A spill of more than 2,700 barrels of saltwater northeast of Williston, ND, over the weekend reinforced the need for oil well pads to have adequate containment berms, one state agency.
Zavanna staff discovered the spill of 2,733 barrels, or 114,786 gallons, of produced water about 10 a.m. Sunday at an oil well pad about 4 miles northeast of Williston.
About 215 barrels that spilled remained on the oil well pad location and the remaining 2,518 barrels got off location, said Travis Pfaff, production manager for Zavanna.
The saltwater — a byproduct of oil production — contaminated an estimated three-tenths of a mile of privately owned pasture land, Pfaff said.
The cause of the spill was an above-ground valve that failed, Pfaff said, adding the valve had been pressure-tested two weeks earlier.
The North Dakota Department of Health has had an inspector on site and work is still ongoing to determine the extent of the damage, said Bill Suess, spill investigation program manager.
No surface water suffered from the incident, but it’s unknown if the spill affected groundwater, Suess said Monday. An undetermined amount of the spill flowed into a dry drainage area, Suess said.
Zavanna is coordinating with the landowner, health officials and the North Dakota Industrial Commission to clean up the spill, Pfaff said.
A containment berm at least 26 inches tall surrounded the well pad.
Having said that, the berm was not properly maintained near a cattle guard, which allowed the spill to get off the location, Ritter said.
The North Dakota Industrial Commission is considering proposed changes to state oil and gas rules, including a proposal to require oil sites to be surrounded by 1-foot containment berms to keep more spills on location.
Because such berms are not required by the state, they’re not subject to maintenance requirements, Ritter said.
“Had this rule been in place, inspectors could have caught where the berm had eroded by the cattle guard and required the operator to make the necessary corrections,” Ritter said.