Lithofacies and Shale Oil Potential of Fine-Grained Sedimentary Rocks in Lacustrine Basin (Upper Cretaceous Qingshankou Formation, Songliao Basin, Northeast China)

Shale oil has become a global hotspot of unconventional exploration and development. In this study, the latest drill core experiment analyses Qingshankou Formation in northern Songliao Basin were used to evaluate its lithofacies classification, sedimentary environment, pore types, pore-throat structure characterization, shale potential. Lithofacies classification was determined according total organic carbon (TOC) content, structure, rock mineral content. Laminae genesis micro-sedimentary structures indicate deposition fine-grained rocks (FGSRs) semi-deep deep lacustrine environment; however, evidence also suggests partial reworking by storm events bottom current flows. FGSRs mostly comprise type I kerogen, with small amounts II1. The average vitrinite reflectance 1.37%, indicating middle high stages thermal maturation within generation window. N2 adsorption indicated that silty mudstone (SM), fine mixed (SFMR), argillaceous (AFMR) had ink-bottle-shaped slit-shaped pores, dominated mesopores, accounting for 77.4%, 71.9%, 80.8% volume, respectively. Mercury injection capillary pressure analysis SM SFMR an radius 0.01–0.04 μm, whereas AFMR CM nanopores, mainly distributed range 0.004–0.0063 μm. Based on comprehensive studies TOC development, brittleness, we concluded organic-rich laminated should be focus Basin, followed or organic-moderate layered AFMR, as well calcareous rocks.