Advancement in Subsea Flexible Riser Installation Methodology

Abstract The flexible pipe riser systems are used in various water depths and the advantages are well recognized in the oil and gas industry. The flexible riser systems are markedly advantageous with a floating platform such as FPSO, FPU, etc. The design of the Flexible product and the ancillaries can be custom made and hence, the flexible riser systems result in reduced hang-off load on the floating platform, have better fatigue outcome at the hang-off location and TDP. In general, flexible riser systems when used in suitable water depths will result in better performance over the lifetime, which has an outcome of cost optimization as far as the in-place performance is considered. The broad optimization of the riser systems and in-place configuration many times leads to a set of challenges during the installation stage. Although the weather limitations during the installation process are relatively lower as compared to in-place configuration, some of the intermittent configurations formed during the installation process lead to the equipment subjected to much higher loads than the in-place configuration. The installation loads on the product needs to be identified early in the design stage of the equipment. The early engagement and extensive engineering is performed in order to identify critical stages, provide optimizations, as well as mitigate any risks during the installation process. This paper provides an insight into the engineering and development of practical installation methodology of complex Flexible risers system. The early development of the installation process and the identification of critical steps in order to mitigate the challenges involved which resulted in an optimized design of the equipment as well as avoiding any unexpected behaviors during the installation process. The findings from a recently installed riser system in the East coast of India is used as an example.