Abstract: The development of coal-series oil source rock is found in Mesozoic of Yingjisu sag,Tarim basin, its , abundance can also be well correlated with that of neighbouring producing areas, including Kuche depression, TurpanHami basin and Yingjisu basin. There exist abundant or more abundant matrix vitrinites and resinites found in the carbonaceous mudstone and coal deposit. By inference, there might be a certain organic facies in the open waters in Jurassic, providing good hydrocarbon source materials. Because of very similar thermal evolution comparing the sag with Well Taican 1, Turpan-Hami basin, it is predicted that a vast body of hydrocarbon source rocks has come of age. Dilling reveals that Mesozoic in this sag have ever brought about large- scale processes of petroleum migration. Carbon isotope analysis shows that the oil and gas came from Trissic and Jurassic coal measure strata. In addition, its structural frame work is similar to that of Turpan and Kuche depression, with multiple sets of source-reservoir-seal assemblages and good matched relations among the reservoir-forming elements,in time and space sense, and favorable structural highs surrounding eastern Yingjisu deep-trough for further petroleum exploration. However, a certain risk should be paid attention to due to a small depth of the Mesozoic for this exploration.

Key words: Tarim basin, (Yingjisu sag), Mesozoic, Organic matter abundance, 0il source correlation, 0il and gas exploration, Exploration risk