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  4. Llanos Basin, Colombia Case Study

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- [Instructor] Okay, so let's look at a case where we have biodegradation, but the other thing I kept hearing about in fact I was just in the client office today and the team lead for the ESET team was commenting that she had this comment that everybody's always talking about water washing but nobody ever really measures it, or she doesn't see the measurements so essentially any anomalous behavior people blame on water washing. So I found her comments exactly right, so we want to measure these things and see what's going on. So in order to measure water washing we went to the most active aquifer that I've ever heard of on Planet Earth which is in the Llanos Basin, the eastern fore lands of the Andes Mountains. The surface waters here are the head waters of the Amazon River, the biggest river on the planet by a factor of five. You've got the prevailing easterlies coming from across Brazil loaded with water from the Atlantic and then the hit the very high, the young and high Andes Mountains and dump water throughout this entire region this big catch in the basin, and creating this gigantic river, the Amazon River. So, they've got, that's the surface waters, but the waters get, and just like we saw with the Rocky Mountains and the eastern sedimentary, I'm sorry, Western Sedimentary Basin of Canada, the mountains, the erosion of the mountains, weights down the basin next door and causes the subsidence of well everything, including source rock and you get oil generation so that's what I'm depicting here is this is weighted down by the erosion from the Andes, and you heat up the source rock that shaded source rock and get migration oils up to the east, or to the Llanos Basin. Now this is one, an example, of a reservoir in the Llanos Basin. So what you see is the contour lines. Now, I'm no PhD in reading contour lines, but these are pretty parallel, so I would defy anybody to find the trap. There's no trap, traps would normally be like circles or ellipses, or something like that, so there's no anticline or anything like that. So there's no trap except for the trap created by water flowing down, oil trying to flow up, and the oil got stuck in a so-called hydrodynamic stagnation point in this very famous field in Colombia. It's written in a paper by a person out of Albright here. And so if you look at the oil-water contact across the field it differs by 80 meters. So this is what I call an active aquifer. This is the tilt of an oil water-contact sustained over geologic time of 80 meters, something on that order. So the water that should be washing water cycle components, so lets see if we can detect that. So here's our 2DGC so we're going to look at what are the complications in this oil? So we can see okay, the n-Alkanes are really obvious here, okay so we can see all the n-Alkanes, and this is where we have some isoprenylates so they're smaller, but they're present, that's fine. This is the biomarker range, that's great. We can go check for the biomarkers and see if we have 25 more hopanes, things like that. And here's the two ring aromatics and we can check for water solubility so we can do all these things. Alright, and again, this is a standard GC we just compress everything along the volatility axis, so these peaks would merge with these peaks, and everything turns into kind of a mess, but with 2DGC the second dimension of separation you can see all these distinct different chemical components in the philosophic census like comparing a standard NMR and 2D NMR, you get so much more information. So this project was in ONGC's published. So first we'll look at the biomarker range. So again, the biomarker range is right here, that's where these hopanes show up. These saturated four or five ring compounds. So this is interesting. We see, oh, the hopanes are quite diminished in comparison to the 25-norhopanes, so this would tell us that we have severe biodegradation, because the hopanes are being converted to 25-norhopanes. So there it is, you don't need to be a big expert in geo-chem to see that. Well, there's a little bit of a puzzle though because okay, we have this oil is severely biodegraded, yet, this oil has a full complement of n-Alkanes. So like the bugs ate the shoe leather, but they didn't eat the main course and dessert, so what's going on? Well, maybe we're misreading biodegradation so we had a case just like this elsewhere and we did this project with them and so we thought well, if we do have biodegradation in this oil as being indicated by the appearance of 25-norhopanes, then we should see organic acids. So we went the world's highest Mass Spec, Professor Alan Marshall, and Ryan Rogers run this mass spec, actually Alan Marshall invented the technique, co-invented the technique, ultra-high technique, because they have such exquisite mass accuracy for each compound, better than the mass of an electron, they're able to list a unique elemental composition of the exact number of carbon atoms, hydrogen atoms, nitrogen, et cetera in the compounds. So they can find organic acids if they're present. So here's our 2DGCs, so we're going to look