Continental Resources (CLR) came out with data last winter indicating that at least some of its acreage in the Bakken would be prospective for stacked pay zones. The evidence it provided was results from its Charlotte Unit wells in McKenzie County where the company was producing from three zones, the Middle Bakken, Three Forks 2 and Three Forks 3 (see stratigraphic column below).
As you can see from the picture above, the company’s success in the Three Forks increased its oil in place estimates for the Bakken Petroleum System to 903 billion barrels of oil (BBO) from 507 BBO and recoverable reserves to 32 BBO at a 3.5% recovery factor. CLR has a lot of work to do to prove this assertion and it will be delineating its acreage for multiple Three Forks zone potential.
Producing from the Three Forks is nothing new in the Bakken, but what’s interesting is that CLR is producing from multiple Three Forks (TF) benches which may prove the potential of multiple reservoirs in the Bakken thus more reserves than what has been produced in the Middle Bakken.
I don’t have CLR’s well data organized well enough to show you the results of its TF wells. Part of the problem is having to dig through well files which are large documents that take a long time to open on North Dakota’s Oil and Gas Division website. Luckily, some companies give us clues that a well is a Three Forks well by putting “TFH” or Three Forks Horizontal in the well title.
Marathon Oil (MRO) is one of these companies and I have data from 26 of its wells across Mountrail and Dunn Counties, half of which targeted the Bakken and the other half Three Forks. These wells were drilled very close to each other in pairs indicating that the company believes each section is economic for both the Bakken and Three Forks.
Note: When I say the wells were drilled very close, I’m saying same quarter section at minimum with parallel lateral legs.
I’ve color coded all of the above Bakken wells in green and TF wells in red. The first two wells, Rhoda 24-31H and Oren USA 31-6 TFH, are a pair of wells which were both drilled very close to each other but in different zones. What needs to be determined to prove that the Bakken and the Three Forks are separate reservoirs is that the cumulative production will not be effected by the drilling of either well, that is that one well is not draining oil from the other thus resulting in you drilling two wells for the price one.
All of these wells were drilled during 2011 and 2012 and the quick and dirty average cumulative production from them is 97 thousand barrels of oil (MBO) and I usually use 150 MBO as a target for payback from a Bakken well. This would indicate that these wells are paying back in two to four years which is a solid result and compares well with the company’s historical production in the Bakken.
There’s a lot more to talk about and analyze with regards to this topic and the implications could be large. For instance, if I have 100 Bakken well locations in my inventory but find out the Three Forks zone is productive in all of those same areas, I now have 200 well locations. All of the above wells were drilled in clusters across both Dunn and Mountrail County, meaning Marathon either doesn’t think most of its acreage is prospective for multiple zones, it’s capital has been tied up in the Eagle Ford where returns are better or it’s not following the same naming system with all of its TF wells.
I will be looking into the above for MRO as well as where other companies are drilling TFH wells in the Bakken. When I have more data on CLR, MRO, etc I’ll be writing another article.