Deepwater Mooring Anchor Design and Procurement Experience for Jack/St. Malo Semi-submersible Floating Production Facility

摘要

Chevron is developing the Jack and St. Malo fields located offshore in the Walker Ridge Area in the Gulf of Mexico (GOM). Located about 450 Kilometres south-southwest of New Orleans, La., the host facility is a deep-draft semi-submersible floating production unit (FPU), the largest (by displacement) FPU in the GOM, and is moored in 2130 m water depth by 16 synthetic rope mooring lines. These mooring lines are anchored to the seabed by suction anchors. Each mooring line is attached to the suction anchor at a cast padeye. The anchors are arranged in groups of four at the four corners of the mooring pattern. A single size anchor was chosen for all 16 suction anchors, instead of optimizing the design for the different groups. This suction anchor design pushes the design envelope as it supports mooring loads caused by the largest (by displacement) FPU and interfaces with state-of-the-art mooring components. As the industry progresses into deeper waters in the GOM and other global deepwater basins, increased payload requirements and metocean conditions will lead to pushing the boundaries of suction anchor design. This paper presents key observations and lessons learned during the design and procurement of the suction anchors for the Jack/St. Malo FPU which will benefit the future projects.