at what are the complications in this oil? So we can see okay the n-Alkanes are really obvious here. Okay, so we can see all the n-Alkanes, and this is where we have some isoprenylates, so they're smaller, but they're present, that's fine. This is the biomarker range, that's great. We can go check for the biomarkers and see if we have 25-norhopanes, things like that. And here's the two ring aromatics, and we can check for water solubility. So we can do all these things. Alright, and again, this is a standard GC, we just compress everything along the volatility axis so these peaks would merge with these peaks and everything turns into kind of a mess, but with 2DGC, the second dimension of separation, you can see all these distinct different chemical components in the philosophic census like comparing a standard NMR and 2D NMR, you get so much more information. So this project was in ONGC's published. So first we'll look at the the biomarker range. So again the biomarker range is right here, that's where these hopanes show up, these saturated four or five ring compounds. So this is interesting, we see, oh the hopanes are quite diminished in comparison to the 25-norhopanes, so this would tell us that we have severe biodegradation, because the hopanes are being converted to 25-norhopanes. So there it is, you don't need to be a big expert in geo-chem to see that. Well, there's a little bit of a puzzle though because okay, we have this oil is severely biodegraded, yet this oil has a full complement of n-Alkanes. So like the bugs ate the shoe leather, but they didn't eat the main course and dessert. So what's going on? Well, maybe we're misreading biodegradation so we had a case just like this elsewhere, and we did this project with them and we thought well if we do have biodegradation in this oil as being indicated by the appearance of 25-norhopanes then we should see organic acids. So we went to the world's highest Mass Spec, Professor Alan Marshall and Ryan Rogers run this mass spec. Actually, Alan Marshall invented the technique, co-invented the technique, ultra-high technique, because they have such exquisite mass accuracy for each compound, better than the mass of an electron, they're able to list a unique elemental composition of the exact number of carbon atoms, hydrogen atoms, nitrogen, et cetera, in the compounds. So they can find organic acids if they're present. So they took this sample. They have, they're looking at compounds that contain two oxygens that are likely to be organic acids based on the amount, or the ionization of these compounds in the mass spec, and there are plenty of them. So we have plenty of organic acids. It's consistent with the substantial biodegradation. So how come we have no biodegradation and substantial biodegradation of the same oil? Well, you do a little simple Petroleum System Modeling, this is a 2D Petroleum System Model, this is what you find. That the reservoir temperature shown here, and the subsidence is shown here, so there was subsidence with mountain building in the Andes, and the erosion, and the overburden forming, and driving this down, and at that point in time the reservoir temperature was not at 80 degrees C so all oil charged into the reservoir associated with the subsidence of that was cold enough that the bugs could chew up that oil, which they did, so they consumed all the n-Alkanes, and everything else, and they even consumed the hopanes, and the 25-norhopanes, but then in this space of subsidence of the reservoir, also associated with imperious episodic mountain building in the Andes. At this point in time the reservoir is Pasteurized, and has exceeded 80 degrees, roughly the Pasteurization temperature, and all subsequent oil associated with charging into the reservoir during this episode was not biodegraded as the bugs were dead. So this is where we had all the n-Alkanes coming in and being preserved, and this is where we formed the 25-norhopanes, and formed the organic acids. So that explains that it's multiple charging, and that we have extreme biodegradation and not biodegradation, all these different things. In addition, as an output of this project, we understood why some of these reservoirs contain a nice light oil, and some is much heavier, because almost paleo-Pasteurized at this juncture right here, and if you got deep enough you would kill the bugs here instead of here, so all of this oil would have been unbiodegraded and nice light oil, but in the reservoirs we were looking at they didn't quite Pasteurize, they cooled off here, and lots of more biodegradation until this point. Alright, so now we're going to look at water solubility, in fact that's why I really wanted to do this project on the Llanos Basin in the first place. You know this water-logged reservoir, let's go see what the water is doing. So we're going to look at that by examining Napthalenes. So you may know about BTEX, you may have head about BTEX as an environmental hazard. The BTEX compounds are all Benezes, the B stands for Benezes, the T is Tolulene, Ethylbenzene, and Xylene are all single ring aromatics. An environmental hazard both because Benezes are carcinogenic, they interpolate in DNA and mess up the transcription, the reading of DNA, and also