KILLDEER, N.D. - Oil, gas, chemicals and water continued to spew out of an oil well after a high-pressure blowout about 1:30 a.m. Wednesday, and it is unclear if the town's main water source has been contaminated.
Lynn Helms, director of the state's department of mineral resources, said a mechanical failure during a hydraulic fracturing phase on a Denbury Onshore LLC oil well 2½ miles southwest of Killdeer caused a breach in the well's casing.
Hydraulic fracturing uses extremely high pressure to force a compound of water, sand and/or other chemicals through a well pipe to break up a rock formation, allowing oil to be gathered.
When an oil well is drilled, casing is set in the wellbore, or hole, and in this case, the mechanical failure caused such high pressure it breached the walls of a 7-inch and 9.5-inch pipe, all surrounded by cement.
While it is unclear at what depth the blowout occurred, it was closer to the surface, Helms said.
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The Killdeer city water well is about 2½ miles northeast of the leak location, and was penetrated when the oil well was drilled, Helms said.
"Our first concern was to make sure nothing got into Spring Creek," Helms said. "When they built this drilling location, we made them put a dike around it, so nothing has gotten into the creek."
Helms said monitoring wells will be drilled to check for groundwater contamination.
"If it's a lot of contamination we'll know tomorrow, but if it's really low levels that's got to go through the state laboratory, and that can take several days to get those results," Helms said.
The state has drawn up well head protection areas for oil wells drilled near groundwater sources.
"We're well beyond anyplace that could get to their well in 10 years ... so there's no cause for alarm," Helms said.
Killdeer Mayor Dan Dolechek is very concerned and said the situation could pose a huge problem, but he will not know the extent, if any, until today.
This isn't the first time the state's oil patch has witnessed a wellbore failure.
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"We had a similar incident about two years ago and that's when we implemented some stricter rules on pressure testing wells and how hydraulic fracturing was supposed to be conducted," Helms said.
The surface continued to gurgle late Wednesday afternoon, and according to a North Dakota Department of Health press release, about 500 barrels had leaked thus far.
Ryan Jacob, Denbury HSE field operations manager, said a 4- to 6-foot basin surrounds the wellbore and is collecting leaking fluids at the surface, where it is then being vacuumed out and taken to disposal sites, Jacob said.
Air at the site is also being monitored for any possible explosive properties, Jacob said.
Eight contracted crews were sent to the area to assist, including well control specialists Boots & Coots International Well Control, Inc.
Jacob said the company plans to "kill" or shut off the well tomorrow by injecting a heavy mud.
Plans to permanently plug the well have yet to be decided, but it will take a few weeks to pinpoint the breach's exact cause, Jacob said.
"We're obviously going to make an investigation here," Helms said. "There may have been a violation of those rules and if there was, there will definitely be enforcement action."
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Lisa Call writes for The Dickinson Press
