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  1. Introduction

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- [Voiceover] Today, I'd like to talk to you about the Bakken Petroleum System of the Williston Basin, which is a low-permeability, low-porosity resource play. The Williston Basin, a very large semi-circular basin that exists in North and South Dakota, Eastern Montana, extends up on into Canada and the Manitoba and Saskatchewan, the deepest part of the Basin being located in North Dakota. Recent drilling activity in the Bakken has brought the Bakken formation to light in the Basin, and most of the drilling activity started, although the overall oil play in the Williston Basin based back to the early 1950's; it's the recent drilling activity from 2000 to the present that's brought the Middle Bakken to life. But we'll be talking about the Bakken across the Basin. Some of the older producing areas in the Basin for the Bakken include the Billings Nose area, and then the more recent activity in Elm Coulee, Sanish/Parshall area discovered in 2006, the Viewfield Area in Canada discovered in the 2000's, big large area of activity in continuing to develop. This particular triangle represents the way Ivy picked the resource pyramid, with, in this case, oil on the right and gas on the left. The upper part of the triangle represents easy-to-develop resources, and obviously, the lower part of the triangle represents the harder-to-develop resources which require increasing product price and, most definitely, improved technology. And so what we're gonna be talking about today is what I call a tight-oil system; I'm not gonna call it an oil shale or a shale oil because it does have a middle member which is a silty dolostone or a dolomitic shale stone that is actually the biggest contributor to production, so a tight-oil system, because of the increased technology that's required, you can view these tight-oil systems as being what we call "technology reservoirs". So the tight oil plays just like the tight gas plays, you know, we're in a new game and exploration and development, and I think the Bakken clearly is the leader in all the new plays as we see it. At the top half we have a bon-blake-y diagram in it, and this is the diagram for the Late Devonian- Early Mississippian time, which is a time interval at Bakken deposition; Bakken was deposited largely in the Williston Basin, but there's black shale equivalents that are deposited outside the base, in such as the Exshaw up in the Canadian portion, and then, you can see the rest of the mains as they change around the North America area for this time interval; but a time of quite a few black shale deposits, these are the time equivalents and obviously, there's older and younger Devonian and Mississippian black shales that are not listed on this diagram, that are equally prospective to the Bakken. So, at this time interval, a shallow, epicontinental sea existed over a large part of North America. The Bakken Petroleum System then, is Late-Devonian, Early Mississippian in age, consists of source beds in the lower Lodgepole of shale units that we call the False Bakken, but also in the main source beds are in the Bakken itself. The upper shale and the lower shale in these are really organic rich. Reservoir units are mainly in the Bakken, but also the upper Three Forks, and, in the future, I think the lower part of the Lodgepole will also turn into significant reservoir unit, too, so together, all of that makes up then what we call the Bakken Petroleum System, but people at the North Dakota Survey and Industrial Commission, in their study, released in 2010 estimate that the recoverable volumes from the Bakken Petroleum System will be about four billion barrels with 2.1 billion barrels coming from the Bakken, and then 3, 1.9 billion barrels coming from the Three Forks interval; that correlates very well with the recent USGS estimates where they also estimated that there would be a technical recoverable out of the Bakken Petroleum System of 3.6 billion barrels. This is an isopach map of the Bakken for the US parts of the Williston Basin that was published by Sanberg and republished by Meissner in 1978. It illustrates the overall thickness of the Bakken; ranges in thickness from zero to over 120 feet, the thickest part being located just east of the structural feature in the Williston Basin called the Nesson Anticline. There are three members of the Bakken and those members are shown very diagrammatically on this cross section; the upper and lower organic rich shales, and the middle member that's a silty dolomite or a dolomitic siltstone in this particular case. Each of the units overlaps the underlying unit, so we can see the limits of each of those units, then across the Basin, the lower shale, the heavy dashed line, the middle member by the dotted line, and then the zero contour represents the upper shale limit across the interval. Well, a Bakken Petroleum System, then, as we've defined it, organic rich shales, and then these reservoir units, not only in the Bakken but the lower Lodgepole, the upper Three Forks, and most of that oil, based on the geochemistry that's been done on the systems and analyzing oils up in the Mission Canyon and so on, it looks as if most of that oil has actually stayed within this interval. Generation of hydrocarbons creates abnormal pressure, so we have an abnormal pressure compartment, then, in the deeper part of the Williston Basin. It's not a flat compartment across the Basin, but a tilted one, because of geothermal gradients across the Basin, so the west side of the Basin you have a higher area of thermally mature source rock, and on the east side deeper or lower area of maturity for those same source rocks, so that's the Bakken Petroleum System. There's been some great papers written on the Bakken through the years, and some of the pioneering research that was done on it was done by Sidney Power medalist, Fred Meissner. In the paper he published back in 1978, he stated, "Relationship between source-rock "maturity, hydrocarbon generation, "geopressuring, fracturing suggest "an opportunity in exploration for "unrecognized and unlooked-for 'unconventional' "accumulations of potentially very large regional extent." Those words written by him back in 1978, it took technology 'bout 20 years for the reality to come to being, but that turned out to be absolutely correct, what he stated over 30 years ago. The Bakken Petroleum System basics, what makes it work, the upper and lower black organic-rich shales, the world class source rocks hard, siliceous, pyritic port-loric-anti-carbon contents, average 11 weight percent across the basin in places, can get up to 40 weight percent. The organic matter in the high organic matter indicates anoxic conditions, it's a sapropelic type of organic matter, estimates hydrocarbon generation, the earliest estimate by loli-dal was 10 billion barrels, or the later estimates, the