Construction and Operation of HPHT Pipelines Designed for Lateral Buckling in the South China Sea

Gas production in the South China Sea has seen increasing trend of pipelines operating in HPHT (high pressure and high temperature) condition. This has led operators to stretch beyond the conventional stress-based design and move into strainbased design using the lateral buckling design approach. In previous article by Nils Kristiansen et al [1] and paper by Lim Kok Kien et al [2], the lateral buckling design methodology and initiation method were discussed and verified against field data. This paper presents both construction challenges and operational works following post start-up. Construction cost benefits for proven initiation method and actual laboratory data resulting from material testing for the purpose of welding acceptance criteria are included in this discussion. Routine maintenance practices, engineering post start-up and operating envelope developed for pipeline designed for lateral buckling will also be discussed. The intent is to provide operators with cost effective construction solutions and risk-based maintenance philosophy when considering lateral buckling design.