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  4. Two Examples of Log Interpretation

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- [Narrator] I wanna show you the examples. And these are two examples that we have. And these are very busy slides And I'm gonna have to go through these quite fast. But, this left panel is a probabilistic inversion of a triple combo data, quad combo data. And so first thing we have is the illite, the clay component, and you can see that these are, these are excerpted The red dots are the excerpt e-data. So you can see that we're matching the excerpt e-data quite well. And this is the clay, in gray, this is the sand component, and the blue is limestone, and the purple is dolomite. Porosity is in white, in this particular case. These arrows in the depth track correspond to where we had sidewalk ores and actually the length of those arrows, the length of those bars, are the length of the core. The interesting thing is that we also had a downhole pressure gauge on this thing, an RFT, and we measured the pressure. The blue line is normal pressure, which the reservoir was at about yet discovery time. This is .43 PSI per foot. And this is .43 PSI per foot. This is .5 PSI per foot, so this says that these two data point and this sand here and this sand here were seeing the effects of the water flood. So, has a higher pressure than at the discovery point. We'll see in the next slide that we have some data down here. .3 PSI per foot, which is where it's depleted. So this is the inversion of all the data, crossing data expanded over on this particular slide. The green represents the oil, the put on the right, onto the very right, water that we calculate from the probabilistic model. And, the clay-bound water in gray. And, so, on there in dashed blue is a dielectric data. So, you can see that we have, through this sand, beautiful sand right down here and this sand up here. We have a fairly robust fit between the dielectric data and the deterministic model. Where it does not match, we see more water here at this particular point. And, if you look at the resistivity curves, you can see that the blight here is the MSFL and we do have invasion. Now this is the modified coached permeability from the annamar so you can get some ideas where we are going to have invasion and where it has low high permeability. All right, this is that same well. But, however, if we put on the annamar data on this thing to show you what this looks like with all the rest of the data that we had. Again, this is the mineralogy model, this is a saturation model of resistivity. The interesting thing is that, if you look at a claybound water, I calculate the claybound water from 0 into the T1 and T2 data from the annamar data. And, these are least of the calculated claybound water from T1 and T2. And, as shown over here, this is T2. This is a claybound water cutoff, I don't really use cutoffs, I use a tapered function. But, this gives you anything to the left of this line is going to be claybound water. Anything to the right of this line is gonna be water, free water, irreducible water, or oil. And, this is what it be look like in T1 states. And, so, what you see out here is there's very little clay signal in both T2 and in T1. Red's shown here, in this inversion. The interesting thing is these data points correspond to a clay calculated from the XRD. All right, and we use that relationship that we showed before to go from clay to claybound water and that's what we have out here. And we set this, so this set, that for this amount of clay, and we have, from again, the red dots to the XRD. These blue dots are XRD. That we should have claybound water and there isn't from the annamar data from T1 and T2. Would this led this to the paper that Margaret Lessenger and I and a buncha other guys published last year showing that, in fact, some of these clays are oil wet and that paper was last year and actually we got paper of the year award for it, last year, shows that we have oil wet clays, which was a absolute, something I had not anticipated. All right, the other example that we have is in the zone. Again, the same format. This is a red, this is a terministic, probabilistic inversion model. And, this is a red dots are XRD and this is where we have, the death track where we had points. These are the, again, the RFT pressure measurements. And, you can see that these, this zone up here was depleted, it's down to .3 PSI, .3 PSI, .3 PSI. So this was totally depleted zone and you can see that the match between the dielectric which is this blue dashed line and the version of the probalistic model do not match in that thing so we do have, definitely have invasion here. If you look at the resistivity, this is a lateral of D, in red, and the lateral I'll travel, in blue, and the MSFL you can see that we have invasion all through this point. And, the interesting thing is you can see where we have invasion corresponding to the high permeability rock. Again, when we talked about that a little bit earlier, the invasion's gonna be in the highest permeability rock. This is sultrate invasion and certainly not water flood invasion. So, if it's water flood invasion, these pressures would be up at the .5 range, rather than .3 range. Oh, one of the other things is we have another sand sitting right down here at the bottom. And, you can see that there is some fairly decent match between the dielectric and the high probabilistic conversion model. And, you see absolutely no indication of divasion in that zone. And the permeabilities are a little bit lower, as you can see from right, from the permeability transform. Oh, and that permeability transform is tight in the core, by the way. All the coaccrucients for that permeability model were tied to core. All right, so if we're looking at the annamar relationship in that particular case, you can see that, in this particular case, you can see that we have a fairly decent match between the XRD bound water and the T1 and T2 relationship. So, here's T2. And, you can see the claybound water cutoffs, which I don't use. And, T1 over here. The other interesting thing that you can see, well, so, in this case, it's probably not all the water wet. This portion is all water wet. And this portion up here looks like it might have oil in the, in this upper portion, in the higher porosity, higher permeability region, as, probably mixed wet. The interesting thing is that once we get a little bubble point, which is where we would be, in this particular case, to have this much, this much sultrate invasion. The interesting thing is, look at the T1 out here. This is basically a gas line that I put on here just for references purposes. Again, I don't use cutoffs per se. But you can see that there's a lot of gas in this particular zone. Showing, in this particular zone. Because we're gone a low vocal point If you look at this sand down here at the bottom, there's almost no gas in that zone. And, this is something we saw over and over again when we were running dilectrics in this oil. And, lastly, for understanding this reservoir, we had a plug that came from where it was over pressured and you can see the oil in the plug. And this is about, has, you know, about the same porosity and permeability. But, this is in a zone where we had no invasion and this is in a zone that was depleted and we had invasion and look at what happens to the UV signal. It's gone.

