John Flanagan wrote:
On Tue, 15 Jul 2003 18:15:08 GMT, (Gary Coffman)
wrote:


I don't know about the really deep wells, but the average 2300 foot
depth wells around here use sucker rods that are the same size
all the way down. You can get an idea of how heavy it all is by looking
at the weights which counterbalance it on the other end of the walking
beam. It is all nicely counterbalanced so the pump motor doesn't have
to lift the weight of the rod on each stroke. BTW the rods screw together

from 20 or 30 foot sections, they aren't all one piece. That would make

it awfully hard to get them in or out of the well.


I figured as much. I find this drilling stuff interesting. I forget
who but someone was recalling some story about droping a wrench
"downhole". I never thought of that before. These deep holes it'd
probably take five minutes for it to hit bottom. I can't imagine what
it'd take to get it back out, big magnet and a long string....

John


There's an entire industry based on "fishing" stuff out of a well.
Drill bits come loose or get stuck, other tools come loose from the
"drill string" and fall until they get stuck or reach the bottom,
random debris, etc.
Some finished wells leave a "basket" at the bottom which they can
retrieve to keep the little stuff from piling up at the bottom.

NOT a cheap process. Modern wells can cost a million dollars a day
during drilling (that's just the cost of all the people and equipment
sitting idle, more if actually in use!)
I personally know of a case when a drill operator messed up while
extracting a (expensive) tool from a well, and tore it free from the
"drill string" just below the rig floor (that's the main platform of
the rig, about 30' up) The tool fell all the way to the bottom
(26,000'), blocking the bottom of the well, which still needed to be
drilled deeper. They lowered and "investigation fish" which mounts a
camera down, took a look, came back up, sent down a milling head to
grind off the jagged end of the drill string, came back up, sent down
a "radial fish" (basically a big screw extractor) which grabbed the
end of the drill string, and brought the tool out.

The site foreman was less than pleased with the operator G