Page 148: of Offshore Engineer Magazine (May/Jun 2014)

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Vessels

Round and round A new study by RPSEA,

Doris-Inc., and Sevan Marine investigates whether circular- hull FPSOs can provide a low- cost production solution for remote ultra-deepwater Gulf of

Mexico operations.

Audrey Leon spoke with the project leads to ? nd out more.

S-based research nonpro? t

RPSEA (Research Partnership

U to Secure Energy for America) selected Doris-Inc. to conduct a feasibility study on circular-hull FPSOs for applica- tion in ultra-deepwater Gulf of Mexico.

This region poses many technical and economic challenges, including extreme water depth, complex Paleogene reser- voirs with high pressure and tempera- approximately 250km south of Louisiana. anchored, until the storm passes and the tures, not to mention the distance from In 2012, the BW Pioneer FPSO, which crew can recover it back to the host vessel. shore and existing pipeline infrastruc- serves the ? elds, was forced to shut-in Nine hours before the storm made ture. The GOM also is prone to hurri- during Hurricane Isaac, a category one landfall, the buoy recorded wave canes in the summer months with high storm that made landfall along the coast of heights of about 5.9m, according to a wind and high seas. Louisiana on 28 August 2012, a mere six US Geological Service report entitled,

RPSEA’s members discussed what other months after production ? rst came online “Hurricane Isaac: Observations and options could serve the ultra-deepwater at the Cascade ? eld in February 2012. Analysis of Coastal Change.” The FPSO

GOM at a lower cost than giant spars and The BW Pioneer boasts a production was able to stay moored while shut down

TLPs. FPSOs, mostly due to regulations capacity of 80,000bo/d and 500,000 with its riser turret remaining in vessel, and the Jones Act (1920, 46 U.S.C.A. § cu. m/d of gas, and storage capacity of since the hurricane’s winds were below 688), have not been favored. However, for 500,000 bbl. It also utilizes a disconnect- the vessel’s mooring capacity. one operator, Brazil’s Petrobras, it’s the able riser system. In the event of a severe The RPSEA study aims to investigate only preferred production option. hurricane, the turret riser buoy can be storage options for the Central GOM.

Currently, Petrobras operates the GOM’s disconnected and submerged to a depth While the BW Pioneer ship-shaped FPSO ? rst FPSO at its Cascade/Chinook ? elds, of 46m; the buoy remains at that depth, can store 500,000 bbl, RPSEA aimed to

A moonpool was added to specs for a Sevan-designed circular FPSO to accommodates steel catenary risers. Images from Sevan Marine.

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