Thursday, July 15, 2010

For the first time since April 20, no oil is flowing into the Gulf of Mexico, though the halt may be temporary, as integrity testing began on a new sealing cap. The cap was installed on a leaking well in an effort by the BP energy company to contain oil spewing into the Gulf of Mexico. The previous containment cap, which was removed Saturday, had a much looser fit than the new one and allowed oil to escape into the Gulf. It took about three days for the cap to be removed, the site prepared, and the new one to be slowly lowered into position.

The energy company had planned to begin running integrity tests Tuesday to measure the performance of the well under pressure. The tests were delayed a day for further analysis, but clearance to proceed was given Wednesday afternoon, then a leak in a choke line had to be repaired. BP senior vice president Kent Wells announced at his Thursday afternoon briefing that the final valve on the cap assembly started to close at 1:15 PM Thursday and was fully closed at 2:25 PM, finally shutting in the oil flow. If the tests show that the well is strong enough, the sealing cap valves will likely remain closed. If the well cannot be safely closed from the top, the new cap is designed to funnel almost all the oil to ships above while two relief wells are constructed for a permanent fix. After the old cap was removed, oil flowed freely into the waters of the Gulf until the present cap was installed at about 7:00 PM CDT Monday (00:00 UTC Tuesday).

BP has stated that this oil containment system has never been deployed at the current depths, nor has it been tested in the conditions that it will be expected to operate in. During the testing period, which could last anywhere from six to forty-eight hours, all undersea oil containment systems will be temporarily suspended. The company made clear that, even if the tests succeed, this does not mean that oil leakage has permanently ceased.

Doug Suttles, a BP executive, explained that during the test, the well pressure will be carefully monitored. Suttles said at a Monday briefing that the ideal would be for tests to show high pressure around the seal, indicating that no oil is escaping. He also stated that on the other hand, the pressures could be lower than anticipated, leading to the assumption that the well is damaged and is leaking oil and gas into surrounding rock. If this were to happen, keeping the cap shut could further damage the well. The solution for this scenario is to reopen the valves and funnel most, if not all, of the oil to ships above.

Drilling of the first relief well was suspended until completion of the integrity test. Kent Wells explained at his Wednesday morning briefing that the first relief well is now 4 feet from the original well and there is a remote possibility that the pressure test could open a path to the relief well. Drilling of the second relief well has stopped at 16,000 feet so as not to interfere with the first well and to keep routing options open in case the first relief well fails. Even if the pressure tests do succeed and the main well is shut, work on the first relief well will continue until it intercepts the main well. When this occurs, mud and cement will be pumped into the well for a permanent seal. Containment and clean up operations will continue even after the relief wells are finished to deal with oil already released.

The Deepwater Horizon oil spill began on April 20 when the Deepwater Horizon oil rig exploded, killing eleven and marking the start of the worst offshore oil spill in United States history.