Numerical modelling of disconnectable turret mooring systems

Abstract

Floating, Production, Storage, and Offloading systems (FPSOs) have become a popular option for operators in almost all areas of oil and gas production around the world. The FPSO as a concept is the only production platform that has virtually no water depth limitations. When fitted with a disconnectable turret mooring (DTM) system, FPSOs can be used in areas where it is desirable to remove the production unit from the field temporarily to prevent exposure to extreme events such as hurricanes or large icebergs. This paper provides an overview of the key issues involved in the numerical analysis of a DTM for deep water. The paper focuses on the hydrodynamic loading and the global analysis of the FPSO system and the response of the various components during disconnection and reconnection of the system. The paper also makes direct comparison between the numerical analysis and the data obtained from model tests of the system with an emphasis on the impact of deep water on the analysis and design of such systems.