SEDIMENTARY MICROFACIES STUDY OF CHANG 21 SECTION IN PENGTAN-YANGJING DISTRICT, ORDOS BASIN
鄂尔多斯盆地彭滩-杨井地区长21层段沉积微相研究

By analyzing the data of drilling cores, costing thin sections, image granularities as well as logging, it indicated that deltaic-plain meandering river deposition is the main sedimentary system of Chang 21 in Pengtan-Yangjing district. This text marks off six microfacies such as upper-river channel, crevasse, overbank, overbank-splay, overbank-marsh and lake microfacies. And the upper-river channel sandbodies were developed widely. The evolution and the distribution of the microfacies in every number have been studied,and also builted the deposition model. The accumulation of oil and gas are controlled by microfacies. The upper-river channel deposit of Chang 21 is the good reservoir, and also is the direction of the developing in.