Shale Oil Exploration and Development with Microstructural Characterization Innovations: Breakthrough Pathways and Challenges in Continental Reservoirs

This review systematically synthesizes global advancements in shale oil exploration and development, while analyzing current progress in microstructural characterization technologies. It further elucidates the synergistic evolution of geological characteristics, hydrocarbon accumulation mechanisms, engineering practices, and technological innovations. By contrasting marine and continental shale oil systems across dimensions of resource distribution, reservoir heterogeneity, and pore network architecture, the study reveals fundamental distinctions between North America’s large-scale development paradigm and China’s breakthrough strategies for continental shale oil. Key findings demonstrate that North America’s marine shale oil achieved commercialization through horizontal well fracturing technological innovations, with homogeneous reservoir properties and engineering compatibility driving a production capacity of 4.8 million barrels per day in 2021. China’s continental shale oil reservoirs contain technically recoverable resources of (30–60) × 108 tons, yet exhibit sub-5% recovery efficiency due to pronounced heterogeneity and mesopore-dominated (> 70%) multiscale pore architectures. These geological constraints necessitate precision engineering solutions, including “sweet spot” prediction systems and in-situ conversion technologies. Microstructural characterization integrates Field Emission Scanning Electron Microscopy (FE-SEM), Small Angle X-ray Scattering (SAXS), and low-temperature adsorption for nanoscale 3D pore network reconstruction. Digital rock physics enhances modeling accuracy through SAXS-NMR (Nuclear Magnetic Resonance)-mercury intrusion multiphysics coupling, achieving < 15% parameter inversion errors. Machine learning algorithms markedly enhance SEM image quantification efficiency. The review further identifies critical challenges in multiscale pore connectivity analysis, microscale seepage mechanism modeling, and interdisciplinary data integration, proposing a digital twin-driven intelligent characterization framework to overcome continental shale oil development bottlenecks. This comprehensive analysis provides systematic insights bridging foundational theories and engineering practices for unconventional hydrocarbon resources, offering strategic guidance for global energy transition.