Deep set safety valve
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.
1. A safety valve, comprising:
an actuator including a motor which displaces an actuator member of the safety valve;
an operating member which is displaced to operate the safety valve, thereby selectively permitting and preventing fluid flow through a passage in a subterranean well; and
a magnetic coupling between the actuator member and the operating member, the magnetic coupling including a magnetic force exerted by a first magnetic device connected to the actuator member on a second magnetic device connected to the operating member.
2. The safety valve according to claim 1 , wherein there are no dynamic seals between pressure acting on the actuator member and pressure acting on the operating member.
3. A safety valve, comprising:
an actuator including a motor which displaces an actuator member of the safety valve;
an operating member which is displaced to operate the safety valve; and
a magnetic coupling between the actuator member and the operating member, the magnetic coupling including at least one first magnetic device attached to the actuator member, and at least one second magnetic device attached to the operating member.
4. A safety valve, comprising:
an actuator including a motor which displaces an actuator member of the safety valve;
an operating member which is displaced to operate the safety valve, the operating member being an opening prong of the safety valve which opens and closes a flapper; and
a magnetic coupling between the actuator member and the operating member.
5. A safety valve, comprising:
an actuator including a motor which displaces an actuator member of the safety valve;
an operating member which is displaced to operate the safety valve;
a magnetic coupling between the actuator member and the operating member; and
a flow passage extending axially through the safety valve, the flow passage being pressure isolated from the actuator member, without the use of a dynamic seal.
6. A safety valve, comprising:
an actuator including a motor which displaces an actuator member of the safety valve;
an operating member which is displaced to operate the safety valve;
a magnetic coupling between the actuator member and the operating member; and
a flow passage extending axially through the safety valve, the flow passage being pressure isolated from an annulus surrounding the safety valve, without the use of a dynamic seal.
7. A safety valve, comprising:
an actuator including a motor which displaces an actuator member of the safety valve;
an operating member which is displaced to operate the safety valve;
a magnetic coupling between the actuator member and the operating member; and
a flow passage extending axially through the safety valve, without any dynamic seal being exposed to pressure in the flow passage.