Reclamation of oilfield sites has proven to be a thornier problem than farmers and oilfield companies alike want, but area research is kicking into high gear to look at the problem, which is exacerbated in part by North Dakota’s geological features.
Among the researchers already working on the problems is Dr. Erin Espeland, research ecologist out of the USDA-ARS in Sidney, and Zach Sylvain, a research assistant, are among those with projects that seek to improve oilfield reclamations.
“Our prairie is not well-adapted to disturbance,” Espeland said. “Pretty much all we have are prairie dogs, and that’s not really a lot of disturbance. It’s not like some others where there is a lot of fire or river beds with a lot of flooding and sediment deposits. We don’t have a history of that kind of extreme disturbance, so there is no natural recovery process in play. So how do we as humans go in and try to create some process to get sites recovered?”
Espeland is conducting an ecological survey of both oilfield and non-oilfield sites in the Little Missouri National Grassland to first get a handle on what’s happening in the real world with the sites.
“We did a huge sweep in 2015 looking at how insects used the landscape, how plants are distributed on the landscapes and what soils are like on the landscape,” Espeland said.
Reclaimed sites are being compared to those that have not been disturbed, to see what kind of differences there are.
Meanwhile, Espeland is also working on a cover crop study to see what kinds of plants can be used to improve interim reclamation, and improve the success of native plants while reducing weeds.
That work is being done with WPX Energy at Fort Berthold.
“One thing we are finding with that work is it takes a really long time for these final reclaimed sites to recover and look like adjacent undisturbed grasslands, and it is probably because the soils get so disturbed in the process of pad construction,” she said.
North Dakota soils often have a layer of salt that has settled below the surface. Rain water carries minerals downward into the soil, including salts.
That layer can be as little as 6 inches from the surface to a foot or more.
“Plants can deal with a concentrated layer,” Espeland said. “They can punch through it or avoid it, but once it’s mixed they have a hard time.”
Pad construction may need some modification, Espeland suggested, to avoid mixing the salt layer with the rest of the soil.
In cases where the salt layer is already mixed in, there can be serious problems with reclamation. Solutions for that, too, are being researched.
Soil amendments and salt tolerant plants to pull it out of the soil are among some of the approaches being explored.
“I’m working on a project with Julie Ederson out of the University Minnesota in Duluth where we are looking at how restoration materials might evolve in response to being planted in reclamations,” Espeland said. “We know we think we are planting these native grasses that might be adapted to historical conditions in the Northern Great Plains, but when we plant them on reclamation sites with high salt and other characteristics that differ from surrounding grasslands, do we see evolution in these materials at the site?”
Espeland said the reclamation problems for the oil field extends outside of northwestern North Dakota and northeastern Montana. They extend all the way down the Great Plains and on into Texas at oil field sites. She is hoping to find grant money to expand the research to a broader area.