Sedimentary characteristics and evolution during Upper Triassic Chang 6 stage in Yan'an Area

According to analysis results of logging curve and cores in Chuankou oilfield,the study area's rock-logging model of Chang 6 is established.Moreover,the sedimentary facies and evolution model are also established through analyzing sedimentary evolution processes,logging and physical characters,the geometry form of sandbody framework.A conclusion is got that the facies of lake,delta front and plain and river appear in turn.The intervals of Chang 6₁ and Chang 6₂ are the main oil-bearing intervals and their characters are the best among 4 oil-bearing intervals of Chang 6.