The cause of an apparent “well control incident” at a Chesapeake Energy Corp. natural gas drilling site in Wyoming was under investigation Wednesday, and the producer was preparing resources and equipment to get it under control. No injuries were reported.

The incident was reported on Tuesday at a unit of Chesapeake’s near the town of Douglas, WY, in Converse County, where the producer operates in the Niobrara formation. Sixty-seven residents within a 2.5-mile radius of the well reportedly were evacuated voluntarily, while another 17 voluntarily chose to stay in their homes.

An Oklahoma City-based spokesperson for Chesapeake told NGI’s Shale Daily that the well incident occurred at the Combs Ranch Unit 29-33-70 1H drilling site. The operator is focused on containing the incident and protecting the public’s, as well as its employees’ and contract workers’ health and safety.

According to Chesapeake, the incident occurred when steel casing was being installed in the well. At some point “a leak of oil-based drilling mud occurred,” which apparently was largely being contained on the location as natural gas dissipated into the atmosphere, the spokesperson said.

“Planning is currently underway to prepare the necessary resources and equipment to bring the well under control,” which is to be done “as quickly and safely as conditions permit.” Updates are to be issued “when warranted,” the spokesperson added.