103:01 | back around uh 10, 38 and half missing, missing one from uh |
|
| 103:20 | America Carlos. It might be the zone. The internet shuts off. |
|
| 103:41 | . Any questions? It's OK. . Hang with me. We're way |
|
| 103:55 | there and I don't know how to down there without screwing everything up. |
|
| 104:08 | . Wrong class one. A bo righty. Um I, I do |
|
| 104:17 | a story to tell about Brian He's the one that led us to |
|
| 104:23 | the very, very far offsets. in the upper and mid night scene |
|
| 104:30 | class two, they were absolutely I mean, you, you got |
|
| 104:36 | sections and all that was on the sections were reflection from hydrocarbon beds. |
|
| 104:42 | else disappeared. You couldn't ask for more. And when we discovered that |
|
| 104:50 | did, I went back to the company that gave us the 3D data |
|
| 104:56 | we could show. And I told that this is what happened. And |
|
| 105:04 | said, nobody else knows this. said, but as soon as we |
|
| 105:07 | processing data for somebody, it's gonna leaked out. Somebody at the bar |
|
| 105:13 | gonna listen to his buddy that's with company and it, it's gone. |
|
| 105:17 | said to him, it's not gonna a genius. I said, |
|
| 105:22 | we're not as smart as a lot those guys out there. They'll get |
|
| 105:25 | real quick. So I said, we do have a time that you |
|
| 105:30 | make a, a AAA good deal money off of this and all the |
|
| 105:35 | sales for the next six months, the Gulf of Mexico Lial, you |
|
| 105:40 | be able to go ahead and bid lot better than you've been bidding on |
|
| 105:46 | transition zone, this Miocene uh type trend. And I told that to |
|
| 105:55 | uh oil company or X. And said, OK, let us think |
|
| 105:59 | it. And, and what they is they immediately went over to Western |
|
| 106:04 | and also PGS and they showed him work and said, can you do |
|
| 106:09 | but only cheaper than what the, company wanted to charge him? And |
|
| 106:17 | never heard back from them. I heard that from my friends at Western |
|
| 106:21 | . They called up, hey, guys are doing good work over |
|
| 106:25 | Thank you. So we went down another company and it's called Zilka. |
|
| 106:30 | I tell you who Zilka was? ? Mister Zoka made his money fortune |
|
| 106:39 | motherhood, a store. I think was, it was in the United |
|
| 106:43 | and it was a store for providing and baby support issues. Uh And |
|
| 106:51 | had it throughout the United Kingdom. sold that and he wanted to be |
|
| 106:54 | movie producer. So he went to and bought Sony movies and that didn't |
|
| 107:03 | out too good. So he sold . He came to Houston and |
|
| 107:07 | son-in-law, you're 26 years old. got a GE geology degree. You're |
|
| 107:14 | new exploration manager. I'm gonna form oil company. So he formed an |
|
| 107:18 | comic and he went to Fairfield Geophysical said, I want all the seismic |
|
| 107:25 | you shot or they shot all all the very shallow water and add |
|
| 107:32 | about 100 and 50 ft water depths they had it all up in Texas |
|
| 107:37 | the way across Louisiana. Also my . And he said, what we |
|
| 107:46 | is you give us this data And if we find something, we |
|
| 107:52 | drill, we'll come to you and you, we'll either give you a |
|
| 107:57 | amount of money, 102 105 $100,000 up front or you can wait till |
|
| 108:04 | start producing it and then you can a certain percentage of the uh output |
|
| 108:10 | we get. It's a good deal Fairfield didn't cost them anything. And |
|
| 108:17 | Mr Zoka came to us and ok, don't tell anybody else about |
|
| 108:23 | week later. He says we'll provide enough data to for you to process |
|
| 108:29 | that way you'll make money on it we'll pay the initial price you |
|
| 108:35 | We're not squabbling, it was very , it was three times ordinary |
|
| 108:42 | And uh so this is fine. , they provide us a lot of |
|
| 108:47 | and they had a processing center and would prepare the data for us and |
|
| 108:52 | just had to put it through the processes. We made a lot of |
|
| 108:57 | by a lot, meaning that we giving bonuses that were a year's salary |
|
| 109:03 | some even more. And uh iii hate to tell you that our profits |
|
| 109:12 | like 75% of our revenue. It just unseen Mr Zilka, his old |
|
| 109:20 | after being a year and a half . He sold it. Remember he |
|
| 109:24 | have anything. He sold it for 1.5, about $1.75 billion for a |
|
| 109:32 | that just started. And they would him, how do you, what |
|
| 109:38 | your success? Every hole you drill successful. You don't drill dry |
|
