Analysis and Fracturing Optimization of Horizontal Principal Stress Difference in the Basal Tight Zone of G Reservoir Based on Rock Mechanics Parameters

Abstract

This study investigates the distribution of horizontal principal stress differences in the basal tight zone of G Reservoir through rock mechanics parameter analysis, aiming to address regional variations in fracture creation/proppant placement difficulties and non-targeted proppant strategies during fracturing. A rock mechanics parameter calculation workflow was established using zonal shear wave time-difference prediction models, dynamic elastic parameter computations, dynamic-static parameter conversion, and formation pressure-strength parameters. Fracturing operation data were then utilized to invert tectonic stress coefficients, enabling horizontal principal stress calculation via Huang’s model and generation of a planar difference distribution map. Results indicate negligible vertical stress variation but significant planar differences (9.82–27.4 MPa in the main zone). Low-difference areas (<15 MPa) favor complex fractures requiring diversion fracturing, while high-difference areas (>20 MPa) accommodate long-fracture proppant placement. Field validation confirmed that parameter optimization guided by the difference map (e.g., diversion fracturing in low.g., diversion fracturing in low-difference zones) prevents screen-outs and enhances production (case well sustained 18-month stable output). This work pioneers a partitioned stress-difference mapping methodology for G Reservoir, providing quantitative foundations for dynamic fracturing optimization and process selection, significantly reducing operational risks and improving well productivity.