| 摘要 |
An inner mandrel extends the full length of the bridge plug, and carries a top sub at its upper end for latching engagement with a conventional overshot to retrieve the plug. A tubular outer mandrel is slidably mounted on the inner mandrel for limited axial sliding movement. A partial central bore in the inner mandrel and coacting ports adjacent the upper ends of the two mandrels provide a valved bypasss passage bridging the seal element. External slips are carried in a slip carrier axially fixed to the inner mandrel by shear screws. A tubular setting assembly consisting of a lower top wedge for expanding the external slips, an upper compression member, and an annular elastic seal element disposed for compression between the wedge and compression member, is yieldably secured to the outer mandrel by means of shear pins. Second yieldable shear pins couple the top wedge and compression member. The outer mandrel and tubular setting assembly are adapted to be coupled to electric line operated pressure setting apparatus for lowering the tool and for effecting upward pull of the mandrel and downward push of the setting assembly to set the tool. During the setting, the setting assembly first shears from the mandrel to set the top wedge and the seal element is then compressed. A bottom wedge assembly includes a collet wedge releasably coupled to the outer mandrel to be moved into engagement with the external slips, the setting movement of the collet wedge compressing a compression spring. For release of the bridge plug the coupling between the outer mandrel and collet wedge is released; and upward movement of the outer mandrel, provided by coupling to the inner mandrel, effects release of the collet wedges allowing the compression spring to retract the collet wedge, and picks up the compression sleeve and the top wedge to release the seal element and the top wedge.
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