NEW YORK, Feb 16 (Reuters) - Natural gas from a well being drilled by Apache Corporation in the U.S. Gulf of Mexico has flowed underground, leading U.S. regulators to order the company to prepare to drill a relief well to control the flow if necessary, the U.S. Bureau of Safety and Environmental Enforcement said.
Apache shut in the well on Feb. 5 after it had a "kick" upon encountering a zone of "abnormally pressured" natural gas while drilling, the company said in a statement on its website.
A kick commonly refers to a temporary loss of control over the well due to higher than anticipated pressures being encountered while drilling, leading to fluids or gas flowing into the well.
Non-essential personnel have been evacuated from the Ensco Plc drilling rig Ensco 87 and no gas or oil has leaked into the Gulf of Mexico, Apache said.
The incident occurred in shallow waters in Main Pass block 295, approximately 50 miles (80.5 km) east of Venice, Louisiana.
Apache is moving another rig it has under contract owned by drilling firm Rowan Companies Plc to the site to drill a relief well if necessary to stop the gas from flowing underground.
A relief well is typically used to stop an uncontrolled flow of gas or fluids from a well when other methods fail.