Workers began pumping drilling mud into a gas well 74 miles off the Louisiana coast on Thursday, in a bid to stop condensate leaking into the Gulf of Mexico.
The operation began late Thursday afternoon, more than three days after a briny mix of gas, light condensate and salt water began flowing from the 40-year-old Energy Resource Technology well.
Specialists at Wild Well Control were leading the effort from a nearby platform. It was expected to take just a few hours to rein in the well.
If monitoring reveals the well is still under control overnight, workers likely will begin pumping cement into the well to permanently plug it.
Equipment was being moved into position Thursday morning in preparation for the work, after the Bureau of Safety and Environmental Enforcement approved the operation. The Coast Guard is also overseeing the spill response.
A light rainbow sheen — spanning about four miles — was first detected at the site on Tuesday. It has diminished in size, as the gas evaporates. That suggests the fluid coming out of the well now is a higher concentration of salt water, with fewer hydrocarbons. ERT has estimated that it is also flowing at a relatively low rate, with approximately 3.6 barrels of light condensate being discharged every 24 hours.
Unlike spilled oil, some of which may have to be contained and sopped up to prevent environmental damage, leaked gas evaporates naturally over time.
Houston-based Talos Energy acquired Energy Resource Technology earlier this year as part of a $610 million deal to buy the firm from Helix. In the deal, Talos took over a portfolio of Gulf assets, including new exploration wells as well as older facilities.
Talos was in the process of permanently plugging and abandoning the well as part of an approved idle iron program for decommissioning old equipment when the leak began.
The leaking well is located in Ship Shoal block 225 in 146 feet of water about 74 miles from Port Fourchon, La. Southern Production and Refining Co. first drilled the well in 1973, but for years it was operated by SONAT Exploration Co. According to federal records, Energy Resource Technology’s working interest partners in the well include Noble Energy Inc. and Fidelity Exploration and Production Co.
When the well last produced in 1998, it was discharging mostly water at a low-flowing pressure of 175 pounds per square inch, company officials said.