posted on Jun, 16 2010 @ 04:09 PM
Op I was interested in your posting & since I am a petroleum engineer and have drilled, completed and operated oil & gas wells for over 30 years I am
responding to offer a few facts to the interested readers. Under Peak Oil I have written rather lengthy posts that could provide additional detail.
A few facts:
1)BP reported rat hole mud of 14 #/gallon. If the mud weight balanced the formation pressure then the bottomhole pressure is around 13,000 psi. Matt
Simmons' hysterical raving about 40,000-50,000 psi is ludicrous.
2) A "top kill" is never easy. When I've taken a kick I seldom get concerned as long as the pipe rams are working & I have drillpipe/tubing in the
hole at least halfway to the inflow. The problem with top kill is it can't be pumped at high rates. The oil & gas & other fluid flowing on a top kill
have to go somewhere, so as to not fracture the earth above the area of fluid entry the pressure must be kept from exceeding the fracture gradient as
well as the burst strength of the protection casing. Ideally the oil is pumped back into the formation it came from. The oil comes from the tiny pore
spaces between sand grains. Therefore Darcy's equation controls at what rate I can pump into the well. In many instances the pressures increase near
the wellbore where they are higher than the formation pressure(supercharging). If this happens then when the pumps are shut down, it will even flow
back the wieghted mud & you have to start all over. Bottom kills are infinitely simpler.
3) I don't know about the casing problems, but the top kill looked to me like most of the mud was flowing out into the ocean. So if 1 bbl goes down
the hole versus 100 into the ocean and we are pumping into the 9 5/8" X 7" annulus to get heavy mud to 13,000' is around 350 bbls. Therefore it
would take 35,000 bbls of mud to have a chance. If the surface pressure is not dropping indicating that mud was going down hole then it was over. By
the way the 'Junk shot" was not to seal the wellbore only an attempt to seal the leaks in an attempt to get less mud into the ocean and more staying
in the well. It obviously didn't work. The high rates they were pumping was only an effort to create higher pressure through hydraulic horsepower to
overcome the surface flowing pressure of the oil, not necessarily to help in the kill procedure.
4) Once the relief wells intersect this wellbore at depth, even if there is a casing split at 1000', it is a relatively easy calculation to increase
the mud weight to make up for the loss of the column. By the way mud is brown, barite is grey and generally doesn't affect the color of the mud.
5) Even if the well craters, the relief wells will still be able to kill.
The overall disaster is due to the fact that we now have an entire generation of petroleum engineers that have been trained by accountants. Their
entire job performance since 1986 has been measured by how much money they saved rather than if they produced oil without killing anyone. Much of what
I do is design a job that avoids disaster. To an accountant, when we don't have a problem, then it was an unnecessary expenditure and money was
wasted all the way to the point that the next guy doesn't take into consideration and it ends up costing 10 fold what the preventative measures
I was flabbergasted when I found out that they did not circulate bottoms up prior to performing the cement job. Standard procedure during a production
casing job entails having a static hole for 24-48 hrs. The well is made static & we start pulling out the drill pipe and laying it all down. Then we
pick up the production casing & started running it in. The process means that we have not seen what's happening in the hole for a long time. During
this time hopefully only small volumes of oil & gas seep into the hole, since we have it overbalanced with heavy mud. Nevertheless when we land on
bottom, we kick in the pumps and circulate all the fluid from the annulus---cont.