Just How Good Is The Bakken -- A Reminder and a Utica Update -- The Bakken, North Dakota, USA

This link about the Bakken TOC was posted May 24, 2010. By then, the Bakken boom had begun, but investors and entrepreneurs still had the opportunity to get in near the ground floor, as they say.

The higher the total organic carbon (TOC) in the source rock, the better the formation.

TOC: total organic content -- this has to do with the "source rock" -- the rock that generates the oil. Look at this definition of TOC from the Schlumberger website:

A rock rich in organic matter which, if heated sufficiently, will generate oil or gas. Typical source rocks, usually shales or limestones, contain about 1% organic matter and at least 0.5% total organic carbon (TOC), although a rich source rock might have as much as 10% organic matter. Rocks of marine origin tend to be oil-prone, whereas terrestrial source rocks (such as coal) tend to be gas-prone. Preservation of organic matter without degradation is critical to creating a good source rock, and necessary for a complete petroleum system.

Note that the Bakken source rock has 11% TOC. [If you want to see this data for yourself, go to this link: https://www.dmr.nd.gov/ndgs/bakken/bakkenthree.asp; then, scroll down to GI-2. The fifth presentation "Bakken TOCS" is what you are looking for; click on "PDF 52 Meg" -- due to the size it will take a few moments to download. Incredible numbers; even an amateur can see the TOCs -- but there is a lot more than TOC, but it's a start.]

So, what's the TOC in the Utica? Verbatim excerpts from this link (pay particular attention to Point Pleasant and Utica references):

The final isolith map includes the thickness of all organic-rich beds, shale beds and interbedded limestones from the top of the Utica Shale to the bottom of the Logana Member of the Lexington Formation in Ohio; the Logana Member in eastern Kentucky and West Virginia where the Point Pleasant and Utica are not present; and the interval from the top to the bottom of the Utica Shale where only the Utica is present in Pennsylvania, Ontario and New York ...

Data for total organic carbon (TOC) were overlain ...

Adding these data defined areas .. indicates that nearly the entire assessmetn area is in the good to very good range. Exceptions are thin, linear, northeast-southwest trends of fair to poor TOC values along the Ohio River between West Virginia and Ohio and smaller, parallel trends farther west in Ohio; and ...

The map of minimum TOC values presents a more pessimistic picture. Small areas in Ohio, Pennsylvania and New York are deemed to be very good and occur within a much larger area of these same three states that isin the good range for TOC. However, southern Ohio and most of West Virginia is mapped as having mostly poor potential.

... TOC data from 28 deep wells in the basin indicate that in 11 of the 28 wells, TOC values were greater than 0.5% [not a typo; 0.5%; compare to 11% for the Bakken] in the Beekmantown Formation and deeper formations. The highest values are 4.4% from the Rogersville Shale ...2.83% and 1.12% from the Conasauga Formation ... Other TOC values range from 0.57% to 0.88%. [Again, compare these numbers with the Bakken].

When you get to the maps, the "very good" areas generally have a minimum TOC of 4% and less.

The relatively lower TOC's compared to the Bakken, are counterbalanced by the very thick Utica, measured at 100 to 150 feet, and as thick as 500 feet at places. An undated article at Geology.com states that not much is known about the true TOC of the Utica.

Having said that, I believe the Lodgeple to the Bakken (three sub-formations) and the Three Forks (several sub-formations) is also 100 - 150 feet thick in the better Bakken.

The TOC in the Bakken is quite simply, incredible.