Abstract: Deep carbonate reservoirs are commonly characterized by low porosity, low permeability, and strong heterogeneity, resulting in complex fracture propagation behaviors and great challenges for reservoir stimulation. Based on a 10,000-ton-capacity ultra-large true triaxial hydraulic fracturing physical simulation platform, large-scale carbonate specimens with dimensions of 2 m×2 m×1 m were used to conduct hydraulic fracturing experiments under three typical completion schemes: cased perforation in vertical wells, open-hole vertical wells, and open-hole horizontal wells. By integrating high-frequency pressure monitoring with multi-channel microseismic monitoring, fracture initiation, propagation, and spatial distribution characteristics were systematically characterized. The results indicate that open-hole horizontal wells (energy utilization efficiency 0.70, fractal dimension 1.78) are most effective in activating natural fractures and dissolution cavities, forming highly complex three-dimensional fracture networks, with the stimulated reservoir volume (SRV) approximately 2.3 times that of perforated completions. Cased perforation completions exhibit well-controlled fracture orientations but the lowest fracture complexity, whereas open-hole vertical wells show lower fracture initiation pressure and relatively stable fracture geometries. Energy analysis reveals a significant positive correlation between energy utilization efficiency and fracture complexity, with an increase of approximately 0.1 in the fractal dimension for every 0.05 increase in energy utilization. A quantitative relationship among energy utilization, fracture complexity, and SRV is established, providing a basis for fracturing parameter design and completion selection in deep carbonate reservoirs.