| 109:43 | Mobile. They Exxon, they tried duplicate the processing but they didn't have |
|
| 109:48 | very, very far offset data that have. So he was able to |
|
| 109:53 | go ahead and keep going and get these good holes. Made a good |
|
| 110:00 | . Anyhow, we didn't care if Zucker made all that money. We |
|
| 110:05 | good. Funny too. That was . Ok. Let's look at a |
|
| 110:08 | this is the very unusual deepwater It's offshore Texas and you can see |
|
| 110:15 | dipping beds, how all of a they're counteracted. Look at them, |
|
| 110:19 | all dipped on to the right, all dipped on to the left and |
|
| 110:25 | drill the, well, it's a blade. They have a, they |
|
| 110:29 | a cable that's 31,000 ft long and going at a zone that's 16,000 ft |
|
| 110:37 | . So they have acquisition out to the depth that they're gonna have. |
|
| 110:43 | at this section here. I see that makes me say drill here. |
|
| 110:50 | this is Elf Alcoa sitting there. so we looked at the three angle |
|
| 110:57 | , 0 to 1212 to 2424 to . And I, I draw your |
|
| 111:03 | to this right here. We, , picking that peak and as I |
|
| 111:10 | down to the far offsets, it like I misplaced that little arrow in |
|
| 111:17 | , but it's not, the peak disappears as we get the far offset |
|
| 111:23 | that's gonna be critical because you're gonna Rother Fred and Williams. So, |
|
| 111:32 | is the conventional. Well, and Depp, we're gonna assume it's |
|
| 111:36 | Don dip and I will show you CD P together. Now, I |
|
| 111:41 | to ask you a favor and please look at the seismic D No, |
|
| 111:49 | look. I see you're peeking. , you weren't working. You |
|
| 111:55 | you weren't awake a couple of minutes . As soon as I said, |
|
| 111:58 | look. OK. Now you can . I compare the CD together. |
|
| 112:04 | Depp, the CD P gather at well site. So both of |
|
| 112:12 | here's the zone of interest. The decays with offset. Same here. |
|
| 112:17 | amplitude decays with off. I, don't see anything about the near trace |
|
| 112:23 | here and the near trace amplitude here make me jump up and down with |
|
| 112:29 | and the fact that the amplitude is with offset, it makes me feel |
|
| 112:34 | they're the same, you know, not gonna be able to measure |
|
| 112:37 | this small difference. But what do see when a takeaway? Don't |
|
| 112:42 | see. Now, what do you about the upper one all of a |
|
| 112:47 | looking at this, we see the does decrease its offset right there. |
|
| 112:55 | , excuse me, you got a reversal, it goes from trough to |
|
| 113:06 | . Come over here, you don't any amplitude at all. Ouch, |
|
| 113:13 | is what Rutherford and Williams were talking and of course, they did not |
|
| 113:18 | to go out to this far of all. If I look at separatist |
|
| 113:24 | , what do they show? They that the wet, which is this |
|
| 113:27 | de the amplitude decreases, but it goes through the zero amplitude on the |
|
| 113:35 | far offset. However, for the charge right here, the amplitude decreased |
|
| 113:43 | offset and it became negative. So direct detection indicator for this is, |
|
| 113:50 | they find where this goes negative sitting there that remember Rother Fred and |
|
| 113:59 | they said we're drilling the hard What we do is we follow this |
|
| 114:04 | . There's a big amplitude. We don't drill, don't drill, don't |
|
| 114:07 | all of a sudden the amplitude disappears we say drill hard to say s |
|
| 114:14 | to sell to management, especially if have a gap in your coverage like |
|
| 114:20 | do right there. But when you at the Hartshorn that they showed you |
|
| 114:25 | the article, you'll notice where they a peak at one little small line |
|
| 114:31 | in the middle of my red it's a trough, it goes right |
|
| 114:35 | against the peak now all of these there is a peak right above all |
|
| 114:42 | way across a peak, all the across. How did I do |
|
| 114:47 | Because I was trying to show that peak, the trough, it's really |
|
| 114:53 | . We have isolated it like a above and below to say I didn't |
|
| 114:59 | up the normal mover. That's And, but being able to say |
|
| 115:06 | that's another requirement that makes you believe is really a truly an amplitude going |
|
| 115:12 | zero reversing polarity and having any well be able to make that plot goes |
|
| 115:21 | and reduces the risk for you, you feel very secure and drilling. |
|
| 115:29 | class one, a vo gas in wet sand amplitude decreases with offset may |
|
| 115:36 | phase and may be if it does on the right hand side, that's |
|
| 115:42 | good thing to note that becomes your detection indicator. A lot of times |
|
