Abstract: According to a large number of data about core observation, thin section analysis and reservoir properties, systematic study is conducted on diagenesis type and diagenetic sequence, pore types and diagenetic pore evolution, major controlling factors of reservoir properties of Fuyu oil beds in Zhaoyuan-Taipingchuan Area of Songliao Basin. It is indicated that silicate dissolved pore developed well in sandstone reservoir in Sanzhao sag. Secondary pore belt is also found, of which the contribution rate to porosity may reach 10%. This leads to the development of two types of sandstone reservoir: one is the residual primary intergranular pore reservoir which is distributed in Changchunling anticline belt, Chaoyanggou sidestep, Taipingchuan and Shangjia structures; the other is a mixture of residual primary intergranular porosity and secondary dissolved porosity which is distributed in Sanzhao sag. The lower limit of effective reservoir is raised by the development of secondary dissolved pore

Key words: Songliao Basin, Zhaoyuan-Taipingchuan Area, sandstone reservoir, diagenesis, reservoir prediction, residual primary intergranular pore reservoir, mixture of residual primary intergranular porosity and secondary dissolved porosity