price estimate of the amount of oil generated was 400 billion barrels of oil. Most people who have estimated the amount of oil generated put it north of the 100 billion barrel number, so it's very significant amount of oil that's been generated then within the Bakken Petroleum System. The targets of horizontal drilling are the middle member of the Bakken, and as I've stated before, dolomitic siltstone to a silty dolomite, some cases, are very fine defined-grain sandstone, low-porosity, low permeability system. Porosity's less than eight percent, permeability's less than 0.1 millidarcy. The Upper Three Forks is a recent target of horizontal drilling in the Williston Basin, and the recoverable reserves for the Three Forks, most of us feel will be close to what has been found within the Bakken; because of the hydrocarbon generation creating abnormal pressure, most of the pressure gradients are graded in 0.5 psi per foot across the Williston Basin, and many of them, at least on the East Plank, can get up to 0.7 plus psi per foot gradient. This map just illustrates, then, across the US part of the Williston Basin, the drilling activity in the Bakken and the Three Forks and the producing wells from those formations, those wells productive from the Bakken are the green dots, and the wells productive from the Three Forks are the orange dots. The oldest production in the Basin is from the Antelope Field, which is on the southeast point of the Nesson Anticline; that production goes back to 1953, and most of the production there came from the upper Three Forks, and the Sanish, and a little bit from the lower Bakken shale. So, that's the oldest production illustrating that we had this system in the Williston Basin. The next area that came into production was during the 1970s and 80s and that's the upper shale play that's located down in the southwest part of North Dakota on this particular slide, what we call the Billings Nose or Fairway trend, area of the first vertical well drilled in 1976, first horizontal well drilled in the upper shale in 1987. 1990's came around, price collapsed with the price of oil, but a Billings independent dig dimly put together a play over in Richland County, Montana, and that resulted then in the discovery in the development of the giant Elm Coulee field, and that development activity continues even yet today. With the discovery of that very significant field, and the significant production of the play came back into North Dakota, and in 2006, Mike Johnson, a Denver independent put together a play in the Parshall field area, turned that to one of the companies here in Denver, EOG, and that resulted in the discovery of Parshall, Weidinget, it at the same time interval, made a discovery in the Sanish field, and then the areas to the north and the south along the Nesson Anticline, we have also seen lots of drilling activity. Most recently, the "Rough Rider" area, Texas independent Briggins developing that area, and illustrating that with lots of multi-stage fracks, lots of production can come from the Bakken even from that area. Lots of production all across the Williston Basin, and interesting thing, perhaps into the plays looks like it's headed back into Montana, although it started there, and then North Dakota sent it back to Montana, the recent activity, that is. We can go back and look at some of the things that, in a classic AAPG article that Murray wrote 1968 on the Antelope Fields, some of the unusual characteristics about the Bakken Petroleum System mainly the Three Forks, he saw very high reservoir pressure, high productivity from several wells with lower productivity right next to those wells, indicating fracturing, of course, production associated with steep dip, kind of a nebulous, ill-defined reservoir that didn't conform to structural closure, almost complete absence of water, low porosities, low permeabilities, so even back in 1968 the idea of unconventional system, he didn't use that word 'unconventional', but was very close to using it at that particular time. Back to the development, then, of the Bakken across the basin and the various cycles that we've seen in the development activity Antelope Field, discovered in 1953, down this production plot, obviously, maybe not obviously but oil production is green, gas production red, and the gas oil ratio in orange on this particular slide, so just look at the green line, then, and you can see the cycles in oil production. And it's in barrels of oil per day the way I have it plotted out, but the development of Antelope, each peak production about 1967, when our production declined the first vertical well drilled, largely for the upper shale, although the surrounding intervals also proofed in 1976; the first horizontal well drilled in the Williston Basin in the upper shale in 1987, and you can see the peak of production in about 1992, too, there, when our production declined, and then Elm Coulee ticked off with horizontal wells in 2000, and that development activity continues to the present, Parshall found in 2006, and oils are 200,000 barrels per day of oil production in the last 10 years. So, here's a mature basin that most people thought that with recent giant fields they found within it just as of late. This is a log that represents the Bakken Petroleum System then in the Williston Basin and illustrates those units that I previously talked about that the Bakken, the upper lower organic rich shale the middle member that can be subdivided into a number of facies, based on lithologic and biological aspects, or a logical lowest most-carbonate interval called the scallion; overlying the scallion's the False Bakken, and then the Upper Three Forks below the Bakken, we can subdivide that into the number of facies, too. Factors related to Bakken and Three Forks production, I've mentioned these, but the source beds, mainly the upper lower organic rich fields, there is a source bed within the False Bakken, too. We're doing quite a bit of those organic chemistry on that source bed package, the reservoir's principally the Middle Bakken and the Upper Three Forks that's the targets of horizontal drilling. The reservoir has favorable facies, diagenetic history, although we have no porosity and permeability, we still do have some matrix permeability, within these systems. We have mature source rocks over a large area that forms a continuous oil column. But we have fracturing that results from a number of causes, folds, faults, solution of the deeper prairie evaporite, high fluid pressures created by hydrocarbon generation, and then the regional stress field, probably the most important of where you find the open fractures, so a variety of ways to get fractures within the Bakken Petroleum System. The last bullet and most importantly the drilling and completion technology, if it wasn't for the horizontal drilling and the fracking of those horizontal wells with the multi-stage fracking, this place still would not even exist.