because they dissolve in water. If they didn't dissolve in water then you wouldn't get them from drinking water, but since they dissolve in water they become an environmental hazard, linked with the effect of the carcinogenic and water soluble. Well, two ring aromatics, Naphthalene, this is Naphthalene, actually the active substance in mothballs for an example, I would not recommend it, I'd recommend getting holes in your clothes instead of cancer, but anyway, so Naphthalene has water solubility and there it's listed right here, and then you put a methyl group on it the water solubility drops, this is the estimated some measurements on specific compounds, but I didn't have all the measurements so I had to use estimated. Two carbons you're reducing the water solubility with more alkane carbon, here's five carbons. Now when you put five carbons on here, five alkane carbons, they could be in a single chain or they could be five different methyl substitutions, or a methyl and propyl group et cetera, but five carbons. Okay it's kind of like putting wax on the aromatics. We know that aromatics are water soluble, we know that wax in insoluble in water so as you add alkane you drop the water solubility by two orders of magnitude. So that means we can look at a range of the Naphthalenes and check the extent of water solubility. So that's what we do. So we take the oils from the Llanos Basin, and here we can see that Naphthalene is missing, the most water soluble of the Naphthalene series, right there. And then we see, uh, the one methyl nap, the C1-Naphthalenes are present here. And C1 there's two locations, it's either adjacent to the other ring or further away from the other ring and all other positions around here are equivalent. So there's only two C1-Naphthalenes, and there are the two peaks. So, and the C3's are there, and the C4's, and that's actually the C5's. And in this sample okay, and remember we did have all the alkanes because this oil charged subsequent to being paleo-Pasteurized so we have all of our n-Alkanes and the isoprenylates, these things. Okay, but over here we see okay the Naphthalene is missing and really the C1-Naphthalenes are missing, the C2's, there's a lot more options for how you put two carbons on the rings, or three carbons, so these are present. Here the C2's are starting to go away, they're not all gone, and the C3's are pretty much present. Fluorene by the way is there, and it doesn't have any more solubility, or not much. Okay, so there you go, you can see the water washing, so we're pretty content with that. Everything is making sense. Alright, so here we have multiple charging, water washing, and we can disentangle all that in 2DGC.

- [Instructor] Okay, so let's look at a case where we have biodegradation, but the other thing I kept hearing about in fact I was just in the client office today and the team lead for the ESET team was commenting that she had this comment that everybody's always talking about water washing but nobody ever really measures it, or she doesn't see the measurements so essentially any anomalous behavior people blame on water washing. So I found her comments exactly right, so we want to measure these things and see what's going on. So in order to measure water washing we went to the most active aquifer that I've ever heard of on Planet Earth which is in the Llanos Basin, the eastern fore lands of the Andes Mountains. The surface waters here are the head waters of the Amazon River, the biggest river on the planet by a factor of five. You've got the prevailing easterlies coming from across Brazil loaded with water from the Atlantic and then the hit the very high, the young and high Andes Mountains and dump water throughout this entire region this big catch in the basin, and creating this gigantic river, the Amazon River. So, they've got, that's the surface waters, but the waters get, and just like we saw with the Rocky Mountains and the eastern sedimentary, I'm sorry, Western Sedimentary Basin of Canada, the mountains, the erosion of the mountains, weights down the basin next door and causes the subsidence of well everything, including source rock and you get oil generation so that's what I'm depicting here is this is weighted down by the erosion from the Andes, and you heat up the source rock that shaded source rock and get migration oils up to the east, or to the Llanos Basin. Now this is one, an example, of a reservoir in the Llanos Basin. So what you see is the contour lines. Now, I'm no PhD in reading contour lines, but these are pretty parallel, so I would defy anybody to find the trap. There's no trap, traps would normally be like circles or ellipses, or something like that, so there's no anticline or anything like that. So there's no trap except for the trap created by water flowing down, oil trying to flow up, and the oil got stuck in a so-called hydrodynamic stagnation point in this very famous field in Colombia. It's written in a paper by a person out of Albright here. And so if you look at the oil-water contact across the field it differs by 80 meters. So this is what I call an active aquifer. This is the tilt of an oil water-contact sustained over geologic time of 80 meters, something on that order. So the water that