At a water depth of 2100m, the Chevron-operated Jack and St. Malo oil and gas fields are the deepest installation to date for Nexans’ innovative power umbilicals that integrate HV power supply and umbilical functions within a single cable cross-section. The Jack and St. Malo fields are located within 25 miles of each other approximately 280 miles south of New Orleans, Louisiana. The project comprises of three subsea centres tied back to a hub production facility with a capacity of 170 000 boe and 42.5 million ft3 of natural gas per day.
Nexans’ specialised cable and umbilical manufacturing facilities in Halden, Norway, have designed and manufactured the 42 km power umbilical for the two fields in two separate lengths.
The power umbilical is an innovative design pioneered by Nexans that integrates the functions of power cables and umbilicals in a single cable, enabling a high-voltage supply to be provided for deep-water projects. A power umbilical includes a number of steel tubes as well as fibre optic elements and signal cables for control and monitoring purposes. By eliminating the need to transport and install a separate power cable, and a control umbilical, the power umbilical significantly reduces transportation and installation costs.
The design of this complex power umbilical, capable of operating at a water depth of 2400m, and with a design life of 30 years, has required an experienced multi-discipline engineering team to meet the many technical challenges. The two power umbilicals were successfully manufactured and delivered on a transportation barge to a storage location in Mobile, Alabama. The two power umbilicals were successfully installed in July 2014.
”It has been a pleasure to work with such professional engineers, both from Nexans and Chevron, whose dedication and teamwork has been the key to a successful project”, says Project Manager David Rasmuss of Nexans.
Adapted from press release by Joe Green