Competitive CVAR-FPSO concepts with Dry trees in ultra-deepwater; Weathervaning CVAR-FPSO for Brazil and Indonesia vs. Non-weathervaning for West Africa

摘要

A new FPSO concept termed CVAR-FPSO is underrndevelopment by a JNOC headed Joint Industry Project (JIP).rnThe concept, using Compliant Vertical Access Risersrn(CVARs), dry trees, a workover rig, and including the abilityrnto complete and workover wells, offers enormous economicrnand operational benefits to deepwater oil field development.rnThe JIP introduced the CVAR-FPSO - “OTC 12990 An FPSOrnwith Surface Wells and Workover System in Deepwater” atrnthe OTC2001. The original CVAR-FPSO design for Indonesiarnand Brazil allows weathervane with a turret, fluid transferrnsystem, and riser centering system, which are the mostrnexpensive facilities of the FPSO. However, the CVAR-FPSOrndoesn’t require these expensive facilities in West Africa,rnbecause a spread mooring system works withoutrnweathervaning there. Hence, CVAR-FPSO with CVAR, arnspread mooring system and a skidding W.O. rig delivers muchrnmore practical and economical performances in West Africa.rnThe central attribute of the CVAR-FPSO is the use of CVARs.rnThese compliant but rigid risers connect wells from thernseafloor to the dry trees mounted on the FPSO, and therncompliancy can compensate for vessel motion. The CVAR,rnbeing vertical access to the wells, also allows completion andrnworkover operations to be performed from the FPSO. Thernfield development concept involves the drilling and temporaryrnabandonment of wells by a MODU. The CVAR-FPSO is thenrnmoved onto location. CVARs are installed, and wells arerncompleted from the CVAR-FPSO.rnCVAR-FPSO would be more economical and practical withrnthe following system; weathervane system in Indonesia andrnBrazil, and non-weathervane system in West Africa.