should be washing water cycle components, so lets see if we can detect that. So here's our 2DGC so we're going to look at what are the complications in this oil? So we can see okay, the n-Alkanes are really obvious here, okay so we can see all the n-Alkanes, and this is where we have some isoprenylates so they're smaller, but they're present, that's fine. This is the biomarker range, that's great. We can go check for the biomarkers and see if we have 25 more hopanes, things like that. And here's the two ring aromatics and we can check for water solubility so we can do all these things. Alright, and again, this is a standard GC we just compress everything along the volatility axis, so these peaks would merge with these peaks, and everything turns into kind of a mess, but with 2DGC the second dimension of separation you can see all these distinct different chemical components in the philosophic census like comparing a standard NMR and 2D NMR, you get so much more information. So this project was in ONGC's published. So first we'll look at the biomarker range. So again, the biomarker range is right here, that's where these hopanes show up. These saturated four or five ring compounds. So this is interesting. We see, oh, the hopanes are quite diminished in comparison to the 25-norhopanes, so this would tell us that we have severe biodegradation, because the hopanes are being converted to 25-norhopanes. So there it is, you don't need to be a big expert in geo-chem to see that. Well, there's a little bit of a puzzle though because okay, we have this oil is severely biodegraded, yet, this oil has a full complement of n-Alkanes. So like the bugs ate the shoe leather, but they didn't eat the main course and dessert, so what's going on? Well, maybe we're misreading biodegradation so we had a case just like this elsewhere and we did this project with them and so we thought well, if we do have biodegradation in this oil as being indicated by the appearance of 25-norhopanes, then we should see organic acids. So we went the world's highest Mass Spec, Professor Alan Marshall, and Ryan Rogers run this mass spec, actually Alan Marshall invented the technique, co-invented the technique, ultra-high technique, because they have such exquisite mass accuracy for each compound, better than the mass of an electron, they're able to list a unique elemental composition of the exact number of carbon atoms, hydrogen atoms, nitrogen, et cetera in the compounds. So they can find organic acids if they're present. So here's our 2DGCs, so we're going to look at what are the complications in this oil? So we can see okay the n-Alkanes are really obvious here. Okay, so we can see all the n-Alkanes, and this is where we have some isoprenylates, so they're smaller, but they're present, that's fine. This is the biomarker range, that's great. We can go check for the biomarkers and see if we have 25-norhopanes, things like that. And here's the two ring aromatics, and we can check for water solubility. So we can do all these things. Alright, and again, this is a standard GC, we just compress everything along the volatility axis so these peaks would merge with these peaks and everything turns into kind of a mess, but with 2DGC, the second dimension of separation, you can see all these distinct different chemical components in the philosophic census like comparing a standard NMR and 2D NMR, you get so much more information. So this project was in ONGC's published. So first we'll look at the the biomarker range. So again the biomarker range is right here, that's where these hopanes show up, these saturated four or five ring compounds. So this is interesting, we see, oh the hopanes are quite diminished in comparison to the 25-norhopanes, so this would tell us that we have severe biodegradation, because the hopanes are being converted to 25-norhopanes. So there it is, you don't need to be a big expert in geo-chem to see that. Well, there's a little bit of a puzzle though because okay, we have this oil is severely biodegraded, yet this oil has a full complement of n-Alkanes. So like the bugs ate the shoe leather, but they didn't eat the main course and dessert. So what's going on? Well, maybe we're misreading biodegradation so we had a case just like this elsewhere, and we did this project with them and we thought well if we do have biodegradation in this oil as being indicated by the appearance of 25-norhopanes then we should see organic acids. So we went to the world's highest Mass Spec, Professor Alan Marshall and Ryan Rogers run this mass spec. Actually, Alan Marshall invented the technique, co-invented the technique, ultra-high technique, because they have such exquisite mass accuracy for each compound, better than the mass of an electron, they're able to list a unique elemental composition of the exact number of carbon atoms, hydrogen atoms, nitrogen, et cetera, in the compounds. So they can find organic acids if they're present. So they took this sample. They have, they're looking at compounds that contain two oxygens that are likely to be organic acids based on the amount, or the ionization of these compounds in the mass spec, and there are plenty of them. So we have plenty of organic acids. It's consistent with the substantial