Research on the mechanism of water lock removal in tight sandstone gas reservoirs under microwave radiation

Water lock in the near-wellbore region severely constrains the productivity of tight sandstone gas reservoirs. Unlike conventional methods limited by high energy costs and secondary pollution, microwave heating offers a high-efficiency alter native capable of simultaneously reducing flow resistance and inducing fracture-enhanced permeability. This study investigates these mechanisms using Sulige sandstone cores through a combination of CT scanning, XRD, physical experiments, and coupled thermo-hydro-mechanical simulations. Key findings include: (1) Microwave radiation induces pore water vaporization and thermal stress fracturing, significantly improving pore connectivity once a temperature threshold of 500 °C is surpassed. (2) Under optimal conditions (800 W, 15min), the stable production period extended by 23–48 times, and ultimate recovery improved by approximately 20–26% across varying water saturations. (3) Numerical modeling, exhibiting high agreement with experimental data, predicts an effective remediation radius of 0.6 m and a total gas production increase of 0.34 × 106 m3. These results confirm the efficacy of microwave heating in alleviating water lock, offering a robust theoretical and technical basis for optimizing field development strategies.