Characterization Analysis on the Prediction of Natural Gas Phase Behaviour

The existence of heavier hydrocarbons as hexane, heptanes and etc in the pipeline natural gas will significantly influence its phase behaviour, as the obvious increment of the critical pressure and temperature, even worse it could lead to condensation of hydrocarbon during transporting and might cause other severe problems. However, since the exact composition of heavier hydrocarbons commonly can't be resolved by field gas chromatography, the amounts of all hydrocarbons heavier than hexane are added together as C6+ components. Combined with the computational and experimental analysis, it's found that the method used to characterize the distribution of C6+ components will have a large impact on the predicted phase behavior. Further, proper characterization methods of C6+ components are proposed and discussed in present paper, which will guidance the design and operation of natural gas pipeline.