Factbox: BP moving ahead on containment cap

(BestGrowthStock) – BP Plc has switched gears from trying to plug a leak in the Gulf of Mexico to trying to corral it with a containment cap after its “top kill” failed.

The company also is making plans to use equipment installed at the seabed for the top kill to enhance its containment efforts, and to interrupt containment efforts if a hurricane blows through the Gulf.

Here is an explanation of how the lower marine riser package (LMRP) cap is supposed to work, as well as other technologies BP is employing to attempt to bring the well under control:

LMRP CAP

* BP has begun sawing off extraneous pipes to clear the way to shear off the larger middle pipe from which two leaks are spewing. Underwater robots are doing the work with a diamond saw.

* The robots will then use huge shears to cut off the pipe that extends from the top of an LMRP that sits atop a failed blowout preventer. The saw will then shave off any jagged bits to provide a clear opening.

* BP will lower a containment cap with a grommet seal over the opening, while the leak continues, to capture about 80 percent of the oil and gas. The rest is expected to escape from the cap.

* The cap will be connected by pipe to a drillship at the water’s surface.

* The captured oil and gas is expected to be channeled to the ship, where the oil will be stored to bring ashore later for processing and the gas will be flared.

* BP expects the process to take four to seven days, although Chief Executive Tony Hayward said it would take four days.

* BP monitored pressure data from the failed blowout preventer during the top kill operation, and determined that cutting off the pipe at the top of the LMRP would not have a significant impact on the flow of the leak.

* U.S. government scientists estimated the flow could temporarily increase by as much as 20 percent.

* The cap effort is, in theory, similar to one involving a much larger 98-tonne containment dome that was placed at the end of the broken pipe in early May. That dome was also connected to the ship by pipe and was intended to corral and channel oil and gas to the surface.

Too much seawater got inside, mixed with natural gas at high pressures and cold temperatures, and formed ice-like hydrates that blocked oil from flowing up the pipe to the ship.

* The smaller cap and seal are designed to exclude seawater and avoid the hydrate problem.

ENHANCEMENT TO LMRP CAP PLAN

* BP will use seabed equipment installed to conduct the top kill to enhance the containment cap system.

* The top kill involved pumping heavy drilling fluid into the failed blowout preventer to try to smother the leak. Mud was pumped from a ship to a service rig, down to a manifold, which routed the fluid to “choke and kill” hoses connected to the blowout preventer.

* BP will try to reverse direction and pull oil and gas from the blowout preventer through the hoses and manifold to a vessel at the water’s surface.

*That system is expected to be ready by mid-June.

HURRICANE PREPAREDNESS

* BP also is planning a system to allow the drillship connected by pipe to the containment cap to suspend operations and move if a hurricane approaches.

* BP will install a pipe that extends about 300 feet below the drillship. Then a hose would connect the pipe to the containment cap.

* Described by BP as a “long-term option,” the system would allow BP to disconnect the hose from the pipe and move the ship out of a storm’s path, then return when weather calms to resume the operation.

* The system is expected to be implemented in late June or early July.

* The Atlantic hurricane season began June 1.

THE RELIEF WELLS

* Drilling continued on a relief well begun May 2 intended to intercept and cap the leaking well beneath the seabed. Drilling was suspended last week on a second relief well begun May 16 while the top kill was in progress, but that rig resumed drilling on Sunday. Both wells are expected to be finished in August.

BOP ON BOP:

* BP suspended drilling of the second well so that rig’s blowout preventer could be on standby to place atop the failed blowout preventer and plug the well if the containment cap system fails. BP said on June 1 that option has been sidelined “at the moment” with the focus on the LMRP cap and enhancement because the company lacks sufficient information about the state of the failed blowout preventer.

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(Reporting by Kristen Hays; Editing by Eric Walsh)

Factbox: BP moving ahead on containment cap