| 115:47 | go into an area not knowing what gonna see. Gas vent is smaller |
|
| 115:55 | than wet on the stack section. , the gas is reducing the amplitude |
|
| 116:00 | like refer Williams mentioned, the wave a peak rough on a near |
|
| 116:06 | It might be hm tropic on a we don't know. But when you |
|
| 116:13 | a sand velocity, if it's above ft per second, expect the class |
|
| 116:20 | because if it's sitting up against the very seldom do you have a shell |
|
| 116:26 | gonna be 14,000 ft per second. it is, it's different. So |
|
| 116:33 | when you put gas into this, that's not gonna go for it, |
|
| 116:38 | might get down to 13,100 ft per . That's a consolidated rough. It's |
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| 116:43 | depend upon the ferocity and any So what, what, what did |
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| 116:48 | learn now from this? Class one class two avi both of them required |
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| 116:59 | that were greater than one times the they required very far offset. Say |
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| 117:05 | another way they require angles at the 40 50 degrees. And Marie, |
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| 117:15 | isn't, I will say too bad you can put nodes on the ocean |
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| 117:20 | and use your boat to go to far far offsets in order to record |
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| 117:26 | on land. This is tough because land, you gotta permit people and |
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| 117:34 | gotta see what the activity is in area. So your area, it |
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| 117:39 | become twice as big, becomes four as big. And that's what makes |
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| 117:46 | getting the very far offsets of land little bit difficult culture. Evaluation of |
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| 117:54 | P gathers often necessary for class one vo the, the nice thing is |
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| 118:03 | as you get the farther offsets, get rid of the ground rule and |
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| 118:08 | , which really kills you when you uh for signal to noise. |
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| 118:16 | properties of Avio anomalies how the carbon makes reflections more negative. Can I |
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| 118:24 | a question real quick. Yes. uh so the class one, you |
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| 118:30 | the phase reversal and I guess you call that a dim out. Is |
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| 118:34 | , that's correct? Or you you can, you might have a |
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| 118:38 | reversal might have. Ok. And if you do have a phase |
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| 118:44 | that's a really great, great sign cla for class two. If your |
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| 118:53 | incident starts positive, it could potentially a phase reversal as well. |
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| 118:59 | That's correct. So could it also a demo could also have what? |
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| 119:06 | ? Well on class two, if want a, if if you wanted |
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| 119:18 | classify it as a class two, can have small positive or small negative |
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| 119:26 | incidence. The ref the normal incidence is below plus or minus 0.03. |
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| 119:34 | when you get then remember it, you slope is negative. So if |
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| 119:44 | negative, it's gonna get more negative comparing the far offset to the near |
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| 119:50 | got, you got more negative and when you have a slightly positive number |
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| 119:58 | you have the A VO class what happens is, yeah, you're |
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| 120:04 | get a phase reversal but the far is not going to look as big |
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| 120:10 | it did if you started negative on normal incidence. That's the main |
