Controlling actuation of tools in a wellbore with a phase change material
A technique is provided for actuating devices deployed in a wellbore. The technique utilizes an actuator that cooperates with a downhole device, such as a well tool. The actuator has a phase change material that can be caused to undergo a phase change upon an appropriate input. The phase change of the material is used to provide the force necessary for actuation of the downhole device.
1. A system for use in a well, comprising:
a downhole device;
an actuator to actuate the downhole device, the actuator comprising a volumetric phase change material positioned to physically actuate the downhole device upon undergoing a phase change; and
a thermal unit powered by electricity, the thermal unit being positioned downhole and coupled to the actuator in a manner that enables the thermal unit to control the phase of the volumetric phase change material.
2. The system as recited in claim 1 , wherein the phase change is initiated by an electrical input.
3. The system as recited in claim 1 , wherein the downhole device comprises a valve actuated by the volumetric phase change material.
4. The system as recited in claim 1 , wherein the downhole device comprises a packer actuated by the volumetric phase change material.
5. The system as recited in claim 1 , wherein the volumetric phase change material is formed of a polymer material.
6. The system as recited in claim 1 , wherein the actuator comprises a chamber closed by a movable piston, the volumetric phase change material being disposed in the chamber.
7. The system as recited in claim 6 , further comprising a heating element position to heat the volumetric phase change material in the chamber.
8. The system as recited in claim 6 , wherein the chamber is thermally insulated from the surrounding environment.
9. The system as recited in claim 6 , wherein the movable piston is coupled to the downhole device by a linkage.
10. The system as recited in claim 6 , further comprising a position sensor to detect movement of the movable piston.
11. The system as recited in claim 1 , wherein the actuator comprises a pair of dynamic seals.
12. A method, comprising:
deploying an actuatable device in a wellbore;
actuating the actuatable device with a force applied via volumetric change of a phase change material; and
controlling the volumetric change of the phase change material with a downhole thermal unit controlled from a surface location.
13. The method as recited in claim 12 , wherein actuating comprises trapping the phase change material in a cavity with a movable component.
14. The method as recited in claim 13 , wherein trapping comprises trapping a polymeric phase change material.
15. The method as recited in claim 12 , wherein actuating comprises actuating a packer.
16. The method as recited in claim 12 , wherein actuating comprises actuating a downhole valve.
17. A system for use in a well, comprising:
a downhole actuator configured for connection to a well device to actuate the well device, the downhole actuator having a cavity, a volumetric phase change material in the cavity, a movable member in contact with the volumetric phase change material, and a linkage deployed to transfer force from the movable member; and
a downhole thermal unit that controls both heating and cooling of the volumetric phase change material.
18. The system as recited in claim 17 , further comprising the well device, wherein the linkage is coupled to the well device in a manner to actuate the well device upon sufficient movement of the movable member.
19. The system as recited in claim 17 , wherein the volumetric phase change material comprises a polymeric material.
20. The system as recited in claim 17 , wherein the volumetric phase change material is thermally insulated from the environment surrounding the downhole actuator.
21. A system for use in a well, comprising:
a downhole device;
an actuator to actuate the downhole device, the actuator comprising a polymer material, wherein a force to actuate the downhole device is provided by the polymer material undergoing a phase change; and
a thermal unit located downhole to enable selective control of the phase change material from a surface location.
22. The system as recited in claim 21 , wherein the phase change is initiated by an electrical input.
23. The system as recited in claim 21 , wherein the downhole device is a packer.
24. The system as recited in claim 21 , wherein the downhole device is a valve.