US Patent 7510013 Hydraulic metering valve for operation of downhole tools

Methods and systems for operating a sliding sleeve valve or other downhole well tool that is axially shiftable among a finite number of increments between two extreme configurations such as open and closed configurations. A metering device is described having a pair of piston metering assemblies that operate in parallel fluid flow paths. The first piston metering assembly moves the sleeve of the well tool from a fully closed position to the zero position. The second piston metering assembly can be repeatedly pressurized and depressurized to meter predetermined amounts of fluid from an actuator sequentially to move the sleeve of the sleeve valve in consecutive increments toward a fully open position.