Vortex Induced Vibration and Thermal Cycle Analysis of a Complex Subsea Clad Jumper

Abstract

PANYU 35-1/2 project loaded in South China Sea is designed to use rigid jumper to transport production fluid between two subsea components, for example, a well and a PLEM, or a PLEM and a PLET. The offset distance between the components (such as trees, flowlines, and manifolds) dictates the jumper length and characteristics. The petroleum resource in this field is high erosion (CO2 up to 17.2mol%), and usual under high pressure(up to 40MPa) and/or high temperature(up to 103°C), which turn out to be several technical difficulties for the jumper design. The assessment of the fatigue life of a subsea jumper subject to vortex induced vibration (VIV) and thermal cycle is a difficult and important engineering problem. The paper focus on:State the key points of CRA clad pipe material used for the rigid jumper design, fabrication, and operation;When in areas of significant currents the jumper is subject to VIV. The complex shape of the jumper means that numerical methods are used to solve for the vibration modes of the jumper;Jumpers are expected to experience low-frequency/high-stress fatigue during successive heating and cooling cycles. Fatigue at the jumpers shall be evaluated based on expected number of cycles with FEA method;Coupling VIV and Thermal Cycle Analysis for the jumper, get the optimization method for the jumper design. This paper examines each problem area, and sets out a optimization method, which is economical and practical for jumper design analyses.