Abstract: A control or other line with a hole downhole can be repaired by pumping a device that is driven by pressure delivered behind a leading seal. The device advances until the leading seal passes the opening in the line where its forward movement is stopped. Upstream of the opening a fluid activated seal is energized so that seals now straddle the opening in the wall. A passage that extends between the seals is opened by blowing a rupture disc with internal pressure to once again give access to the downhole tool through the passage that has external seals to straddle the hole in the tubing wall. Normal operation of the downhole tool can then resume.

Abstract: A control system for a subsurface safety valve references the surrounding annulus to put the operating piston in pressure balance. Depending on the configuration and which seal in the system fails, the various embodiments can differ in their failure modes. With the lower end of the piston exposed to annulus pressure all failure modes close the flapper. With the lower end of the piston exposed to tubing pressure, failure of any of the seals except one will result in flapper closure.