| 摘要 |
<p>An apparatus for launching at least one plug into a tubular in a wellbore, said apparatus comprising a hollow upper section and a hollow lower section, said hollow upper section comprising at least first and second upper ports (12, 13) longitudinally spaced therein, said second upper port (13) being disposed above said first upper port (12), a landing seat (7) between said hollow upper section and said hollow lower section, and a fluid displaceable member (4) retained below said second upper port (13), said hollow lower section adapted to retain at least one plug (8) and comprising at least a first lower port (10) thereabove and a landing collar (6) for said fluid displaceable member (4), the arrangement being such that in use, when the apparatus is installed at the top of a liner and lowered into a wellbore, and a dart lands on said landing seat (7) blocking said first upper port (12) a fluid pressure differential can be created about said fluid displaceable member (4) through said second upper port (13) which displaces said fluid displaceable member (4) to said landing collar (6), allowing a fluid pressure differential about said plug through said first lower port (10) to launch said plug.</p> |
