STUDY ON SEDIMENTARY FACIES OF CHANG 6TH RESERVOIR IN THE EAST OF GANGUYI OILFIELD,ORDOS BASIN

The analysis of massive core samples,logging data and chemical materials reveals the depositional characteristics of sand groups,the rule of depositional microfacies distrubition in plane,and the existence of the secondary mineral of glauconite in sandstones and siltstones.The Chang 6th reservoir of eastern Ganguyi Oilfield,northern Shaanxi develops a set of deltaic front sandstones instead of deltaic plain subfacies.Deltaic front includes river mouth bar,far sand dam and branch bay microfacies.With macroscopic depositional settings and microscopic depositional characteristics into consideration,a depositional mode of the research area is established according to the evolving rule of sedimentary facies,which is significant for planning the water-injection development of oil-gas fields.