BALANCE LINE SAFETY VALVE WITH TUBING PRESSURE ASSIST

摘要

The present invention generally relates to a subsurface safety valve configured to control fluid flow through a production tubing string. In one aspect, a safety valve for deployment beneath a surface of a wellbore is provided. The valve includes a control piston and a balance piston. The valve is configured to b e connected to a controller at the surface by a control line so that the control piston is actuatable between a first position and a second position in response to receiving pressurized fluid from the controller through the control line. The balance piston is configur ed to compensate for hydrostatic pressure in the control line. The valve may have a bore therethrough and the control piston may be configured to utilize tubing pressure within the valve bore to urge the control piston towards the second position.