Posted 7/22/09 (Wed)
By Tina Foreman
Farmer Staff Writer
Because of its success, the Bakken continues to be a hot topic among the oil industry. But recently, conversations have changed from the success of the Bakken to the potential of the Three Forks Sanish (TFS) Formation.
The TFS Formation is made up of sand and porous rock directly below the Bakken shale. When companies first began drilling into the TFS Formation, it was thought that the oil found there was seeping down from the Bakken. But now geologists aren’t sure if TFS is Bakken oil or if it is a separate Formation.
“It is very early, and we won’t know for some time if there are two separate Formations,” says Ron Ness, North Dakota Petroleum Council president. “But so far things look promising that this is a separate Formation, and we are very excited about that possibility.”
Continental Resources, an Oklahoma-based company with leases in North Dakota believes that the TFS Formation is separate from the Bakken Formation and they are drilling in McKenzie County in hopes of proving this theory.
“The TFS Formation lies directly below the lower Bakken,” states Jack Stark, Continental Resources senior vice president of exploration. “The difference between the Bakken and the Three Forks Sanish is that the Bakken rocks are more porous, allowing the oil to leak out, while the rocks around the TFS are acting like a seal, keeping the pool of oil locked inside.”
The jury is still out on the difference between the Bakken and the TFS Formation, but Continental hasn’t stopped running tests. Since the beginning of the second quarter of 2009, Continental has participated in completing five notable wells in McKenzie County with two of those wells targeting the TFS zone, the Merton 1-3H averaging 912 barrels per day and the George 1-18H averaging 896 barrels per day.
“A number of companies have been conducting their own tests,” says Ness. “But, because they are private companies we can’t use any of their results. So the Oil and Gas Commission has begun its own tests on a well in McKenzie County.”
Tests are completed by placing two wells close together with one being drilled into the Bakken and the other into the TFS. Pressures and performance of both wells are monitored during and after completion of the new well to determine whether the Bakken and TFS zones act as separate producing reservoirs in that part of the play.
“I am excited about the potential of the TFS because if it is separate, it would add to production all across western North Dakota,” says Ness. “This could open up additional opportunities for Bakken leaseholders.”
According to Ness, TFS has had a positive impact on oil production in McKenzie County whether it’s a separate Formation or not.
“If you look at the statistics,” says Ness, “you can plainly see that McKenzie County’s oil production is on the rise and that’s always a good thing.”
According to Lynn Helms, North Dakota Department of Minerals and Resources director, recent tests on 103 TFS wells have come back looking as good or better than Bakken wells, with some of them bringing in 800 barrels per day.
“Right now, because of low prices, most rigs are focusing on the best parts of the Bakken,” adds Ness. “If tests come back showing that the TFS Formation is separate, that will add a lot more targets for development and expand the oil opportunity, especially in western North Dakota.