Quantitative Assessment Method and Application of Natural Fracture Risk in Shallow Shale Gas Based on Geomechanics-A Case Study of Zhaotong Shale Gas Area in Southern China

Abstract The presence of natural fractures in the study area, combined with complex stress conditions, poses challenges for accurately quantifying fracture stability, directly impacting block development. This study employed a three-dimensional geomechanical model and a natural fracture model to calculate the critical stress states of natural fractures across the region. It provided a quantitative characterization of fracture shear slip stability through normalized analysis and classified the risk of natural fracture slip. The stress state of the block was quantitatively described using the Q index, and the stability of fractures under different stress conditions was analyzed. Additionally, the study examined the relationship between fracture stability and interference from horizontal well fracturing, casing deformation in horizontal wells, and well productivity. These findings are crucial for optimizing the exploration and development of shallow shale gas resources in southern China.