- [Narrator] I wanna show you the examples. And these are two examples that we have. And these are very busy slides And I'm gonna have to go through these quite fast. But, this left panel is a probabilistic inversion of a triple combo data, quad combo data. And so first thing we have is the illite, the clay component, and you can see that these are, these are excerpted The red dots are the excerpt e-data. So you can see that we're matching the excerpt e-data quite well. And this is the clay, in gray, this is the sand component, and the blue is limestone, and the purple is dolomite. Porosity is in white, in this particular case. These arrows in the depth track correspond to where we had sidewalk ores and actually the length of those arrows, the length of those bars, are the length of the core. The interesting thing is that we also had a downhole pressure gauge on this thing, an RFT, and we measured the pressure. The blue line is normal pressure, which the reservoir was at about yet discovery time. This is .43 PSI per foot. And this is .43 PSI per foot. This is .5 PSI per foot, so this says that these two data point and this sand here and this sand here were seeing the effects of the water flood. So, has a higher pressure than at the discovery point. We'll see in the next slide that we have some data down here. .3 PSI per foot, which is where it's depleted. So this is the inversion of all the data, crossing data expanded over on this particular slide. The green represents the oil, the put on the right, onto the very right, water that we calculate from the probabilistic model. And, the clay-bound water in gray. And, so, on there in dashed blue is a dielectric data. So, you can see that we have, through this sand, beautiful sand right down here and this sand up here. We have a fairly robust fit between the dielectric data and the deterministic model. Where it does not match, we see more water here at this particular point. And, if you look at the resistivity curves, you can see that the blight here is the MSFL and we do have invasion. Now this is the modified coached permeability from the annamar so you can get some ideas where we are going to have invasion and where it has low high permeability. All right, this is that same well. But, however, if we put on the annamar data on this thing to show you what this looks like with all the rest of the data that we had. Again, this is the mineralogy model, this is a saturation model of resistivity. The interesting thing is that, if you look at a claybound water, I calculate the claybound water from 0 into the T1 and T2 data from the annamar data. And, these are least of the calculated claybound water from T1 and T2. And, as shown over here, this is T2. This is a claybound water cutoff, I don't really use cutoffs, I use a tapered function. But, this gives you anything to the left of this line is going to be claybound water. Anything to the right of this line is gonna be water, free water, irreducible water, or oil. And, this is what it be look like in T1 states. And, so, what you see out here is there's very little clay signal in both T2 and in T1. Red's shown here, in this inversion. The interesting thing is these data points correspond to a clay calculated from the XRD. All right, and we use that relationship that we showed before to go from clay to claybound water and that's what we have out here. And we set this, so this set, that for this amount of clay, and we have, from again, the red dots to the XRD. These blue dots are XRD. That we should have claybound water and there isn't from the annamar data from T1 and T2. Would this led this to the paper that Margaret Lessenger and I and a buncha other guys published last year showing that, in fact, some of these clays are oil wet and that paper was last year and actually we got paper of the year award for it, last year, shows that we have oil wet clays, which was a absolute, something I had not anticipated. All right, the other example that we have is in the zone. Again, the same format. This is a red, this is a terministic, probabilistic inversion model. And, this is a red dots are XRD and this is where we have, the death track where we had points. These are the, again, the RFT pressure measurements. And, you can see that these, this zone up here was depleted, it's down to .3 PSI, .3 PSI, .3 PSI. So this was totally depleted zone and you can see that the match between the dielectric which is this blue dashed line and the version of the probalistic model do not match in that thing so we do have, definitely have invasion here. If you look at the resistivity, this is a lateral of D, in red, and the lateral I'll travel, in blue, and the MSFL you can see that we have invasion all through this point. And, the interesting thing is you can see where we have invasion corresponding to the high permeability rock. Again, when we talked about that a little bit earlier, the invasion's gonna be in the highest permeability rock. This is sultrate invasion and certainly not water flood invasion. So, if it's water flood invasion, these pressures would be up at the .5 range, rather than .3 range. Oh, one of the other things is we have another sand sitting right down here at the bottom. And, you can see that there is some fairly decent match between the dielectric and the high probabilistic conversion model. And, you see absolutely no indication of divasion in that zone. And the permeabilities are a little bit lower, as you can see from right, from the permeability transform. Oh, and that permeability transform is tight in the core, by the way. All the coaccrucients for that permeability model were tied to core. All right, so if we're looking at the annamar relationship in that particular case, you can see that, in this particular case, you can see that we have a fairly decent match between the XRD bound water and the T1 and T2 relationship. So, here's T2. And, you can see the claybound water cutoffs, which I don't use. And, T1 over here. The other interesting thing that you can see, well, so, in this case, it's probably not all the water wet. This portion is all water wet. And this portion up here looks like it might have oil in the, in this upper portion, in the higher porosity, higher permeability region, as, probably mixed wet. The interesting thing is that once we get a little bubble point, which is where we would be, in this particular case, to have this much, this much sultrate invasion. The interesting thing is, look at the T1 out here. This is basically a gas line that I put on here just for references purposes. Again, I don't use cutoffs per se. But you can see that there's a lot of gas in this particular zone. Showing, in this particular zone. Because we're gone a low vocal point If you look at this sand down here at the bottom, there's almost no gas in that zone. And, this is something we saw over and over again when we were running dilectrics in this oil. And, lastly, for understanding this reservoir, we had a plug that came from where it was over pressured and you can see the oil in the plug. And this is about, has, you know, about the same porosity and permeability. But, this is in a zone where we had no invasion and this is in a zone that was depleted and we had invasion and look at what happens to the UV signal. It's gone.