From Tanker-Ships to the First FPSO in the US GoM

During the 1970s, the Oil and Gas (O&G) offshore industry undertook the first few projects that exploited oil fields by using a tanker-ship as a hull to host its process plant and store the produced oil. Both the Shell project in the Castellon field in Spain and the Petrobras project in the Garoupa field in Brazil are considered pioneers of the Floating Production Storage and Offloading (FPSO) concept. The FPSO concept has many inherent advantages when compared to other types of floating facilities. However, the concept did not immediately become a preferable option for operators around the world. Throughout the 1980s, the industry did not experience a significant increase of FPSO-type projects. During this time, there was a clear preference for non-FPSO floating production units, despite the need for additional storage and a continuous export system. Additionally, port administrations treated all ship-shaped production units, including FPSOs, as tanker-ships. As such, they had to be compliant with International Maritime Organization (IMO) tanker requirements. This classification made it difficult to use FPSOs as permanent solutions to exploit offshore oil and gas fields. The IMO tanker requirements mandated that FPSOs could not stay on location longer than 3 years, although a 1-2 year extension could be granted, depending on inspections and other operational requirements. These requirements were enforced even if the operators and FPSO contractors designed the FPSO for a longer life. This paper describes the first steps, both regulatory and standardization of technical design requirements, in the approval process related to FPSO use for oil and gas fields. The paper describes how the United States (US) Environmental Impact Statement (EIS), and other initiatives between 1999 and 2001, paved the way for the US acceptance of FPSOs. Finally, the paper explains why the first FPSO in the US Gulf of Mexico (GoM) had a moored, single point, internal turret with a planned disconnection system as opposed to other design options that were evaluated and rejected.