At the time, the well was spilling crude oil, but that plume did not leave the well pad, state regulators said.
In general, oil companies have been producing oil and pumping associated natural gas back into reservoirs.
The leak was discovered on Friday and a team from BP, the Alaska Department of Environmental Conservation (ADEC), U.S. Environmental Protection Agency and local government was brought in to coordinate efforts.
The well is part of the Prudhoe Bay field, which in March produced an average 315,395 barrels a day, according to data from the Alaska Department of Natural Resources.
The safety valve at the top of the well has stopped one leak, but a second leak from the bottom continued as of Saturday afternoon. What's more, an earlier statement from the Unified Command Task Force tackling the spill said that the amount of oil leaked was small compared to the amount of gas that is being released.
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Pressure in the well was monitored all night and excess pressure released from the well. Back in 2009, a pipeline spilled some 1,100 barrels of crude in a BP-operated field.
Though no injuries or damage to wildlife had been reported, crews trying to secure the well had failed amid biting winds blowing up to 38 miles an hour. The authorities have not established yet, what prompted the well to discharge oil and gas.
On Monday, almost three days after the leak was found, ADEC announced the unified command had to managed to "kill" the well overnight and end the gas leak.
The leak comes as the remote North Slope, once home to the US' biggest oilfields, sees a revival with companies working to boost output from ageing wells and seeking access to new supplies. The infamous Exxon Valdez, which in 1989 spilled tens of millions of gallons of oil into the Gulf of Alaska, was carrying oil extracted from Prudhoe Bay.