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| 120:16 | Uh can you have a crossover? , they called those AVO two class |
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| 120:23 | and that was Dan, that was Ross and Dan Kinman published an article |
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| 120:29 | that back in the, I don't um early eighties. Oh, any |
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| 120:40 | question, ah gas reservoirs have the magnitude of far offsets for class two |
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| 120:54 | three. So again, it's pointing the importance to note, am I |
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| 120:59 | class two or class three regimes? do we use? The velocity? |
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| 121:06 | ? The velocity profile processors? Have ask for your two D data, |
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| 121:11 | for it if you're three, once 3d depth, make sure you get |
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| 121:16 | interval velocity volume. Normally they always depth because that's your QC. In |
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| 121:23 | depth migration is updating that interval velocity and over again. Class three hydro |
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| 121:33 | have large amplitude on all offsets. one and two can have direct hydrocarbon |
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| 121:40 | on offsets greater than depth. They start to really show themselves until they |
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| 121:46 | way out there. And that's on two. That was the Zilka. |
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| 121:52 | When you come to Euston, there's concert hall with his name on it |
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| 121:58 | that he donated some of his He used to class one though. |
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| 122:03 | the one that Taylor was asking about gonna have AAA demo or phase reversal |
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| 122:09 | a very far off set past we're looking for bright amplitude, bright |
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| 122:17 | class two AVI interpretation works best because near offset amplitude is small. It's |
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| 122:24 | relative comparison. If you look at far versus the near it's a death |
|
| 122:29 | . Hate going for small to B easy to see. Class one and |
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| 122:37 | four A vo require good signal to ratio to discriminate hydrocarbon from brine |
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| 122:45 | I, I did have a class that I would normally go over, |
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| 122:51 | I'm not really proud of it. I can't find a real good class |
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| 122:56 | in literature. Uh People say, I got one and you look at |
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| 123:02 | and I, I even question it the processing correct that they really process |
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| 123:07 | correctly. Class four requires an abnormally shall velocity. That's one of the |
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| 123:16 | get it high. It has to , I don't know about 20%. |
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| 123:23 | shell velocity has to be about 20% than the sand. In order to |
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| 123:28 | to class four hydrocarbon and risk indicators the book from 1973 I kind of |
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| 123:46 | various high to carbon indicators from the papers and Bob Sheriff uh iterate them |
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| 123:57 | his encyclopedia dictionary. One of Of course, there's a newer |
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| 124:05 | Amplitude changes bright spots. The amplitude in the Edwards play limestone dey, |
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| 124:20 | gonna be pros fractures that are Hydrocarbons would be there change in the |
|
| 124:28 | parent. This is when you have gas and you're drilling for it, |
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| 124:34 | can get bright spot and it just back and forth up and down and |
|
| 124:39 | multiples throughout the whole seismic section velocity . When you go through the hydrocarbon |
