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liner strings save the operator money.

Drilling to final depth

The final part of the hole, whether crew members drill it through surface
casing or through one or more intermediate casing or liner strings, is what the operator
hopes will be the production hole. In the case of our example well, crew members make
up a bit that fits inside the 9-inch (244.5-millimetre) casing. Let's say the bit is 7 inches
(200 millimetres). Crew members trip in this bit, drill out the intermediate casing or
liner shoe, and head for what everyone hopes is pay dirt—a formation that produces
enough oil and gas to make it economically feasible for the company to complete
the well. The question the operator faces is, "Does this formation contain enough
oil or gas to make it worthwhile to run the final production string of casing or liner
and complete the well?

4 Find synonyms in the text for the following words.
Pull in to blunt
hit proceed
common mistake bring into action
withdraw a drill string of hole get
on a provisional basis ultimate

5 Find antonyms in the text for the following words.

Bottom to complicate a problem
including insert
slowly watery
stop drilling soften
shut down to make loose

6 Say whether the following statements are true or false.
1) Crew members use swivel to buck up one drill pipe joint to another.
2) After stabbing the joint, crew members use a spinning wrench to thread the joints
together.
3) Intermediate casing is run and cemented in the surface hole.
4) The sequence with a top drive is much the same as with a rotary table and kelly.
5) The driller uses a built-in wrench in the top drive to spin up the joint and
torque it to final tightness.
6) The casing protects these shallow zones from being contaminated by the drilling
mud used to drill the hole below the casing.
7) The monkeyboard is a small working platform on which the derrickman
handles the bottom of the pipe.
8) Surface casing is usually small in diameter
9) The casing crew sometimes installs centralizers and scratchers on the outside
of the casing before they lower it into the hole.

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