The researchers studied the sedimentary microfacies of sandstone Group I in the Sartu oil-bearing layer at Yueliangpao area in the South of Songliao Basin. They used logging, geological, and seismic data to analyze the distribution of river sandstone bodies. The sandstone Group I of Sartu reservoir is found to be delta front sedimentary, with major sand bodies consisting of underwater distributary channel, mouth bar, and bays between distributary channel sedimentary microfacies. The distributary channel sand bodies are identified as favorable areas for oil and gas accumulation, especially when combined with structural development.