|
| 124:51 | , you get a lower velocity. , the lower velocity doesn't in the |
|
| 124:58 | chromes doesn't necessarily say when you do velocity analysis, you're gonna be able |
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| 125:02 | see it, but there should be time sag underneath the hydrocarbon zone. |
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| 125:10 | it's a un unconsolidated s it could the velocity drop significantly and you can |
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| 125:17 | deeper reflectors and, and it deeper could be even dipping, but you |
|
| 125:22 | see going down and then a little and back up coming again. And |
|
| 125:27 | can see that sometimes when you look the stacking velocity at the edge of |
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| 125:39 | and you're looking beneath, you're looking a bed beneath the gas zone. |
|
| 125:47 | happens is you might have a gas right in here and here is your |
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| 125:56 | reflector and this is depth going You can have a CD P gather |
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| 126:06 | your near traces are here, but trace goes through the CD P gather |
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| 126:17 | goes through the gas zone or it be one where I didn't do that |
|
| 126:31 | good. You give uh you can the near traces here, go through |
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| 126:41 | gas zone too. Each one of will each one of these considerations. |
|
| 126:49 | right here will give an enormous stacking because of delay here. Now, |
|
| 126:55 | have three delays, that'll give an velocity analysis. In other words, |
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| 127:01 | of being a nice hyperbole like where time is going down, where |
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| 127:08 | have one that comes out, right there and then you have a |
|
| 127:13 | So you try to fit the best to this one with a little bit |
|
| 127:17 | delay. That was those type of analysis and changes were done a lot |
|
| 127:25 | we had just two D data. right here you can actually predict the |
|
| 127:29 | of the zone of interest. Oh there are other velocity variations too. |
|
| 127:38 | Tom Davis, former professor at school mines, retired uh when he was |
|
| 127:45 | Amaco, he wrote a kind of interesting paper. He showed that in |
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| 127:51 | , something like 75% 75% of all reservoirs had a velocity anomaly above the |
|
| 128:02 | . Of course, he said most these were on structure. If you |
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| 128:08 | structure, you're gonna have a relief tension on the top of the reservoir |
|
| 128:13 | all the beds above you. So beds above they're on the peak, |
|
| 128:18 | could have a lower velocity just because structure wave, the changes polarity reversals |
|
| 128:28 | you associate them with the right a that we have, they occur at |
|
| 128:33 | edges. Burma is a classic example where they have multiple pay and a |
|
| 128:43 | , you have multiple pays and there's reservoir and she, it almost looks |
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| 129:05 | you have a fault coming down here what it is, it's just m |
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| 129:11 | of reservoirs that have a phase reversal from the gas to the wet and |
|
| 129:22 | of them seems like just all Burma. Ok. This is for |
|
| 129:35 | recent current graduate students who's a, taking the regular program, you tell |
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| 129:42 | a regular graduate, you're a regular student. Have you had, who's |
|
| 129:47 | advisor? Doctor who? Joe Doctor Harry Joe, is that |
|
| 129:55 | Ok. Ok. Your advisor Rob . Ok. Anybody have Yin |
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| 130:04 | Ok. You've taken Doctor Kagan's haven't you? Have you taken doctor |
|
| 130:13 | study? Doesn't he advocate the frequency below the reservoir? Here, this |
|
| 130:20 | right here, lower or frequency beneath reservoir because of attenuation, doesn't he |
|
| 130:28 | hydro reservoirs say lower frequent have an of a lower frequency? Five years |
|
| 130:41 | , five years ago, five we've just had a gentleman in our |
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| 130:47 | in real life who just announced, can't remember a class of five years |
|
