After drilling, logging, testing and formation evaluation for economic worth and profit, work will ensure to set casing,
prepare well for production and then "bring in “the zone or zones.
The several steps required are generally termed "completion operations".
Completion operations might be as simple as 2 7/8" pipe for tubing-less producer if productive life is expected to be
short and without problems of sand or water or stimulation. Completion may be complicated requiring large size casing
and testing of several zones, two or more string with various accessories may be needed for multiple-zone completion.
Sometimes it is necessary to perform acid, fracturing or sand control before completion.
If artificial lift is expected, casing and tubing sizes should be large enough; Packers should be carefully selected according
to the long-life requirements. Completion equipment and methods may be quite variable dependent upon type of oil or
gas and economic circumstances.