| 摘要 |
<p>The invention provides a Christmas tree (160) for a wellbore, comprising a plurality of modules (162, 164, 166, 170), each module including: at least one module opening (172), the modules being connected to each other to form a housing (174), the respective module openings being connected to form a continuous passage (180) though the housing, said continuous passage being adapted to be connected to the wellbore; a retrievable valve insert (182, 184, 186, 190) arranged in the module opening; and control means (202, 206, 210) coupled to the module to control the valve insert between a closed position and an open position.</p> |