| 130:54 | . He barely remembers who taught Not bad, you know, and |
|
| 130:59 | thought I was bad with my Oh, that's OK. He's only |
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| 131:06 | years old. It, hey, , I'm 50 years older than he |
|
| 131:11 | 60 years older. I still can't the guy's name, but that's |
|
| 131:17 | There is a group of folks that that when you go through a gas |
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| 131:30 | , it will attenuate the signal. there are groups that said yes, |
|
| 131:37 | not for the reason that you're And so this as not a large |
|
| 131:46 | but a following that like to prove one way or the other whenever you |
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| 131:55 | a gas zone, you can have right in here. What then beneath |
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| 132:08 | you got the wet too high up . Let's go. Let's put gas |
|
| 132:20 | , interface this and this is what here. And we have a low |
|
| 132:29 | 10%. And down here it's all sw water saturation equal to one. |
|
| 132:40 | in this zone, right in you can have a water saturation that |
|
| 132:46 | is like 0.4 there's a residual gas here. 60% of this is still |
|
| 132:53 | , not economic. That might be little bit too. It's 2.5 50% |
|
| 133:00 | , 50%. We it might not economic to drill it vertically but |
|
| 133:05 | Yes. And so a sort of presence right in here could be something |
|
| 133:13 | the order of 40 ft, 50 . If you have a porosity of |
|
| 133:22 | then this thickness right in here might six inches and this is the capital |
|
| 133:31 | pressure uh that does this puts a still in here and then you get |
|
| 133:36 | here and you're into an all water when you get into residual gas |
|
| 133:45 | Remember what we said, a little of gas, like 15% to 15% |
|
| 133:52 | 20% that gives you bubbles and bubbles to attenuate the signal. If you |
|
| 134:00 | one big bubble that's not gonna you need many, many bubbles. |
|
| 134:06 | this is the article that Ed White pointing out when you get millions of |
|
| 134:11 | , it'll just wipe the energy all . So it's still up in the |
|
| 134:19 | if you have residual gas saturation and a thick section. Yes, the |
|
| 134:26 | frequency is expected but not in the gas section. OK. Mylo Backus |
|
| 134:36 | at the University of Texas for many since passed away was a big advocate |
|
| 134:41 | flat spot. He was one of founders of the digital technology. Back |
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| 134:47 | the early sixties, he worked for Services Incorporated G SI G si then |
|
| 134:56 | Texas instruments, one of the big makers. But at G SI Milo |
|
| 135:04 | on the digital technology and he always that there are horizontal reflections produced at |
|
| 135:13 | fluid interface and we just don't look them enough. And so he developed |
|
| 135:19 | at the UT in order to look fluid interfaces. You know what a |
|
| 135:26 | effect is. I showed you a effect, Lake Geneva, anybody ever |
|
| 135:31 | there guys? You gotta make enough to go there. OK. |
|
| 135:38 | it's called the Arab Playground where the men go there and they don't have |
|
| 135:45 | wear all the white gowns and that they could bring out their gold necklaces |
|
| 135:52 | even have a beer or drink wine hard drinks there. Chimney effect, |
|
| 136:01 | gas can deteriorate all your reflections underneath energy does not go through the shallow |
|
| 136:11 | sands. It tends to go Well, that's good news and that's |
|
| 136:16 | news. The good news is there was hydrocarbons here. The bad |
|
| 136:20 | is, is there any left in reservoir? And so that, that's |
|
| 136:25 | thing. Now Malaysia, they have chimney effects all over the place and |
|
| 136:32 | have big reservoirs. There was a by the name of Fred Alzada who |
|
| 136:39 | have analyzed, I don't know, chimney effects and he could tell the |
|
| 136:46 | . Was there an, was there reservoir gas level? He now is |
|
| 136:52 | professor over at uh Southern California. , hydrocarbon indicators is a gas and |
|
| 137:00 | high gas oil reservoir reservoirs exhibit a two A VL. No, the |
|
| 137:13 | and this one is one you better into your mind. And I think |
|
| 137:19 | you join a company, they'll tell that if you have a structural reservoir |
|
| 137:26 | you think its hyder combs in the hydrocarbon reflection should be different than |
|
| 137:32 | wet. And when you map, you map your reservoir, you can |
|
| 137:41 | a structural conforming put over top of , the amplitude contours as a |
|
