Re: [Paddlewise] gulf oil spill

On Mon, Jun 7, 2010 at 4:10 PM, Bob Myers <qajaqbob_at_gmail.com> wrote:

> http://en.wikipedia.org/wiki/Ixtoc_I_oil_spill
>
> Bib Myers comes through again with this link to a wikiepaedia article on
the "Ixtoc 1" oil spill.

According to this article the Sedco 135F (which I believe was not a
dynamically positioned rig but an anchored semi-submersible) was drilling in
water depths of about 160 feet. The day before the blow out they experienced
a loss of mud through soft strata (which was what I thought had happened on
Deepwater Horizon until I found out that the "three" places oil was escaping
were just broken places in the riser which was dropped onto the ocean
bottom).

There was still mud in the Ixtoc 1 well bore which, combined with the weight
of the drill string itself, was keeping the pressures balanced. That is, the
weight of drill string and mud matched the upward pressure of the gas/oil.
However when they started to pull the drill string out of the well bore this
"balance" was lost and first the mud and then the drill string and then the
gas/oil bubble itself rose to the surface.

Again, the BOP should have been able to stop this blowout but if you recall
earlier in this series I mentioned that the "shears" (clamps on the BOP
which can also cut the pipe) are unable to cut the drill string when there
is a joint (drill collar) in the way. Generally the driller has to have
enough time to "hang off" the string on a closed ram above or below the
shear rams so he will know exactly where the collar is. This did not happen
on the Sedco 135 and all that mess ended up at the surface and on fire.

The well blew out for 9 months although a "top kill" was somewhat successful
as well as a "junk kill". The well was finally killed by directionally
drilling a well bore to intersect with the original (blown out) bore (just
as will be the final end to this blowout as well).  Mexico claims that the
oil either burned up, evaporated, or was collected (one third of each) but I
have heard that you can still see signs of the oil if you dig deep into some
beaches.

What I'd like to know is that this blowout seems relatively similar to the
Deepwater Horizon blowout although it was in shallow water and not as deep a
bore. It was also much closer to shore (which one might assume would make
things worse). The well was located some 100km northwest of Ciudad de
Carmen.

Does anyone know just how much lasting damage this blowout caused to the
environment?


Craig Jungers
Moses Lake, WA
www.nwkayaking.net


PS: And thanks again, Bob. :)
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