SAN FRANCISCO (Reuters) - Schlumberger Ltd, the world's largest oilfield services company, said on Wednesday it had a crew on the Deepwater Horizon that departed only hours before the explosion and fire that engulfed the rig.
The company, which had not previously revealed its work on the Horizon, said in an emailed statement that it performed wireline services for BP Plc on the rig in March and April, completing the last services on April 15 and leaving a crew on standby in case any more were needed.
"On the morning of April 20, 2010, BP notified the Schlumberger crew that it could return to its home base in Louisiana," Schlumberger said in a statement, which a company spokesman confirmed by phone. He declined to comment further.
Wireline services relate to any aspect of well measurement logging that employs an electrical cable to lower tools into the borehole and to transmit data.
The wireline standby crew departed the Horizon at about 11 a.m. on one of BP's regularly scheduled helicopter flights, Schlumberger said. The explosion occurred at about 10 p.m. that night, and the rig sank into the Gulf of Mexico two days later as a massive leak from the well started.
Other oilfield services companies whose names were attached to the Horizon have seen their share prices battered due to fears about liability over the loss of the rig and 11 workers, and the resulting environmental damage of the oil spill.
Shares of Halliburton Co, which did various services on the Transocean-owned rig including well cementing, are down 22 percent since it sank. Shares of Cameron International Corp, maker of the rig's blowout preventer, are down 23 percent.
Schlumberger shares have fallen about 8 percent over the same period.