| 137:50 | the amplitude contours should conform to the contours. They should have the same |
|
| 138:00 | water contact all the way around. is I would say the primary risk |
|
| 138:11 | that's done on all structural type of . And that's the first thing that |
|
| 138:18 | asks for, show me the structural to the amplitude. And if you |
|
| 138:24 | show that you, you, you a good chance. You, you |
|
| 138:28 | sold the prospect, but they're gonna for it. The last one right |
|
| 138:40 | is one, as I said, came from Bob Sheriff, but this |
|
| 138:44 | came from Tom Lee and Tom Lafa to teach, uh, continue education |
|
| 138:51 | here for the U OF H and was a gravity person and he was |
|
| 139:01 | apt on gravity mapping, contouring et cetera. It was very, |
|
| 139:08 | good. But all of a sudden said, when the computer came around |
|
| 139:15 | in the pot seventies, going into eighties making maps for the regional |
|
| 139:25 | What's the gravity of the regional So you could subtract the regional charging |
|
| 139:34 | gravity from the regional geology. You to subtract from that, that you |
|
| 139:41 | to give you what's enormous observe. he saw these maps, he |
|
| 139:47 | coming out of the companies where they to apply some constraint and they replied |
|
| 139:56 | , what was it though? Third , fifth order, seventh order polynomial |
|
| 140:05 | to the data, the higher the you get, the more enormous smaller |
|
| 140:11 | got. And they just kept piling up automatic contour maps. And Tom |
|
| 140:20 | it. Amplitude interpretation must make geologically apply less principles of least squares |
|
| 140:31 | more principle of least astonishment. In words, look at what you're saying |
|
| 140:39 | the answer and look at the person you and they are they saying, |
|
| 140:45 | know, I'd be astonished if that geologically. It just is impossible. |
|
| 140:52 | of course, the least squares is upon maps based on the square contouring |
|
| 140:59 | more on doing it geologically. that means not 3D. This used |
|
| 141:08 | be two D where you didn't have data in between contour line in between |
|
| 141:15 | to the seismic data. And you to say what was the structure in |
|
| 141:21 | and how to use a little geological . And of course, a lot |
|
| 141:28 | new folks would do. You'd have clients every mile apart. North and |
|
| 141:35 | . And the young person getting on P A big high. You right |
|
| 141:38 | the middle of where there's no seismic out there. Hey. Oh, |
|
| 141:53 | . This is a article 2009 by Road. Ro Rocky is a |
|
| 142:02 | It's all by himself. He lives Center Texas. Do you know where |
|
| 142:08 | Texas is? Center Texas is, famous for a grocery store in that |
|
| 142:16 | store makes sandwiches all galore. But also has the largest selection of uh |
|
| 142:29 | beef, jerky camel, jerky, , jerky, sheep, jerky dried |
|
| 142:39 | . All selection you love. And is, you're going from Dallas, |
|
| 142:47 | to Dallas is exactly half white. why it's called Center Texas between Houston |
|
| 142:53 | Texas. People. Good place to , good drinks, good beef |
|
| 142:58 | great sandwiches that they make. Rocky there. And he has a cattle |
|
| 143:05 | , but he's a very well known and manager and they used to drive |
|
| 143:12 | distance 100 miles to work every day then have his home that he went |
|
| 143:19 | and he was part of this. he said we have over 200 prospects |
|
| 143:27 | that's 12 years ago. And he most of them, however, 90% |
|
| 143:33 | tertiary, most of them here are Gulf of Mexico or the deep |
|
| 143:39 | It's a major portion And here are of this classification, primary DH O |
|
| 143:54 | don dip amplitude contours. Over you see a structural map by the |
|
| 144:03 | line by the single black lines. is where the amplitude was above a |
|
| 144:11 | value. And so the amplitude was . The amplitude map does not conform |
|
| 144:18 | the structure map over here. This been better, excellent, almost perfect |
|
| 144:24 | and that got the highest grade So what is this great threat? |
|
| 144:30 | and associate? Have a computer And they're gonna ask you a series |
|
| 144:37 | 100 questions and you're gonna get graded each question. So if your |
|
| 144:46 | that's what it's grading your prospect. it has this, that's a great |
|
| 144:53 | , you're gonna probably get 20 That's, that's one of them. |
|
| 145:01 | other thing is what's the amplitude consistence the mapped area? So here it |
|
| 145:11 | the consistency or her just random type thing where the amplitudes go inside. |
|
| 145:17 | again, that's grade five, but not worth 20 points that's only gonna |
