Study On The Controlling Factors On Hydrocarbon Accumulation For Es₃^s Reservoir In The Middle Part Of Central Uplift Belt Of Huimin Depression

The middle part of central uplift belt in Huimin depression already discovered nearly 100 million tons petroleum geological reserves.The reservoir found in the Es₃^s have the characteristics of moderate burial and high yield.However,due to the development of the fracture system in the area,the research on fracture and migration system is not deeply,so the exploration targets and direction are not clear,which restricts the exploration of oil and gas in the Es₃^s.The thesis studied the distribution and characteristics of source rocks,identified the sources of oil and gas by analyzing the evolution and the formation environment of crude oil through the geochemical data and biomarker parameters,then combined with the distribution of oil and gas to determine the relationship between source and reservoir.By studying the active features of the main oil control fault-Linyi fault,and studying the fault sealability based on mechanical properties and shale smearing.Combined with the development of sand bodies,a comprehensive study of the spatial configuration of sand bodies and faults is made to clarify the characteristics of the migration system,then based on the physical property and biomarker of crude oil to determining the possible migration direction of oil and gas.Combined oil source relationship and migration system,mainly study the control of hydrocarbon accumulation on source rocks,faults,sand bodies and their dispositions in the area.Established a reservoir model and preferred exploration targets.The research shows,the oil and gas is medium-mature oil in the central uplift belt in Es₃^s sublayer.The oil is mainly from the Es₃ source rocks in the south of Linnan sag.There is a brush distribution along the oil control fault-Linyi fault and its branch fault.The Linyi fault was the most active during Es₂ to Es₁,and basically quiescence in Es₃^s,with good sealability.The delta sand body has a good configuration relationship with fault in the study area and can be an effective fault-sand migration system,in order to providing a pathway for oil and gas migration.The source rocks,faults and sand bodies are the main controlling factors in area.The source rocks control the distribution of oil and gas,the fault main control the accumulation of oil and gas,and the sand bodies assist oil and gas accumulation.Established near-source mixed-anti-“Z”reservoirs accumulation modes in the west and near-source lateral sand migration in the east.Finally,classified three?favorable goals and six?favorable goals.