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Federal Helps Pegasus Get Bluewater ATP Telemark Flowing with a Closer Look at a Critical Component

Between 2006 and 2008, Pegasus International developed Telemark, a floating production facility in 4,450 feet of water, for Bluewater Industries. The project supported a dry tree development located at Atwater Valley Block 63 in the Gulf of Mexico.

Pegasus provided all manner of management for the project from design of the subsea structures to procurement. And that included flow assurance. It needed to ensure that a critical component to the facility’s operation, a 4-1/16 swivel flange assembly, could do its job effectively and safely. Downtime for the facility or danger to its crew was not an option. That’s where Federal came in.

The swivel flange assembly was designed to create a product that met API 17D, with geometry generally consistent with a 4-1/16 API 15k type BX flange. The service demands for this piece were extremely dynamic, presenting questions about future performance. The external unbalanced loads were all over the place.

Federal experts analytically derived a set of unbalanced forces and moments to determine a safety factor. The team used allowable stress based on API Formula 2(SY/3). Resultant stress intensity was judged using the Tresca criterion, or greatest shear stress as given by ASME Section VIII, Division 2, Appendices 4 and 5.

The resulting data showed a safety factor of 2, minimum, on the unbalanced external loads. And the materials were perfectly elastic, as well, so it was clear that the flange assembly was more than fit for service. Our experts showed that the greatest stress actually occurred in the adjacent pipe as opposed to the swivel flange assembly itself. And that meant less stress for the Pegasus team.

Now Pegasus could move forward with confidence and documentation. Bluewater/ATP Telemark is expected to double ATP’s production numbers in 2010. Read the full case study for this project’s technical details (will download in PDF format)