Michael H Goldhaber wrote:
> Of course the Deborah Solomon weekly personality interview is hardly technical, nor does anything suggest Brownfield knows much about the problem. (His name is amusing though.) But Les, you seem well informed about the issues at and under the sea bottom. Could you summarize for us what they are?
ok, i take that as an invitation to be very brief ;-)
1. Pressures: the hydrostatic pressure at the bottom of a mile of water
is approx 2200 psi. the oil field is located down below another 13,000
feet of bedrock. the pressures in the well are estimated to be
10,000-13,000 psi. 8,000-9,000psi was measured at the base of the blow
out preventer a few weeks ago. differential pressures in the BOP
apparently are lower now for a couple technical reasons.
2. THE BOP sustained injuries. and there is evidence that the well hole
itself has been damaged. two pieces of evidence: mud flowing back up
during pumping operations, and observations of leaks from elsewhere on
3. That is serious pressure at the base of a compromised wellhead/BOP.
a top kill operation that worked from above would have faced enormous
pressures on already injured equipment.
4. the notion that explosive charges set near the top of the well could
successfully close off this well has to deal with the pressures that are
available from this well as well as the structural damage already felt,
plus what might have occurred that can't be sure of.
5. re/ serious explosives near the surface?: explosions in bedrock would
fracture that bedrock and could produce a jumble of rocks that could not
hold against those pressures. only an explosive charge that sealed the
well below the existing damage is sure to work.
6. the nuclear explosion used in the Soviet Union to seal a gas leak was
exceptional in one regard: there was a layer of clay located well below
the surface within which the nuke was detonated. the theory was that the
nuke pushed the layer of clay hard enough that the gas pipe was
seriously bent/distorted, hence sealing that well. i do not believe the
pressures were as high as in this case. need to check.
7. one could try an explosive charge near the bottom of the well. but
then one has to drill down that far anyway. but then again, if the
explosion only breaks the rock and the well casing, that is not a seal.
8. the traditional approach is to drill down to the base of the well,
intersect the well hole, and pump mud in FROM BELOW. who cares if
pressures build up down there. once one has 15,000 feet of mud filling
the well, the differential pressure drops enough to do a final seal with
the only place where i have seen decent technical discussions of the
issues involved are at http://www.theoildrum.com/ ... if you go there
today, you will see an article from yesterday explainging why a
sand-filled oil-and-gas stream at the velocities this thing is running
at has the potential to cut through steel thereby opening up the
restrictions already in place and further enhancing the flow. besides
occasional excellent technical discussions, there are also numerous
links to the little information that BP and the US government is releasing.
on another point: there is a 1997 memo written by the Minerals
Management Service pointing out that deepwater plumes of oil can go
neutrally buoyant at mid-sea. so the notion that MMS and the oil
companies could not have known about deep-sea plumes is absurd.