Dynamic pigging modeling and simulation of condensate gas pipelines

Pigging is an effective way of removing condensate liquid and improving the transportation efficiency of condensate gas transportation pipelines. Prediction of pig velocity, total pigging time and slug length are of great importance for pigging operation. The pipelines are divided into a reformation two-phase flow section, single-phase gas section, liquid slug section and downstream undisturbed two-phase flow section to model the pigging process. The dynamic model for each section is built based on the mass, momentum and energy conversation equations of the liquid and gas phase. Since the locations of the pig, liquid slug front and reformation two-phase section front are moving, a couple of method based on the fixed coordinate system and internal moving boundaries is applied the pigging model. Finally, a condensate gas transportation pipeline is used to validate the methods. The simulation results show how to predict total pigging time, pig velocity and its position reasonably.