Shifting apparatus and method

A device for shifting a sliding sleeve from a first position to a second position, the sliding sleeve being concentrically positioned within a well, and wherein the sliding sleeve contains a moveable inner member and wherein the well is in communication with a hydrocarbon reservoir, the device comprising:

• an outer housing forming an annulus with the well;
• a power piston slidably disposed within said outer housing, and wherein said power piston comprising:
• an upper shoulder configured to form an annular chamber and a tubular chamber relative to the outer housing;
• and a lower shoulder c configured to form an atmospheric chamber relative to the outer housing;
• an up latch means for preventing upward movement of said power piston relative to said outer housing;
• a down latch means for preventing downward movement of said power piston relative to said outer housing;
• and wherein downward movement of the power piston shifts the moveable inner member from the first position to the second position.

A method of shifting a sliding sleeve valve from a first position to a second position, the sliding sleeve being positioned within a well, the method comprising:

• providing an activating device operatively attached to the sliding sleeve valve, the activating device including:
• an outer housing forming an annulus with the well;
• a power piston disposed within said outer housing, and wherein said power piston comprising:
• an upper shoulder configured to form an annular chamber and a tubular chamber;
• and a lower shoulder configured to form an atmospheric chamber;
• a collet member engaging the outer housing;
• an inner support member disposed within said collet member;
• a shear ring insert, shear pins connecting the shear ring insert to said upper piston;
• and wherein the sliding sleeve valve contains a moveable inner member and wherein movement of the power piston shifts the moveable inner member from the first position to the second position;
• lowering the sliding sleeve valve and attached activating device into the well on a work string;
• preventing upward movement of the power piston via said collet member;
• preventing downward movement of the power piston via a snap ring engaging the power piston;
• performing a well intervention technique on the well;
• shifting the collet member upward;
• pressuring an internal bore of the activating device;
• shearing the shear pins that connected the shear ring insert to said power piston;
• moving the power piston upward into engagement with the collet member;
• moving the inner support member upward;
• disengaging a snap ring disposed about the power piston so that the snap ring is allowed slide along the power piston;
• capturing the snap ring within a groove on the power piston;
• releasing the applied pressure to the internal bore of the activating device;
• expanding the annular chamber relative to the atmospheric chamber thereby allowing the power piston to move downward;
• engaging the power piston with the sliding sleeve valve;
• moving the sliding sleeve valve from the first position to the second position.