From 60 Minutes Blowout: The Deepwater Horizon Disaster:

A Survivor Recalls His Harrowing Escape; Plus, A Former BP Insider Warns Of Another Potential Disaster

The gusher unleashed in the Gulf of Mexico continues to spew crude oil. There are no reliable estimates of how much oil is pouring into the gulf. But it comes to many millions of gallons since the catastrophic blowout. Eleven men were killed in the explosions that sank one of the most sophisticated drilling rigs in the world, the "Deepwater Horizon."

This week Congress continues its investigation, but Capitol Hill has not heard from the man "60 Minutes" correspondent Scott Pelley met: Mike Williams, one of the last crewmembers to escape the inferno.

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Deepwater Horizon was in 5,000 feet of water and would drill another 13,000 feet, a total of three miles. The oil and gas down there are under enormous pressure. And the key to keeping that pressure under control is this fluid that drillers call "mud."

"Mud" is a manmade drilling fluid that's pumped down the well and back up the sides in continuous circulation. The sheer weight of this fluid keeps the oil and gas down and the well under control.

The tension in every drilling operation is between doing things safely and doing them fast; time is money and this job was costing BP a million dollars a day. But Williams says there was trouble from the start - getting to the oil was taking too long.

Williams said they were told it would take 21 days; according to him, it actually took six weeks.

With the schedule slipping, Williams says a BP manager ordered a faster pace.

"And he requested to the driller, 'Hey, let's bump it up. Let's bump it up.' And what he was talking about there is he's bumping up the rate of penetration. How fast the drill bit is going down," Williams said.

Williams says going faster caused the bottom of the well to split open, swallowing tools and that drilling fluid called "mud."

"We actually got stuck. And we got stuck so bad we had to send tools down into the drill pipe and sever the pipe," Williams explained.

That well was abandoned and Deepwater Horizon had to drill a new route to the oil. It cost BP more than two weeks and millions of dollars.

"We were informed of this during one of the safety meetings, that somewhere in the neighborhood of $25 million was lost in bottom hole assembly and 'mud.' And you always kind of knew that in the back of your mind when they start throwing these big numbers around that there was gonna be a push coming, you know? A push to pick up production and pick up the pace," Williams said.

Asked if there was pressure on the crew after this happened, Williams told Pelley, "There's always pressure, but yes, the pressure was increased."

But the trouble was just beginning: when drilling resumed, Williams says there was an accident on the rig that has not been reported before. He says, four weeks before the explosion, the rig's most vital piece of safety equipment was damaged. Read on...