Transocean spokesman Guy Cantwell told UpstreamOnline that that Development Driller II was “expected to be in the area” of the Macondo blowout late yesterday.
The rig is expected to “race” the Transocean semi-submersible rig Development Driller III, which already spud the first relief probe, to reach the Macondo well bore on Mississippi Canyon Block 252 in the US Gulf of Mexico.
Macondo is dumping an estimated 5000 barrels of oil per day into the Gulf after a blow-out on 20 April.
A BP representative said the Development Driller II was “en route” but he had no further update on its location.
BP spokesman John Crabtree said the UK supermajor had not set a target date to spud the second relief well and he was not sure if BP had received approval from the US Minerals Management Service for its drilling plan.
However, BP America president Lamar Mackay told congressional hearings on Wednesday that he expected the Development Driller II to spud the second relief well this weekend.
Relief well stalled
Development Driller III has been stalled briefly while crews perform a battery of tests on the rig’s blowout preventer (BOP).
The tests follow new protocols developed by the Minerals Management Service (MMS) in the wake of the Deepwater Horizon disaster and apparent failure of the BOP on that rig, BP operations boss Doug Suttles said at a press conference yesterday.
He said the relief well drilling stalled just above 9000 feet, as measured from the surface of the water, which means the well has drilled about 4000 feet into the ground.
The drilling crew is expected to wrap up the BOP testing and resume drilling by the weekend.
Riser insertion
Meantime, BP plans to begin deploying a "
riser insertion tube” into the end of the riser tonight, Crabtree said.
The plan calls for ROVs to put a 6-inch pipe into the end of the 21-inch riser.
Around the pipe is a stopper-like washer that will plug the end of the riser and diver all the flow into the smaller tube, Crabtree said.
“Hopefully it will make a seal,” he told UpstreamOnline.
The tube will then be linked to the Transocean drillship Discoverer Enterprise, which can process the oil-water mix and lighter the oil to a tanker.
Crabtree estimated that about 85% of the leak was coming from the end of the riser versus about 15% coming from a crimp in the riser just above the crippled BOP.
He did not know how long it may take to put the tube in place.
In choosing the riser insertion method, BP decided to delay putting on a “top hat,” a dome that would cover the riser leak.
'Top hat' doffed
The “top hat” had been lowered to the sea floor yesterday.
BP tried a larger containment dome earlier this week and was foiled by the build up of methane hydrates, which form when natural gas hits extremely cold water.
Crabtree said he was not aware of any way to clear a hydrate build up in the riser insertion tube such as a valve that would allow BP to pump methanol or hot water through the pipe.
The top hat does have a port that would allow BP to intervene if there is a hydrate build-up.
On Wednesday, Suttles said BP has lowered the subsea manifold needed for it to attempt to plug the blow-out Macondo well with a “junk shot".
Deploying the manifold to the sea floor was the first step in a bid to plug the well’s blowout preventer (BOP) and stop the flow of oil.
The UK supermajor is still about a week away from attempting the junk shot, which is the first step in an attempt to staunch the well with a top kill, Suttles said at a press conference yesterday.
Top kill option
The top kill option involves a junk shot - shooting pieces of shredded tyre, knotted rope and even golf balls, among other material at high pressure into the Deepwater Horizon's crippled BOP in an attempt to clog it.
Once the BOP is clogged by the junk shot, BP can then pump kill fluid and cement into the blown-out wellbore, sealing it permanently.
The junk shot and top kill is just one method BP is considering to intervene in the well.
Other options include trying to stab a second BOP on top of the malfunctioning one, but all the alternatives depend on determining interior pressures in the wellhead, BOP and lower marine riser package that sit atop the wellbore.
BP, with the help of the US Department of Energy, is using radiography to get better imaging of the Macondo equipment package before deciding the best course of action, Suttles said.
Crabtree said he had not heard any further progress on those top kill plans.
Cement job failed test
During a Congressional hearing on Wednesday it was revealed that the cement job on the Macondo well had failed a key test.
Statements and documents tendered to the committee can be found
here .
House Energy & Commerce Committee chairman Henry Waxman the results of positive and negative pressure testing on the well varied widely, when they should have been fairly uniform.
Waxman said that James Dupree, BP's senior vice president for the Gulf of Mexico, told House investigators that the test was "not satisfactory" and "inconclusive," according to a Wall Street Journal report.
Less than five hours before the explosion, workers on the Transocean rig lowered pressure inside the well to see if any gas was leaking through the cement.
By this time, the cement had been hardening for more than 16 hours but Dupree told Congress that it appeared the cement job had not sealed off the well and gas was leaking into it.
A second negative pressure showed pressure was mounting in the well.
Dupree said the result "could signal" natural gas was building up inside the well.
Less than two hours before the explosion BP officials decided the additional tests "justified ending the test and proceeding", the newspaper quoted Waxman as sayig.
BP said that after this test, it began to remove heavy drilling mud in the pipe and replace it with seawater that was about 50% lighter.
BP told investigators that "following the test, hydrocarbons were unknowingly circulated to surface while displacing the riser with seawater".
As gas flowed up the pipe, it got warmer and expanded, pushing drilling mud and seawater ahead of it, and then burst through the top of the pipe.
Halliburton's chief safety officer, Tim Probert, repeated assertions that the only way to fully test the quality of Halliburton's cement work would have been to conduct a final evaluation involving a "cement bonding log", which was not done.
But BP's Mackay said that such tests are only used "when there is an indication of a problem" and said that the "better way" to test cementing work is through positive and negative pressure tests.
Earlier in the hearing, it was revealed that the BOP on Transocean's semi-submersible drilling rig had a leak in its crucial hydraulic system.
Blame game
At a hearing before the Senate's Energy & Natural Resources committee on Tuesday, the three executives traded blame over the disaster as they were grilled by committee members.
BP has confirmed oil had washed ashore at three locations: Dauphin Island, Alabama; the Chandeleur Islands off Louisiana; and the South Pass-Port Eads area on a remote stretch of Louisiana's mainland.
The National Oceanic & Atmospheric Administration forecast persistent south-east winds throughout the week, which have the potential to move new oil onshore.
The Macondo well - a discovery well which was to be temporarily abandoned ahead of later completion as a subsea producer - blew out on 20 April.
The well had been drilled to 18,000 feet by the Transocean semi-submersible Deepwater Horizon. An explosion rocked the semisub before the rig was engulfed in flames.
The rig sank on 22 April, extinguishing the blaze.
The initial cause of the accident is still unknown, although a senior Transocean executive, Adrian Rose, earlier indicated it seems likely the well blew out.
Eleven of the 126 crew on board the Deepwater Horizon at the time of the explosion are missing, presumed dead.
Drilling giant Transocean has confirmed nine of its employees are among the missing. Two worked for services outfit Smith International and Schlumberger's M-I Swaco joint venture.
BP has a 65% stake in Mississippi Canyon Block 252. Anadarko has 25% and Japanese player Mitsui the remaining 10%. All are liable for costs on a proportionate basis.
