Frontiers in deepwater geotechnics: Optimising geotechnical design of subsea foundations

Susan Gourvenec and Xiaowei Feng

This paper outlines a toolbox of methods for optimising the geotechnical design of subsea foundations. Subsea foundations are becoming increasingly widespread as offshore development moves away from the conventional template of a fixed platform over a set of wells to subsea development of multiple wells and fields tied back to a single facility. Subsea developments comprise a network of infield flowlines and assorted pipeline and wellhead infrastructure, which is typically supported on shallow, mat foundations. The optimisation methods presented cover (i) capacity assessment methodology, (ii) foundation configuration, (iii) geotechnical input and (iv) mode of operation. The research results derive from a combination of physical model testing in a geotechnical centrifuge, numerical analysis and theoretical modelling. Many of the research results have been immediately adopted in engineering practice in Australia and overseas, demonstrating the relevance of the methods to the national and international offshore hydrocarbon industries.