Mekanisk forskjøvet kuleventil med toveis forsegling for bruk i borehull

摘要

A downhole ball valve is mounted n a string and features a rotating ball that turns on its axis as it is held against an upstream and a downstream seal by a cage. The cage accepts a slide that engages the ball off-center to rotate it between the open and closed positions. The slide is operated by a sleeve attached to a piston assembly. The sleeve is mechanically operated in opposed directions such as by a wireline shifting tool. Differential pressure on a closed ball does not affect the actuation piston because pressure across the actuating piston is balanced while holding pressure differential across the closed ball. A check valve allows the actuation piston to be in pressure balance as the ball stays closed.