Paper Title
Stress Analysis of J-Lay Offshore Pipeline Installation Method

Abstract
Offshore pipeline installation is one of the important phases of offshore fields functioning. For deep water commonly used method is J-lay offshore pipeline installation method. In J-lay method, pipeline requires less tension capacity as the pipe is laid in a near-vertical position and the pipeline consists of sag bend region only unlike both sag bend and over bend in S-lay method. Keeping the pipe within an acceptable range of axial stress and bending stress is necessary for maintaining the pipe under tension. In this paper, analysis of effect of axial tension in the offshore pipeline induced in J-lay method during installation statically using a numerical method i.e., Finite Element Method (FEM) by using a computer program is shown. Analysis has been carried out by considering pipeline as a plane frame element with top end subjected to axial tension with orientation angle varying from 0.1° to 90° from bottom to top and one end at touchdown point as hinged. For analyzing the tension induced in the offshore pipeline during installation by using J-lay method, vertical displacement and horizontal displacement diagrams are plotted. Keywords - J-lay, Offshore pipeline, Finite element method, Axial tension, Plane frame element, Orientation angle