How The Subsea Oil Recovery System Works

n its efforts to minimize the widening oil spill in the Gulf of Mexico, BP will deploy a large structure in the next 6 to 8 days to capture leaking oil. Here's how it works.

Called the Subsea Oil Recovery System, the 125-ton structure is designed to be placed over the largest source of oil leaking 5,000 feet beneath the Gulf of Mexico. The system collects the leaking oil and pumps it through a funnel and pipe to a tanker at the surface, which stores it and ships the oil to shore.

BP SPENDING $6M PER DAY ON SPILL

April 28, 2010

BP is spending more than $6 million per day to contain an oil spill from the Macondo well in the US Gulf of Mexico, while efforts continue to bring the well under control after an explosion on the Transocean semi-submersible rig Deepwater Horizon.

BP is fabricating components to connect a subsea oil recovery system to Transocean's drillship Discoverer Enterprise in order to collect oil emanating from the Macondo well and store it within the rig's storage tanks.

The Discoverer Enterprise is capable of receiving 20,000 barrels per day and can store over 125,000 barrels within its hull, according to BP chief operating officer Doug Suttles.

The oil will then be offloaded using the 300,000 barrel Overseas Cascade shuttle tanker, which was recently converted for Brazilian operator Petrobras to transport oil production from its floating production, storage and offloading vessel BW Pioneer.

BP expects to deploy this recovery system within two to four weeks.

The same system has been used in shallow water but never in the deep-water Gulf.

"The issue is to make certain it can withstand the pressure of the much deeper water at the side and to be able to sort out the various topsides processing issues," BP chief financial officer Byron Grote said in an analysts call today.

'Trying to shut the source'

Attempts to shut off the flow through the blowout preventer with the ROV have not been successful, said Suttles, but those efforts will continue with eight different ROVs.

Suttles said the ROV was able to hook up a hydraulic hose to the BOP to trigger the closing mechanism but mechanism has not closed.

BP spokesman Daren Beaudo confirmed that the company had contracted three ROV support vessels, each carrying a pair of ROVs; Ocean Intervention III from Oceaneering, Boa Sub C from Boa and Skandi Neptune from Subsea 7.

Meanwhile, Transocean's semi-submersible rig Development Driller III, which arrived on location about 9:45 pm local time last night, will be used to drill a relief well.

Development Driller III was already under contract to BP in Mississippi Canyon Block 778, where it was working on the Thunder Horse South development, according to MMS information.

The well will be spud about one-half mile from the Macondo well and will attempt to intercept the wellbore around 18,000 feet.

Once that is accomplished, heavy fluids will be pumped downhole, followed by cement, to kill the well.

MMS will approve the permits submitted for drilling the relief well today, MMS regional director Gulf of Mexico region Lars Herbst said.

BP declined to comment on when the UK supermajor would spud the well.

Grote estimated the well would take two to three months to drill and is expected to cost BP about $100 million; in line with estimates for drilling costs at that total depth and water depth.

Herbst said it is unknown why the Cameron BOP did not automatically close, which under one system he referred to as the "deadman system" is supposed to occur when hydraulic and electronics to the BOP are lost.

'Burning away the oil'

Meantime, the US Coast Guard may try to burn off a portion of the oil slick beginning tomorrow.

Coast Guard Rear Admiral Mary Landry said the Coast Guard was considering using booms to isolate an area of the spill and then ignite the slick.

Landry said a similar strategy was effective at reducing a spill off Newfoundland, Canada by more then 95%.

"It's a tool in the tool kit," Landry said. "I want to have it at my availability."

"We are possibly 90 days out from securing the source permanently."

Charlie Henry, with the National Oceanic and Atmospheric Administration, said a similar technique had been used on a spill off Coos Bay, Oregon in 1999 to burn oil remaining inside a ship, and it had little impact to the neighbouring community while effectively reducing the size of the spill.

It has also been used to treat spills in wetlands areas where equipment to skim the slick would have damaged the ecosystem

The plan was endorsed by Texas General Land Office commissioner Jerry Patterson, who said he would send a special fire-proof boom for the job.

"Burning this oil on the surface is one of the best ways to deal with an open-water spill of this magnitude," Patterson said in a release.

The Coast Guard will evaluate weather conditions and weigh risks and benefits before deciding tomorrow whether to light the slick on fire.

'Response team grows'

BP and the US Coast Guard have bumped up the number of vessels responding to the Macondo spill in the US Gulf to 50 vessels, as they try to contain a slick now estimated to cover an area the size of Rhode Island.

The Coast Guard confirmed that the spill has grown, covering an area 600 miles in circumference and there are now more than 1000 people working on containment.

Landry said the spill, which is now about 20 miles off the Louisiana coast, is not expected to make landfall within the next three days.

Henry said he was not comfortable trying to estimate beyond three days, saying winds were expected to shift from the north to the south over the next 24 hours.

