MICROFACIES CHARACTERISTIC OF YANCHANG FORMATION IN ANSAL DISTRICT
安塞地区延长组沉积微相研究

According to the outcrops observing and the cores describing, Yanchang formation has been classified 9 petrology facies and 6 petrology facies units. On the basis of establishing the model between petrology and electricity, the types of the electrofacies have been analyzed. Connecting the petrology facies with the electrofacies, the types and the characteristics of the sedimentary microfacies in Yanchang formation have been studied. It indicated that Chang 2 belong to the braided river facies, Chang 3 and Chang 10 are the meandering fluvial facies, Chang 9,Chang 7 and Chang 4+5 are lacustrine facies, while Chang 6 and Chang 8 are front-delta facies. The sand bar microfaces and the distributary channel microfaces are the good reservoir. They led to the directions of oil and gas exploration and development.