SOME GOOD NEWS BUBBLES UP FROM THE BOTTOM: Things have gone well for BP and the Gulf of Mexico in the last week, relatively speaking. In spite of the challenge of working with remote-operated vehicles (ROVs) in harsh conditions at 5,000 feet below sea level, on Monday BP engineers managed to attach a new sealing cap to a well that has spewed millions of gallons of crude oil into the Gulf of Mexico.
What is a sealing cap? How does it work? I’ll explain.
Since June, BP has been collecting oil at the well with a device called a containment cap. That sits on top of the well’s non-functional blowout preventer (BOP), where the oil is leaking from. Oil and gas is pumped up a long pipe, called a riser, to ships on the surface, where it is collected or burned off in a process called flaring. That system was capturing about 25,000 barrels a day, or less than half of the oil escaping from the well.
BP removed the old containment cap on Saturday, allowing oil to temporarily flow freely from the top of the BOP. In the meantime, engineers used a hydraulic ram system to straighten up the flex joint (a piece of pipe extending from the top of the BOP that was damaged when the Deepwater Horizon drilling rig sank and the rig’s riser pipe collapsed). ROVs also removed a damaged piece of equipment called a flange, which is a flat, circular piece of metal attached to the well with six huge bolts and allows (when not damaged) the well assembly to connect to pipes above.
The new sealing cap, a monstrous 30-foot tall, 80-ton device sometimes called a three-ram capping stack, was then ready to be installed. It consists of two major parts:
a 12-foot tall, 15,000-pound pipe/connector device called a flange transition spool, and a 150,000-pound, 18-foot tall three-ram connector. This second part is where the action is—it includes three massive hydraulic rams used to control the well’s flow. BP completed the installation of the capping stack around 7 p.m. Monday.
BP hopes that the new cap will collect 60,000 to 80,000 barrels of oil a day. Aside from the increased collection capacity, a BP press release issued Saturday explained that the new cap offers several other advantages, one being simplifying “future well kill and cementing procedures through the relief wells, which in turn could increase the probability of success for those operations.”
The cap also allows BP to test the well’s integrity. As I am writing this on Tuesday afternoon, Associated Press reports say BP is still waiting to activate the three hydraulic rams on the capping stack, which will shut off the leaking well. BP hopes to begin that process soon. When the well is sealed, the company will then begin a series of pressure tests, as the company explained in a release on Tuesday:
“For the duration of the test, which will be a minimum of six hours and could extend up to 48 hours, the three ram capping stack will be closed and all sub-sea containment systems (namely, the Q4000 and Helix Producer) will be temporarily suspended, effectively shutting in the well,” the release stated. “It is expected, although cannot be assured, that no oil will be released to the ocean for the duration of the test. This will not however be an indication that flow from the wellbore has been permanently stopped.”
If the pressure tests reveal that the pressure in the well is low, that may mean “that the drilling pipe is leaking below the floor of the Gulf of Mexico,” according to a report Tuesday from the Mobile Press-Register. If it is high, it will indicate that the well is intact. From there, engineers are looking for a Goldilocks situation—if pressure is too high for the sealing cap to contain it, BP will have to vent the cap and collect some oil, but if it’s just right, the rams could remain closed, effectively sealing the leaking well for the first time since the Deepwater Horizon drilling-rig exploded on April 20.
Another advantage of the new sealing cap is that it offers some comfort if some sort of 2012-esque can’t-look-away there-is-no-God disaster-movie scenario plays out in the Gulf of Mexico, and a hurricane hits the oil spill. With the new cap, it’s much easier and faster to disconnect a riser pipe so collection ships on the surface can skedaddle to a safe harbor.
“It’s instrumental in terms of our ability if a hurricane comes through,” BP executive Kent Wells said last Friday in a technical briefing.
“Our quick disconnect/reconnect process, it’s fundamental to that.”
RELIEF WELL(S) ON ITS WAY: Though the cap BP installed Monday could potentially stop the oil from leaking from the floor of the Gulf of Mexico, officials from the federal government and BP insist that the only permanent method of killing the well is via the use of relief wells. Drillers have been working for months to bore a hole 18,000 feet below sea level (which includes 13,000 feet of sea bed) to intercept a well pipe about the size of a dinner plate. Then heavy drilling fluids will be pumped into the well to cement it permanently, or “kill” the well.
The good news is that the drilling process is on schedule—early estimates put the relief well’s completion date in August, and BP thinks that’s still true. “Our best estimation is towards the latter part of July we’ll make the intercept, and then we’ll go into the kill process,” Wells said last Friday. “The killing and cementing can take a number of days to a few weeks.”
There are two ships drilling separate relief wells. On Monday, the first was at 17,840 feet, and the second at 15,960 feet below the surface. The last few feet of the well will be the most challenging, as drillers have to hit a 9-inch target. “This is the precision place, the precision part of the well,” Wells said.
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