Impact of Fracture Density of Stimulated Reservoir Volume on Casing Deformation in Horizontal Shale Gas Well

Casing deformation in horizontal shale gas wells is a critical issue during multistage hydraulic fracturing. This study investigates the impact of fracture density and its nonuniformity on casing deformation using a coupled flow-mechanical model based on microseismic data from a deep shale gas well in China. The spatial distribution and internal fracture density of the stimulated reservoir volume were characterized through kernel density estimation and finite-element analysis. Results show that higher fracture density significantly increases casing stress and lateral displacement. Repeated fracturing in overlapping zones induces severe “S”-shaped bending deformation, with casing curvature increasing by 42% in high-density regions. Field data validation confirms the model’s accuracy, with predicted deformation locations aligning with actual tool resistance points. This study provides a quantitative framework for optimizing fracturing designs to balance production enhancement and casing integrity.