Tubular Bells Development – Export Pipeline Crossing Design

The Tubular Bells Oil and Gas Export Pipelines project in the Gulf of Mexico presented a number of design and installation challenges. In particular, the gas export line is required to cross over existing export lines in order to tie into existing infrastructure. A potential trigger point for lateral buckling is created by the elevation change of the pipeline at the crossing and, because the crossing is very close to the PLEM tie-in location, it is possible that buckling may occur at the crossing location before the PLEM has an opportunity to move and relieve the build-up of axial compressive force. This paper summarizes the pipeline system routing, the design options that were considered viable, the rationale for selecting the option considered the most reliable, and the analyses performed to confirm the acceptability of the crossing design.