Pigging simulation for horizontal gas-condensate pipelines with low-liquid loading

摘要

Liquid condensation in natural gas transmission pipelines commonly occurs due to the thermodynamic and hydrodynamic imperatives.Condensation subjects the gas pipeline to two phase transport,which dramatically affects their delivery ability and operational modality and the associated peripheral facilities.It is therefore imperative for the pigging simulation in gas-condensate flowlines to be taken into consideration in their design.Periodic pigging helps keep the pipeline free of liquid,reducing the overall pressure drop,and thereby increasing the pipeline flow efficiency.A new simplified pigging model has been developed for predicting the pigging operation in gas-condensate horizontal pipelines with low liquid-loading,which couples the phase behavior model with the hydro-thermodynamic model.The comparison of the calculating results with those of the two-phase transient computational code OLGA (with a dynamic,one-dimensional,extended two-fluid model),indicates the new pigging model has a good precision and high speed in calculation.The model also contains the capability of pig-tracking and slug-length-increasing model,which can be suitable for engineering design.