Tieback connection method and apparatus
A tieback connection apparatus effects a metal-to-metal type seal between a riser run from an overhead vessel and a subsea well casing suspended from a casing hanger in a subsea wellhead member. The apparatus includes a tubular mandrel connected to and run by the riser into the wellhead, and a metal-to-metal type annular seal mounted at the lower end of the mandrel. The end of the mandrel is positioned in coaxial alignment with the casing hanger with the seal ring position between the mandrel and the hanger to effect a seal between the riser and the casing when compressive force is applied to the seal ring. A seal activating mechanism, associated with the mandrel and operated by a tool run from the vessel, engages the casing hanger and applies the compressive force to effect the seal. The seal activating mechanism includes a locking collet, a reaction sleeve, and a drive sleeve. Rotation of the drive sleeve by the operating tool moves the reaction sleeve into contact with the collet to maintain locking engagement between the casing hanger and the collet. The collet also prevents further movement of the reaction sleeve whereby further rotation of the drive sleeve causes the reaction sleeve to apply the compressive force to the mandrel, seal ring and casing hanger. A method is also provided for effecting a metal-to-metal type seal between the riser and the casing.
- Assignee:
- Hughes Tool Co.
- Patent Number(s):
- US 4456070
- OSTI ID:
- 6506306
- Resource Relation:
- Patent File Date: Filed date 26 Jul 1982; Other Information: PAT-APPL-401508
- Country of Publication:
- United States
- Language:
- English
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