BP caps Gulf of Mexico oil spill

Shares of the besieged British oil giant BP surged by more than 5 per cent in London trading today after the company late last night was able to temporarily stop the biggest oil spill in history.

BP engineers last night sealed the 87-day old oil leak by closing down the last of three valves on a giant new sealing cap placed on the blown-out Mocondo oil well, a process that took two hours, but BP would require another 48 hours to see whether the cap will hold.

After having fixed a leaking valve on the new sealing cap designed to stop the flow of oil from its blown-out Deep Water Horizon rig, BP had said yesterday that it will start a twice-delayed critical pressure test to determine whether it can temporarily shut off the leaking well. (See: BP to start critical pressure test after fixing leak) 

BP, however, remained cautious about its success of sealing the well and said, "The sealing cap system never before has been deployed at these depths or under these conditions, and its efficiency and ability to contain the oil and gas cannot be assured," the company said in a statement.

"Even if no oil is released during the test, this will not be an indication that oil and gas flow from the well bore has been permanently stopped."

BP has always maintained that capping the well, if successful, will still be a temporary measure until drilling of two relief wells that are expected completed by the middle of next month, which will be a permanent solution.