BP to retrieve Macondo blowout preventer next week

Crew members look over a blowout preventer on an idle oil rig in the Gulf of Mexico near Port Fourchon, Louisiana August 11, 2010.

HOUSTON (Reuters) - BP Plc aims to retrieve a failed blowout preventer from its ruptured Macondo well in the Gulf of Mexico Tuesday or Wednesday next week, the top U.S. official overseeing the spill response said on Friday.

The failure of the blowout preventer set off the world's worst offshore oil spill and it will be critical evidence in criminal and civil investigations into the cause of the April 20 explosion that killed 11 men on the Deepwater Horizon drilling rig.

Efforts to remove pieces of a drill pipe inside the blowout preventer -- a giant stack of pipes and valves -- have failed this week so the company will move on to recovering the blowout preventer whether or not pipe remnants remain stuck inside, retired Coast Guard Admiral Thad Allen said at a briefing in Washington.

"We've come to the conclusion that any more attempts at fishing are probably not going to result in success," Allen said.

Allen said federal investigators are on site to ensure the equipment is properly preserved.

"They've been allowed unfettered access to observe and record the entire removal process and recovery process," he said.

Once the blowout preventer is retrieved, BP will replace it with another and then resume drilling on a relief well. That well is on target to intercept the Macondo well near its bottom about 13,000 feet beneath the seabed and pump in mud and cement to kill the leak for good.

Allen said the intercept remains on target to occur after the U.S. Labor Day holiday on September 6, barring weather or technical delays. More than 4 million barrels of crude spewed into the Gulf before BP capped the well on July 15.

(Reporting by Kristen Hays; Editing by Bill Trott)