Importance

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Abstract

Downhole valves comprise a housing having a bore, a port, upper and lower recesses disposed in an inner wall surface of the bore, the upper recess disposed above the port and the lower recess disposed below the port, and upper and lower pistons disposed in the bore. The upper and lower pistons each comprise a bore with a port in communication with housing bore. During run-in, the housing port is blocked by the lower piston. Actuation of the lower piston unblocks the housing port and aligns the lower piston port with the lower recess. Actuation of the upper piston closes the housing port and aligns the upper piston port with the upper recess. Alignment of the ports of the pistons with their respective recesses permits fluid flow through the tool both when the valve is opened by the lower piston and closed by the upper piston.

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First Claim