Gulf Oil Spill
This image taken from video provided by BP PLC at 15:57 CDT, shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwat...
This image taken from video provided by BP PLC at 15:57 CDT, shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwater Horizon oil spill in the Gulf of Mexico Thursday, July 15, 2010. BP finally choked off the flow of oil into the Gulf of Mexico on Thursday _ 85 days and up to 184 million gallons after the crisis unfolded _ then began a tense 48 hours of watching to see whether the capped-off well would hold or blow a new leak. Engineers will monitor pressure gauges and watch for signs of leaks elsewhere in the well. (AP Photo/BP PLC) NO SALES
Gulf Oil Spill
This combo made from images taken from video provided by BP PLC shows oil flowing from two of three valves on the new 75-ton cap atop the site of the...
This combo made from images taken from video provided by BP PLC shows oil flowing from two of three valves on the new 75-ton cap atop the site of the Deepwater Horizon oil spill in the Gulf of Mexico at 17:04 CDT Wednesday, July 14, 2010, left, and the top of the cap at 17:56 CDT on Thursday, July 15, minutes after the flow of oil was choked off. BP vice president Kent Wells said the oil stopped flowing into the water at 14:25 CDT after engineers gradually dialed back the amount of crude escaping through the last of three vents in the cap, an 18-foot-high metal stack of pipes and valves.(AP Photo/BP PLC) NO SALES
Gulf Oil Spill
This image taken from video provided by BP PLC at 14:27 CDT, shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwate...
This image taken from video provided by BP PLC at 14:27 CDT, shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwater Horizon oil spill in the Gulf of Mexico Thursday, July 15, 2010. BP vice president Kent Wells said the oil stopped flowing into the water at 14:25 CDT after engineers gradually dialed back the amount of crude escaping through the last of three vents in the cap, an 18-foot-high metal stack of pipes and valves. (AP Photo/BP PLC) NO SALES
Gulf Oil Spill
This image taken from video provided by BP PLC at 17:56 CDT shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwater...
This image taken from video provided by BP PLC at 17:56 CDT shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwater Horizon oil spill in the Gulf of Mexico Thursday, July 15, 2010. BP finally choked off the flow of oil into the Gulf of Mexico on Thursday _ 85 days and up to 184 million gallons after the crisis unfolded _ then began a tense 48 hours of watching to see whether the capped-off well would hold or blow a new leak. Engineers will monitor pressure gauges and watch for signs of leaks elsewhere in the well. (AP Photo/BP PLC) NO SALES
Gulf Oil Spill
In this combo made from images taken from video provided by BP PLC, oil flows from two of three valves on the 75-ton cap atop the site of the Deepwat...
In this combo made from images taken from video provided by BP PLC, oil flows from two of three valves on the 75-ton cap atop the site of the Deepwater Horizon oil spill in the Gulf of Mexico at 17:04 CDT Wednesday, July 14, 2010, left, oil flows from one of three valves at 22:25 CDT Wednesday, July 14, 2010, center, and oil no longer flows from the cap at 15:57 CDT Thursday, July 15, 2010. (AP Photo/BP PLC) NO SALES
Gulf Oil Spill
This image taken from video provided by BP PLC at 15:13 CDT shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwate...
This image taken from video provided by BP PLC at 15:13 CDT shows that oil has stopped flowing from the new 75-ton cap atop the site of the Deepwater Horizon oil spill in the Gulf of Mexico Thursday, July 15, 2010. BP finally choked off the flow of oil into the Gulf of Mexico on Thursday _ 85 days and up to 184 million gallons after the crisis unfolded _ then began a tense 48 hours of watching to see whether the capped-off well would hold or blow a new leak. Engineers will monitor pressure gauges and watch for signs of leaks elsewhere in the well. (AP Photo/BP PLC) NO SALES
BP said its capped-off well appeared to be holding steady Friday morning, almost midway into a white-knuckle waiting period in which engineers watched the pressure gauges for signs of a leak.
Results monitored from control rooms on ships at sea and hundreds of miles away at the company's U.S. headquarters in Houston showed the oil staying inside the cap, rather than escaping through any undiscovered breaches, BP PLC vice president Kent Wells said on a conference call.
Two underwater robots scoured the sea floor looking for signs of new leaks.
President Barack Obama said BP's capping of the spill was "good news" but cautioned that testing continued.
There was no evidence of a leak in the pipe under the sea floor, Wells said, one of the main concerns. Wells spoke 17 hours after valves were shut to trap oil inside the cap, a test that could last up to 48 hours.
He said pressure continued to rise inside the tight-fighting cap, a good sign that oil was not getting out somewhere else. The pressure was above the minimum they were hoping to see, but not yet in the high range they were hoping for.
"The pressures
