3 to 4.3 Billion Barrels of Oil in North Dakota and Montana

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Clarice

Welcome, and thanks for listening to the USGS CoreCast. I'm Clarice Nassif-Ransom. North Dakota and Montana have an estimated 3 to 4.3 billion of barrels of undiscovered, technically recoverable oil in an area known as the Bakken Formation. That is according to a USGS assessment released April 10th. Today, we are here with USGS scientists Brenda Pierce and Rich Pollastro to find out more about the Bakken Formation. Thank for joining us, Brenda and Rich.

Brenda

Happy to be here.

Rich

You're welcome.

Clarice

So Brenda, tell me a little bit about the results of the assessment to put it into context. What does this mean?

Brenda

Well, what we found when we finally did the assessment, the results at 3.65 billion barrels, this is-of the current USGS estimates-this is the largest oil accumulation in the lower 48. It is also the largest continuous type of oil accumulation that we have ever assessed.

There are two main types of oil and gas accumulations: conventional and continuous. This is a very specific type of geology. It's the fastest growing resource in the United States. It takes a little bit extra care to assess, as well as to produce it, and so this is the largest one of this type of oil deposit that we've ever assessed.

Clarice

And Brenda, why did you do this assessment?

Brenda

Well the USGS is the sole provider of publicly available information on undiscovered, technically recoverable resources-oil and gas resources-of the United States and the world. And in that sense, we use a consistent methodology so that all of the basins are comparable and that one can compare those results to put it into context of what is there, what is not, what has production potential, etcetera.

This is one of the missions of the USGS Energy Resources Program: to provide this unbiased, transparent set of information on the oil and gas resource potential-technically recoverable resource potential-of the United States and the world. So that's why we did it. It's because it's just part of this national assessment, and that is our job to provide this information.

Clarice

What is the definition of technically recoverable oil, Brenda?

Brenda

Technically recoverable oil is that oil or gas, but oil in this case, that is recoverable using today's technology, and we get at that by actually working with industry to understand what they are doing in a particular formation so . . . to interview them, work with them, and understand actually what recoveries their getting, what their drainage areas are, what processes they're using, what technology they're actually using so that we understand what is technically recoverable.

Clarice

Rich, tell me a little bit about the science behind conducting a study or assessment like USGS did.

Rich

The best way to answer that is the Bakken is not the same everywhere. So you really have to understand the geology and the history of the Bakken to really get an understanding of what factors are favorable to production and which ones are not so favorable. We only know the Bakken Formation in the subsurface. It doesn't crop out on the surface, and you can't walk up to it and touch it and feel it and walk on it and look at it, but the only way we can really study it is from the core that is taken from wells.

The Bakken typically is at 9,000 or 10,000 feet, where it's produced, and so we have to go to core facilities like the USGS Core Research Center or the core research center up in North Dakota to really look and touch and feel and examine the Bakken Formation and try to understand how it was deposited and what were the variations in the rock composition and the rock structure.

Clarice

And how did you do that?

Rich

That's done, again, in a core library. And you observe the core, and you describe the core, and you look for significant features for production like porosity and fractures, and  analyze the source rock, the dark organic source rock, and find out how much organic matter is there.

I mean, there's a number of different parameters that we look at that are critical to petroleum generation and since the Bakken is both the source rock and the reservoir rock, we look at those factors that involve those particular elements of the Bakken.

Clarice

What's been the most fascinating aspect of this assessment from a scientific perspective, from your perspective?

Rich

Well, the Bakken has been a challenge for decades, and that's shown in the literature and also in our understanding of the Bakken. And a good example of that is our assessment in '95 compared to this one. But the Bakken has some hidden secrets that we're trying to unveil, and one of them was when did it really start to generate oil, and that has changed our geologic model a little bit and it added to the degree of the geographic area.

And also the technology certainly has brought the Bakken back on the map again. It's gone through a number of different exploration cycles, but with the present day technology, the Bakken has become a significant exploration target.

Clarice

And so when-when did it start producing oil? What was your discovery?

Rich

As far as the time frame, we . . . our modeling showed that the Bakken started generating somewhere between 50 and 90 million years ago. However, the level which the Bakken had generated was a bit different than we formerly believed. So our models have to try to get that understanding so we could try to outline the area for the Bakken oil potential.

Clarice

Brenda and Rich, thanks again for joining us today. We really appreciate it. And thanks to all of you for listening to this episode of CoreCast. You can find out more information about the oil assessment of the Bakken Formation at energy.usgs.gov. CoreCast is a product of the U.S. Geological Survey, Department of the Interior. Until next time, I'm Clarice Nassif Ransom.

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Music credit:

"Walk Right In" by Cannon's Jug Stompers

Mentioned in this episode:

• USGS Energy Resources Program
• USGS Core Research Center