Abstract: In view of the problems of production decline of unconventional gas wells, large differences and low accuracy in the EUR (predicted ultimate recovery factor) results, the theoretical basis and advantages and disadvantages of the various methods such as Wattenbarger linear flow method, PLE power exponential decline model method, and SEPD extended exponential decline model method were compared and analyzed to evaluate the objects of use, required data and applicable conditions of various methods. At the same time, the prediction results of the four models of PLE, SEPD, Duong and LGM in the linear flow stage and the quasi-boundary flow stage were compared with the prediction results of the numerical simulation well, and practical applications were carried out. The research result shows: Various commonly used production decline methods for unconventional gas wells are suitable for different formation flow regimes; Wattenbarger linear flow, quasi-constant flow pressure, and horizontal well multi-stage fracturing model are more suitable for flow conditions with variable production and variable bottom-hole pressure. PLE and Duong models are more accurate for prediction within 2a. This study provides a reference for production prediction of unconventional gas wells.

Key words: unconventional gas well, production decline, EUR prediction method, shale gas