State and federal regulators were hurrying to the North Slope on Monday in an effort to determine why a relatively new pipeline at a field owned by Hilcorp and BP ruptured over the weekend, spilling an unknown amount of crude oil, water and other fluids at a site about 25 miles from Deadhorse.
Hilcorp, a North Slope newcomer that began operating the Milne Point field in November, discovered the spill in the 6-year-old line early Saturday morning.
Initial cleanup efforts were stopped by what the state Department of Environmental Conservation called "severe blizzard-like conditions." But by that afternoon responders had used a vacuum truck to recover an estimated 4,000 gallons that was a mixture of spilled liquids, snow and ice.
Hilcorp hopes to soon determine the cause of the leak, said Lori Nelson, external affairs manager with Hilcorp in Alaska.
"There was no field activity directly related with this pipe that would have caused this," she said. "The breach occurred at some point when there was not any personnel or equipment operating in this area."
The leak occurred in the bottom of the pipe, aimed "straight to ground," said Nelson. Fluids pooled beneath the pipe and oily mist sprayed out in strong gusts. About 1 acre of gravel pad and tundra were affected.
Field staff had visually inspected the 10-inch pipe the evening before the leak, said Nelson. Hilcorp is hopeful the release did not occur for more than 12 hours, said Nelson.
After the discovery of the leak, the affected 15-foot section of pipe was isolated and sealed off with valves. Producing wells from that portion of the field were shut down. A wooden plug was inserted into the quarter-inch hole and the damaged pipe was wrapped to prevent further leaking, environmental regulators said.
Responders included teams from Hilcorp, Alaska Clean Seas and ConocoPhillips' Kuparuk oil field.
By Sunday afternoon, Hilcorp had installed a bypass line to resume normal production flow and prevent freezing in other portions of the operation. The flow line carries about 4,200 barrels of oil each day from producing wells, part of the 20,000 barrels of daily production at the unit.
Getting flow back up quickly and safely with the bypass pipe was a "big win," said Nelson.
Brad Dunker, environmental program specialist with the state, said that accomplishment is "huge." If flow is stopped, "you can get into situation where you have an ice plug or something like that that can damage the pipe," he said.
Temperatures in the area more than 600 miles north of Anchorage did not exceed zero on Sunday.
Because of strong gusts and snow, responders had to do what they could to keep the contamination in check, said Dunker. That included spraying the area with water to create an ice cap over the spill. The cap will not hurt recovery efforts, the state said.
Houston-based Hilcorp has become an important operator in the state's oil and gas fields, after boosting production levels in Cook Inlet in Southcentral Alaska in recent years. It moved to the North Slope in November, acquiring half the assets at Milne Point as part of a $1.5 billion deal with BP that also involved three other North Slope fields.
Hilcorp suffered another setback in October in Cook Inlet when a fire erupted on the half-century-old Baker platform. The fire stemmed from a malfunctioning wall heater that had been recently inspected, Nelson said. No one was injured and nothing was spilled.
As for Milne Point, state and federal regulators are expected to arrive Monday evening, now that weather conditions have improved and the road to the site has been cleared of snow, Dunker said.
Hilcorp hopes to better delineate the contaminated area and estimate how much fuel and other liquid spilled, Nelson said.
After regulators arrive, the damaged pipe will be removed for analysis. "We're anxious to get that section of pipe and figure out the nature of the failure," she said.
Nelson said Hilcorp will learn from the spill.
"We definitely take the investigation seriously and will take the lessons learned moving forward, working with regulators to ensure it doesn't happen again," she said. "We certainly want to be a responsible producer in the state."