Design of subsea jumper and spool pipelines

In the past 40 years, subsea systems have advanced from shallow water, manually operated systems in Water Depth less than 1,000ft (305m), into systems capable of operating via remote control at water depth from 1,000ft up to 10,000 ft (3,000m). The design of the subsea components able to operate correctly in such extreme environment has become more and more complex because of the non-accessibility of the seabed. Multiple possibilities of locations and events have to be foreseen and tested. This thesis project aims at developing FEA design tools to compute automatically design models and to check international standards for Jumpers and Spools subsea pipelines. This mission was conducted in the Flowline Design Departement of the company SAIPEM SA Eni in Paris as an internship project. In this document, first of all, the usage of Jumpers and Spools among the subsea engineering system will be explained. Since those pipelines are usually designed in compliance with the international standards ASME B31.8 and DNV-OS-F101, a brief description of the different design load and stresses checks of those will be given. Then the complete range of components of Jumpers and Spools as well as the design conditions to be taken into account will be detailed. The life cycle of those structures, starting from the installation to the long term operations are be considered in the design. Eventually the Finite Element design spreadsheets developed will be explained. Both ABAQUS and AUTOPIPE software will be used to design Jumpers and Spools pipelines extracted from previous Saipem Eni projects. Verification and comparison of the results of stresses and reaction loads at the two bases will be used to validate the tool created for FE design of Jumpers and Spools. Jumpers and Spools design requires the consideration of multiple displacements cases corresponding to the different tolerances (installation and metrology) and multiple loading cases corresponding to the life cycle loads. Moreover the design of such an adaptable structure should be made in different geometrical configurations since the correct dimensions are only known at the very last step of installation. Taking into account the complete range of load cases is necessary for the design of the Jumpers and Spools . That’s the reason why an automatic VBA tool generating the input FE files and post-processing the outputs is useful for the Flowline Design Departement of Saipem SA. By reviewing the results obtained with the spreadsheets on both ABAQUS and AUTOPIPE, similar and comparable results are obtained, which indicates that models on both software are coherent. Safety margins ratios are computed and comply with international standards.