As response crews work to clear obstructions from a blown-out well on Alaska’s North Slope, the rig used to drill Qugruk No. 2 well for Repsol E&P USA has been cleaned up and is once again operational.
“The biggest thing was getting the frozen mud and dirt out of the rig. It cleaned up really well, and yes, it’s operational,” Dave Hebert, manager of Nabors Alaska Drilling, told Petroleum News on March 8.
Nabors rig 105AC has been disconnected from the drill pipe in the well and a coiled tubing unit has been attached in its place on the rig floor. It will be used to clean out any obstructions inside the drill pipe.
Those crews recently began using a wireline tool to log the Q-2 well and the first log, on March 2, showed a blockage of the drill pipe. Crews contracted the coiled tubing unit and crane to clear the obstruction, but cold temperatures delayed its use until later in the week, according to a report from the Alaska Department of Environmental Conservation.
That March 6 report said the crews first used the coiled tubing unit to pump heavy mud into the well annulus to stabilize the space between the drill pipe and the formation, and then would use the unit to melt the obstruction and clean it from the well, getting closer to the drill bit. Next a heavy completion fluid will be pumped into the well.
The crews have been working around the clock to steam thaw the frozen drilling mud blocking access to components of the rig needed to kill the well. Through March 6, crews had shipped 78,036 gallons of thawed drilling mud and water and 1,411 cubic yards of frozen drilling mud from the well site for disposal, according to the DEC report.
No injuries, spilled oil
The Q-2 well blew out on Feb. 15, when the exploration well hit a shallow pocket of natural gas at around 2,500 feet en route to a deeper oil target at around 7,000 feet.
The 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 lead to any injuries or explosions and did not cause any oil to be spilled on the tundra.
Repsol suspended its North Slope drilling operations following the incident to comply with a promise it made to the village of Nuiqsut prior to starting its exploration program.
(For more about the status of Repsol’s exploration program, see page 1 exploration story).
—Eric Lidji & Kay Cashman
