Patent ID: 8616291
Filing Date: 2013-12-31
Classification: E21B

Abstract:
1. A hydraulic control system for a sub-surface safety valve, the system comprising: a first control line in hydraulic communication with the sub-surface safety valve and communicating first hydraulic pressure to actuate the sub-surface safety valve; a second control line in hydraulic communication with the sub-surface safety valve and communicating second hydraulic pressure to compensate for hydrostatic pressure associated with the first control line; and a regulator repeatedly operable between at least two repeatedly operable conditions and regulating hydraulic communication between the first and second control lines in response to a pressure differential therebetween, the regulator in at least one of the repeatedly operable conditions permitting hydraulic communication from the first control line to the second control line in response to the second hydraulic pressure falling below a pressure level related to the hydrostatic pressure associated with the first control line.