•After the well is drilled, logged, tested and cased it is time to proceed to completing the well •Completion simply means making the well ready to produce oil and gas under controlled pressures and flow rates •The most common types of completions are open hole, gun-perforated, liner, and gravel-packed liner •Open hole completion –If the formation is competent and can hold together by iteself(such as a limestone or dolmiteformation) a simple open hole completion is adequate.
•Gun-perforated completion –In this case the casing or liner is ran and cemented right through the zone of interest –Perforations are shot through the casing or liner and cement in the formation •Slotted liner completion –a pre-perforated or slotted liner is hung from the bottom of the last string of casing. –If the producing formation is weak or poorly consolidated, sand and other solids will be carried into the well as the oil or gas is produced. –To prevent this “sand production,”the slotted or perforated liner may contain a wire-wrapped or a prepacked-gravel protective layer to keep the sand from entering the wellbore.
Gravel-packed liner –A gravel-packing operation consists of circulating and placing carefully sized gravel into the annular space between the liner and the wellbore wall –Used when there is a weak formation such as loose sand
