thunder wrote:
On Wed, 16 Jun 2010 18:18:45 -0500, Jim wrote:
4. Deep offshore drilling can be made safe with correct procedures. One
way is to require an initial 100' cemented caisson with double failsafe
shutoffs instead of a single blowout preventer on the seabed. Drilling
then proceeds through the caisson. Oh, that adds $20-40 million to the
well cost? Big deal.
Standard procedure when spudding in a new hole. IIRC, you drill several
hundred feet, set casing, and cement it in. That "single blowout
preventer" is a bit of a misnomer. The BOP has three rams, a shear, an
annular, and another ram I forget the name of. BOPs, properly sized and
maintained, work. They are not meant for abandonment of the hole, but in
a pinch ... There real purpose is be able to seal the whole, while
weighting up the mud, circulating on choke, and regaining control of the
well.
I'm not talking about "standard procedure" protective casing cementing
or a single BOP closure redundancy.
That didn't work. None of it. That's why all that oil is in the Gulf.
Saying you just keep doing what you've been doing after this won't cut it.
The BOP process in use is itself flawed and the Cameron BOP shear isn't
designed to cut through fittings, which are 10% of drill pipe length.
You can find some info on that here
http://energycommerce.house.gov/Pres...12.2010.oi.pdf
Why do you think they haven't fitted another closure on top of the BOP?
You've seen that undamaged flange just waiting to retain a valve that
could shut the flow down.
I won't bother to describe the process in detail, because there's more
than one way to design it, but essentially you drop a specially
fabricated and large throated open valve over the flange, and when in
place the valve bottom is hydraulically actuated to clamp under the
flange. Suitable gasketing is included or sealant can be injected.
As the valve is closed, the well pressure pulls it tight against the
flange bottom. This isn't a brilliant idea of mine. It all simple
plumbing and BP maybe has already had the fitting fabricated.
But they won't use it because they are afraid the well pressure will
blow out that "standard procedure" casing and the oil will flow from the
seabed with no chance of containing some of it as they are now.
That's the same reason they don't try another top kill now that they can
make a decent connection for the mud, instead of sticking a tube in a
holed riser as they initially tried.
They aren't saying what they fear, which is that they don't trust the
well casing can hold the pressure.
I think you will find when the investigation is complete, BP made some
decisions based on economics, that were rather short sighted. One, they
continued operation with a damaged annular ram. Two, switching the mud
for seawater, was, I believe, the direct cause. 5,000 feet of properly
weighted mud may have kept the gas incursion from ever happening. Using
seawater was reckless.
We'll see. But no amount of regulating inadequate procedures will make
them adequate. There will be no proof that the drillers knew the BOP
was damaged. I saw the Kenner Coast Guard hearings and heard the
driller boss (OIM) testimony. Unless he changes his testimony there was
no indication the BOP had a problem.
It is possible that many deep wells are waiting to surprise drillers
with totally unexpected pressures.
There's so much BS and uninformed opinion on the net like what I'm
writing that I gave up trying to get a handle on possible pressures.
But this is an interesting link with interesting embedded links.
http://www.dailykos.com/story/2010/5...pwater-Horizon
BTW, the oil lease cost and royalty payments mentioned there completely
contradict what I just heard a congresscritter say - he said it was all
totally free oil for BP. You can't trust the pols any more than BP.
I firmly believe pressure containment caissons with multiple and perhaps
non-retrievable sub-seabed BOPs are the best way to minimize spill
chance to an acceptable level. That level is 0% chance.
The stakes are too high to keep using "standard procedure."
Jim - Now I'm going the change the kitchen sink trap. It's dripping.