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– How are the perforations made?
– What happens after the well is perforated?
– What is tubing?
– How deep can the well be completed with the help of coiled tubing?
– The main advantage of coiled tubing?
– What is a packer?
– What is a Christmas tree?
– How much acid can an acidizing service company pump down the well's
tubing?
– What is another treatment that may improve flow?
– What does the fracturing crew add to the fracturing fluid?

Completing the Well

The operating company carefully considers the data it obtains from the tests.
Then it decides whether to set production casing or liner and complete the well or to
plug and abandon it. If the company decides to abandon it, the hole is dry. Dry in the
sense of an oil or gas well means the well cannot produce oil or gas in commercial
quantities. Some oil or gas may be present but not enough to justify the expense of
completing the well. If the well is dry, the operator hires a cementing company to
place several cement plugs in the well to seal it permanently.

SETTING PRODUCTION CASING
If the operator decides to set production casing, a supplier brings it to the well.
For the final time, the casing and cementing crews run and cement a string of casing
in the well. In the case of our model well, the crew could run 5-inch (127-millimetre)
casing in the 7-inch (200-millimetre) hole. Keep in mind that the operator may elect
to set a liner string. As you recall, a liner string is the same as a casing string except
that a liner does not run all the way to the surface. Instead, the casing crew hangs it

inside a previously run casing or liner. Usually, the casing and cementing crews set
and cement the production casing or liner through the pay zone. The drilling crew
drills the hole so that it goes all the way through the producing horizon and stops a
short distance below. Then the casing crew runs the production string almost to the
bottom of the hole. (It leaves a little room beneath the guide shoe to allow cement to
flow out of the casing.) The production casing or liner and the cement actually seal
off the producing zone. At this point, the drilling rig and crews are finished with their
job: they have drilled, cased, and cemented the well to the depth specified by the
drilling contract. Their only remaining job is to disassemble the rig (rig down) and
move it to the next drilling location.

PERFORATING
The operator is not through, however. Because the production string and the

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