Incident was caused when a blowout preventer on the hydrofracking failed.
HARRISBURG, Pa. — Natural gas and polluted drilling water from an out-of-control well shot 75 feet into the air in a remote area of Pennsylvania before crews were able to tame the flow of explosive gas more than half a day later, officials said Friday.
The well was brought under control just after noon Friday, about 16 hours after it started spewing gas and brine, said Elizabeth Ivers, a spokeswoman for driller EOG Resources Inc. She said she could not immediately respond to questions about how the accident happened.
The well never caught fire and no injuries were reported, but state officials had worried the gas might explode before the well could be controlled. State environmental authorities promised an aggressive investigation of the circumstances surrounding the blowout, which they said shot gas and water 75 feet into the air.
“The event at the well site could have been a catastrophic incident that endangered life and property,” Department of Environmental Protection Secretary John Hanger said in a statement. “This was not a minor accident, but a serious incident that will be fully investigated by this agency with the appropriate and necessary actions taken quickly.”
If the agency finds that mistakes were made, it will take steps to prevent similar errors from repeating, he said. He did not elaborate on any environmental damage.
There were no homes within a mile of the well, and polluted drilling water was prevented from reaching a waterway, said Dan Spadoni, an agency spokesman. The well is on the grounds of a hunting club in Clearfield County, near Interstate 80 and about 90 miles northeast of Pittsburgh.
Houston-based EOG was drilling into the Marcellus Shale reserve, a hotly pursued gas formation primarily under Pennsylvania, West Virginia, New York and Ohio that some geologists believe could become the nation’s most productive natural gas field. Spadoni said details about the accident were still sketchy, but the agency was told that unexpectedly high gas pressure in the new well prevented the crew from containing it.
The crew had just finished a process called hydraulic fracturing — in which millions of gallons of water, sand and chemicals are blasted underground to shatter tightly compacted shale and release trapped natural gas — and were clearing out debris from the well when gas shot out of it, he said.
Workers evacuated the site and contacted the Pennsylvania Emergency Management Agency, Spadoni said. The DEP wasn’t notified until 1:30 a.m. — more than five hours after the blowout.
As a precaution, the Federal Aviation Administration issued a flight restriction shortly after 11 a.m., saying no planes below a 1,000 feet should go within three miles of the site. That restriction remained in effect past 2 p.m., Hanger said.
The polluted water flowing out of the well and into the woods was stopped by a trench and a pump installed by a contractor, Spadoni said. Companies that specialize in securing out-of-control wells were called in, he said.
David Rensink, the incoming president of the American Association of Petroleum Geologists, said gas well blowouts are very rare and can be very dangerous to control, since a spark can set off an explosion. Securing one can take days, he said.
Typically, a series of valves called a blowout preventer sit atop a well and allow wellhands to control the pressure inside, he said. A blowout preventer also figured into the massive oil spill off the coast of Louisiana. The device was supposed to shut off the flow of oil in the event of a catastrophic failure, but failed to do so.