Abstract: Donghe sandstones of Carboniferous,as reservoirs in Tazhong 16 oilfield,are associated with a large amount of fluid inclusions in the process of pool forming with the hom- ogeneous temperatures in the intervals 87.2-101.3℃and 120.43-143.6℃,which indicate two pool forming stages and depths.According to the buried history,the thermal evolvement history and the evolvement history of reservoirs, it is conferred that the first stage for reservoir forming was generated in Jurassic,and the second stage was occurred in Tertiary and was preserved by now.Study on diagenesis in- dicates that the pool forming periods and depths of the two stages were consistent with the conclusion resulting from the fluid inclusions,which suggests that it is feasible to analyze homogeneous temperatures of organic inclusions to define pool forming stages.