Numerical Simulation Analysis of Foam Drainage Gas Recovery in Horizontal Shale Gas Wells

Liquid loading is almost inevitable in most shale gas well developments and has a significant impact on both the gas production rate and the overall recovery efficiency of the reservoir. Foam drainage gas recovery is an effective method for removing accumulated liquid and restoring production in gas wells. This technique is cost-effective, easy to operate, and does not interfere with normal gas production, making it widely applied in gas well liquid drainage. In this study, based on the two-phase level set method in COMSOL, numerical models were established for three key production stages of a horizontal shale gas well: early-stage natural flow, mid-stage gas–liquid interface formation, and late-stage foam drainage gas recovery. The gas production process under different stages was simulated to verify the production behavior of gas wells. By setting appropriate simulation parameters, the model can be adapted to simulate gas well performance under various geological and production conditions. Numerical simulation also enables the evaluation of key parameters in foam drainage gas recovery, laying the foundation for process parameter optimization.