| The coupling of geological and engineering sweet spots constitutes the core scientific issue for the efficient development of shale gas, and the degree of coupling directly affects the exploration potential and development economic benefits of shale gas resources. To systematically sort out the research progress of global shale gas sweet spot coupling, this paper collected geological, engineering and development dynamic data of typical shale gas fields, and adopted methods such as statistical analysis and case comparison to reveal the characteristics of geological and engineering sweet spots in different geological eras and establish differentiated coupling modes. The results show that the coupling modes of shale gas sweet spots vary significantly across different geological eras: the Early Paleozoic developed in platform areas with platform facies as the main sedimentary type, characterized by biogenic silica enrichment, mineral composition controlled by thermal evolution, as well as high total organic carbon (TOC) and high maturity; the Late Paleozoic was mostly distributed in foreland basins with deep-water shelf facies sedimentation, featuring overpressure sealing, well-developed natural fractures and high shale brittleness index; the Mesozoic was dominated by faulted basins with the coexistence of marine and continental lacustrine facies, where faults controlled sedimentation and fracability and overpressure regulated preservation; the Cenozoic was situated in extensional faulted basins and plate transform margins with widespread overpressure, with organic matter abundance controlled by sedimentary centers and reservoir development regulated by siliceous diagenetic facies. Coupling evaluation technology has evolved from qualitative analysis of a single parameter to multi-dimensional quantitative evaluation, forming a technical process of "geological characterization-engineering evaluation-coupling modeling". The development of monitoring technologies and engineering regulation means has pushed coupling research into a new stage of "dynamic prediction-real-time regulation". Differentiated coupling modes should be promoted in all global regions in accordance with the principle of "geological adaptation and technical matching". In the future, it is necessary to focus on breaking through key technologies including coupling mechanisms in complex structural areas, multi-scale coupling modeling and intelligent regulation. The theoretical framework and typical coupling modes constructed in this paper can provide a reference for the optimization of shale gas sweet spot areas and the design of development schemes under different tectonic settings. |