| 摘要 |
A weight actuated tubing valve is shown which is incorporated within a tubing sub, installed within a string of tubing extending from the well surface within a well bore. The tubing valve includes an outer cylindrical sidewall and an inner mandrel which is spaced apart from the sidewall to define an annular space. The outer sidewall and inner mandrel are each provided with one or more openings for communicating the interior bore of the tubing string with the well annulus. A sliding sleeve is located within the annular space and is movable between a first position which closes off the mandrel opening from the annular space to a second position in which the mandrel opening communicates with the annular space, and through the sidewall opening with the exterior of the tubing string. A fluid chamber initially contains a fluid for supporting the sliding valve within the annular space in the first position. A hollow pin initially contains the fluid within the annular space but is sheared by dropping a weight within the tubing string, whereby the support fluid is released from the annular space to allow the sleeve to move to the second, open position.
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