Factbox: How BP will switch oil leak caps?

(BestGrowthStock) – On Saturday, BP removed an oil containment cap from its stricken Gulf of Mexico well so it could be replaced with a bigger cap and seal within four to seven days.

Unlike the initial cap, the new one should be able to contain all crude leaking from the top of failed blowout preventer equipment at the seabed.

Here is how the process will play out, according to BP’s written plan and Kent Wells, BP’s senior vice president of exploration and production, as well as future plans.

THE CAP SWITCH

* On July 10, BP removed the containment cap installed June 3 atop failed blowout preventer equipment at the seabed 1 mile beneath the water’s surface.

* Crude gushed gush unchecked from the jagged remnant of a pipe that the cap had covered.

* Underwater robots will remove the pipe remnant and flange.

* A pair of side-by-side drillpipes jutting out the top of the blowout preventer equipment will be tied together with a strap.

* A new flange will be lowered over the top of the pipes, and then bolted on after the strap is cut away.

* A 160,000-pound (73 tonne) “capping stack” will be lowered onto the new flange.

* The new cap is designed to seal the entire opening with a complete cover of the flange, unlike the previous cap that just covered the pipe remnant.

* If the cap and seal work as designed, there should be no more crude leaking from the top of the failed blowout preventer equipment.

* The previous cap allowed oil to leak out from the its bottom and top to prevent seawater from getting inside. Cold seawater at extreme pressures can mix with natural gas, which leaks alongside crude, and form ice-like hydrates that block collection efforts.

* BP has another cap similar to the one that was removed at the seabed to place atop the leak if the new cap and seal do not work.

MORE OIL-CAPTURE CAPACITY COMING

* On July 10 BP was hooking up and testing a rig, the Helix Producer, that can collect up to 25,000 barrels a day.

* BP connected a hose at the blowout preventer to a floating pipe, which in turn was connected by hose to the Producer.

* The floating-pipe setup allows the vessel to quickly disconnect from the pipe and move out of the way if a hurricane approaches.

* Another rig — the Q4000, installed on June 16 — will continue to siphon and burn off an average of 8,000 barrels of oil per day from the leak.

MORE HURRICANE PREPAREDNESS

* The cap switch and ramp-up of the Helix Producer are two crucial steps to installing a four-vessel oil-capture system that is hurricane ready.

* By the end of July, the Toisa Pisces, a well-testing ship revamped to process up to 25,000 barrels a day, will replace the Q4000 and be connected to the blowout preventer via a second floating pipe.

* Transocean Ltd’s Discoverer Enterprise, which had collected crude via the containment cap removed on July 10, and a second drillship, Transocean’s Discoverer Clear Leader, will each be connected to the new cap and seal via hoses and drillpipes.

* The four vessels will have a combined capacity of up to 80,000 barrels a day and can disconnect quickly to move out of a hurricane’s path.

* If a storm forced a disconnect, crude would gush unfettered until the vessels return and reconnect.

THE RELIEF WELLS

* Drilling continues on two relief wells intended to intercept the well and plug the leak well beneath the seabed.

* The first well was 12,810 feet beneath the seabed on July 10, or 190 feet from the bottom of the blown-out well.

* BP expected to try to drill into the stricken well once the optimal target is found by the week of July 19.

* Plugging the leak could take until mid-August, depending on how deep the relief well must bore into the stricken well and how many times BP must pump in heavy drilling fluid and cement.

* The second relief well, a backup to the first relief well, had bored 10,961 feet beneath the seabed by July 10.

* The second relief well would stop drilling once piping to hold it open was cemented in place so it would not interfere with the first relief well’s use of sensors to find the right intercept target.

(Reporting by Kristen Hays in Houston; editing by Mohammad Zargham)

Factbox: How BP will switch oil leak caps?