Experimental Study on the Recovery Degree of Tight Sandstone Water-Bearing Gas Reservoirs

The development of tight sandstone water-bearing gas reservoirs presents significant challenges due to their inherently low permeability, high water saturation, and complex reservoir heterogeneity. These reservoirs exhibit ultralow permeability and high water content, which impair gas mobility and reduce production efficiency. This study investigates the recovery mechanisms of tight sandstone gas reservoirs through dynamic physical simulation experiments, focusing on the effects of gas production rate, water saturation, and permeability on recovery degrees. The results show that increasing gas production rates lead to a more rapid drop in bottom hole pressure and lower recovery degrees, while high water saturation exacerbates pressure decline and reduces recovery efficiency. Furthermore, the study demonstrates that permeability plays a critical role in determining recovery degrees, with lower permeability causing a more significant decline in production efficiency. A dimensionless recovery degree evaluation model, based on similarity theory, is proposed to extrapolate laboratory-scale experimental results to field-scale applications. The model incorporates parameters such as initial water saturation, pressure depletion degree, and permeability, providing a reliable framework for assessing recovery potential in tight sandstone gas reservoirs. This research contributes to improving the accuracy of recovery predictions and offers practical insights for optimizing gas reservoir development strategies.