Integrity Test

Hoping BP measures high pressures!:

Now that the sealing cap has been installed, all eyes turn to the well integrity test, which BP is starting today, Senior Vice President Kent Wells said at a morning press briefing. The test will involve completely "shutting in" the well so the full pressure of the oil gusher can be measured, giving the scientists and engineers a read on the structural stability of the piping that lines the 13,000-foot-long well.

...Once the valves on the new cap are closed and the well is shut in, high-pressure readings would be good news, suggesting that the well casing is undamaged and that all of the flow is coming up through the well. In this scenario, it would be possible to keep the well closed off indefinitely, effectively ending the spill (the relief wells would still be completed to permanently seal the well with cement). Low pressure, on the other hand, would be a bad sign, suggesting that oil is leaking out below ground through damaged sections of the well casing and percolating into the surrounding rock. In a worst-case scenario, that oil could find its way up to the surface and start an uncontrolled leak from somewhere on the sea floor of the gulf. Either way, a low-pressure result would force engineers to open up the valves and allow oil to flow once more, though BP says it would soon have enough capacity to funnel all of it to the surface for collection.