Device for shifting a port collar sleeve.

摘要

A well tool is disclosed for shifting the sleeve of a port collar in a well casing, to open and close the ports in the collar. The tool is made up of a housing (10) having a double piston (11, 12) assembly mounted slideably in a transverse bore (14) in the housing. The transverse bore (14) is intersected by a lengthwise bore (13) in the housing. Fluid is carried into the housing from a tubing string connected to the lengthwise bore (13). The double piston assembly has an outer face (11a) in contact with fluid in the well casing, and a smaller area (12a) inner face in contact with fluid inside the housing bore. This differential in the piston surface area holds the piston assembly in a "retract" position by the fluid pressure on the outer face. Alternatively, the piston assembly can be moved laterally to engage the port collar sleeve by applying a differentially higher fluid pressure to the inner face. Pulling the tubing string upwardly shifts the sleeve to a position which opens the collar ports. Setting weight on the tubing string moves the sleeve downwardly to close the collar ports.