Static Performance of Compliant Vertical Access Risers Applied to Deepwater Floating Production System

Abstract

The requirements of marine risers applied to deepwater floating production systems become more and more challenging as oil/gas exploration and production continue to shift towards deeper waters. Compliant vertical access riser (CVAR) is a new riser concept being developed to address the potential challenges. Static analysis of the CVAR system is carried out in this study using a model developed from the differential equilibrium of the static forces, modified based on suspended cable theory and catenary equations. This study noted that the static performance of the CVAR system, evaluated in terms of the equilibrium position, the effective tension and the bending moment depends on the buoyancy factor (BF) and other secondary factors including the location of the buoyancy modules away from the wellhead and the degree of compliance. Keeping the BF value low as much as possible for a constant total riser length pushes the equilibrium location of the buoyancy modules to lower riser region, and increases the degree of compliance as well as the operational advantages.