Research Institute of Exploration and Development��PetroChina Daqing Oilfield Company Ltd��Daqing 163712��Heilongjiang��China

In Bayanhushu sag of Hailaer Basin��developed three sets of source rocks��including the first member of Damoguaihe Formation��and the first and second members of Nantun Formation�� The analysis on the source rocks of drilled strata in 7 wells in the studied area shows that the source rocks in the three members are widely distributed with a high abundance of organic matters��and the types of organic matters are mainly type I and II 1�� which reach to the standard of good source rocks with great difference of maturity�� The three sets of source rocks in depression zone all belong to mature source rocks��although the dark mudstone in western steep slope is thick��the source rocks of the first member of Nantun Formation is matured only��the other two are immature and mid-mature source rocks effected by later tectonic events�� Through the analysis of chromatography and mass spectrometry and the contrast of biomarker��the oil in Nantun Formation mainly originated from the source rocks of the same formation�� which are autogenous oil-gas