MMS issues environmental analysis for FPSOs in Gulf of Mexico

The US Minerals Management Service has issued a final environmental impact statement (EIS) examining the possible effects of floating production, storage, and offloading (FPSO) systems proposed for use in the development of deepwater oil and gas resources in the Gulf of Mexico.


HOUSTON, Feb. 9�The US Minerals Management Service has issued a final environmental impact statement (EIS) examining the possible effects of floating production, storage, and offloading (FPSO) systems proposed for use in the development of deepwater oil and gas resources in the Gulf of Mexico.

FPSOs take crude oil from deepwater wells and store it in their hull tanks until the crude can be pumped into shuttle tankers or oceangoing barges for transport to shore.

MMS also released the comparative risk analysis (CRA) on the possible use of FPSOs in the Gulf.

The EIS said potential site-specific impacts are essentially the same as with other deepwater development and production systems. Most of the risk of oil spills is associated with the shuttle tankers, not the FPSO itself, and that risk is comparable to the risks from other deepwater systems and from pipelines.

It said excluding FPSOs would not reduce cumulative environmental impacts because other systems would be used in its place. The analysis did find that emissions associated with shuttle tankers, absent additional restrictions, could exceed air quality limits in the Breton Class 1 air quality area. The EIS was limited to the central and western Gulf of Mexico planning areas.

Use of FPSOs has the potential to improve industry's capabilities of developing oil and gas reserves on the Gulf of Mexico Outer Continental Shelf (OCS) in waters so deep that they either challenge or exceed existing deepwater production techniques and transportation systems, said MMS.

Deepwater is defined in the EIS as water deeper than 200 m or 656 ft.

The EIS considered a generic FPSO system and operation, as well as a range of technical variations. The "base case" evaluated is a permanently moored, double-hulled, ship-shaped FPSO that can store up to 1 million bbl of oil. The seafloor well equipment and onboard production equipment are the same kind used with other deepwater production facilities. The crude is offloaded to shuttle tankers for transport to Louisiana and Texas ports or to the Louisiana Offshore Oil Port. Associated or produced gas is piped ashore.

Several alternatives, including a No Action alternative, were also studied in this programmatic EIS that examines fundamental issues associated with industry's proposed use of FPSOs in the western and central Gulf planning areas.

MMS initiated the CRA to compare the relative risks of an FPSO to a fixed platform production hub, a spar, and a tension leg platform, and their associated oil and natural gas transportation systems.

The production systems studied in the CRA are specific to the Gulf. All of the production systems except the FPSO system are currently in use for deepwater development projects. The FPSO used in the CRA was the same as the base-case system studied in the EIS.

MMS said the intent of this work is to provide the basis for MMS to put the FPSO risks into the proper perspective, and to help MMS with decision making regarding the potential use of FPSOs in the Gulf.

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