Abstract: A system and methods for proportionally controlling hydraulically actuated downhole flow control devices using derived feedback control. The system comprises a downhole flow control device with a moveable element in a stationary housing. The moveable element is actuated by a balanced hydraulic piston. Hydraulic lines are fed to either side of the piston to effect actuation in either direction. A processor controlled, surface mounted hydraulic system supplies fluid to the piston. A pressure sensor measures supply pressure to the piston and a cycle counter indicates pump cycles and both sensors generate outputs to the processor. The downhole moveable element is cycled between end stops until successive moveable element breakout pressures are within a predetermined value as measured by the surface pressure sensor. A relationship is then derived between moveable element movement and pumped fluid volume and the relationship is used to move the moveable element to a predetermined position to control flow.

Abstract: A system and methods for proportionally controlling hydraulically actuated downhole flow control devices using derived feedback control. The system comprises a downhole flow control device with a moveable element in a stationary housing. The moveable element is actuated by a balanced hydraulic piston. Hydraulic lines are fed to either side of the piston to effect actuation in either direction. A processor controlled, surface mounted hydraulic system supplies fluid to the piston. A pressure sensor measures supply pressure to the piston and a cycle counter indicates pump cycles and both sensors generate outputs to the processor. The downhole moveable element is cycled between end stops until successive moveable element breakout pressures are within a predetermined value as measured by the surface pressure sensor. A relationship is then derived between moveable element movement and pumped fluid volume and the relationship is used to move the moveable element to a predetermined position to control flow.