Study on Sedimentary Microfacies of the N_2~2 Reservoir and Its Implications for Oil in the Huatugou Oilfield

Huatugou oilfield is located in the western Qaidam basin,and N22 reservoir is the research area in the upper part of an oil bearing intervals,the current trial mining development.Therefore,understanding the types and characteristics of the sedimentary microfacies,sedimentary microfacies plane,vertical distribution,exploration of the relationship between the sedimentary microfacies and oiliness has guiding significance to the exploration and development.Comprehensive analyses of the core,grain size,lithology,well logging reveal that the reservoir section of the delta plain subfacies is subdivided into 3 types of sedimentary microfacies including distributary channel,floodplain and river flood plain.Analysis of sedimentary microfacies of plane and longitudinal distribution has been performed.Based on the coring oily and oil testing,test mining information on the foundation,relationship between the three sedimentary microfacies and oil-bearing property are explored.Our results show that reservoir branch channel and floodplain depositional microfacies have certain industrial oil flow,which is the main objective for further exploration.