BP has used a “risky” design in one out of every three of its deepwater wells in the Gulf of Mexico. According to a new Wall Street Journal report, BP used the design – called a “long string” – far more frequently than any of its peers in the industry.
That design was used at the site of the April 20 Deepwater Horizon oil rig explosion. The explosion, the result of a natural gas blowout, killed 11 crew and resulted in the worst oil spill in U.S. history. According to The Wall Street Journal, an alternative – and more expensive – design that BP chose not to use includes more safeguards against such blowouts.
The long string design is so dubbed because it uses a single, long “string” of pipe from the sea floor to the bottom of the well. The design is cheaper, the Journal said, because a single pipe runs the length of the well and can be installed in one step. But a different design, known as a ‘liner tieback”, which has more built-in places to prevent oil or gas from flowing up the well uncontrolled, is seen as being safer.
According to the Journal, since 2003, BP has used the long string design in 35% of its deepwater wells. By contrast, Royal Dutch Shell PLC used such designs on 8% of its wells and Chevron Corp. on 15%. Australian firm BHP Billiton PLC used long string on 4% of its wells.
The Journal also reported that Anadarko Petroleum Corp. – BP’s minority partner in Deepwater Horizon – uses the long string in more than 40% of its wells. However, the company maintains that it doesn’t use it for drilling exploration or high pressure wells in unfamiliar areas, like the one involved in the Deepwater Horizon blast.
According to The Wall Street Journal, a liner tieback design is more complex and costlier, which may have been among the reasons BP rejected it for Deepwater Horizon. In one internal BP email released by a Congressional committee, a BP drilling engineer in Houston told colleagues that the long-string design “saves a good deal of time and money.”
Some in Congress have criticized BP’s decision to use the long-string design on Deepwater Horizon. In a letter to BP, Congressmen Henry Waxman (D., Calif.) and Bart Stupak (D., Mich.) asserted that the decision “appears to have been made to save time and reduce costs.” Using the alternate design would have cost an additional $7 million to $10 million, according to an internal BP estimate released by the congressmen, the Journal said.
The Journal does point out that use of the long-string design alone wasn’t enough to cause the Deepwater Horizon explosion. But what it may have done was create a pathway for gas to flow up the well, that could have put pressure on equipment at the sea floor. Still, the Journal said the well would have been secure if the cement plug at the bottom of the hole had held.
BP has defended its use of the long-string design at Deepwater Horizon, pointing out that it was approved by regulators at the Minerals Management Service.