深层碳酸盐岩储层能量演化与裂缝网络复杂度特征OA

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 u tilization.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.