Patent ID: 8733448

Claim:
A method of operating an isolation valve in a subterranean well, the method comprising: transmitting a signal to a detector section of the isolation valve; operating an actuator of the isolation valve in response to detection of the signal by the detector section, the actuator including an actuator valve which selectively permits and prevents fluid communication between high and low pressure sources and first and second piston chambers of a piston of the actuator; operating the actuator valve so that fluid communication is permitted between the high pressure source and the first piston chamber and between the low pressure source and the second piston chamber, thereby displacing the piston in a first direction; operating the actuator valve so that fluid communication is permitted between the low pressure source and the first piston chamber and between the high pressure source and the second piston chamber, thereby displacing the piston in a second direction opposite the first direction; and operating the actuator valve so that fluid communication is permitted between the first and second piston chambers and the high and low pressure sources, thereby permitting the high pressure source to be recharged downhole.