To Buckle or Not to Buckle - Best Practices for HP/HT Pipelines Lateral Buckling Design in Shallow Water

Abstract Mitigation of lateral buckling is one of the key design challenges for HP/HT subsea pipelines. Case studies of lateral buckling designs in shallow water developments are used to examine the merits and shortcomings of the different mitigation techniques. The case studies include both Greenfield and Brownfield developments as well as existing pipelines in operation. The assessment covers the design methodology, design challenges and methodology adopted to overcome those challenges as well as interaction with other pipeline design activities. Key factors such as technical feasibility, constructability and cost-effectiveness of the different mitigation techniques are considered. The different lateral buckling mitigation techniques described are generally applicable to subsea pipelines in shallow water developments. The methods can be classified into two main approaches. The first is to prevent buckling and the second is to allow buckling to occur in a controlled manner. Hence, a key decision for the designer is whether to aim for buckle prevention or buckle control i.e. to buckle or not to buckle. The assessment of the different techniques used for lateral buckling demonstrates that there is no ‘one size fits all’ solution. Unlike deep water applications where buckle prevention might be technically unfeasible or prohibitively expensive, the prevalence of shallow water in the Arabian Gulf region makes both buckle prevention and buckle control generally feasible and cost effective solution. However, each mitigation approach has its own pros and cons as well as limitations on its applicability and therefore the mitigation approach should be determined on a case by case basis based on comprehensive techno-economic assessment. Hence, understanding the merits and shortcomings of the different approaches is considered instrumental for proper selection of lateral buckling mitigation technique. This paper provides guidance to the designer for the selection of mitigation approach through consolidation of the understanding of the merits and shortcomings of typical lateral buckling mitigation techniques in shallow water applications.