The researchers analyzed sedimentary microfacies in the Sartu oil-bearing layer in the Songliao Basin using core, logging, seismic, and grain size data. They found two main types of sedimentary facies: lacustrine and gravity flow. Lacustrine facies consist of shallow lake subfacies with mud and sand mixtures, while gravity flow facies include channels and fans. Areas with gravity flow facies are good for forming oil pools.