Mechanical characterization of continental shale in Sichuan Basin of China and its potential impact on reservoir stimulation

摘要: Abstract Organic-rich shale in Sichuan Basin of China preserves tremendous oil and gas resources, one important type which is the continental gas. Owing to special lacustrine depositional environment, showed strong heterogeneity longitudinal profile had not been fully characterized. Using cores an exploratory well within Lower Jurassic formation, rock mechanical experiments, including tri-axial compression, Brazilian splitting fracture toughness, were performed systematically. Basic parameters entire reservoir section acquired at first time. Reservoir brittleness was also evaluated by a newly proposed method based on complete stress-strain curve. Results that mineral compositions exhibited feature wide fluctuation profile, with good gas-bearing layers (D1-3, D1-4) containing high content clay minerals, 63.93% 59.67%, respectively. Mechanical from compression tests noteworthy difference section. With increasing confining pressure, dispersion reduced certain extent, but still obvious. The index could reasonably reflect influence buried depth lithology difference. Formation tended reduce pressure. Layers D1-3 D1-4 maintained relatively biggest reduction occurred interlayer shelly limestone. Tensile strength type-Ⅰ toughness various depths dispersion. anisotropy obvious, values vertical direction generally higher than those horizontal orientation. experimental findings would provide basis for optimum design stimulation this area.