BP uses shears to cut through riser; placing container cap
BP PLC on June 3 worked to place a lower marine riser package (LMRP) containment cap on the damaged Deepwater Horizon riser, having used shears to cut the riser after a diamond-wire saw got stuck, a spill response spokesman said.
OGJ Senior Staff Writer
HOUSTON, June 3 -- BP PLC on June 3 worked to place a lower marine riser package (LMRP) containment cap on the damaged Deepwater Horizon riser, having used shears to cut the riser after a diamond-wire saw got stuck, a spill response spokesman said.
Crews using remotely operated vehicles in 5,000 ft of water freed the diamond-wire saw on June 2. They used shears to cut the riser from the top of the failed blowout preventer (BOP). Earlier, the shears cut a section of the bent riser that was farther away from the BOP.
National Incident Comm. and Adm. Thad Allen said he was optimistic that a LMRP containment cap could be placed on the cut riser, enabling the collection of leaking oil and gas to begin sometime during June 3.
“The challenge now is to set the containment cap,” Allen said, adding, “This is an irregular cut, it will be a little more challenging,” to set the cap than it would have been if plans had worked for the diamond-wire saw to make a smoother, flat cut.
During a news conference from Louisiana, Allen said crews believe the diamond-wire saw became stuck when it encountered drill pipe inside the damaged riser pipe.
BP to place cap
The cut on the riser pipe is irregular, and the top of the riser is leaning about 10º, Allen said. Crews will place a containment cap with a rubber seal on top of the riser. BP has caps available with different widths and sealing mechanisms so that it can use the cap that best fits the cut riser.
“Once the cap is on, there is some chance that some oil could escape,” Allen said. “It could be close to none, it could be some,” leaking out, he said, adding this only can be determined after the cap is placed.
The reservoir pressure is 9,000 psi, and the pressure of oil coming through the BOP is 3,500 psi, he said. The collected oil and gas will go into a smaller pipe, which could increase back pressure and cause oil to leak out around the seal.
Before the riser was cut, federal scientists estimated the flow rate of the spill could increase 20% between the time of the cut and the time that the cap was placed. A team of scientists had released preliminary findings showing the estimated flow rate is 12,000-19,000 b/d although it possibly could be 25,000 b/d (OGJ Online, May 27, 2010).
Allen said the Flow Rate Technical Group, which released the estimates, is continuing its work to come up with the most accurate estimates possible.
An Apr. 20 fire and explosion on Transocean Ltd.’s Deepwater Horizon semisubmersible, which was drilling for BP and its partners, left 11 crew members dead. The Deepwater Horizon sank Apr. 22. BP announced May 29 that its “top kill” operation had failed to stem the flow from the leaking well. Since then, crews moved to deploy a LMRP cap containment system to collect the leaking oil and gas until a relief well can reach 18,000 ft and permanently seal the well.
BP to pay for Louisiana berms
Allen said federal officials authorized the state of Louisiana to dredge sand and construct temporary barrier islands in an effort to keep spilled oil out of the state’s wetlands. BP said it will pay $360 million for the cost to construct six sections of the barrier islands.
The company added that it will not manage or contract directly for the construction of the islands, and it will not assume any liability for unintended consequences of the project.
“BP is committed to implementing the most effective measures to protect the coastline of Louisiana and reduce the impact of the oil and gas spill,” said Tony Hayward, BP Group chief executive officer.
Previously, BP provided $170 million to Louisiana, Alabama, Mississippi, and Florida to help with response costs and help promote tourism. The company also paid $42 million in claims to compensate individuals and companies affected by the spill.
Meanwhile, oil spill response crews on June 3 moved more boom to Alabama and Mississippi.
“The upper edge of the collection of spill is moving toward Florida,” Allen said June 3, noting the oil slick and emulsified oil on the water’s surface have broken into various pieces.
Contact Paula Dittrick at email@example.com.