BP Relief Wells Bring Risk of Bigger Gulf of Mexico Oil Spill

BP Plc faces the risk of an even bigger oil spill as it attempts to drill two so-called relief wells to plug a leak on the seabed of the Gulf of Mexico that’s gushing 5,000 barrels a day into the ocean.

In a regulatory filing BP made to drill the relief wells it estimates another blowout could release as much as 240,000 barrels of oil a day into the ocean. That’s almost 50 percent more than the company’s worst-case estimate for the first well and equivalent to two-thirds of supply pumped daily from Prudhoe Bay, the largest U.S. oil field.
The relief wells will pump cement into the leak to seal it. To do that, BP will need to first drill into the same deposit of oil and gas that caused a pressure surge known as a blowout at the original well, igniting an explosion that killed 11 workers and sank a $365 million drilling rig.

Golf ball-sized clumps of tar were found this past weekend on Dauphin Island off the Alabama coast and six-foot waves in the Gulf through May 13 may push crude ashore west of the main entrance to the Mississippi River. The U.S. Fish and Wildlife Service on May 8 closed public access to Louisiana’s Chandeleur and Freemason islands, the first areas where oil reached land.

BP began drilling a relief well on May 2 with Transocean Ltd.’s Development Driller III rig. The second well will begin on May 14 with Transocean’s Discoverer Enterprise vessel. The sites of the relief wells are 5,160 feet beneath the sea floor, BP said in its filing.


Sanford C. Bernstein Ltd. analysts estimated April 30 that capping the leaks and cleaning up the spill may cost BP and its partners in the Macondo prospect $12.5 billion.