Thad Allen: Yes not to get too Webster's Dictionary on you here but the annulus is defined as the difference between two concentric circles. Once circle, a larger circle the difference them, that ring if you will. That is what an annulus is and so we're talking about the distance between the casing pipe and the well bore. That may vary at different places in the well but we are talking about inches.
Monica Hatcher: OK thank you.
Relief Wells being drilled
Kent Wells, BP's technical spokesman said on August 11, 2010, that the relief wells will have the mud weight at 13.8 pounds per gallon (0.731 pounds per square inch per linear foot increase with depth) or 13091 psi at near the bottom of the well, the intersection point. (17,909 feet)
There is some concern that the relief wells will pressurize "old oil in the annulus" and break the seal near the blow out preventer. Of more concern should be the worry that this is where the pressurized oil and gas resides and the blown out formations exist. This zone should be the super porous zone that absorbs all the cement and drilling mud and remains very difficult to seal.
My Conclusions
Has BP sealed the well casing or production pipe that did not need sealing? And we are now waiting for them to seal the annulus (the space between the casing and the rock strata) from the actual oil pressure threat, waiting to explode as soon as the cap is removed? Time will tell.
The Controlled oil pressure reading, in the casing, as they gradually depressurize the mud-water- gas mixture is now 4200 psi? That is less than the pressure of sea water, which would have exerted a force of 8228 psi at the bottom of the well. We know the pressure was 7000 psi in the well before the cement plug was put in place. This is the crucial NEGATIVE PRESSURE TEST TAKING PLACE BEFORE OUR EYES. It must have BP on edge as it is this test which led to the blowout. Of course there was no cement plug on April 20, 2010, the day of the blowout. The pressure gauge should eventually read ZERO, when all the gas has been released if the cement seal is in good order. If however there are other breaks in the casing or other horizons of oil and gas at higher levels that are also supplying natural gas pressure, the pressure will fall more slowly and may stabilize at a value above zero psi. Chris Landau.
August 11, 2010 .
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