Full Field and Early Production in Ultra-Deep Waters: The 'DP-FPSO' and 'DP-EFPSO' Concepts

摘要

In the coming years, there will be a growing demand forrnFloating Production and Storage Units (FPSOs) for ultra deeprnwaters (greater than 2000 m [6,000 feet]), as evidenced by thernlarge number of deep water FPSOs being considered for WestrnAfrica, Brazil and possibly the Gulf of Mexico. Severalrnstandard solutions for FPSO systems exist – turret mooredrnFPSOs, turret moored FPSOs with thruster-assistance, andrnspread-moored FPSOs for benign, directional environments.rnHowever, beyond certain water depths, the technical andrneconomical constraints associated with the use of passivernmooring systems may favour a fully dynamically positionedrnFPSO. This system can either be utilized as an earlyrnproduction system designed to operate on many fields, or as arnfull-field development solution with service life up to 25rnyears. The areas most suited for this application are offshorernWest Africa, Brazil and the Gulf of Mexico.rnThe paper describes a joint study undertaken by thernvarious companies represented by the authors to developrndesigns for fully dynamically positioned FPSOs for ultra deeprnwaters. Two systems have been developed – a full-fieldrndevelopment solution for the Gulf of Mexico (DP-FPSO), andrnan early production system for West Africa (DP-EFPSO). Thernvarious technical challenges for both systems have beenrnidentified and solutions to them provided. The differences inrnenvironment and operation of the two systems are discussed.rnResults from computer simulations and model tests are alsornprovided to illustrate system performance in mild and harshrnenvironments, and to study the performance as a function ofrncontrol strategy.