Sunday, June 6, 2010

Deepwater Oil Spill - closing the relief ports

The rate of oil recovery from the Deepwater well in the Gulf of Mexico has increased from the 6,000 bd recovered on Friday, to some 10,000 bd which was recovered on Saturday.
On June 5, a total of 10,500 barrels of oil was collected and 22 million standard cubic feet of natural gas was flared.
Looking at the relative flow patterns still leaking from around the containment cap, it is hard to detect much difference in the amount not being captured. This is the current flow (note the white spot in the cloud which is the triangular shape at the bottom of the cap).

Flow at 10 am Sunday

And this was the picture that I posted from the same ROV at the time that the cap was installed

From Skandi ROV 2 10:55 pm 4th June

The triangular elements at the bottom of the cap are more evident. Now the ROV may have moved, but the depth of the cloud beyond the cap is roughly the same, suggesting the same pressure driving it, and if the gap is the same size, then the volume leaving through the base of the cap may well be the same.

The 4,000 bd increase in flow has thus, likely come from the closing of one or more of the relief ports that allowed oil to escape from the top of the cap.

BP illustration of the cap, showing the relief ports with valves

This cap is likely to stay in place for a couple of weeks, until BP can fabricate and install the next step, which will be to reverse the flow of fluid through the choke and kill lines, so that some of the flow can be directed up to the Q4000. This will both help with managing the flow, and also give an alternate path for oil to be recovered, when this first cap is removed.

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