抄録
The hydrocarbon generation and expulsion efficiency of lacustrine source rocks is a critical scientific issue for petroleum resource assessment and exploration planning, yet its controlling factors are highly diverse and exhibit strong regional variability, resulting in an incomplete understanding of expulsion mechanisms and limiting the refined prediction of both conventional and unconventional hydrocarbon resources. This study aims to elucidate the generation–expulsion patterns of lacustrine source rocks under varying geological conditions, identify their primary geological controls, and construct typological models applicable to different organic matter types. Based on multiple representative lacustrine petroliferous basins, we systematically collected large-scale source rock samples spanning a wide range of thermal maturity stages, and applied integrated organic geochemical analyses, pyrolysis-based hydrocarbon generation potential testing, and geological thermal evolution modeling to extract key indicators of expulsion efficiency, followed by multivariate statistical analysis and model development for comprehensive assessment. The results reveal that lacustrine source rocks exhibit broadly consistent generation–expulsion behaviors across basins, with thermal maturity serving as the dominant factor governing expulsion efficiency, while different organic matter types display distinct expulsion patterns, and the effects of basin structure, depositional environment, and fault activity are comparatively minor. On this basis, we establish a universal typological model of hydrocarbon generation and expulsion efficiency, enabling quantitative characterization of expulsion behaviors across organic matter types. The findings not only enhance the understanding of geological controls on lacustrine source rock generation–expulsion efficiency but also provide robust model tools and theoretical support for the assessment of conventional and unconventional hydrocarbon resources.
