Friday, April 30, 2010

Rig had history of spills, fires before big 1


Rig had history of spills, fires before big 1

During its nine years at sea, the Deepwater Horizon oil rig operated by BP suffered a series of spills, fires — even a collision — because of equipment failure, human error and bad weather. It also drilled the world's deepest offshore well.

But Deepwater Horizon's lasting legacy will undoubtedly be the environmental damage it caused after it exploded and sank, killing 11 crew and releasing an estimated 210,000 gallons of oil a day into the Gulf of Mexico.

What likely destroyed the rig in a ball of fire last week was a failure -- or multiple failures -- 5,000 feet below. That's where drilling equipment met the sea bed in a complicated construction of pipes, concrete and valves that gave way in a manner that no one has yet been able to explain.

Oil services contractor Halliburton Inc. said in a statement Friday that workers had finished cementing the well's pipes 20 hours before the rig went up in flames. Halliburton is named as a defendant in most of the more than two dozen lawsuits filed by Gulf Coast people and businesses claiming the oil spill could ruin them financially. Without elaborating, one lawsuit filed by an injured technician on the rig claims that Halliburton improperly performed its job in cementing the well, "increasing the pressure at the well and contributing to the fire, explosion and resulting oil spill."

Remote-controlled blowout preventers designed to apply brute force to seal off a well should have kicked in. But they failed to activate after the explosion.

Scott Bickford, a lawyer for several Deepwater Horizon workers who survived the blast, said he believes a "burp" of natural gas rose to the rig floor and was sucked into machinery, leading to the explosion.

Halliburton's said "it is premature and irresponsible to speculate on any specific causal issues."

Before last week's catastrophe, Deepwater Horizon's most recent hiccup occurred in Nov. 2005, when the rig — under contract with BP — spilled 212 barrels of an oil-based lubricant due to equipment failure and human error. That spill was probably caused by not screwing the pipe tightly enough and not adequately sealing the well with cement, as well as a possible poor alignment of the rig, according to records maintained by the federal Minerals Management Service.

Following that spill, MMS inspectors recommended increasing the amount of cement used during this process and applying more torque when screwing in its pipes.

Experts say the number of safety incidents experienced by Deepwater Horizon isn't unusual for an industry operating in harsh conditions. And it is difficult to draw any connections between those problems and last week's deadly explosion, they say.

"These are big, floating cities," said Tyler Priest, a historian of offshore oil and gas exploration. "You're always going to have minor equipment failure and human error, and of course they're operating in a hurricane prone environment."