دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a quantity of water, drilling fluid, or compressed gas placed inside drill pipe or tubing to control both annular and formation pressures. Usually mud in the pipe or tubing supports prevents the pipe or tubing from collapsing;mud also holds back formation pressure pushing up the pipe or tubing. But sometimes, such as in drill stem testing, it is necessary to have empty pipe or tubing downhole. The cushion protects the pipe or tubing until it is in place. It also allows control of the rising formation pressure as the cushion is removed, as in drill stem testing, to prevent formation damage.

n: The definite water, drill fluid or compressed gas poured into drill pipe or oil tube.