Method and system for controlling a downhole flow control device using derived feedback control

A system for controlling a downhole flow control device, comprising:

• a. a hydraulically actuated flow control device in a tubing string in a well, said flow control device having a movable element for controlling the downhole formation flow;
• b. a hydraulic system hydraulically coupled to said hydraulically actuated flow control device for supplying hydraulic fluid to said hydraulically actuated flow control device;
• c. at least one first sensor detecting at least one parameter of interest related to a volume of hydraulic fluid supplied to said hydraulically actuated flow control device and generating at least one first signal related thereto;
• d. at least one pressure sensor for determining a hydraulic fluid supply pressure and generating at least one second signal related thereto;
• e. a hydrophone disposed in a hydraulic line detecting a pressure pulse in response to movement of said moveable element and generating a third signal in response thereto;
• and
• f. a processor receiving said first signal, said second signal, and said third signal and acting according to programmed instructions to generate a relationship between a position of said moveable element and said volume of supplied hydraulic fluid, said processor adapted to control said hydraulic system to position said moveable element at a predetermined position according to said relationship.

A method for control of a hydraulically actuated downhole flow control device, comprising;

• a. cycling a moveable element in the hydraulically actuated downhole flow control device in a first direction and a second opposite direction;
• b. determining a breakout pressure for each actuation cycle using at least one pressure sensor;
• c. repeating said cycling until a predetermined criterion is met;
• d. using a processor to generate a relationship characterizing the movement of said moveable element as a function of a pumped fluid volume;
• and
• e. using said processor to control the supply of a fluid volume required according to said relationship to move said moveable element to a predetermined position.

A method for control of a hydraulically actuated downhole flow control device, comprising;

• a. supplying hydraulic fluid to an actuator cooperatively coupled to a moveable element in the hydraulically actuated downhole flow control device through a first line and a second line;
• b. pressuring the first line and the second line to the same predetermined pressure;
• c. bleeding a first measured volume of hydraulic fluid from said second line causing said actuator to move said moveable element;
• d. supplying a second measured volume of hydraulic fluid to said first line until said first line is at said predetermined pressure;
• e. determining a volume difference between said second measured volume and said first measured volume and using a processor to generate a relationship between said volume difference and said moveable element movement;
• and
• f. using said relationship to move said moveable element to a predetermined position.

A method for control of a hydraulically actuated downhole flow control device, comprising;

• a. supplying hydraulic fluid to an actuator cooperatively coupled to a moveable element in the hydraulically actuated downhole flow control device through a first line and a second line;
• b. pressuring the first line and the second line to the same predetermined pressure;
• c. bleeding a first measured volume of hydraulic fluid from said second line substantially equal to a spool displacement volume required to move said spool to a predetermined position;
• d. supplying a second measured volume of hydraulic fluid to said first line until said second line is at said predetermined pressure;
• e. adjusting a pressure in said first line to said predetermined pressure;
• f. determining a volume difference between said second measured volume and said first measured volume and using a processor to generate a relationship between said volume difference and said moveable element movement;
• and using said relationship to move said moveable element to said predetermined position.