| 摘要 |
A plug launching device for use in cementing operations in the construction of oil and gas wells, said plug launching device (3) comprising a tubular member having an upper section (4) and a lower section (5) which can accommodate at least a bottom plug (10) and a top plug (11), characterised in that said upper section has a floor (6) and said lower section is movable relative to said upper section (5), the arrangement being such that, in use, when a first dart (27) is pumped into said upper section (4) by cement said cement is diverted to raise said lower section (5) to release said bottom plug (10) and when a second dart (30) is pumped into said upper section (5) by hydraulic fluid it lands on said first dart (27) and said hydraulic fluid is diverted to raise said lower section (5) further to release said top plug (11).
|