|
| 145:25 | maybe eight points because that was the and so forth. So here are |
|
| 145:34 | most important direct hydro chrome indicators for . Structural Amplitude on the Don dip |
|
| 145:43 | . Does it conform where you have , the gas water contact is it |
|
| 145:53 | both on structure and on the amplitude . Now, here's one here phase |
|
| 146:03 | character change at Don dip anomaly In other words, did the gas |
|
| 146:09 | a negative reflection? And what the on the stat, that's what it's |
|
| 146:17 | d flat spots. And then we the Avio attributes, various ones. |
|
| 146:27 | , Rocky gives him a nice and came from 2014 paper, Rocky gives |
|
| 146:33 | nice presentation on this and he points when they wrote the first program and |
|
| 146:42 | join their consortium, they give you program so you can grade your prospects |
|
| 146:50 | they first wrote all the questions. were geological omens. How co how |
|
| 146:59 | is your prospect to another? that's proven productive is your sin in |
|
| 147:09 | same reservoir as the most productive be you? Are you up dip or |
|
| 147:19 | dip from the last productive will? they had a series and they got |
|
| 147:25 | score. The, how they evaluate escort every prospect before it's thrill. |
|
| 147:33 | after it's drilled, they had plots say, how successful are we? |
|
| 147:40 | many do we say drill and turned to be dry? Hos they would |
|
| 147:46 | , they evaluated that. They said were 60% successful. So that's |
|
| 147:57 | It used to be 25% 25% of walls were successful. But by our |
|
| 148:04 | analysis, we lowered the cost of drilling dry holes as soon as they |
|
| 148:10 | amplitude. All of a sudden it like from 60% successful to 90%. |
|
| 148:18 | was the main emphasis getting amplitude, one amplitude conformance structure, then an |
|
| 148:28 | vo then bright spot, all the like that. No, these also |
|
| 148:37 | upon what clash are in the top . If you're in a class |
|
| 148:44 | a down dip structural conform most then if you're a class two, |
|
| 148:54 | second is C amplitude consistency and mapped . Now on class two, it's |
|
| 149:04 | be the far offset that you have the near or not the staff. |
|
| 149:10 | you gotta watch offset, you you would expect the stack to be |
|
| 149:16 | because it could be positive and But the A vo the first one |
|
| 149:24 | get there Avio observations and gathers or stacks. Now there are certain warnings |
|
| 149:42 | DH I and such a thing as you have watch tuning? And I |
|
| 149:54 | you an example of that where I proven flattened the hot and there's a |
|
| 150:01 | bright spot, bright spot with brighter and it's up to it up de |
|
| 150:08 | it was productive. But just on other side, there was another one |
|
| 150:13 | like it, it turned out it the tuning effect of the wedge. |
|
| 150:18 | was not the hydrocar reservoir thin The bald structure doesn't continue. Velocity |
|
| 150:31 | can affect conformance to closure interpretation. you have a thick velocity, a |
|
| 150:40 | reservoir in the reservoir is like this , you're gonna have a velocity delay |
|
| 150:54 | than on this side right in here it's thicker reservoir and over here. |
|
| 151:00 | underneath, right in here, you're have something that goes like this. |
|
| 151:06 | tilts, this is your gas water , but it's tilted because of the |
|
| 151:15 | velocity. Sitting over here. Oh dang. You always have to put |
|
| 151:32 | in something that doesn't work. Strat democratic traps are tough because they |
|
| 151:39 | necessarily have reservoir don dip conformance. as it shows heresy changes across the |
|
| 151:51 | and yet stratigraphic traps, one of biggest, biggest oil produced birds in |
|
| 151:58 | world and they have the biggest Major reason for dry holes, low |
|
| 152:06 | saturation, thick wet sand, hard volcanoes. Last two I porosity, |
|
| 152:19 | sands. I think that's it. . OK. Any questions that would |
|
| 152:34 | to uh entertain audience here, put in far, far land, |
|
| 152:49 | Anybody going to the rodeo this weekend rodeo playing. I keep seeing something |
|
| 152:56 | the entertainment. Does anybody know here's rodeo going on? What's that? |
|
| 153:08 | , and of the p and the , they're, they're advertising all the |
|
| 153:14 | . They're gonna be at the Rodeo the people entertainment, top names. |
|
| 153:21 | didn't make it again this year. for Rodeo. My singing. |
|
| 153:27 | anything else? Ok. I uh, 1130. We come back |
|
| 153:35 | 1230. That the name of the . 1230. We'll see you |
|
| 153:42 | folks. Bye |
|
