Study On The Petroleum Occurrence Regularity Of The Chang 2 Strata In The Well Geng 19 Area Of The Jiyuan Oilfield

The study area is located in the Jiyuan Oilfield between the North Shaanxi Slope and the Tianhuan depression in the Ordos Basin.It is a oil abundance zone with multiple reservoirs.With the continuous deepening of Changqing Oilfield's exploration of petroleum resources in Jiyuan oilfield,the proportion of low permeability reservoir development is increasing,The confusion of the micro-geological conditions and the oil reservoir distribution laws will directly affects and limit the stable ans high production.Based on the previous research results,this paper according to the main tasks and problems of the area,the data such as drilling cores,test and analysis,logging and well log was comprehensively used in this paper,with methods and theories of sedimentology,stratigraphy,reservoir sedimentology and petroleum geology,we carried out the fine reservoir description of the petroleum occurrence regularity of the Chang 2 strata in the Well Geng 19 area of the Jiyuan Oilfield,on the basis of the fine stratigraphic contrast,starting from the structure,sandstone,sedimentary facies and reservoir in the study area,sedimentary facies,reservoir,controlling factors of hydrocarbon accumulation and enrichment regularity of oil reservoirs in systematically.The main factors controlling the reservoir Chang 2 enrichment,provide the basis for further optimization of the target prediction,and to provide a reliable theory and technic support which the oil field could depend on in future development.The research shows that the Chang 2 belongs to the delta plain distributary channel sedimentary environment,the lithology is mainly composed of gray,grayish green,medium grained feldspar sandstone and lithic feldspathic sandstone,and the sandstone has low mineral maturity and better structural maturity.Because of the difference of sedimentary microfacies and diagenesis,Chang 2 reservoir has relatively good physical characteristics.The sand bodies on the plane are northeast-southwest.The study of Chang 2 oil and gas accumulation regularity shows that the plentiful hydrocarbon source rocks in the study area is the matetial foundation of the lithologic deposit,Sand body in distribution channel is a important palace for storing oil and gas,nosing structure controls the distribution of oil and gas,stability distribution of argillaceous sediment conposes favourable district cpvers,sedimentary facies and structure and the development of fracture in the region play a dominant role in oil storage and migration.the Chang 2 reservoir is mainly made up from three types: lithologic reservoir,tectonic-lithologic reservoir and unconformable screened reservoir,The plane has the characteristics of small distribution area and poor continuity of the oil sand body.Based on the Study of petroleum occurrence regularity in the Chang 2 strata,there are 25 favorable targets in this area,thirteen?type favorable construction regions,twelve ? type favorable construction regions.