EOR Options Explored By Montana Tech Engineers

By The Bakken magazine staff | August 15, 2014

Members of the Montana Tech Petroleum Engineering Department are conducting a pilot project to assess enhanced oil recovery options for the Elm Coulee in eastern Montana.

Conventional horizontal drilling and production methods in Montana’s Bakken oil field extract 9 to 15 percent of available oil, while the remainder goes untouched. The research team, consisting of Leo Heath, John Evans, David Reichhardt and Burt Todd plan to find a method to access the remaining oil.

Funded by the Montana Department of Natural Resources and Conservation, through the Montana Board of Oil and Gas Conservation, the research team plans to restore underground pressure in and around depleted wells to the level that existed when the wells were first drilled. The pilot project will inject either carbon dioxide or natural gas into the shale surrounding the original wells to try to get the unrecovered oil to break free from the rock.

The team has a five-year contract and is two and a half years into the research efforts.

“There are some phases to this,” said Todd. “Until now, we’ve developed a data base that stores well information for all of Elm Coulee. We’ve built some reservoir simulation models to see what happens when you inject carbon dioxide and what happens when you inject produced natural gas. ”

Todd hopes that fine-tuning enhanced oil recovery techniques will lead the Bakken to a more stable oil economy.

“My hope is that as we learn how to do these enhanced recovery techniques, that we’ll move out of the boom economy and into something more stable, more long-term, like the oil economy in Texas and Oklahoma, which has been going on for a hundred years,” says Todd.

The team is very optimistic that injection of CO2 or produced natural gas will be effective in increased recovery.

“In the Bakken, water flooding probably won’t work because the rock is too tight and the water viscosity is too high, so we’re injecting enhanced oil recovery fluids like carbon dioxide or natural gas,” said Todd. “This method acts a lot like water flooding except that we’re using a much lower viscosity fluid.”

The University of North Dakota’s Energy and Environmental Research Center has done similar work with enhanced oil recovery, but unlike UND, the Montana Tech Petroleum Engineering Department is solely focusing on the Bakken in eastern Montana.
“The Bakken behaves differently on the North Dakota side than it does on the Montana side,” said Todd. “The general thinking is that the Bakken on the North Dakota side is more fractured. The Montana side is not very fractured. You have some good wells, but it tends to be a little thinner.”

According to Todd, the hope is that the less fractured, thinner Bakken might perform better under enhanced oil recovery, but that won’t be known for 20 to 30 years.

The team plans to propose a pilot project by the end of the year, which will get them out in the field.

“We have some good relationships with several of the operators out there who are really interested in our work,” said Todd. “We feel like people have been interested in our work and that there’s a lot of different people waiting to see how this comes out.”