Abstract: The carbonate reservoirs in Shunbei Oilfield, shaped by multi-phase complex tectonic movements, host widespread fault-controlled fracture-cavity systems characterized by dissolved pores and cavities coupled with natural fractures. The fracture-cavity configuration within these grid-like, fault-parallel reservoir systems controls both local stress field distribution and the dynamics of circulation loss. Based on a finite element numerical simulation model, we develop a characterization method for the heterogeneous stress field in fracture-cavity systems. This method accounts for the multi-scale coupling effects between fractures and cavities. Using the drilling, logging, and reservoir structure data from Well SHB4-A in the Shunbei No. 4 fault zone, we conduct numerical simulations to analyze the control of fracture-cavity systems on local stress distribution. The results show that within fracture-dominated zones, an increase in the minimum horizontal principal stress coupled with a decreased stress difference results in an environment of high confinement and low anisotropy, thereby reducing the risk of circulation loss. Under connected fracture–cavity conditions, the stress-shielding effect of cavities locally reduces horizontal stress while maintaining a high stress difference. This facilitates the formation of oriented leakage channels along the fractures. When fractures and cavities are adjacent but not connected, significant stress reversal occurs in the regions between the fracture tips and the cavities, leading to instantaneous hydraulic linkage and consequent large-scale circulation loss.