| 摘要 |
<p>A bridge plug tool is arranged such that primary and secondary pressure equalisation can occur. The tool has a mandrel 26 closed by a plug 32 which seals against inner surface 34 of mandrel 26 and is held in inter-engagement by ratchet formations 36 on the inner surface of mandrel 26 and ratchet formation 38 on the upper part of the plug 37. Slots 42 on the plug 37 allow the ratchet formation 38 to flex radially. Disengagement of the ratchet formation 36, 38 is prevented by an end portion 39 of plug locking member 40 which is itself held in place by a shear screw 44. Secondary equalisation can be achieved by removing plug 37 by tapping down locking member 40, shearing screw 44 and pushing locking member 40 down inside plug 37 so that the end portion 39 is moved away from the ratchet formations 38 and thus removing compressive force between the two ratchet portions 36, 38.</p> |
