There are numerous factors affecting the quality of an oil basin. Total organic content (TOC) is one of the Big 5.
A bit more about TOC at this link. Now, how does the Bakken stack up against, let's say, Saudi Arabia?So, that was from the earlier post, back in 2011.
There are five areas in the world where "world class" source rock exists:When I first came across this information, I about fell off my chair: the Bakken has a TOC average of 11 percent, compared to Saudi with varying reports of 2 - 5 percent. Wow.
For comparison, TOCs:
- The Bakken
- Norwegian Sea (North) and North Sea
- Venezuela
- Saudi Arabia
- Norwegian Sea (South) and The Netherlands
- Bakken: as high as 11%
- United Arab Emirates: 0.3 to 5.5%
- Saudi Arabia: 2 to 5%
- Trinidad: 2.2%
- North Sea: 5.6%
Did the USGS 2013 Survey of the Bakken-Three Forks have anything to say about the TOC of the Bakken? Yes, based on new information, and I quote from the first page:
"The upper and lower shale members are the primary source rocks for the Bakken TPS, with present-day total organic carbon (TOC) values from less than 1 weight percent to 35 weight percent (Lillis, 2013)."A TOC of 35% is the highest I have ever seen reported for the Bakken. As noted above, the 30-second sound bite: the average TOC for the Bakken is 11 percent. Most sources quote TOC as high as 16 percent in the Bakken, and there is one source that quotes a TOC as high as 20%.
Again, more recent data suggests the TOC in the Bakken can be as high as 35%. That must be some kind of record.
The four-page USGS 2013 assessment does not provide more detail regarding TOC. It does not matter. But it does put the Bakken into perspective for some folks. Like me. [Ryder Scott, June-August 2011, Vol 14, No 2, states that "a total organic carbon (TOC) of 2 percent is considered a sufficient screening criterion for oil shale plays. However, both the Bakken and Arthur Creek ["Northern Territory, Australia] have been reported to contain much higher TOCs. Greater TOC and shale thicknesses are correlated to higher production." -- Ryder Scott. See comments below.]
power point of USGS presentation
ReplyDeletehttp://energy.usgs.gov/Portals/0/Rooms/oil_and_gas/noga/multimedia/2013_Bakken_ThreeForks_Assessment.pdf
Thank you very much.
DeleteYes, I had that linked at the top of my post on the assessment (I labeled it as a PDF, but have now clarified that it is a PowerPoint Presentation) -- thank you.
Also, I plan to archive the original post and subsequent posts regarding the USGS 2013 assessment in one spot at the sidebar at the right for easy access.
This is the first of several observations regarding the assessment that I have posted. The second observation will probably be the fact that the USGS assessment recognizes the upper and lower Three Forks Formations but does not address the "four benches" as far as I could tell.
know that high TOC is actually bad...in a mature, semi-fully cooked shale the TOC should be a fraction of its original content. Thus higher TOC means it is an immature shale with close to originally deposited material. It is this difference that helps us quantify the potential recoverable position.
ReplyDeleteThank you. I did not know that. Much appreciated.
DeleteAlso know that the 2013 USGS Assessment only includes what is under their nose. We know - we visited twice with them. More to come.
ReplyDeleteThat is my impression also.
Delete