Tectonic-palaeogeographic evolution and potential of natural gas accumulation of the Cambrian in Ordos basin
The Early Paleozoic evolution of the Ordos area is basically consistent with that of the North China Block.Sedimentation in the Ordos basin began in the late Early Cambrian Suyukou period(equivalent to the Canglangpu stage),missing the"Time Window"period corresponding to the critical period for the development of favorable source rocks.However,around the Zhenyuan paleo-uplift,located in the southwestern part of the basin,Cambrian and Upper Paleozoic coal measures source rocks are in direct contact.This creates a"hydrocarbon supply window,"enabling a large-scale supply of hydrocarbon from the Upper Paleozoic coal measures source rocks to the Cambrian reservoir(and it also can be called a"Space Window").The Cambrian tectonic-palaeogeographic pattern of this area is characterized by"one paleo-continent,one depression,and three paleo-uplifts".Among these,the two paleo-uplifts exert the most prominent control on Cambrian gas accumulation in the area:the Zhenyuan paleo-uplift,located in the southwestern part of the basin,is conducive to the formation of karst palaeogeomorphologic trap systems and palaeo-weathering crust gas reservoirs at the top of the Cambrian.This is due to the direct contact of source rocks and reservoir rocks between Cambrian and Upper Paleozoic coal measures strata in this area.The Wushenqi paleo-uplift,located in the central part of the basin,developed effective"stratigraphic pinch-out"traps because Cambrian strata overlap toward the core region of the paleo-uplift on its western side.It could also receive gas supply from the"hydrocarbon supply window"adjacent to the Zhenyuan paleo-uplift,forming stratigraphic pinch-out trap gas reservoirs.
Ordos basinCambrianpalaeogeographic evolutionWushenqi paleo-upliftZhenyuan paleo-upliftstratigraphic trap gas reservoir
万方数据
维普
