Experimental techniques for qualitative and quantitative characterization of shale oil reservoir space, minerals, and fluids

Characterizing shale oil reservoirs encompassing pore space, mineralogy, and fluids is fundamental to effective exploration and development. Recent advances in experimental techniques have significantly improved both the qualitative and quantitative analysis of these components; however, a comprehensive systematic review is lacking. High-resolution imaging technologies, such as Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Focused Ion Beam Scanning Electron Microscopy (FIB-SEM), enable detailed visualization of pore structures. Gas adsorption and high-pressure mercury intrusion methods provide accurate pore-scale quantification. Moreover, techniques like X-ray Diffraction (XRD), X-ray Fluorescence Spectroscopy (XRF), and Electron Probe Microanalysis (EPMA) allow precise mineral identification and compositional analysis. Confocal Scanning Laser Microscopy (CSLM), Raman Spectroscopy, Nuclear Magnetic Resonance (NMR), and Rock Pyrolysis provide insights into fluid occurrence and content within shale reservoirs. Based on a comprehensive review of existing research, this study identifies several key future directions: (1) addressing the challenges of nanopore observation in reservoir space characterization while minimizing the impact of sample preparation on pore structure; (2) improving the accuracy of quantitative mineral analysis and developing advanced new technologies for the precise measurement of complex mineral compositions; (3) enhancing the fluid quantitative evaluation of fluids by more effectively restoring subsurface geological conditions. This paper presents a current synthesis and forward-looking perspective on experimental techniques supporting shale oil exploration, aiming to guide future research and technological innovation in this field.