biodegradation. So how come we have no biodegradation and substantial biodegradation of the same oil? Well, you do a little simple Petroleum System Modeling, this is a 2D Petroleum System Model, this is what you find. That the reservoir temperature shown here, and the subsidence is shown here, so there was subsidence with mountain building in the Andes, and the erosion, and the overburden forming, and driving this down, and at that point in time the reservoir temperature was not at 80 degrees C so all oil charged into the reservoir associated with the subsidence of that was cold enough that the bugs could chew up that oil, which they did, so they consumed all the n-Alkanes, and everything else, and they even consumed the hopanes, and the 25-norhopanes, but then in this space of subsidence of the reservoir, also associated with imperious episodic mountain building in the Andes. At this point in time the reservoir is Pasteurized, and has exceeded 80 degrees, roughly the Pasteurization temperature, and all subsequent oil associated with charging into the reservoir during this episode was not biodegraded as the bugs were dead. So this is where we had all the n-Alkanes coming in and being preserved, and this is where we formed the 25-norhopanes, and formed the organic acids. So that explains that it's multiple charging, and that we have extreme biodegradation and not biodegradation, all these different things. In addition, as an output of this project, we understood why some of these reservoirs contain a nice light oil, and some is much heavier, because almost paleo-Pasteurized at this juncture right here, and if you got deep enough you would kill the bugs here instead of here, so all of this oil would have been unbiodegraded and nice light oil, but in the reservoirs we were looking at they didn't quite Pasteurize, they cooled off here, and lots of more biodegradation until this point. Alright, so now we're going to look at water solubility, in fact that's why I really wanted to do this project on the Llanos Basin in the first place. You know this water-logged reservoir, let's go see what the water is doing. So we're going to look at that by examining Napthalenes. So you may know about BTEX, you may have head about BTEX as an environmental hazard. The BTEX compounds are all Benezes, the B stands for Benezes, the T is Tolulene, Ethylbenzene, and Xylene are all single ring aromatics. An environmental hazard both because Benezes are carcinogenic, they interpolate in DNA and mess up the transcription, the reading of DNA, and also because they dissolve in water. If they didn't dissolve in water then you wouldn't get them from drinking water, but since they dissolve in water they become an environmental hazard, linked with the effect of the carcinogenic and water soluble. Well, two ring aromatics, Naphthalene, this is Naphthalene, actually the active substance in mothballs for an example, I would not recommend it, I'd recommend getting holes in your clothes instead of cancer, but anyway, so Naphthalene has water solubility and there it's listed right here, and then you put a methyl group on it the water solubility drops, this is the estimated some measurements on specific compounds, but I didn't have all the measurements so I had to use estimated. Two carbons you're reducing the water solubility with more alkane carbon, here's five carbons. Now when you put five carbons on here, five alkane carbons, they could be in a single chain or they could be five different methyl substitutions, or a methyl and propyl group et cetera, but five carbons. Okay it's kind of like putting wax on the aromatics. We know that aromatics are water soluble, we know that wax in insoluble in water so as you add alkane you drop the water solubility by two orders of magnitude. So that means we can look at a range of the Naphthalenes and check the extent of water solubility. So that's what we do. So we take the oils from the Llanos Basin, and here we can see that Naphthalene is missing, the most water soluble of the Naphthalene series, right there. And then we see, uh, the one methyl nap, the C1-Naphthalenes are present here. And C1 there's two locations, it's either adjacent to the other ring or further away from the other ring and all other positions around here are equivalent. So there's only two C1-Naphthalenes, and there are the two peaks. So, and the C3's are there, and the C4's, and that's actually the C5's. And in this sample okay, and remember we did have all the alkanes because this oil charged subsequent to being paleo-Pasteurized so we have all of our n-Alkanes and the isoprenylates, these things. Okay, but over here we see okay the Naphthalene is missing and really the C1-Naphthalenes are missing, the C2's, there's a lot more options for how you put two carbons on the rings, or three carbons, so these are present. Here the C2's are starting to go away, they're not all gone, and the C3's are pretty much present. Fluorene by the way is there, and it doesn't have any more solubility, or not much. Okay, so there you go, you can see the water washing, so we're pretty content with that. Everything is making sense. Alright, so here we have multiple charging, water washing, and we can disentangle all that in 2DGC.