| 摘要 |
This invention relates generally to a tubing hanger for use with a subsea wellhead, and in particular, a mechanism for sealing a tubing hanger in a subsea wellhead. A first aspect of the present invention provides a wellhead assembly comprising: a wellhead housing comprising a throughbore having a recessed sealing area, the recessed sealing area comprising a single recess; a tubing hanger positioned in the throughbore; a seal positioned between the wellhead housing and the tubing hanger, the seal being positioned so as to form a gap between the seal and the wellhead housing, wherein the seal is an annular seal capable of sealing an annulus formed in the throughbore between a perimeter of the tubing hanger and the wellhead housing, wherein a length of the seal is shorter than a length of the single recess; a seal energizer capable of moving relative to the seal in a manner that forces the seal against the wellhead housing to bridge the gap; and wherein the tubing hanger comprises a mechanism for de-energizing the seal, the seal energizer and the de-energizing mechanism allowing the seal to be repeatedly energized to bridge the gap and repeatedly de-energized to form the gap. A second aspect of the present invention provides a wellhead assembly comprising: a wellhead housing comprising a throughbore having a recessed sealing area, the recessed sealing area comprising a single recess; a tubing hanger positioned in the throughore; a seal positioned between the wellhead housing and the tubing hanger, the seal being positioned so as to form a gap between the seal and the wellhead housing, wherein the seal is an annular seal capable of sealing an annulus formed in the throughbore between a perimeter of the tubing hanger and the wellhead housing, wherein a length of the seal is shorter than a length of the single recess; a seal energizer capable of moving relative to the seal in a manner that forces the seal against the wellhead housing to bridge the gap; and at least one of a landing mechanism and a locking mechanism, wherein the operation of the seal energizer is independent from the operation of the landing and/or locking mechanism(s) 100--,, 144 ill 138 o 136 "'-140 142 |
