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  3. Facies

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- [Voiceover] Next, I'd like to visit briefly about the Bakken Facies and first we'll take a look at an isopach map of the Middle Bakken itself. And we see it ranges in thickness from zero to over 70, 80 feet, the thickest parts being, again, located on the east blank of the Nesson Anticline. There's a pronounced thick in the Richland County, Montana area which that would coincide with the Elm Coulee Field, the partial field area is located over here in Montrail County, North Dakota. The Bakken, again, can be subdivided into facies based on lithologic and biologic aspects. Those various facies can be recognized on logs. They're not present everywhere in the basin. Overall they represent deposition in the shelf environment which would be a shallow to a deeper shelf environments. We really don't see an subaerial evidence of subaerial exposure within the Bakken itself. A lot of work that's been done on the facies through the years pioneering work done by Julie LeFever back in the 1990s. And this diagram, I'm not going to walk through it but just illustrates some of the recent workers on the facies from the people from Canada to people in North Dakota, people from Whiting, Lynn Canter, Mark Sonnenfeld. And our facies are similar assignations or similar to the previous workers in the CSM 2010 are the types of facies designations, then, that we use. So when we look at the overall facies from bottom to the top, we go from a skeletal wackestone, Facies A, Facies B would be the bioturbated siltstone, interval is Facies C would be more of a laminite or a laminated interval, very fine grain sandstones and siltstones but couturious to dolomitic, Facies D cross-bedded bioclast, sandstone interval, Facies E and F, I'll just combine those together but thin bedded dolomud to wackestones and then of course we have our organic-rich shales both at the top and bottom of the Bakken interval. So the facies, themselves, are important. They're deposited in what we think is an epicontinental sea area, land areas to the north and to the south. We think this basin was connected to the open sea to the northwest during early Bakken time and then during later Bakken time when we get to the Mississippi and perhaps more of a east-west connection to that open seaway. The facies themselves result from differing water depths. The amount of clastic input, the amount of carbonate generation within the basin, salinity of the waters and a variety of other factors. Overall, the facies, in our opinion, represent units that go A through D would represent a shallowing, upwards succession and then E through F, overall deepening succession. Work that we're continuing to do and the distribution of facies within the Williston Basin. We've had a number of thesis projects that are ongoing on the Bakken. Seven completed to date and one of them, by Simenson, just this year, illustrating some of the core descriptions from Sanish Field area and the facies designations from those units from Sanish Field, from the A through the F facies, in this particular case. Can also look for the same wells and mineralogy within that and compare then the mineralogy to facies types. The G facies designation is just given toward the Bakken shales themselves. A and B are combined together into just the B facies in this particular case. The colors, for composition, again, the quartz being pink, the feldspar sort of the turquoise color, the greenish colors representing illite, calcite the light blue, and dolomite the dark blue, pyrite, again, with the yellow color. Overall, we see the silica content begins to decrease towards the uppermost part but still is dominated by silica. So we would refer to it then as either a siltstone or a very fine, grain sandstone across quite a bit of the area. The D interval, where we actually have some bioclastic component to it, we have an increase in the calcite content or the limestone content in that particular interval. And then overall, we also see in this particular area of the Sanish Field the amount of dolomite increases quite significantly as we get to the upper part of the middle Bakken. So overall, dolomite content increasing upward, silica content decreasing upward in this particular case. We can look a the same well and just look at the residual saturations based on core analysis. In this particular case, we see the highest oil saturations in the sea in D Facies and white area on this particular plot where we total up to 100 percent with it, represent the gas saturation. Then on one of these core analyses as you bring this core to the surface and the gas coming out of solution but that also, in my opinion, represents then the idea that you do have movable hydrocarbons based on this core analysis, so within these systems, although they are low porosity and low permeability, all that, to say that the highest saturation in the C and D intervals that we see saturation throughout. Can also do a plot of permeability and porosity which Simenson did in her thesis and that illustrates in this particular case that all of the facies have some kind of reservoir aspect to them where you have greater than six percent porosity and greater than 0.001 millidarcies permeability. In general, the F facies and the targets for horizontal drilling end of being the C, D, and E facies from what the operators tell me across the area. In fields, such as, which in that well that we were looking at comes from the Sanish Field and this cross-section goes from the Sanish Field over to the partial field, an area of intense development activity by Whiting and EOG and others. What you see facies-wise is the pinching out of facies as you go eastward to the east flank of the basin. The D, the highest energy facies is pinching out quite dramatically. And then the C interval, the laminite interval, also pinching out and then once you get over on the east side you can see what the target of horizontal drilling was, in that particular case, in a well that was temporarily abandoned. So where you have the favorable facies and end up with early, high initial production from the wells, this change in facies and this boundary also coincidences with thermal maturity of source rocks across the area. So not only do we see stratigraphic changes but we also see a thermal maturity change that almost coincides right where we see the stratigraphic change. Most people then envision the Sanish partial, trapping mechanism being largely stratigraphic but having a huge component of thermal maturity thrown on top of that, too.