Retired Coast Guard Adm. Thad Allen told reporters it could be late Monday or early Tuesday before officials know the results of those tests, which will be designed to minimize any potential risks with the final plugging procedure.
If Allen gives his final order to proceed with the relief well then, it could be next weekend before the relief well intercepts the blown-out well. Once that happens, engineers will pump in mud and cement to plug the well from below, a process known as the bottom kill.
Before that happens, Allen wants to know if pressure inside the well has to be lessened. He has instructed BP to provide an analysis to determine if the bottom kill could risk damaging the well further without some kind of pressure relief.
BP began drilling its primary relief well in early May to permanently seal the ruptured well. But about two weeks ago, around the time the company had done a successful static kill pumping mud and cement into the top of the well, executives began signaling that the bottom kill procedure might not be done. In recent days, Allen suggested that was a possibility.
But pressure tests this week reaffirmed the original plan. "The relief well will be finished and the bottom kill will be executed," he said.
Allen also said that BP's failed blowout preventer may be replaced before the relief well is completed. He said when it is replaced, officials will take precautions to preserve it for evidence.
Investigators want to analyze the contraption to determine why it failed to prevent the Deepwater Horizon explosion April 20 that killed 11 workers and caused 206 million gallons of oil to spew from the well a mile beneath the surface of the Gulf of Mexico.
Meanwhile, BP warned residents of the Gulf region to watch out for scammers posing as company employees and seeking personal information or money for "safety training" and other purposes.