LONDON — French energy company Total says it’s preparing to drill relief wells to help control a gas leak which forced the evacuation of 238 staff at a North Sea platform earlier this week.

Gas is still being burned off above the company’s Elgin platform about 150 miles off the coast of eastern Scotland and activists are worried about the risk of explosion.

Total S.A. says it will try to choke off the flow of gas using so-called “heavy mud,” a mixture which contains mineral compounds. The company says it’s also trying to drill relief wells into the sea floor to help stop the leak.

Total’s U.K. managing director Phillipe Guys told reporters today that about 260,000 cubic yards of gas have been escaping from the platform every day.