US Patent 8387707 Bellows type adjustable casing

A tieback connection between an offshore production platform and a wellhead on the sea floor has a riser and a tubular expandable and contractable member within the riser. The expandable and contractable member compensates for axial movement within the riser while maintaining axial tension in the riser. The expandable and contractable member is of uni-body construction having a wall configured to correspondingly expand and contract to compensate for the riser movement. In cross section, the member wall comprises folds formable by alternating slots formed into the inner and outer wall surface or an undulating surface.