Cap Leak Delayed Pressure Test of Oil Well

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Despite reports yesterday evening that pressure testing of the well had begun, BP announced this morning that a hydraulic leak in the new cap prevented the company from fully closing it. The test was originally scheduled to start midday Tuesday, less than a day after the new, tight-fitting cap was installed on the well, but was then pushed back until late Wednesday so there would be more time to analyze the plan for conducting it and interpreting its results. Last night's equipment failure was the latest setback.

BP replaced a malfunctioning valve—part of the cap's choke line—overnight, and is once again preparing to shut in the well for the test. "We're looking to start this test as soon as we can," BP senior vice president Kent Wells told reporters at a morning press briefing.

This latest series of delays followed several days of relatively seamless operations. The cap-installation procedure went smoothly and was completed ahead of schedule, on the third day of what was expected to be a four- to seven-day operation.

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When BP is ready to start the test, the new cap will be used to completely seal off the well, allowing sensors to measure the full pressure of the oil inside. The results will allow government and industry scientists to assess the well bore's condition and determine whether it's safe to keep the well closed long term.

If the well's integrity is good, the pressure within it should rise and hold at a high level once the well is fully shut in. But if oil is able to escape through damaged underground sections of the well, then the pressure would not build and would remain at a lower level or even decrease over time.

Should the test indicate that damage has occurred, BP would have to reopen the well and allow oil to flow once more, although containment operations would soon be able to funnel most or all of it to the surface for collection.