Slug Flow: Occurrence, Consequences, and Prediction

BP Exploration currently has an interest in hundreds of kilometres of operating multiphase flowlines. Most of the company's proposed field developments also involve multiphase flowlines. A large number of these do or will experience slug flow, either as the normal flow regime, or as a result of transient behaviour.Data on flow regime and slug flow characteristics have been collected from many lines over the past 8 years. Information on slug characteristics from a number of different systems is presented in this paper, including velocity, length and holdup. Some unfavourable consequences of slug flow on both process performance and system integrity are highlighted, including plant shutdowns and mechanical damage.The need to be able to predict slug flow for the design of future systems, and to advise the operators of existing systems, remains a high priority for R&D activities, as ever longer and more complex multiphase systems are proposed. BP's latest slug frequency method is described, followed by guidelines for pipework layout, and comments on current R&D on corrosion in multiphase flow.