The crude, which is leaking at an estimated 1000 barrels per day from the broken riser of the well, is about 37 API with a high gas to oil content, BP exec Byron Grote told analysts today.

Seven skimming boats have collected about 1152 barrels of oily water, according to the latest figures from the Coast Guard.

"At the centre of the spill - that's about 3% of the surface area of the wider sheen - the spill has an average thickness of 0.1milimetre - about the width of a human hair - and is subject to skimming operations," Grote said on the call.

"And the wider sheen, which has a thickness of one or two hydrocarbon molecules - so that is very tiny - is being addressed through the use of dispersant."

So far, crews have sprayed 29,140 gallons of dispersant and have another 119,734 gallons ready.

Most of the sheen should dissipate on its own, Henry said earlier.

Coast Guard Rear Admiral Mary Landry also said there is no evidence that as much as 700,000 barrels of diesel fuel stored in the pontoons of the Deepwater Horizon, which sunk after the explosion and fire, was leaking.

The plan is to monitor the diesel and leave the diesel in place while crews focus on the crude, unless the ROVs show that it is beginning to leak.

Boats have set more than 29,000 feet of boom and have another 36,000 feet on order.

Crews have set up staging areas to protect sensitive coastlines at Biloxi, Mississippi; Pensacola, Florida; Venice, Louisiana; Pascagoula, Mississipi and Theodore, Alabama.

Officials in Louisiana have already asked the Coast Guard to boom-off the Delta National Wildlife Refuge.

'Feds begin investigation'

The Department of the Interior and Department of Homeland Security today officially announced the launch of their investigation into the incident.

"We will remain focused on providing every resource we can to support the massive response effort underway at the Deepwater Horizon, but we are also aggressively and quickly investigating what happened and what can be done to prevent this type of incident in the future," Interior Secretary Ken Salazar said in a release.

The Coast Guard, which has jurisdiction over marine accidents and the Minerals Management Service (MMS), which oversees offshore oil development, will share jurisdiction in the case.

The regulators will have the power to issue subpoenas, hold public hearings and call witnesses.

Senior officials are meeting with BP officials today, including boss Tony Hayward and BP Americas head Lamar McKay.

'Congressional Hearing'

The US Congress has a hearing set for early next month where it will discuss the Deepwater Horizon tragedy and the ongoing oil spill in the US Gulf that is flowing from BP's Macondo exploration well.

The Senate Energy and Natural Resources Committe will meet at 930 am local time on 6 May to discuss issues surrounding US offshore oil exploration, including the Deepwater Horizon disaster.

"We were planning this hearing before the Gulf tragedy to discuss the five year plan," committee spokesman Bill Wickers told UpstreamOnline, but members added the Deepwater Horizon to the agenda.

"Many members on committee interested in knowing more about this tragic accident," he said.

A witness list for the hearing has not been set, a committee spokesman told UpstreamOnline.

'ExxonMobil rig shut down'

Herbst said rig owner Diamond Offshore evacuated its semisub rig Ocean Endeavor "in an abundance of caution" due to the sheen in the water in the area of the rig.

Ocean Endeavor was working on a well workover on the Mica field for ExxonMobil in Mississippi Canyon Block 211 when it was evacuated.

"The drilling rig will likely be moved off location and resume work at a later time," Herbst said.

Diamond spokesman Les Van Dyke said he was not aware of any imminent plans to re-man the rig for relocation.

'Greens slam offshore drilling expansion'

A Greenpeace representative told UpstreamOnline that his organisation was especially concerned about the spill's effect on bluefin tuna, which spawn in the northern Gulf, and sea turtles, which are making their way to Gulf coast beaches to spawn.

Three sperm whales were also spotted in the vicinity from the air but according to Henry they were not in the immediate area of the spill.

John Hocevar, oceans campaign director for Greenpeace USA said animals will avoid the slick "but with something this scale, a lot of marine life isn't going to have the option."

"The nature of marine food webs - once it is taken up by plankton and smaller fish it keeps circulating through the food chain," he told UpstreamOnline.

"It is going to end up in the food we eat."

Hocevar said the problems shutting the well and containing the spill in the Gulf, where there is a concentration of industry resources, shows why the US should not open drilling in more remote areas.

'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 when an explosion rocked the semisub before the rig was engulfed in flames.

The semisub sank on Thursday morning, extinguishing the blaze.

A senior Transocean executive, Adrian Rose, said the company had not begun to determine if the rig, which was found in 5000 feet of water Saturday, could be salvaged.

Transocean said yesterday the rig was insured for up to $560 million.

The initial cause of the accident is still unknown, although 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."

'Lost are mourned'

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.

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 supermajor 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."

BP holds 65% of the Macondo prospect and operated the well. US independent Anadarko holds a 25% working interest and Japan's Mitsui holds the remaining 10%.

Coast Guard maps showing the extent of the spill and the location of the Deepwater Horizon, as well as an isometric view of the spill, are available in the related media section to the left of this article.

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