John Oluwasegun Oladimeji¹, Chinwuba Victor Ossia^1,, John Umunna Okoli¹

This study presents a design template to analyse and check the structural integrity of subsea pipelines installed by S-Lay method. A typical static configuration of the pipeline in equilibrium with wave, current, drag, etc forces was considered in the structural analyses of the installation method. In the template, two scenarios namely: the laying of a single-pipe and the laying of a pipe-in-pipe, were considered. The template developed which was based on a Microsoft Office Platform also considered the lay barge/vessel specifications, met Ocean data, the pipe parameters, critical parameter, and the pipe-lay equipment specifications. The output results from the template include; catenary parameters, tension in pipe, stresses at subsea level and maximum deflection during installation. Typically, with applied top tensions T_T of 1177.2kN and 1842.4kN on a pipeline of length 36 m, maximum deflections of (0.26m) and (0.17m), respectively were obtained. The results obtained by the user-friendly template developed corroborate those obtained by manual calculation for the relevant deflections, stress and catenary models for the structural integrity of the pipeline for an S-Lay installation.

Single Pipe (SP), Pipe in Pipe (PIP), Subsea stress, Structural integrity