"We'll keep trying until we bring this thing to a close," Doug Suttles, BP's Chief Operating Officer, told CBS' "The Early Show", adding that the current techniques the company is using now "won't stop" the leak caused by an oil rig that exploded April 20.
Eleven crewmembers were killed in the explosion.
Calling BP's efforts "fairly successful" at keeping the oil from reaching shore, Suttles did not directly respond to questions over whether his company's - and the government's - estimate that 5,000 barrels a day were pouring into the Gulf might be too low.
"We're putting every effort into this. It's really not tied to the rate," Suttles said.
Complete Coverage: Disaster in the Gulf
BP officials said Thursday they would thread a small tube into a jagged pipe on the seafloor to suck oil to the surface before it can spew into the Gulf and add to a disaster apparently set in motion by a long list of equipment failures.
Engineers will have to make sure the 6-inch-wide tube is inserted deep enough into the 21-inch-wide pipe so gas and seawater don't mix, which can form crystals that could clog the tube. They'll also have to thread the tube into the pipe without hitting debris around the riser.
The smaller tube will be surrounded by a stopper to keep oil from leaking into the sea. The tube will then siphon the crude to a tanker at the surface, though BP declined to estimate how much oil the tube will be able to collect.
Company spokesman Bill Salvin said engineers hope to start moving the tube into place Thursday night, but it will take 12 hours to get the tube fully hooked up. Another option is a small containment box called a "top hat," which is already on the seafloor and also would siphon oil to a tanker on the surface.
Officials are waiting to use the box until they know if the tube works, and how well it's working, Salvin said. Engineers still might consider trying to fill the leak with golf balls and other debris - the "junk shot," though that won't be until at least next week. And a relief well is being drilled, but that is at least two months away.
BP's updates came a day after hearings in Washington and Louisiana uncovered a checklist of unseen breakdowns on largely unregulated aspects of well safety that apparently contributed to the April 20 blowout aboard the Deepwater Horizon: a leaky cement job, a loose hydraulic fitting, a dead battery. Company officials insist what caused the accident is not yet clear.
The trail of problems highlights the reality that, even as the U.S. does more deepwater offshore drilling in a quest for domestic oil, some key safety components are left almost entirely to the discretion of the companies doing the work.
More Oil Spill Coverage
BP Says Its Gulf Oil Spill Costs Now $450M
Gulf Oil Rig Plagued by Problems, Probe Finds
Obama Seeks Greater Liability from BP on Spill
2nd Oil Containment Box Reaches Gulf Seafloor
Fla. Gov. Crist Wants $35M from BP for Tourism