| 摘要 |
A slimbore marine riser and BOP are provided for a subsea completion system which includes a tubing spool secured to a wellhead at the sea floor. The tubing spool has an internal landing profile for a reduced diameter tubing hanger which is arranged and dimensioned to pass through the bore of the riser and BOP at the end of a landing string. The tubing hanger, arranged and designed to be sealingly positioned in the tubing spool landing profile, has a production bore and a relatively large multiplicity of electric and hydraulic passages which terminate at a top end of the hanger with vertically extending electric and hydraulic couplers. A passage is provided through the body of the tubing spool which provides communication from above the tubing hanger to the well annulus below the hanger. A remotely controllable valve is placed in the annulus bypass passage. After the hanger is positioned in the tubing spool, the BOP may be set aside the wellhead, so that a substantially conventional xmas tree (with a BOP adaptor connected to its top profile) may be secured at its bottom end to the tubing spool. Subsequently the BOP may be secured to the top of the xmas tree by means of the BOP adaptor. After downhole and subsea completion operations are finished, the BOP and marine riser may be disconnected from the xmas tree by unlocking the bottom of the BOP adaptor from the top of the xmas tree. A tree cap can then be installed in the top profile of the xmas tree. For well intervention operations, a conventional BOP or LMRP of convenience can be reestablished to the top of the xmas tree via the BOP adaptor.
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