Discoverer Enterprise en route to Macondo

MMS weighs up relief well plans

A second Transocean rig, the drillship Discoverer Enterprise, is en route to the site of the Macondo blowout in the Gulf of Mexico, where it will spud an additional relief well, if required, in efforts to halt a leak of about 1000 barrels per day of crude from the damaged well.

Anthony Guegel, Noah Brenner, Jonathan Davis & Anthea Pitt 25 April 2010 22:13 GMT

Meanwhile, Diamond Offshore has confirmed the semi-submersible rig Ocean Endeavor, currently under contract to ExxonMobil in the Gulf of Mexico, evacuated safely yesterday.

The evacuation was by the slick from Macondo, which is heading towards the unit.

The Ocean Endeavor was drilling the Mica prospect on Mississippi Canyon Block 211.

A US Coast Guard spokeswoman told Upstream the drillship was expected to arrive on scene on 2 May.

Transocean spokesman Greg Panagos later said: "I can confirm the Discoverer Enterprise is moving to assist at at Macondo.

"However, we have no arrival date at this point."

The Discoverer Enterprise will join Transocean’s semi-submersible drilling rig Development Driller III, which is expected to arrive near the site of the BP-operated well in Mississippi Canyon Block 252 this morning, local time.

The high-performance drillship was already under contract to BP in Mississippi Canyon Block 778, where it was working on the Thunder Horse South development, according to Minerals Management Service (MMS) information.

Meanwhile, the MMS is reviewing BP's plan to drill multiple relief wells to halt the blowout, which is spewing around 1000 barrels of crude per day from a ruptured drilling riser .

'Multiple relief wells'

While a remotely-operated vehicle (ROV) is at the subsea blowout preventer (BOP) attempting to kill the well, BP filed the first of its permit plans with the MMS on Saturday and will send the final permits within the next 24 hours for multiple relief wells.

MMS regional director for the Gulf of Mexico region Lars Herbst and BP’s chief operating officer for exploration and production Doug Suttles confirmed the plans in a press conference held near New Orleans.

Suttles said: “Right now we are planning multiple relief wells if required and it depends on how successful we are with the existing BOP.”

Suttles said the ROV has already started work on the BOP connecting lines to pump fluids to close the rams and bring the well “under control”.

“These actions will take approximately 24 to 36 hours to complete,” he said.

At least three other ROVs are deployed to monitor the operation.

“I should emphasize that this is a highly complex operation being performed at 5000 feet below the surface,” Suttles cautioned.

“It may not be successful.”

This action suggests that the BOP – which weighs about 450 tonnes and is over 50 feet tall and 18 feet wide – is intact, at least enough to attempt the kill operation. However, the state of the well casing is unclear.

When asked if Macondo is a high-pressure well, Suttles said Macondo was not considered to be “unusually high pressured” but he was unable to say what the exact pressure is since there is no way to monitor it.

It is hoped the Development Driller III will be able to spud a relief well soon after it arrives on the scene.

However, it is understood that the relief wells could take several months to complete.

According to the MMS, the Development Driller III has been working in Green Canyon Block 743 on BP's Atlantis field development.

Suttles and Rear Admiral Mary Landry pointed out that the roughly 1000-bpd leak is many times less than it was when the Deepwater Horizon was ablaze last week.

Weather favourable

Meanwhile, Landry expects favourable weather conditions to help keep the oil slick 30 miles (48 kilometers) off the Louisiana coast at least for the next three days, based on projections and satellite imagery.

“We have no shoreline impacts at this time,” Landry said, despite recent poor weather which hampered earlier efforts to contain the spill.

However, the Coast Guard has used about 6400 gallons of additional dispersants on the slick, which she said is working “very effectively”.

“Today we have successfully recovered about 48,000 gallons of oily water mix by the surface skimmer vessels, which is equivalent to about 1142 barrels," she added.

Suttles said efforts had also begun to collect oil near the well by deploying an underwater dome over it, but it was unclear how it would perform as it had never been used at this water depth before.

Landry said the “overarching goal” is to secure the well and keep the oil spill as far from the shoreline as possible, as well as mitigate any other environmental fallout.

As federal on-scene co-coordinator, Landry said she has the full support of the federal government “for any resources we need to minimize the economic and environmental impact”.

Landry said several million dollars have already been spent in response to the incident.

Deadly blowout

The Macondo well - a discovery well which was to be temporarily abandoned ahead of later completion as a subsea producer - blew out late last Tuesday evening.

The well had been drilled to 18,000 feet by the Deepwater Horizon. An explosion rocked the semi sub before the rig was engulfed in flames.

The semi sub sank on Thursday morning, 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.

“We don’t know what caused the accident,” he said. When asked if the incident involved a blowout, he replied: "Basically, yes."

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.

Lost crew mourned

Transocean chief executive Steven Newman said: "As the nation and everyone in the Transocean family mourns the tragic loss of these people, our deepest sympathies are with their families and friends today.

"Transocean is doing everything we can to meet their needs during this difficult time, and our family response team members are in close contact to provide all necessary support,” he said.

He added: “ I would once again like to express our gratitude to the US Coast Guard, BP and everyone involved for their exhaustive search and rescue efforts, despite this very sad outcome."

BP chief executive Tony Hayward also offered his condolences on behalf of the super major to the families of the missing men.

“No words can express the sorrow and pain when such a tragic incident happens," he said.

“On behalf of all of us at BP, my deepest sympathies go out to the families and friends who have suffered such a terrible loss.

"Our thoughts also go out to their colleagues, especially those who are recovering from their injuries."

Hayward added: “BP will be working closely with Transocean and the authorities to find out exactly what happened so lessons can be learnt to prevent something like this from happening anywhere again.”