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From: ke4zv!gary@gatech.edu (Gary Coffman)
Newsgroups: sci.military
Subject: Re: Capping oil fires
Message-ID: <1991Mar18.134342.18503@cbnews.att.com>
Date: 18 Mar 91 13:43:42 GMT
References: <1991Mar13.004310.8409@cbnews.att.com>
Sender: military@cbnews.att.com (william.b.thacker)
Organization: Gannett Technologies Group
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From: ke4zv!gary@gatech.edu (Gary Coffman)

In article <1991Mar13.004310.8409@cbnews.att.com> dnwiebe@cis.ohio-state.edu (Dan N Wiebe) writes:
>in order to blow the rising smoke and fumes over to one side.  Then
>have one of those big twin-rotor Chinook choppers haul a large hollow
>steel hemisphere to right over the well, and lower (or drop) it to the
>ground.  'Twould seem that this course of action might keep oxygen from
>the fire long enough for the hot things to cool off, at which point the
>big bowl could be removed and the well capped.

>	What's wrong with this picture?
>Dan Wiebe

>[mod.note: I'd think that any steel bowl a Chinook could lift would
>be floated away by the rising oil... just my guess. - Bill ]

Oil wells vary from zero natural pressure to over 2,000 PSI. The ones in
Kuwait tend toward the high end of this scale.  Now the wellhead is a
mass of junk so you would need a hemisphere of between 10 and 50 feet
diameter to have the rim touch ground all around and make a seal. This
would result in a total pressure against the hemisphere of between
226080000 and 2826000000 pounds. The hemisphere would have to be heavier
than this to avoid being pushed off. No helicopter or crane can pick up
this much weight. Considering that the soil of Kuwait is very sandy,
just making a seal with the ground that could withstand 2000 PSI with-
out blowing out would be very tricky. If you don't get a good seal, the
flames just start up *around* the edges of the dome.

A new technique will be tried in Kuwait to put out the fires. A very
large dry ice making machine will be brought to the site and dry ice
in large quanities will be pumped over the wellhead. The combination
of the intense cold and the boiling gaseous CO2 is expected to put out
the fire and cool the junk so it won't relight. This has been tried
on small fires here in the states, but this will be the first time
it's tried on a high pressure well fire.

Regardless of how the fire is snuffed, the major problem is clearing
away the junk and getting to undamaged casing so that a cap valve
can be put in place. One spark during this process and *VOOM* the
fire starts again. By keeping the wellhead smothered in a blanket
of CO2 during the capping process, it's hoped to make this operation
much safer.

Gary