NEW ORLEANS - BP froze activity on two key projects Wednesday meant to choke off the flow of oil billowing from its broken well in the Gulf of Mexico after days of moving confidently toward controlling the crisis.
The development was a stunning setback after the British oil giant finally seemed to be on track following nearly three months of failed attempts to stop the spill, which has sullied beaches from Florida to Texas and decimated the multibillion dollar fishing industry.
BP PLC and the government said more analysis was needed before testing could proceed on a new temporary well cap — the best hope since April of stopping the geyser. Work on a permanent fix, relief wells that will plug the spill from below with mud and cement, also was halted.
Oil continued to spew nearly unimpeded into the water, with no clear timeline on when it would stop.
"We want to move forward with this as soon as we are ready to do it," said Kent Wells, a BP senior vice-president.
BP had zipped through weekend preparations for getting the 75-ton cap in place and undersea robots locked it smoothly into place Monday atop the well, raising hopes the gusher could be checked for the first time since the Deepwater Horizon rig leased by BP exploded April 20, killing 11 workers.
Wells said that it was the government's call late Tuesday to re-evaluate plans for testing the new cap, and that plans were on hold for at least 24 hours. Federal officials and the company will re-evaluate the best path forward after that time period.
But he did not commit with certainty to going forward with the testing, which would shut off the leak by closing valves on the cap and watching to see if it could hold the pressure from oil and gas in the well. Wells suggested other oil collection options might be redeployed.
Wells said the cap test, which could put added pressure on the oil as it comes out of the ground, could have an effect on the relief well. He did not elaborate.
The relief well's timeframe has always been hazy, with company and federal officials giving estimates ranging from the end of July to the middle of August before it can be completed.
Roger N. Anderson, a marine geologist at Columbia University, said he believes BP and government scientists are just being very cautious. They may have found something surprising around the well during the countdown Tuesday to testing the cap, but he's not worried.
"So I wouldn't panic, is the answer. They're going to be very, very deliberate about this," Anderson said.
BP had originally planned to start closing valves on the cap Tuesday to test if the oil spewing from the well is coming from a single leak or if there may be more. If it's the latter case, the company would leave the valves open on the cap and try to collect the oil by piping it to as many as four vessels on the surface above.
The leak began after the Deepwater Horizon offshore drilling platform exploded on April 20, killing 11 workers. As of Tuesday, the 84th day of the disaster, between 90 million gallons (342 million litres) and 179 million gallons (676 million litres) of oil had spewed into the Gulf.
BP underwater video: http://bit.ly/bwCXmR
Weber reported from Houston. Associated Press writers Colleen Long in New Orleans and Matt Sedensky in Pensacola Beach, Florida, contributed to this report.