Hydraulic fracturing in shale formations is controlled by dual-scale layering effects that range from microscopic laminae to macroscopic bedding planes. At the microscopic scale, fine-scale laminae are homogenized, manifesting as the intrinsic anisotropy, where directional variations in elastic modulus and permeability exert a critical influence on fracture propagation. At the macroscopic scale, bedding planes introduce interlayer heterogeneity through contrasts in elastic modulus, in-situ stress, and permeability, thereby giving rise to distinct propagation modes. To capture these integrated effects on hydraulic fracturing, a fully coupled three-dimensional poroelastic–hydromechanical model is developed using the cohesive element method. The model quantitatively elucidates how key dual-scale parameters dictate fracture behavior. Comprehensive phase diagrams are constructed based on the dimensionless parameters λ (relative interface strength) and C_V (in-situ stress difference), combined with the dual-scale factors of microscopic anisotropy (α_E and α_P) and macroscopic heterogeneity (R_E, R_P and R_S). These maps delineate quantitative regimes of termination, deflection, crossing, and penetration. Results demonstrate that the in-situ stress contrast R_S primarily governs vertical fracture growth, while the elastic modulus contrast R_E and permeability contrast R_P exert differential effects: a low modulus ratio or low permeability ratio acts as a strong barrier leading to termination or deflection, whereas higher ratios facilitate crossing and penetration. The microscopic anisotropic parameters further modulate these behaviors: elastic anisotropy α_E promotes fracture crossing by redistributing interface stresses, and permeability anisotropy α_P enhances full penetration through fluid-driven tensile opening. Overall, the proposed framework provides a basis for predicting fracture propagation in shale formations with pronounced dual-scale heterogeneity.