دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a special coupling device inserted one or two joints above the bottom of the casing string that contains a check valve to permit fluid to pass downward but not upward through the casing. The float collar prevents drilling mud from entering the casing while it is being lowered, allowing die casing to float during its descent and thus decreasing die load on die derrick or mast.

n: a special device inserted one or two jionts above the bottome of a casing string,the float collar contains a check valve that permits fluid flow in a downward direction only,the collar thus prevents the back-flow of cement once it has been displaced.

a short piece of casing run one to two joints above the end of casing. The collar contains a backpressure or check valve which stops cement from reentering the well after displacement into the annulus. It is useful to prevent channels in the cement until