Research On The Oil And Gas Reservoir And Pathway Systems In Y Anchang Group Of Huaqing Area,Ordos's Basin

Low permeability reservoir which is located in Huaqing area is the main block of oil reserve and production in Changqing Oil field.In this thesis,we do the research about the low permeability reservoir's genetic types,characteristics,pathway systems,migration and accumulation of oil and gas as well as the dominant factor which affect tight sand reservoir,understand the regularity and mechanisms of forming low permeability reservoir,and verify the distribution of oil in Yanchang Group of this area.All of these provide reliable scientific guidance and technical support for further exploration.Using geological,drilling,well logging,well testing data,we analysis connectivity and development law of fissures in sand and discuss the type of pathway system,development law of superiority migration pathway in Yanchang Group of reserach area.We use reservoir geochemistry methods such as crude oil reservoir,fraction(fraction of saturated hydrocarbons,aromatic hydrocarbons),carbon isotope,parameters of Nitrogen compounds and Hydrocarbon inclusions and other applications to verify the characteristics,paths,direction and trend of lateral and vertical migration of crude oil of low permeability reservoir in Huaqing area.By the means of reservoir geochemistry,comprehensive analysis of geological and reservoir geological section,we do comprehensive research of the main pathway systems of oil migration in research area.After study the hydrocarbon source kitchen of the low-permeability reservoir,geochemical characteristics of crude oil,regular pattern of petroleum migration and accumulation and the accumulation period comprehensively,we analysis distribution characteristics,regular patterns and the controlling factors of low permeability reservoir,create reservoir forming mode,and predict favorable zones.The reservoir sands in Huaqing Area are developed by variety of causes.Chang 6 area developed delta and gravity flow deposits.Chang 8 area developed shallow water delta deposits.Distribution of relatively high permeability reservoirs are controlled by sedimentation and diagenesis.Favorable sedimentary facies is the basis for the formation of relatively high permeability reservoirs;favorable diagenesis is a key factor which controls the relatively high permeability reservoirs.In this area,relatively high permeability reservoirs are developed in chlorite-feldspar dissolved pores diagenetic facie.Huaqing Area developed many kinds of pathway systems.Yanchang Group mainly developed three types of pathway:connected sand body,fractures and kerogen network.The important means of migration and accumulation of oil and gas in this area is vertical migration in close distance.