Composition, Sorption and Stress Sensitivity of Intact and Cleaned Shale Oil Cores

Shale oil and gas resources are abundant and widely distributed in the world. Research on shale oil is growing rapidly recently, and shale oil is expected to become a major contributor to the oil production growth in the near future. Shale cores drilled from Luo 69, Fanye 1, Niuye 1 and Liye 1 wells have been systematically analyzed in terms of mineral composition, pore structure, and porosity and permeability stress dependency using thin section examination, X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen sorption, and porosity and permeability apparatus. Clay content in these wells ranges from 16.55% to 22.60%. Three types of shale oil formations are classified for the target shale formations. Oil cleaning reveals the potential of recovering shale oil and establishing seepage paths in shale matrix. Shale core porosity after cleaning becomes more stress sensitive, whereas both permeability measurements before and after cleaning show strong stress dependency. These systematic analyses of shale petrophysical properties provide a fundamental reference for understanding the microscopic characteristics of shale oil formations and formulating efficient stimulation techniques for shale oil reservoir development.