CHEYENNE, Wyo. (AP) — Workers at a blown Chesapeake Energy Corp. oil well in eastern Wyoming took advantage of changing winds Friday to plug the well with mud and end a powerful, three-day eruption of potentially explosive natural gas.

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. By 11 a.m. the flow of gas had stopped, according to Tom Doll, supervisor of the Wyoming Oil and Gas Conservation Commission.

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.

"We are still in the process implementing our well control action plan," company spokeswoman Kelsey Campbell said by email.

Houston-based well control company Boots & Coots and parent company Halliburton pumped mud down the well bore through steel lines.

The blowout happened Tuesday afternoon. Methane gas roared from the ground at the drilling site five miles northeast of Douglas.

The blowout pushed drilling mud to the surface. Clouds of gas blurred the horizon. Authorities issued an evacuation advisory to 67 people in homes within two and a half miles of the well, and 50 people heeded it.

Nobody was hurt.

Though the well was fairly close to Douglas, population 6,100, the nearest home was over a mile away.

Fickle winds delayed work to bring the well under control.

Workers staged equipment near the well Wednesday, but shifting winds blew gas over the equipment that night. Wind patterns remained unfavorable Thursday.

On Friday, westerly winds enabled workers to re-approach the well.

The blowout happened as crews installed steel casing into the well, which had been drilled to a vertical and horizontal distance of almost 18,000 feet. The well targeted the Niobrara Shale 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, involves 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.