Shares of Anadarko Petroleum Corp and Transocean Ltd , companies that may face liability related to BP Plc's Gulf of Mexico oil spill, rallied on Wednesday after an effort to kill the ruptured well showed promise.

BP on Tuesday claimed a significant milestone in efforts to plug the leaking well for good as heavy drilling mud pumped into the Gulf of Mexico well was stemming the flow of crude.

Anadarko, which owns a 25 percent stake in the well, was up 4.2 percent, also helped by quarterly results that topped Wall Street expectations.

Shares of Transocean, the owner of the rig that drilled the well, climbed 8 percent. That company is due to report earnings after the close of regular trading.

Cameron International Corp , the company that supplied the blow-out preventer that failed to stop the well from rupturing, reported a higher-than-expected profit on Wednesday. . Its shares fell slightly, however.

We've all gained a measure of guarded hope this morning that last night's 'static kill' operation is reported to have been successful, Jim Hackett, Anadarko's CEO, said on a call to discuss the company's second-quarter earnings.

Anadarko, which has an ambitious deepwater exploration program in the Gulf of Mexico, said the U.S. government's moratorium on drilling has not hurt its oil and gas production this year. In fact the Houston company raised its output forecast for the year.

Anadarko has also secured loan commitments of $6.5 billion in part to cover any liability from the oil spill.

Cameron, which made the blow-out preventer on the Macondo well, said it was gearing up for customers to seek manufacturer certification for their equipment due to tighter regulations.

It's going to happen all over the world, Chief Executive Jack Moore told analysts on a conference call. We're getting requests in every corner of the world from our customers to support this, and so we have to ramp that up to meet it both with personnel and with infrastructure.

Cameron said its blow-out preventers were on about half of all deepwater rigs around the world.

Excluding items related to the Gulf disaster and other one-time charges, Cameron earned 58 cents per share, beating the 54 cents expected by analysts on average, according to Thomson Reuters I/B/E/S.

Since the accident on April 20, which killed 11 workers and sank a drilling rig, Anadarko's shares have fallen 25 percent, Transocean shares have tumbled 41 percent and Cameron shares have dropped 14 percent.

(Additional reporting by Braden Reddall in San Francisco; Editing by Steve Orlofsky)