| 摘要 |
Apparatus and methods are provided for actuation of downhole tools. In one example, a deep set safety valve uses a magnetic coupling which permits a portion of the safety valve at control line pressure to be isolated from tubing string internal pressure, without requiring the use of a dynamic seal therebetween. A piston of the safety valve may be displaced in response to a differential between control line pressure and pressure in an annulus surrounding the tubing string, pressure in another control line, or pressure in the tubing string. Other types of well tools may benefit from actuation using principles of the invention. |
