(Reuters) - Chesapeake Energy's delayed response to warning signs at a natural gas well contributed to a blowout in Wyoming in April, which led to a leak and the evacuation of dozens of nearby residents, state regulators said on Thursday.
Chesapeake's "delay in observation of and response to a gain in drilling mud in the pits during the running of the production casing prior to the incident," was a contributing factor in the eventual loss of control at the well, according to a Wyoming Oil and Gas Conservation Commission report.
It said that "improper engagement of wellhead lockdown pins" also contributed to the blowout, which was eventually triggered by a mechanical failure at the surface of the well.
Chesapeake lost control of the well late on April 24 while installing a well casing, leaking natural gas and drilling mud. A cloud of gas could be seen a mile from the well, emergency service officials said at the time.
Workers stemmed the leak about three days later.
The OGCC said that less than 2 million cubic feet of natural gas was leaked during the 66-hour incident.
(Reporting By Edward McAllister and Selam Gebrekidan. Editing by Bernadette Baum)