| The Wulanhua sag is a newly discovered oil-rich sag in the southern part of the Erlian Basin in recent years, but there are obvious differences in proven petroleum resources in the south and north sub-sags. In order to accurately evaluate the petroleum resource potential of the Wulanhua Sag, the characteristics of source rock kitchens in the Wulanhua Sag were systematically analyzed, and the relationship between source kitchens and petroleum distribution was discussed. Studies show that source rock contains organofacies C, D/E and F. Organofacies were primarily controlled by tectono-stratigraphy evolution of the sag. The development of high-quality oil-prone source rock (organofacies C) in the south and north sub-sags shows significant differences. In the south sub-sag, organofacies C mainly occurs in the Aershan formation (k1ba), and the source rocks in the first member of the Tengger formation (k1bt1) mainly consist of organofacies D/E. However, organofacies C occurs in both k1ba and k1bt1 in the north sub-sag. Thermal history calibration results of many wells indicate that the maturity threshold of the source rock in the Wulanhua Sag is approximately 2000 m. According to this rule, only the source rock in k1ba in the south sub-sag have entered the mature stage. Oil expelled from organofacies C in the k1ba is 0.5-7.9 mmt/km2, which makes a major contribution to proven oil accumulations. However, organofacies C is mainly developed in the upper part of the k1ba in the north sub-sag with lower maturity, and the maximum value of thermal maturity is only 0.78 %Ro. The hydrocarbon expulsion intensity of source kitchen is less than 0.2 mmt/km2 in the north sub-sag and not enough to form oil accumulation. The proven oil accumulations in the Wulanhua Sag are all located in the south sub-sag, and concentrated around the source kitchens, indicating efficient the accumulation of nearby source kitchens. |