Sunday, February 5, 2012

For Newbies, Including Myself -- A Re-Look at the Original Leigh Price Paper -- The Williston Basin, North Dakota, USA -- Part I

I've been blogging about the Bakken for about four years now (I deleted my original site and started over with this one), starting with a knowledge level of about two (2) on a scale of 1 to 100. After all this time/blogging I may be up to eight (8) or nine (9) on the 1 to 100 scale.

Someone's comment pushed me to look at the original Leigh Price paper (1999/2000) again which is linked elsewhere at this blog.

A bit lower down, I will quote the opening two paragraphs of that paper. I'm sure I have read this paper several times, certainly the introduction and the summary, but now I find the statements in the paper mean so much to me, and some of the sentences are packed with huge amounts of information, easily overlooked.

Even if you "know" the Bakken well, these opening two paragraphs should still get your attention:
As discussed in section 2.0 [of the research paper to follow], the Williston Basin, the most structurally-simple basin in the world, is characterized by unvarying flat-lying sediments. Most (75%) of the conventional  oil production of this basin is found in the Mississippian mid-Madison limestones, the principal oil reservoir of the basin. Sediment age in the basin ranges from Cambrian to early Tertiary with numerous unconformities present. The lower Mississippian-upper Devonian Bakken Formation contains two black shales, the richest source rocks in the basin, indeed, among the richest source rocks worldwide. The rocks adjacent to the two Bakken shales are organic-poor, carbonate-rich, brittle, low-porosity, impermeable rocks, which, with the two shales, form a tight, closed-fluid system which cannot transmit fluids. These rocks have been termed the "Bakken Source System" (Price and LeFever, 1992).

Due to several unrelated circumstances, the North Dakota portion of the Williston Basin has the best rock, oil, and well-history sample base worldwide. Because of this sample base, and because of the relatively simple geologic history of the basin (compared to many other basins), the Williston Basin is also one of the best-studied petroleum basins worldwide. This unique sample and data base, and the structural simplicity of the Williston Basin, has led to the recognition and delineation of an unconventional base-centered oil-resource base there, possibly 200 - 400 billion barrels in place, the point of this discussion.
Wow.

The general consensus is that with current technology, the operators expect to produce six (6) percent of the original oil in place. Six percent of 400 billion is 24 billion. Harold Hamm has opined that there are 24 billion barrels of recoverable oil from the Bakken, which I believe he includes the Three Forks. When one does the math, EURs and the number of wells proposed for the Bakken, the number also approaches 20 billion bbls of recoverable oil. It is my understanding that EURs are primary production numbers. I believe I have seen a Denbury presentation in which the company opines that a similar amount of oil can be produced through secondary and/or tertiary production (I forget the actual presentation) as in primary production.

Just some idle rambling, that last paragraph. Those first two Price paragraphs are the "wow's" for me this morning.

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