| 摘要 |
AN HYDRAULIC LOCK ALLEVIATION DEVICE FOR A WELL CEMENTING STAGE TOOL, SUCH A TOOL AND A METHOD OF ALLEVIATING AN HYDRAULIC LOCK An hydraulic lock alleviation apparatus alleviates hydraulic lock, for example in a cementing stage tool when a closing plug is employed. The apparatus has a channel for transmitting trapped fluid (which causes a hydraulic lock) from the trapped volume to another volume. The channel is blocked by a pressure responsive member which ruptures, moves, breaks, or is punctured to permit trapped fluid to flow from the volume of hydraulic lock. In one embodiment of a stage tool with such an apparatus puncture means is actuable to puncture the pressure responsive member. In another embodiment a movable spool is mounted in the channel for actuation to be displaced and thereby to permit the flow of trapped fluid. |
