Study on the Mechanism of the Relationship Between Fracture Properties and Water Invasion Characteristics in Fractured Gas Reservoirs

Water invasion plays a crucial role in the development of fractured gas reservoirs, with fracture permeability, orientation, dip angle, density, and connectivity significantly influencing water invasion characteristics. Guided by seepage mechanics theory, this study systematically analyzes the impact of fractures (such as aperture, orientation, and dip angle) on water invasion using discrete fracture numerical simulation technology. Through mechanistic modeling and parameter sensitivity analysis, a quantitative relationship is established between these factors and water invasion as well as gas reservoir development performance. The results indicate that when the fracture dip angle exceeds 60°, it promotes bottom water coning but inhibits edge water lateral expansion. In contrast, a dip angle below 30° promotes uniform edge water advancement while delaying bottom water breakthrough. When the fracture aperture exceeds 100 μm, preferential water flow paths form, leading to localized rapid water channeling. In contrast, an aperture below 50 μm can inhibit water invasion through capillary forces but may exacerbate reservoir heterogeneity, complicating the flow paths. High-permeability fractures exhibit strong conductivity, accelerating water invasion and forming dominant flow paths, thereby hastening both bottom water coning and edge water advancement. Conversely, low-permeability fractures, with weak conductivity, slow down water invasion. When the angle between the fracture orientation and the maximum principal stress direction is less than 30°, the water invasion front advances 3–5 times more rapidly. These findings provide theoretical insights for formulating water control strategies infractured gas reservoirs.