Thu Apr 12, 2012 1:48pm EDT
* Shell says sheen is estimated at 6 barrels
* Sheen spotted near Shell’s Mars and Ursa oil platforms
* Shell says sees no leaks from its operations
* Regulator says sheen near a natural seabed seep
* Shell shares pare earlier losses
By Kristen Hays
HOUSTON, April 12 (Reuters) – Royal Dutch Shell said an oil sheen near two of its offshore Gulf of Mexico oil and natural gas platforms was estimated to total about six barrels of oil and that its seabed wells showed no signs of leaks.
Shares of Shell traded on the New York Stock Exchange were up 39 cents, or less than 1 percent, at $68.14 at midday. The stock closed down less than 1 percent in London after falling as much a 5 percent earlier in the day, temporarily erasing about $5 billion in value from Europe’s largest oil company by market capitalization.
The company, based in the Hague, said the source of the one-mile by 10-mile sheen was unknown.
News of the sheen came nearly two years after BP Plc’s deep sea Macondo well blew out on April 20, 2010, killing 11 workers and spewing more than 4 million barrels of oil into the Gulf of Mexico.
The U.S. Bureau of Safety and Environmental Enforcement (BSEE), which regulates offshore oil and gas activity, said on Thursday that its personnel spotted the sheen near Shell’s Mars and Ursa platforms and notified the company.
Shell said a Marine Spill Response Corp vessel with skimming and boom capability was on site near the platforms. The company also deployed two remote operating vehicles (ROVs) to inspect the seabed oil equipment in the area and to search for naturally occurring seeps in the ocean floor.
ROVs were assessing permanently plugged wells in the surrounding area “and a known natural sea floor seep located in proximity of the sheen,” the BSEE said.
Shell spokeswoman Kelly Op de Weegh added that the ROVs were “checking the whole area,” including wellheads, pipes and other equipment for both the platforms, and so far no leaks or plumes have been found.
The company said in a statement that although Shell is confident that the sheen did not originate from its operations, the company would continue to respond.
BSEE said it also has directed pipeline companies with operations in the area to survey their lines.
A U.S. Coast Guard helicopter also was sent to investigate the sheen at about 9 a.m. local time (1400 GMT). “We are treating this very seriously, as we do all reports of possible pollution,” Coast Guard Capt. Jonathan Burton said in a statement. “We will ensure that all measures are taken to fully investigate and, if necessary, mitigate any impact this could potentially have.”
The earlier drop in the company’s London-listed share price showed that investors remain anxious over potential oil accidents two years after the BP offshore spill, the worst ever in the United States.
Shell had reported the sheen to the National Response Center, which is run by the Coast Guard and monitors marine oil spills, pipeline leaks and other incidents of pollution.
Shell owns a 71.5 percent interest in Mars and a 45.4 percent stake in Ursa, and operates both. BP owns a 28.5 percent stake in Mars and a 22.7 percent interest in Ursa.
The Mars platform can produce up to 160,000 barrels of oil and 121 million cubic feet of natural gas per day. Ursa can produce up to 150,000 barrels of oil and 400 million cubic feet of gas per day.
Both are about 130 miles (209 km) southeast of New Orleans, and are about seven miles (11 km) apart.
The Marine Spill Response Corp is a nonprofit organization created in 1990 by the oil and shipping industries to enable members to fulfill requirements of the U.S. Oil Pollution Act of 1990.