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.
The effort started late May 13 and continued May 14, a spokesman told OGJ from the Deepwater Horizon Response Unified Command in Robert, La. Previously, BP has said deployment of a deepwater containment system is unprecedented.
“All of the techniques being attempted or evaluated to contain the flow of oil on the seabed involve significant uncertainties because they have not been tested in these conditions,” BP said in a May 13 news release.
The riser insertion tube is intended to prevent leaking hydrocarbons from contacting seawater 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).
With the riser insertion tube, crews used remotely operated vehicles as they attempted to position a pipe inside the Deepwater Horizon riser on the seabed. Plans called for the smaller pipe to be encircled by flapper system on the end of the damaged riser.
Doug Suttles, chief operating officer of BP Exploration & Production, and US Coast Guard Rear Adm. Mary Landry scheduled an afternoon news conference in Robert, La.
Transocean Ltd.’s semisubmersible rig, Deepwater Horizon, drilled the runaway Macondo oil and gas well 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.
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
Meanwhile, BP already has another containment option called a “top hat” sitting on the seabed near the riser. The idea behind the small containment device is to prevent the leaking oil and gas from contacting water, which is 30° F. at 5,000 ft.
Engineers believe the volume of water in the large dome contributed to the formation of gas hydrates. The smaller containment dome allows less water to contact the oil and gas.
In addition, the US Minerals Management Service authorized the use of methanol to prevent the formation of gas hydrates.
Once the leaking oil and gas is collected, it will be pumped to Transocean’s Discoverer Enterprise drillship for processing and storage.
Meanwhile, BP also is working on ways to stop the flow of oil 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.
On May 2, BP started drilling the first of two relief wells, and it plans to start drilling a second relief well soon, possibly as early as May 14. The second relief well is a backup to the first relief well, which is expected to take 3 months to complete.
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.
Contact Paula Dittrick at firstname.lastname@example.org.
BP positioning riser insertion tube to capture oil spill