Fracture development characteristics in carbonate reservoirs: insights from stress field simulation with a heterogeneous rock mechanics model and adaptive boundaries

Structural fractures serve as critical storage and flow pathways in carbonate reservoirs, with their development directly governing hydrocarbon enrichment and fluid migration. However, prediction accuracy is often limited by the simplified treatment inherent in traditional homogenized models, hindering the exploration of deep carbonate reservoirs. Focusing on the Ordovician fractured reservoirs within the deep coverage area of the Tahe Oilfield, Tarim Basin, this study constructs a 3D heterogeneous rock mechanical model. Integrated with an adaptive boundary constraint algorithm, high‑precision paleo‑stress field simulations are conducted for the Middle Caledonian, Early Hercynian, and Neotectonic periods. Fracture development intensity is quantitatively predicted based on rock failure criteria and validated against core observations and production data. The results demonstrate that: (1) The heterogeneous rock mechanical model coupled with adaptive boundary conditions significantly improves the reliability of stress field simulations. (2) Fracture development exhibits a strong correlation with the paleo‑stress field, with fractures predominantly concentrated around fault peripheries, tips, and intersections. (3) Fracture intensity shows a pronounced positive correlation with both the horizontal stress difference (∆ σ _h ) and the stress heterogeneity coefficient ( k ); this correlation strengthens markedly once these parameters exceed certain thresholds. (4) Predicted fracture linear density matches well with cumulative oil production from individual wells, confirming that the fracture system is a key controlling factor for hydrocarbon enrichment in deeply buried carbonate reservoirs. This study provides a robust methodological framework and practical guidance for quantitative fracture prediction and efficient exploration in carbonate reservoirs.