On the evening of March 16, Repsol E&P USA successfully secured and finished plugging its Qugruk No. 2 exploration well on Alaska’s North Slope, some 20 miles northeast of Nuiqsut in the Colville River delta.
The well blew out on Feb. 15 when the drill bit hit a shallow pocket of natural gas at about 2,500 feet en route to a deeper oil target at around 7,000 feet. Natural gas was diverted away from the drilling rig and crews shut down equipment to avoid igniting gas. The Alaska Department of Environmental Conservation said the well stopped flowing the next day.
No fire or injuries were associated with the incident.
Repsol recently set and pressure tested two cement plugs in the Q-2 well.
At that point the state “determined it was safe to begin the off-pad cleanup activities,” DEC said in a March 16 report.
The crews then divided the off-pad cleanup area into four zones, completed delineation of two zones and plan to complete the other two as weather permits.
In a March 17 statement Repsol spokesman Jan Sieving said crews set the third cement plug the evening of March 16. “The cleanup work on the rig and well pad has been under way for several weeks,” he said, confirming cleanup for the area off the well pad had begun, managed by Alaska Clean Seas, a spill response cooperative that was working with DEC.
Repsol said it had removed 91,938 gallons of liquids (thawed drilling mud and water), and 2,363 cubic yards of solids (frozen drilling mud and downhole materials) from the site during cleanup efforts.
“There was a lot of mud and debris on the drilling rig that had to be cleaned up before they could actually do the work and they went about it in a very meticulous and safe manner,” Alaska Oil and Gas Conservation Commission petroleum engineer Jim Regg told the Alaska Public Radio Network.
The Q-2 well blowout sent some 42,000 gallons of freshwater-based drilling mud onto the ice pad and the surrounding snow-covered tundra, and vented an unknown amount of gas, but did not cause any oil to be spilled on the tundra.
Following the incident, Repsol suspended its North Slope drilling program and AOGCC subsequently withdrew the drilling permits for all three Qugruk pads and asked Repsol to reapply for them, which the company has since done for Q-1 and Q-4, but the company has no intention of doing any more drilling from the Q-2 ice pad. That well has been plugged and abandoned.
On March 8, Repsol restarted drilling operations at its Kachemach 1 ice pad. Both the Q-2 and K-1 drill sites are on Alaska’s North Slope, but K-1 is farther south and not geologically similar to the company’s Qugruk drill sites.
—Eric Lidji & Kay Cashman
