| 摘要 |
<p>Subsea casing hanger suspension system in which each of a plurality of concentric casing strings (26, 28, 30) and its hanger (20, 22, 24) is directly and totally supported on a wellhead housing (38) independently of all the other strings and their hangers, by a plurality of expandable load ring slips (48, 50, 52) that are run into the housing in retracted position with, and as a component of, the previous casing's packoff assembly (32, 34, 36). When the packoff assembly is pressure tested following its installation, the load ring slips expand radially into an annular groove (42, 44, 46) in the inner surface of the housing, and as this expansion occurs the slips rise off the packoff assembly into proper position for supporting the next casing hanger. When this next hanger is lowered into the wellhead housing it precisely positions the load ring slips against the groove prior to imposing the hanger load on them, and in this final position the slips are spaced above, and thus out of contact with, the packoff assembly, resulting in a direct and compressive tansfer of the total casing hand load onto the wellhead housing. </p> |
