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What we’re doing here is we’re going to demonstrate the origin of the predominant type of residual oil zone in the Permian Basin. This is our source for the next generation of CO2 EOR production for oil. What we’ve got is a cross-section that we have adopted here in the Permian Basin. This would be west to east cross-section showing the layers of geology that run all the way from modern-day sediments through the cretaceous down to the Permian, from which the basin is named and down into the older Paleozoic to the basement.  

We’ve got over 200,000 wells that have penetrated this geology, so we know it very well. We are trying to recreate the tectonic events that have formed the basin and then altered the basin, including the original mega trap of oil in the San Andres formation of the Permian age. We have an animation for you here that tends to recreate the formation of the Permian basin and shows the original oil trap that was formed in the San Andres formation, and then we’re going to animate how part of that mega trap was swept out by mother nature. The way it was in the geologic past is not how it is in the present and so what we try to do with the animation is recreate that for you.

This our idealized cross-section showing the basin and its early tectonic stage in the early Permian time; we cut out a section of that because we’re going to concentrate on that in the first part of this animation. On the right of that is the central basin platform, which basically divided the Permian Basin into two regions.  The west was the Delaware Basin region, on the east was a Midland Basin region, and was separated by this platform of carbonate rock, limestones and ultimately become mostly dolomites, calcium magnesium carbonates. Our reservoirs, which we’ve targeted for many years, are the San Andres formation, which lies in the middle to late Permian time. 

Let’s look at that cutout section of our animation. You see this central basin platform on the right and the Delaware Basin on the left, and as you can see, as the subsidence is occurring, the central basin platform continues to grow upwards near the water surface, and the basin to the left is filling in. These fine-grain sediments we’re exploiting today with shale production, and then it’s covered up by the cretaceous rock 2,000ft deep in many places. Then we’re going to move out to the west, and we’re going to see forming of the mountains in New Mexico. In the animation, you see the outcrop of the San Andres formation that occurs in the area west and north of Roswell, New Mexico, and west and north of Carlsbad and Artesia, New Mexico. There, the water is meteoric in origin, coming from the atmosphere and comes into the casted outcrop of the San Andres formation and then begins to move down deep into the modern Permian Basin and sweep into the San Andres and into this mega trap that’s on the central basin platform. 

The black represents the large-scale or mega entrapment of oil, and then the water below it is the aquifer that the San Andres formation has. You can see we’re changing that. We’ve got a big section of the former trap that’s now being swept of oil from left to right and moving out of the basin. That region then becomes what we call residual oil zone or ROZ, and that is mother nature’s waterflood.

We are now going after that much like we’ve gone after our waterfloods, and we’re going after the oil left behind. We’re doing that now with 12 projects, and we’re successfully producing oil from the residual zone in the San Andres formation. We think that this is the only place in the world that that’s occurring, but we know there are other places in the world that these ROZs exist.

Contact Melzer Consulting at (432) 682-7664 or fill out our contact form for more information.

The oil and gas industry has learned in recent years that oil entrapments may have undergone some changes in their geologic past. It isn’t proper in many basins to think that the original stage of tectonics, which includes: burial, oil generation, and migration into a structurally high trap, might not have been altered by a second or third, or fourth stage where water and oil moved around in the sub-surface. We like to call this mother nature’s water floods, and for the purposes of discussion in this presentation, we’re going to look at four slides and show what we like to call the type two residual oil zone or ROZ type 2. This first slide is a hypothetical trap that might be representative of the original stage of tectonics and the original entrapment. Sometimes, we like to call that the paleo entrapment first stage. This left side here is a type two ROZ, one in which we breach a seal to that trap and move oil out vertically.

But there are two other types as well; one that would be just due to a basin-wide tilt, and this slide here would show that we’ve moved the basin down to the west and moved oil out to the east, and changed the oil-water contact due to that tilt of the basin. 

The Second Stage, as I mentioned, is a breached seal, a third type of ROZ is one where we have a hydrodynamic gradient. We will not discuss that today but what that represents is an outcrop perhaps of the reservoir formation somewhere out here to the west on the left side of this slide, and water moves down deep through the basin, tilts the oil-water contact, and moves oil out to the east. 

We’ve animated this type two ROZ, and we’ve shown the fault here to make the discussion a little bit easier. Due to pressure, earthquakes, and the paleo history of this reservoir, the oil may leak out vertically; it may find a new reservoir above the former reservoir, and as you see in the animation, it accumulates under a seal up above that and what’s happened is the water has moved into the formerly oil occupied portion of the lower part of that lower trap and moved the oil up and created a horizontal bottom to the residual oil zone and horizontal top which is also the base of the new modern-day oil trap. That’s the target that we go after with enhanced oil recovery. When the oil saturation is sufficient, we can get that economically in today’s methods of EOR.

Contact Melzer Consulting at (432) 682-7664 or fill out our contact form for more information.

The oil and gas industry has come to recognize now that oil reservoirs and the sub-surface can undergo multiple stages of tectonics beyond the original one, which involves burial, oil generation in the original entrapment stage where oil moved into a structurally high trap in the sub-surface. Those multiple stages of tectonics can take one of three different forms. 

We are going to talk about the first kind of tectonic adjustment that occurs in the sub-surface, which moves the oil around and creates what we like to call a residual oil zone or ROZ, where water has invaded a former oil trap portion of a reservoir and the only oil left in that portion of the trap is that what we call residual oil that’s in the corners of the pore spaces or perhaps attached to the rock surface itself.  

For the purposes of this discussion, we’ll walk through four slides in the first part and then go to animation to make it clear how this might work for ROZ type 1. What we’ve got in the first slide is a hypothetical origin entrapment that might have been formed many ages ago in the geological past, and what we’re going to do is, in the case of this first type of ROZ, we’re going tilt the left side (what we call the west side) of this hypothetical trap down and actually move oil out of the trap and displace a portion of that pore space (a wedge of that pore space) with water, that’s what we call type 1.

Type 2 is a different kind of readjustment due to tectonic activity, and it’s one that would activate a fault perhaps in the sub-surface and some of the oil or maybe all of the oil leaked out of that sub-surface trap (paleo trap/ original trap) and water invaded vertically from below and created a smaller trap or perhaps no trap at all.

The 3rd type of trap is what we call a type 3 ROZ, wherein we have a hydrodynamic gradient where we might move water from left to right and displace oil to the right, leading to a tilted oil-water contact. This particular type is very common in the Permian Basin. 

Let’s go back to type one, and that’s what we’re going to concentrate on in this presentation, and we have an animation to help you understand how this might occur in the sub-surface. We have, in this case, a downward tilt; what we call the Westside is tilting downward, and you see the water encroach vertically upward into the former paleo trap, move the oil out, and let water into the pore spaces.

On the east, we’re losing oil past the spill points, going out to the east, probably to another entrapment—a secondary entrapment somewhere off to the east. In this case, the ROZ that’s formed is a wedge shape with its thickest side on the west, and the oil-water contact that was in the paleo trap has now moved down and forms the base of the ROZ, whereas the new oil-water contact which has to be horizontal, due to gravity effects creates the top of the ROZ. So, we have a wedge shape with its thickest side on the west side of the paleo trap, and that’s the target that we go after with enhanced oil recovery. When the oil saturation is sufficient, we can get that economically in today’s methods of EOR.

Contact Melzer Consulting at (432) 682-7664 or fill out our contact form for more information.

Research in the massive living laboratory that is the Permian Basin has unlocked unexpected sources of crude oil and natural gas for decades.