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USGS Releases Latest Bakken Oil and Gas Assessment

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Detailed Description

On April 30, 2013, USGS released an updated assessment of the Bakken Formation of North Dakota and Montana as part of the National Oil and Gas Assessment. We are joined by USGS Energy Resources Program Coordinator Brenda Pierce and Bakken Assessment Lead Stephanie Gaswirth to learn more about the assessment itself; why it was performed; and some context for the Bakken Formation.




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Alex Demas: Welcome to another edition of USGS Corecast. I’m your host, Alex Demas. Today, we’ll talk about the latest USGS oil and gas assessment for the Bakken of North Dakota and Montana. The Bakken, which is located in the Williston Basin, is the site of an oil boom that began around 2008. Also in 2008, USGS, as part of the National Oil and Gas Assessment, released an assessment of oil and gas in the Williston Basin that quickly became one of USGS’ most-downloaded publications.

Now, in 2013, USGS has reassessed the Bakken to update part of that 2008 assessment. Joining me to discuss the latest assessment is USGS Energy Resources Program Coordinator Brenda Pierce and Bakken Assessment Lead Stephanie Gaswirth. Brenda, Stephanie, thank you for joining me.

Brenda Pierce: Thanks, Alex.

Stephanie Gaswirth: Thanks, Alex.

Alex Demas: Let’s start with the numbers. Brenda, just how large is this resource basin?

Brenda Pierce: This is a very large resource, Alex. The Bakken and the Three Forks Formations contain 7.4 billion barrels of oil. It’s important to understand, though, that what these resources represent and what a USGS assessment represents are undiscovered, but technically recoverable resources. So these resources are not necessarily economic to produce but they are technically recoverable using today’s technology and standard industry practices so they represent potential economically recoverable resources.

Alex Demas: Ok. Give me a little perspective here. How does this assessment stack up against other USGS assessments in terms of the size of the resource basin?

Brenda Pierce: The United States is a very resource-rich country, but this is the largest unconventional oil resource that the USGS has ever assessed, and of conventional and unconventional resources, it’s the largest basin we’ve assessed in the Lower 48.

Alex Demas: Stephanie, you were the lead for this assessment. How was this assessment different from the one in 2008?

Stephanie Gaswirth: I think it’s important to start by mentioning that it is comparable to the last assessment that was done in 2008 in that the methodology and geologic approach to the assessment was the same this time around as it was in 2008. The difference this time is that there is a substantial amount of new geologic information for the Bakken Formation and there’s been about 4,000 wells drilled since 2008 in the Bakken Formation. Also this time around, we included the Three Forks Formation, which fits below the Bakken Formation; is sourced by Bakken oil; and was not included last time for various reasons.

Alex Demas: Why was the Three Forks Formation not included in the 2008 assessment?

Stephanie Gaswirth: The Three Forks Formation at the time was generally considered unproductive. There was almost no production data in the last assessment, and now there is a large amount of new geologic and production data that we can base our assessment on.

Alex Demas: Back to you, Brenda. Why did USGS decide to re-assess the Bakken? Does USGS normally reassess basins?

Brenda Pierce: Alex, we reassess basins all the time. The timing of that new assessment depends on the availability of new data and our understanding of the geology and the technology that is applied to the oil and gas resources at the time.

So the Bakken, for example, has gone through this revolution of new technological applications, so, lots of new wells, new geologic understanding, as Stephanie just explained. We took a very close look at the data that were available after the release of our 2008 assessment when we were asked about re-evaluating our assessment of the Bakken, and we sat down and took a very close look at that data and realized that there were so many new data, so many new drill wells that provided new geologic information and new production in a whole new formation—the Three Forks—that it really was valuable to reassess it because of all this new information, new stratographic data, etc.

Alex Demas: So what kind of oil are they producing in the Bakken right now? Is it different from conventional oil?

Brenda Pierce: No, it’s not. The oil in the Bakken is the same as some types of conventional oil. The difference is not the oil itself; the difference is the rock that it’s trapped in, which we call the reservoir rock. It’s trapped in a tight formation, what we call “tight,” and what that means is it needs to be artificially stimulated, or hydraulically fractured, to get the oil or gas to flow to the well bore. And that’s what’s different.

There are many different qualities of oil, and this is a very high quality of oil, but it’s not necessarily different from conventional oil. It is the rock that it’s trapped in and how it’s trapped in that rock.

Alex Demas: Last question. Does the Bakken require special techniques to develop it?

Brenda Pierce: So as we just discussed, yes, it requires horizontal drilling and hydraulic fracturing, because it’s in what we call a tight formation or tight rock, and therefore the oil is held very tightly in the micro-pores of the rock. Those pores need to be connected—connected to each other and to the well bore—so that the oil and gas can flow to the surface so it can be produced.

Alex Demas: And that should do it. Thank you again, Brenda, Stephanie, for joining me. To learn more about this assessment and all USGS energy research, please visit I’m Alex Demas, and this has been another edition of USGS Corecast, a product of the U.S. Geological Survey, Department of the Interior.

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