Study on Sedimentary Facies in Chang8-9 of Yangchang Formation,Upper Triassic in Hu Jianshan Area,Ordos Basin

The Hujianshan Area is dominated by fluvial and lacustrine-fluviolacustrine delta sediments in Yanchang Formation,which locates in the south extensional of delta system of Anbian.The types of sedimentary facies were identificated through core observation and description,data of log,lithology,and experimental analysis in Chang8-9 of study area.Confirm that lacustrine-delta depositional system is largely developed,and delta front subfacies is predominance.Due to the weaker tectonic movement in study area,distribution of sand controlled by sedimentary microfacies is very important to distribution and enrichment of hydrocarbon.Therefore,the favor reservoir can be indicated by correct subdivision of sedimentary facies.