A Critical Review on Permanent Catenary Mooring Health Monitoring and Evaluation Technologies

Lee Hsiu Eik; M.S. Liew

Abstract

Recent times have seen the proliferation of Oil and Activities in increasing deeper waters. In such context, fixed structures are no longer a viable option. Floating structures applied for deepwater developments comprise of several major floater concepts that are either moored in position or employ dynamic positioning. For permanently anchored Floating Production Systems, the vessel and mooring systems are expected to withstand up to 10,000 years return period storms. Permanent catenary moorings have been known to fail prematurely due to various interconnected factors at the manufacturing, installation and operation stages. Such failures have led to serious aftermaths with consequences to human safety, environment and incurred costs. Catenary mooring integrity monitoring technologies to date are mainly focused on predicting line failure and are based either on geometric or tension based monitoring solutions. This paper presents a review of mooring line-based failure and the current integrity technologies in the market. The existing technologies are either geometrical or tension based, with latest systems being a combination of the two. A holistic review on wire-chain mooring line deterioration is discussed alongside challenges facing the industry. An overview of a proposed alternative methodology for mooring integrity is presented based on vessel-mooring dynamicity. Keywords: Deepwater, floating structures, mooring line integrity, monitoring technologies