A Combined Riser Mooring System for Deepwater Applications

For deepwater developments, riser and mooring system requirements become a significant factor in the cost of the overall field development. Therefore, methods for reducing the riser and mooring design requirements and minimizing the cost of these systems become increasingly important. This paper presents the design methodology for a combined riser mooring (CRM) system and demonstrates the feasibility of the system for a test case application in a deepwater development offshore West of Africa. The CRM system offers significant benefits over the independent riser and mooring systems, namely reduced riser dynamics, reduced vessel offsets, a smaller seafloor footprint and system installation prior to the arrival of the FPSO.