沉积斜坡、超临界浊流、流体转换在鄂尔多斯盆地延长组的应用OA

The Ordos Basin is the largest petroleum-bearing basin in central China.During the Middle-Late Triassic period,it developed a large-scale lacustrine depression basin,which contains abundant oil and gas resources.However,the genetic mechanisms of gravity flow sandstones in the deep-lacustrine area are complex.It is difficult to use the traditional genetic models to explain their sedimentary evolution.This results in an unclear understanding of the spatial distribution of sandstones,which hinders efficient oil and gas exploration and development.Therefore,there is an urgent need to introduce advanced marine sedimentological theories to overcome the limitations of current research,thereby providing deeper insights into the sedimentary dynamic processes and evolutionary models of the sandstones,and improving the predictive capability for high-quality reservoirs in the deep-lacustrine area.This study introduces new sedimentary theories such as clinoforms,supercritical turbidity currents,and flow transformation.By integrating previous research results and based on multi-scale data including 3D seismic,multi-beam bathymetry,core samples and outcrops,this study systematically explores the feasibility of applying these new sedimentary theories in the Yanchang Formation of the Ordos Basin,with a focus on paleotopographic features,sandstone distribution patterns and core diagnostic criteria.The study suggests that clinoforms were widely developed in the deep-lacustrine area during the sedimentary period of the Yanchang Formation,providing key topographic control conditions for the occurrence of supercritical turbidity currents and flow transformation.Compared to traditional turbidity currents models,supercritical turbidity currents exhibit stronger erosive capability,significantly influencing the spatial distribution and geometric morphology of sandstones.The flow transformation process further enhances the optimization of sediment transport and reservoir space.The synergistic effects of these two sedimentary processes not only shape a complex gravity flow sedimentary system,but also promote the spatial coupling of high-quality reservoirs and source rocks,forming a favorable"source-reservoir integrated"petroleum accumulation model.This discovery breaks through the limitations of traditional genetic theories of lacustrine basin sandstones and offers a new framework for studying sedimentary systems in deep-water lacustrine basins.This study innovatively introduces the latest marine sedimentological theories into lacustrine basin,deepening the understanding of the formation mechanisms of sandstones in the Yanchang Formation and providing scientific support for the precise prediction of shale oil sweet spots in the deep-lacustrine area.Future research should further integrate multi-source seismic attribute analysis,numerical simulations,and physical experiment simulations to systematically explore the control mechanisms of supercritical turbidity currents and flow transformation on sandstones under the sedimentary background of clinoforms development,build refined sedimentary dynamics models,optimize reservoir prediction methods,and enhance the efficiency of oil and gas exploration and development in deep-water lacustrine basins.