Formation and evolution of the Wushenqi and Central paleo-uplifts,Ordos Basin and their control on hydrocarbon accumulation
Using the latest 2D framework section of the Ordos Basin,along with high-precision 3D seismic data and drilling data,we systematically reinvestigate the Wushenqi and Central paleo-uplifts within the basin.Accordingly,the Cambrian-Ordovician sedimentary structural framework of the basin is reestablished and the evolutionary history of these two paleo-uplifts is clarified.The results indicate that during the Ordovician,the Wushenqi paleo-uplift exhibited a structural framework characterized by high in the north and low in the south.The Wushenqi and Central paleo-uplifts produced significant controlling effects on the deposition of the Cambrian and Ordovician strata,respectively.The 3D seismic data reveal that during(or even before)the Huaiyuan movement,the Wushenqi paleo-uplift underwent greater exposure and denudation compared to the Central paleo-uplift,though remaining higher in altitude during the pre-Ordovician.The Wushenqi paleo-uplift was active during the Precambrian,followed by gradual diminishment until the Ordovician when it became largely inactive.In contrast,the Central paleo-uplift got uplifted and came into being in L shape connecting the Yimeng paleo-uplift in the north and the Qingyang paleo-uplift in the south before the deposition of the Ordovician Majiagou Formation,prior to which the Qingyang and Yimeng paleo-uplifts,located in the southwestern and northern parts of the Ordos Basin,respectively,were independently active.The Wushenqi and Central paleo-uplifts jointly govern the distribution of sedimentary facies zones,resulting in the favorable reservoir-caprock assemblages in the eastern and central Ordos Basin.Promising targets for hydrocarbon exploration in the Ordos Basin include the Pre-Ordovician gas play s in weathering crust,lithologic gas plays in the central part,and fault-fractured gas plays in the eastern part.
万方数据
维普
