Shale oil and gas differ greatly in reservoir characteristics and accumulation mechanisms. This work compares the enrichment characteristics of marine and continental shale oil and gas, and systematically summarizes targeted green-efficient exploitation technologies for shale resources. Two quantitative theoretical models are established, namely the multi-field coupling accumulation model for shale gas and the nanoconfinement synergistic conversion model for shale oil. The integrated framework provides theoretical support for the differentiated low-carbon development of shale oil and gas and facilitates the achievement of dual carbon goals. Future research directions regarding mechanism study, technological innovation, and green evaluation systems are also prospected.

The multi-source mixed sedimentation resulted in a unique series of mixed fine-grained sedimentary rocks evolved within the Permian Lucaogou Formation in the Jimusar Sag, located in the southeastern Junggar Basin, China. The variety of lithofacies within this series resulted in pronounced heterogeneity of pore structures, complicating the analysis of fluid occurrence space and state within reservoirs. As a result, the impact of lithofacies on fluid mobility remains ambiguous. In this study, we employed qualitative methods, such as field emission scanning electron microscopy (FE-SEM) and thin section observation, and quantitative analyses, including X-ray diffraction (XRD), total organic carbon (TOC), vitrinite reflectance (R_o), high-pressure mercury intrusion (HPMI) porosimetry, and nuclear magnetic resonance (NMR), along with linear and grey correlation analyses. This approach helped delineate the effective pore characteristics and principal factors influencing movable fluids in the fine-grained mixed rocks of the Lucaogou Formation in the Jimusar Sag, Junggar Basin. The findings indicate the development of three fundamental lithologies within the Lucaogou Formation: fine sandstone, siltstone, and mudstone. Siltstones exhibit the highest movable fluid saturation (MFS), followed by fine sandstones and mudstones sequentially. Fluid mobility is predominantly governed by the content of brittle minerals, the sorting coefficient (S_c), effective pore connectivity (EPC), and the fractal dimension (D₂). High content of brittle minerals favors the preservation of intergranular pores and the generation of microcracks, thus offering more occurrence space for movable fluids. A moderate Sc indicates the presence of larger connecting throats between pores, enhancing fluid mobility. Elevated EPC suggests more interconnected pore throat spaces, facilitating fluid movement. A higher D₂ implies a more intricate effective pore structure, increasing the surface area of the rough pores and thereby impeding fluid mobility. Ultimately, this study developed a conceptual model that illustrates fluid distribution patterns across different reservoirs in the Lucaogou Formation, incorporating sedimentary contexts. This model also serves as a theoretical framework for assessing fluid mobility and devising engineering strategies for hydrocarbon exploitation in mixed fine-grained sedimentary rocks.

Climate constitutes a crucial factor in the oil shale mineralization, given its pronounced influence on the growth of lacustrine organisms and the depositional environment.. During the late Middle Jurassic, the Qaidam Basin experienced a major climate shift from humid to arid conditions. Amid this transition, a continuously distributed sequence of lacustrine oil shales was deposited in the basin. Focusing on these oil shales, we explore the coevolutionary relationships between aridification and oil shale mineralization using methods such as palynology and geochemistry. The results indicate that the oil shales of the shale interval of the Shimengou Formation were deposited under varying humidity conditions. Specifically, the black, massive oil shales in the lower part are formed in freshwater lakes under a relatively humid climate, while the laminated oil shales in the upper part in saline lakes under arid conditions. During the humid phase, lush terrestrial vegetation and a high flux of terrigenous sediments supplied abundant terrigenous organic matter and clastics to the lakes. This created mixed organic matter sources and a dysoxic environment for organic matter preservation. As a result, medium-quality oil shales with high hydrocarbon-generating potential are created. During the arid phase, reduced terrestrial vegetation and the proliferation of algae led to the formation of algae-dominated organic matter sources. Concurrently, the anoxic, high-salinity sediment-water environment significantly enhances the preservation efficiency of organic matter. Hence, medium- to slightly high-quality oil shales with excellent hydrocarbon-generating potential occur. The salinization of lacustrine basins, induced by the aridification, is identified as the key factor in driving the transition between the two oil shale metallogenic models. This study provides insights into the coupling mechanism between aridification and oil shale mineralization and enrichment while also offering an important basis for predicting high-quality oil shales within the Qaidam Basin.