In PLAY: The Other Geologists

Geologists don't have to work at finding oil in the Williston Basin. Citadel Energy's recent hires prove that in the Bakken, there is opportunity for geologists well-versed in saltwater disposal.
By The Bakken Staff | December 29, 2013

Citadel Energy is in the water rental business, at least that is what Bruce Langhus, chief geologist for the company, calls it.  “I tell people we are in the rental business,” he says jokingly, “because we sell fresh water and then take back dirty water.”  Langhus recently joined the Citadel Energy team in North Dakota to streamline fresh water depot sites and to develop a new saltwater disposal well south of Watford City, N.D. 

Although Langhus is a geologist, he isn’t looking for oil. Langhus is one of many geologists who have moved to the state to research and provide knowledge on geological structures in the Williston Basin that don’t pertain to tight oil. “I’m looking for either acquisition targets or places to drill new disposal wells in the Bakken,” he says. The company currently operates three fresh water depots on the Fort Berthold Indian Reservation, he says, but the main focus for Citadel is in the saltwater disposal business. The focus makes sense given his background. Langhus is the former state director for Class II Underground Injection Control for the Oklahoma Corporation Commission, an entity responsible for roughly 25,000 oil and gas saltwater disposal wells in the state. For the past 25 years, he has been in the geology industry, and according to Langhus, the Bakken is an exciting play to work in. 

For saltwater disposal wells, it’s all about location. Langhus and his team look for areas featuring abundant oil retrieval activity for potential sites of new wells, but they also look for fringe areas where a well may be the first in an area. Because most of western North Dakota offers the appropriate geologic formations in which to drill a saltwater disposal well, most areas are appropriate. There are sweet spots, however, he says. 

The process to drill a saltwater disposal well is similar to that of a vertical oil well. The state does require each disposal well to run a mechanical packer on the top of the disposal well. Mechanical packers are components in the well used to seal the outside production tubing from the inside of the casing or liner. The packer provides for the presence of a monitoring annulus between the casing and the tubing so that personnel monitoring the well can detect if a leak occurs in the casing or tubing. 

The injection capacity per day varies from well to well, Langhus says of the Bakken. Some operators utilize their own disposal wells and can inject 100 to 200 barrels of saltwater per day. Commercial sites can dispose of much greater quantities per day, reaching capacities of 20,000 barrels of saltwater per day. Depending on which reservoir an injection well is placed into, a well can last 10 to 50 years. 

In the Williston Basin, most geologists are looking for porous sandstone or limestone as geologic layers to inject water into. The sandstone looks like a sandy beach that has been solidified and has many holes in it, he says, adding that limestone looks similar. The injection formation “is hard and solid and rigid, but it has a network of pores that we are injecting water into.” 

To inject the water into the well, pumps are used in most cases. In the Bakken, wells are injected using very low-pressure pumps. “We have a lot of experience in Texas and Oklahoma as well. A lot of the disposal wells there operate with no pressure at all, and they are going essentially into caves or cavern systems at very little pressure.,” he says. 

Citadel Energy may be focused on saltwater disposal, but the team is also working to advance its freshwater depots while also exploring the possibility of taking oilfield waste. “We have some very capable water depots that can deliver a lot of water on a short notice,” he says. To date, several operators have installed temporary pipelines to take water from a Citadel Energy depot to a well site. There is no current pipeline system installed at any of the depots, but Langhus says the company has talked to a number of people who are interested in that option. 

“We are always on the lookout for new things in terms of disposal wells or freshwater supplies. We are also looking at new technologies that we might want to take advantage of,” he says. “There is always something new out there for disposal wells.”