Patent ID: 7128160

Claim:
A service tool for use in a well, comprising: a tubular having a central passageway therethrough; a crossover through which fluid flowing down the central passageway can exit the central passageway and enter a lower annulus below a packer and fluid flowing up the central passageway can exit the central passageway and enter an upper annulus above the packer; a valve mounted to the tubular, the valve comprising a valve housing and a piston slidably mounted in the valve housing to allow or block fluid flow from the lower annulus into the central passageway through an opening in a wall of the tubular, the valve housing comprising a chamber and the piston comprising a piston head extending into the chamber to divide the chamber into a first subchamber and a second subchamber on opposed sides of the piston head, the first subchamber and the second subchamber being at atmospheric pressure prior to actuation of the valve; and in which the valve is actuated by a pressure-responsive member responsive to absolute pressure to expose the first subchamber to pressure in the lower annulus which moves the piston and opens the valve, the valve being located adjacent a screen in the well.