Reliable multiphase flow simulators have contributed to recent field development trends, but generate large amounts of data requiring careful and thorough analysis. Wide experience from development projects and operation support has been distilled into a consistent and comprehensive methodology for generating steady state operating envelopes for multiphase pipelines. The approach presented improves the consistency and quality of steady state analysis, focusing efforts of flow assurance engineers away from the laborious generation and collation of data, towards the understanding, communication and application of the analysis of simulation results, allowing the correct choices of line size throughout the system to be easily identified.
Multiphase flow is now widely used in oil and gas gathering systems, reducing the requirement for distributed processing and so significantly reducing development costs. This is thanks in no small part to the development of enabling simulation technologies over the last couple of decades. Correct and timely selection of system architecture and line sizing are crucial to the economic and operational success of field developments. Ideally these decisions should be made during Concept Selection and solidified at the beginning of Front End Engineering, based on the best information available and consideration of the widest feasible range of criteria. However, this may require a significant amount of simulation, typically steady state, generating large quantities of data, which need careful and expert analysis. Various approaches have been used to select simulation cases, choose the data to analyse and to present the results. The efficiency of this work-flow and the quality of the resulting design are highly dependent on the methods used to generate and format the data, which frequently distract from what should be the key role of the flow assurance engineer – understanding, communicating and applying the results of the analysis.
If the maximum possible knowledge is gained from the steady state modelling, this has the added benefit of allowing subsequent use of transient simulation to be carefully targeted to optimize the benefits gained in the time available during the design phase.