DW RUPE: A New Deepwater Pipeline Repair Capability for the Gulf of Mexico and Other Deepwater Regions

ABSTRACT

Described herein is a chronology for developing a deepwater pipeline repair system and cooperative ownership group for affecting emergency repairs of damaged pipelines. Using a Joint Industry Project (JIP) funding model, technology development started in 2004, and continued as Hurricanes Katrina and Rita hit in 2005, and resulted in the formation of DW RUPE – Pipelines Co-Ownership Group in May of 2007. Included in this paper is a description of the repair methods developed, and repair tools being procured and developed for affecting 10 to 24 inch ANSI pipeline repairs in 1,000 to 10,000 feet of water. A recently-developed spreadsheet-based pipe lifting analysis laptop computing tool is described for use in planning pipe lifting and cutting operations for a specific emergency pipeline repair operation in deep water.

Background on the Formation of DW RUPE

In 2004 Phase 1 of a JIP was formed to develop a low CAPEX emergency repair capability for pipelines and flowlines in water depths in the 1,000-10,000 ft range, in the US Gulf of Mexico. Stress Subsea, Inc. (SSI) performed a Failure Mode and Effects Analysis, conducted interviews with suppliers and operators and included input from the JIP Steering Committee.

Phase 1 JIP Conclusions

As a result from DW RUPE, Phase 1, the following conclusions were drawn for export pipelines:

The probability of needing a deepwater repair is low, but the consequences resulting from pipeline damage are high. Because of this, the project agreed upon pursuing a low CAPEX repair solution, recognizing the need to minimize capital expenditures since the probabilities of occurrence are low.

• The most likely damage types are wet and dry buckles caused by anchor snags (the DW RUPE shallower water depth range is 1,000 ft., hence anchoring damage is still a consideration).
• Potential repair solutions for a low CAPEX pipeline repair and a low CAPEX flowline repair are different.
• Traditionally a leak clamp and a spool piece connector set are needed for each pipe size. The project pursued a new paradigm of adapting and employing full structural clamps in place of connectors. This allows two clamps to be used in a spool piece repair or one of the structural clamps to be used alone for a pinhole leak from a cracked weld. Two clamps serve the same function as two connectors and a clamp (Pipeline Repair), thus reducing the CAPEX investment for inventory.
• Cracked welds are the most likely cause for pinhole leaks. Full structural clamps are advised to arrest crack propagation (Pipeline Repair).

Ayers, R.R., Hoysan, S., Gage, E., Rebello, A., Stark, M., “DW RUPE: A New Deepwater Pipeline Repair Capability for the Gulf of Mexico and Other Deepwater Regions,” OTC 19207, Presented at the 2008 Offshore Technology Conference, May 8, 2008, Houston, Texas.