Rain falls on oil sheen on the surface of the Gulf of Mexico near the site of the Deepwater Horizon oil well leak off the coast of Louisiana Thursday, July 15, 2010.
A new oil sheen has been spotted in the Gulf of Mexico, although energy company BP said Thursday the discovery had nothing to do with its operations and was far from the site of its disaster-hit Macondo well.
A spokesman for another company involved in investigating the sheen said he believed it had already dissipated since being first spotted last week.
BP spokesman Daren Beaudo said his company had sent several remotely controlled mini-submersibles into the water over the weekend to investigate the source of the sheen -- a shiny coating that floats on the surface of the water which generally comes from leaked or spilled oil -- but had concluded "that it couldn't have been from anything of ours."
A statement from BP PLC placed the site of the sheen near two abandoned exploration well sites in the Green Canyon Block in the Gulf of Mexico, although its size and exact location wasn't disclosed.
According to an online map published by the U.S. Department of Energy, the Green Canyon Block -- a huge square-shaped area of water south of Louisiana -- is south and west of the Mississippi Canyon Block where the Macondo well blew up.
A U.S. government official also said the area around Macondo was clear.
"They are not investing any sheens in the vicinity of the BP well," Paul Barnard, Operations Controller for the New Orleans sector of the Coast Guard, told the AP on Thursday.
Beaudo, asked to estimate the distance between the sheen and the Macondo well, said he believed it was far away.
"We're talking 10s of miles (kilometers) if not further," he said.
A catastrophic April 2010 explosion at the Macondo well killed 11 men and led to the worst offshore oil spill in U.S. history. The stricken well spewed more than 200 million gallons of oil into the Gulf before it was capped some three months later.
BP's operations in the Gulf of Mexico have seen particular scrutiny following the disaster and it remains the area's largest leaseholder, but other energy companies have operations in the Gulf as well.
Among them is Royal Dutch Shell PLC, which is still investigating the cause of a recent oil spill in the North Sea -- the area's worst in a decade. The Dutch company counts several projects in the Gulf's Green Canyon Block.
Shell did not immediately return a call seeking comment Thursday.
Rick Rainey, a spokesman for the energy services firm Enterprise Products Partners L.P., said the U.S. Coast Guard had asked his company to check one of its pipelines in the Green Canyon area over the weekend because of the sheen.
"We spent the last few days inspecting our lines. Everything's fine with the line," he said. "What I understand from our guys who have heard from the Coast Guard is that the sheen has since dissipated."
Exxon Mobil Corp., Chevron Corp. and the Bureau of Ocean Energy Management, Regulation and Enforcement did not immediately respond to AP calls for comment.
Some oil naturally seeps from the floor of the Gulf and the AP has reported that at least 27,000 abandoned oil and gas wells in the Gulf are not routinely inspected when plugged or subsequently monitored for leaks.
In an email, London-based BP spokeswoman Sheila Williams noted that "there is a lot of sheen in the Gulf of Mexico area."
Janet McConnaughey and Bill Fuller in New Orleans and Toby Sterling in Amsterdam contributed to this report.