The role of shear wave velocity and dynamic elastic properties in hydraulic fracturing optimisation of unconventional shale reservoirs: a comprehensive review

The optimisation of hydraulic fracturing (HF) in unconventional shale reservoirs is fundamentally guided by an accurate characterisation of in-situ rock mechanical properties. Shear wave velocity (Vs) has emerged as a cornerstone geophysical parameter, providing direct insight into the dynamic elastic moduli – shear modulus, Young’s modulus, and Poisson’s ratio – that govern fracture initiation, propagation, and geometry. This comprehensive review synthesises the multidisciplinary pathway from Vs estimation to HF model integration, addressing a critical gap between geophysical measurement and engineered stimulation design. Unlike previous reviews that have treated Vs prediction, rock physics, and HF modelling as separate domains, this research provides an integrated framework that explicitly links Vs-derived dynamic elastic properties to operational decisions such as hydraulic fracture model selection (PKN, KGD, P3D) and stage/cluster spacing optimisation. We systematically evaluate the strengths and limitations of primary Vs acquisition methods, including laboratory ultrasonics, empirical correlations, rock physics models, and machine learning (ML) techniques, highlighting their dependence on lithology, porosity, and mineralogy. Furthermore, the paper elucidates the pivotal role of Vs-derived dynamic properties in controlling key HF processes, such as fracture height containment, interaction with natural fractures, and proppant transport. A dedicated analysis demonstrates how these properties are integrated into classical and advanced HF models to predict fracture geometry and optimise treatment parameters. Ultimately, this study provides a unified framework for translating spatially continuous Vs measurements into actionable inputs for HF design, offering practical strategies to enhance stimulation effectiveness in heterogeneous, anisotropic shale formations. The review concludes by identifying key future research directions, including improved dynamic-to-static conversions and the incorporation of full anisotropy and poroelastic effects into coupled simulation frameworks.