BISMARCK — North Dakota geologists are re-evaluating whether local sources of sand could be used for hydraulic fracturing as oil industry demand increases.
Oil companies now use greater volumes of sand for fracking, averaging about 2,500 to 5,000 tons per well, according to the Department of Mineral Resources.
Operators are interested in finding a North Dakota source of sand to save on transportation costs rather than importing it by rail, said Ron Ness, president of the North Dakota Petroleum Council.
"This would be absolutely another game-changer for the Bakken," Ness said.
Hydraulic fracturing, or fracking, involves injecting water, sand and chemicals into underground formations to extract oil and gas. Sand, or proppant, is used to "prop open" the fractures in the rock created by the fracking process to allow the oil to flow from the rock formation into the wellbore.
Fred Anderson, geologist with the North Dakota Geological Survey, authored a study in 2011 that said North Dakota sand sources approach oil industry standards for use in fracking but are lower in overall quality than other U.S. sources.
There's a renewed interest in that research, however, as demand for sand increases and companies experiment with lower-cost options.
"They're accepting sands that we probably never would have accepted 10 to 15 years ago," said Monte Besler, owner of FRACN8R Consulting in Williston.
Now the Geological Survey is conducting a second phase of research, with a focus this summer and fall on collecting sandstone samples from Billings and McKenzie counties in western North Dakota. Previously, the Geological Survey collected samples from wind-blown sands in north-central and eastern North Dakota.
"We're trying to test and characterize our sand resource so that industry can decide whether or not we have a usable alternative," Anderson said.
The preferred sand for fracking is spherical and close to pure quartz, such as Northern white sand that is shipped to the Bakken from Minnesota, Wisconsin and Illinois.
North Dakota's sand contains quartz, but it is a mixed mineralogy rather than pure quartz, Anderson said.
North Dakota sand could potentially be processed to get it closer to the desired sand, he said.
Samples the geologists collect will be sent to an industry-accepted lab to analyze characteristics such as how crush-resistant the sand is and how round the grains are.
"We want to classify these sandstones and get as detailed information on them as possible because we never know," said State Geologist Ed Murphy. "Something that may not work this year might work two, three, four years down the road."
The Geological Survey has collected sand samples from rugged areas of the Badlands this summer, primarily from federal and state lands. One area of interest is a 50-foot thick sandstone of the Sentinel Butte formation in Billings County, which extends over multiple townships, Murphy said.
"It's pretty expansive out there in that area," Murphy said.
Geologists are collecting the samples from the Badlands because the sandstones are exposed and accessible from the surface, Murphy said. But if mining of the sand resources were to occur, it would be in a different area with flatter terrain, Murphy said.
The agency obtained collection permits from the Bureau of Land Management, the U.S. Forest Service and the North Dakota Department of Trust Lands, Murphy said. They are primarily collecting samples that fit into a gallon-size bag, returning to collect a five-gallon bucket for the most promising samples.
In addition to sandstone deposits, geologists also have taken samples from North Dakota's major wind-blown sand deposits, which are the Denbigh Dunes east of Minot, the Sheyenne Dunes southwest of Fargo and the Pembina Dunes in northeast North Dakota.
Other samples have been collected around the state.
"Industry would like to be as close to the wells that they're completing as possible to cut down on transportation," Murphy said.
But he added that if sand from central and eastern North Dakota requires less processing, it may be a more viable option.
Timing of the research will depend on funding. Samples are being collected in conjunction with another study that's looking at rare earth elements in the state. But testing the samples will require additional funding, Murphy said.
If a promising source of North Dakota sand is found, the Department of Mineral Resources would regulate the mining under its subsurface minerals program, Murphy said.
Private landowners who want to talk to geologists about possible sources of sand can call the Geological Survey at 701-328-8000.