9. Structural Analysis and Riser Operations (Geoff Lyons and Minoo Patel)

Chapter 9 serves as an industrial case study in this book. This chapter investigates the structural analysis and the riser operations of fixed and floating offshore structures using pipe connections between surface facilities and seabed as well as pipes laying on or below the seabed for transportation of oil and gas. The analysis of vertical marine risers under the influences of both internal and external forces is described. Four configurations of the marine risers are introduced, including free-handing mode, connected mode, operational mode, and nonoperational but connected mode. A marine riser can be maintained in an operable condition by ensuring that the lower ball joint angle remains below about 4 degrees. Three operating procedures are given to bring the angle down. The marine riser monitoring system provides information on the behaviors of the platform and the marine riser, and comparisons can be made with previous results for evaluating the projected fatigue life of the riser. BPP-RMS, an example of the comprehensive Riser Management System (RMS) for riser maintenance and inspection, is presented. BPP-RMS is an on-board riser operation management system that provides real-time guidance for carrying out connected and disconnected mode drilling riser operations on board a vessel.