| 摘要 |
1,265,868. Wells. DRESSER INDUSTRIES Inc. 31 July, 1969 [15 Nov., 1968], No. 38497/ 69. Heading E1F. A well tool anchor, e.g. on a packer or bridge plug consists of a slip 100 (Fig. 5) which is loosely mounted or pivoted at 136 on the tool so that it can move between a position with the axis 108 along the tool axis, when edges 120, 122 (with optional 'teeth) grip the walls of the well bore or outer tube and a position with the axis 112 along the tool axis, when the slip has a diameter 130 less than that of the well bore or tube. The slip is pivoted into the anchoring position by abutments engaging the upper and lower edges 114, 116, or only one edge if the slip is mounted on pivots 68 which limit its axial displacement, and is released by abutments such as 70. The slip is normally held in the released position by leaf spring 88. The slip may be operated by rotation of a body member 36 to move a screw-threaded upper head 46. The slip is released by rotation in the opposite direction or by a straight pull on the body member 36 to shear a shear pin 92. In other embodiments the upper and lower heads are moved under the control of a T-slot connection between the centre body and a block body (214) on a drag block assembly (212, Figs. 8A-14, not shown) or by hydraulic pressure developed within the tool after dropping a valve and ball (427) onto a seat (426) at the bottom of the tool to seal the lower end of the tool (Figs. 15A-16C, not shown). The valve seat is designed to shear at a predetermined pressure above the slip operating pressure, so that the obstruction caused by the ball is removed. In another embodiment (Figs. 17A-21B) slips are used in a bridge plug connected to a sinker with. a J-slot connection, and operated by differential pressure in the well. Releasing the slip may be facilitated by forming it with an offset projection, e.g. 287, Fig. 10A, not shown) on the axial end to which the engaging load is not applied, so that engagement of the projections with an abutment face will tend to relieve the slip. Alternatively, the abutment face (384, Fig. 13, not shown) loading the slip may be supported on tapered blocks (372) which are withdrawn by removal of a sleeve (306) supporting them to release the slip. |
