Study On Conduit And Preferential Petroleum Migration Pathway Of QHD29-2 Structure In The Bozhong Area

On the basis of theories of petroleum accumulation kinetics,by integrating geological,geophysical and geochemical data,this paper investigated hydrocarbon generation potential of source rock,characterized the frame of conduit system in Qinnan sag,precdicted the preferential petroleum migration pathway and clarified the mechanism of petroleum accumulation on QHD29-2 structure.On basis of this limited research,the preliminary conclusions can be drawn as follows:In Qinnan Sag,Shahejie Formation source rock intervals are of good quality and generally stay at the main stage of oil generation,providing the abundant oil source to the traps distributed along the slope of the QHD29-2 structure.The distribution of effective Dongying Formation source rock may be limited to the center of the Qinnan Sag.On the basis of hierarchical cluster analysis of ten saturated biomarker parameters,indicating that Es1-derived oil is mainly contained in Paleogene reservoirs,whereas Es3-derived oil is generally accumulated in Neogene reservoirs in the QHD 29-2/2E oil field,and the oil was charged from the Qinnan Sag.Faults and sand bodies are major petroleum conduit in Qinnan Sag.Fault activity intensity during the stage of neotectonic plays a controlling role in vertically petroleum accumulation,however the distribution of sandstone domains the laterally hydrocarbon accumulation in Qinnna Sag.The high activity intensity segment of boundary fault vertically communicated deep CO2 fluids and transferred deep Es3-derived oil to shallower reservoirs.Fault may vertically serve as a barrier in the segment of low activity intensity.In Es1 layers,sandstones connected the mature source rock and focused the Es1-derived oil in the Eocene reservoirs without extensive migration.Es3-derived oil in Neogene traps mainly originated from the Qinnan Sag and was laterally transported by Neogene sandstones.