Research on Critical Effusion Volume for the China-Burma Natural Gas Pipeline

Under certain temperature and pressure conditions, natural gas condensates and the liquid is accumulated in the pipeline during transmission of gas. It is therefore important to calculate the critical effusion volume accurately so that a reasonable pigging cycle can be determined. Frequent pigging operation not only affects the normal gas supply, but also causes unpiggable obstacles. This study has developed a liquid prediction model in which the effusion volume is dependent on the liquid holdup and the capacity of the gas to carry liquid. Using the analysis software OLGA and applying the model to the China-Burma pipeline, the critical effusion volume and the parameters distribution curves along the pipeline have been determined. The results show that the critical effusion volume in the pipeline decreases with increasing throughput. The method is a significant advancement in determining the pigging cycle and mitigating the pigging risk.