Research On Sedimentary Facies For Chang6 And The Regularity Of Petroleum Accumulation At The N104 Well Area In The Southeast Part Of North Shananxi Slope

Southeast Ordos basin is a chief target of increasing resources and production,recently,which have plenty of petroleum resources,so it is crucial for petroleumexploration to understand evolving rules of Sedimentary Characteristics and sandbody.Applied with profile observation,core description,logging data interpretation,thin section identification,reservoir lithology and physical property analysis,and some effective theories of other subjects such as sedimentology,petrology,logging science,events sedimentology,stratum of the oil containing interval chang-6 oil formation of yanchang formation were devised and comparision scientificly,and identified the symbol of sedimentary facies and the characteristics of sedimentary facies,established the sediment frame,summaried sedimentary facies of the basin.Systemic study in the research area including sedimentary facies,sedimentary microfacies,sand body morphology and development of Bout points,and analysed of control factors of the oil and gas deposits,besides,combining the distribution of sandsbodies with several factors analysis of geologic conditions,reservoir characteristics and reservoir control factors,etc,study and do research on regularity of hydrocarbon enrichment,favorable exploration areas of the main Chang-6 oil formation in the research region are selected out in the end.Acorrding to the previous results,based on outcrop observation,core description,single well facies and comparison of connecting-well sections,combined with rock type,structure characterisc,sedimentary texture,logfacies,paleontology cycle,etc,the paper points out that the main facies developed in study area of Rriassic Yanchang Formation of Ordos basin Shanbei slope are lake-delta facies.The deposition is strengthened commonly when the lake basin got to the Chang-6 stage.The sedimentary environments of Chang-61,62,and 63 subages have good inheritance,and all of them are delta plain.During different stage,sedimentary sand body obviously dominated by sedimentary facies distributes in the direction of northeast-southwest.The characteristics of reservior of Chang6 in study area show the medium-high maturity of sandstone components and textural maturity of clastic component,and good reservoir physical property.The major types of porosity are corrosion pore between grains?residual corrosion pore between grains and corrosion pore in grains,but microcrack is seldom.Porosity has good correlation withpermeability.It showsthe characteristic of pore reservoir.The research of factors and distribution of Oil Reservoirs,shows that the chief oil reservoir type of Chang-6 is lithologic reservoir which have good lithologic trap condition.Obviously and universily the reservoir is controlled by nose structure which is the importance factor of high production of oil pool.