Chesapeake Energy Corp. contractors have halted the flow of gas from a well in eastern Wyoming, 68 hours after the company lost control of its well, the state's top oil and gas regulator said.
Aided by favorable winds Friday, contractors began pumping drilling mud into the well, about seven miles northeast of Douglas, to stop the flow of natural gas from the blowout, said Tom Doll, Wyoming's oil and gas supervisor.
Chesapeake lost control of its Combs Ranch Unit 29-33-70-1H well into the Niobrara Shale formation at about 4 p.m. Tuesday. The blowout didn't hurt anyone.
The blowout happened as crews installed steel casing into the well.
While the company's air testing hasn't indicated any problems, Chesapeake officials asked almost 70 nearby residents to evacuate. Fifty people heeded the warning and spent three nights in hotels in Douglas and Casper.
Though the well was fairly close to Douglas, population 6,100, the nearest home was more than a mile away.
Chesapeake and its contractors hoped to regain control of the well Thursday but were hampered by shifting winds that kept venting natural gas in the area where crews needed to work.
The operation to stem the air pollution -- not to mention risk of an explosion that could destroy a multimillion-dollar drilling rig -- began at about 9:30 a.m. Friday, The Associated Press reported. By 11 a.m., the flow of gas had stopped.
Workers continued to pump mud down the well, which Oklahoma City-based Chesapeake Energy recently drilled more than three miles vertically and horizontally under the rolling prairie.
Houston-based well control company Boots & Coots and its owner, Halliburton, pumped mud down the well bore through steel lines.
The blowout had pushed drilling mud to the surface.
Workers staged equipment near the well Wednesday, but shifting winds blew gas over the equipment that night.
On Friday, westerly winds enabled workers to approach the well.
The well is in the Niobrara Shale formation underlying eastern Wyoming, northern Colorado and western Nebraska.
Drilling into the Niobrara has picked up over the past couple of years by companies using the latest methods for horizontal drilling and hydraulic fracturing. Hydraulic fracturing, or fracking, means pumping large amounts of pressurized water mixed with fine sand and chemicals into wells to create fractures.
Nearly all new oil wells in Wyoming are fracked, but fracking had not yet taken place at the Chesapeake well.