Sedimentary microfacies of Qingshankou Formaiton, West-Yao block, Yaoyingtai Oil Field, Changling Sag, Songliao Basin

Based on the studies of core samples and well-logging data from the West-Yao block of the Yaoyingtai Oil Field in the Changling Sag of the Songliao Basin,combined with seismic fine interpretation,guided by sedimentary theory,the types of sedimentary facies of the Qingshankou Formaiton were classified,and the subfacies and microfacies were also divided.15 sandbodies(2-4 m thick each layer) from Q1-Ⅱ and Q2-Ⅳ were described,and the division characteristics of sedimentary microfacies of each sandbody were concluded.The sedimentary microfacies of Q1 and Q2-Ⅳ reservoirs are mainly underwater distributed channels in delta front,and debouch bar was less popular.Channels in each layer overlap each other,yet the channel width is only 200-300 m.The studies of sedimentary microfacies of thin layers are significant for oilfield well arrangement and development performance improvement.