| 摘要 |
<p>A hydraulic release mechanism for retrieving a stuck downhole tool (250) from a well casing (202) having an elongated, cylindrical jack body (216), a piston (208) carried in a bore in the jack body and a latching portion (212) carried co-axially by the jack body for connecting with the stuck tool (250). The piston is movable within the jack body under the influence of fluid pressure from a first position to a second position. The movement of the piston to a position intermediate its first and second positions causes an anchor slip member (234) to ramp over a wedge member (236) and expand radially outward against the well casing to restrain further longitudinal movement of the piston in the casing. A shearable element (244) prevents relative motion between the anchor slip member and the jack body until the anchor slip member is moved radially outward against the well casing. The shearable element shears and releases the jack body for longitudinal motion in the casing relative to the piston when the anchor slip member is expanded radially outward against the casing, locking the piston in place. The latching portion (212) is operatively engageable with the tool in a manner permitting the stuck tool (250) to be lifted loose when the jack body is moved longitudinally relative to the locked piston under the influence of hydraulic pressure until the locked piston assumes its second position in the jack body.</p> |
