BP positioning riser insertion tube to capture oil spill

BP PLC worked May 14 to install a riser insertion tube within the damaged Deepwater Horizon riser to collect leaking oil from a deepwater blowout that has resulted in an oil spill in the Gulf of Mexico.

This story was updated with comments from an afternoon news conference on May 14.

Paula Dittrick
OGJ Senior Writer

HOUSTON, May 14 -- BP PLC worked May 14 to install a riser insertion tube within the damaged Deepwater Horizon riser to collect leaking oil from a deepwater blowout that has resulted in an oil spill in the Gulf of Mexico.

Drilling of a second relief well was expected to start May 16, Doug Suttles, chief operating officer of BP Exploration & Production, told reporters during an afternoon news conference from Robert. La.

On May 2, BP started drilling the first relief wells. The second relief well is a backup to the first relief well, which is expected to take 3 months to complete.

Transocean Ltd.’s semisubmersible rig, Deepwater Horizon, drilled the runaway Macondo oil and gas well in 5,000 ft. on Mississippi Canyon Block 252. The rig exploded Apr. 20, leaving 11 crew members missing and presumed dead. On Apr. 22, the Deepwater Horizon sank. An estimated 5,000 b/d of oil is spilling into the gulf.

Efforts to install the riser insertion tube started late May 13, and Suttles estimated that if successful, then collection of oil and gas through the riser insertion tube possibly could start on May 15.

“We believe it will work. The challenge is deploying it,” Suttles said. “The concept is simple, the challenge is deploying it in 5,000 ft of water where people can’t work.”

Crews used remotely operated vehicles as they attempted to position a smaller pipe with a rubber sealing device inside the damaged Deepwater Horizon riser on the seabed. Once oil and gas is collected, it will go into Transocean’s Discoverer Enterprise drillship.

BP operates the block with 65% interest. Partners are Anadarko Petroleum Corp., 25%, and Mitsui Oil Exploration Co. Ltd., 10%.

‘Top hat’ available, if needed
BP already has another containment option called a “top hat” sitting on the seabed near the riser. The “top hat” is 4 ft in diameter by 5 ft tall. Engineers specifically designed the small containment device is to prevent the leaking oil and gas from contacting water.

Likewise, the riser insertion device also was designed to prevent hydrocarbons from coming in contact with the water and forming gas hydrates, which created a problem with an earlier large containment dome that had to be set aside on the seabed on May 8 (OGJ Online, May 10, 2010).

Engineers believe the volume of water in the large dome contributed to the formation of gas hydrates.

In addition, the US Minerals Management Service authorized the use of methanol to prevent the formation of gas hydrates. MMS also authorized both the riser insertion tube and the “top hat” container device.

Lars Herbst, director of the MMS Gulf of Mexico Region, said video of the leaking riser indicates that possibly more gas is coming out of the riser than had been the case in previous days. ROVs have been monitoring the flow daily.

Suttles said it’s difficult to measure the pressure of the flow of both oil and gas coming out of the riser.

Meanwhile, BP also is working on ways to stop the flow from a leaking wellhead and then plans to seal the wellhead. Options include a “top kill” or “junk shot,” which involves plugging the interior of the blowout preventer and then using the BOP’s choke and kill lines to pump heavy fluids and cement into the well.

Other options under consideration involve installing another BOP on top of the existing BOP stack or possibly installing a shutoff valve. BP has said engineers and scientists are carefully examining each option in order to prevent worsening the spill.

USCG Rear Adm. Mary Landry said May 14 that BP has received necessary approvals from the necessary federal government agencies to continue applying chemical dispersants on the oil at the seabed.

The Ocean Horizon spill response is the first time dispersants have been applied at the subsea level so three tests were conducted and their results reviewed before authorization was granted, Landry said.

The USCG reported 559 vessels were involved in the response effort as of May 14. Crews have deployed more than 1.5 million ft of boom and collected more than 6 million gal of oily water. More than 17,000 people are involved in the response effort along Louisiana, Mississippi, Alabama, and Florida where 14 staging areas have been set up to protect sensitive shorelines.

Suttles said BP paid more than $8 million in claims as of May 14 to fishermen and other coastal residents for lost revenue as a result of the oil spill.

Contact Paula Dittrick at paulad@ogjonline.com.

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