Abstract: The distribution characteristics and factors of reservoir movable fluid saturation in different diagenetic facies of Chang 6 in Jiyuan oilfield are analyzed by using high pressure mercury injection, constant mercury injection and nuclear magnetic resonance. Results show that: (1) there are three significant types of diagenetic facies in research area, including the chlorite cementationresidual intergranular pore facies, feldspar corrosion facies and kaolinite cementation facies, whose microscopic porethroat structure have remarkable difference, especially in throat. (2) Analyzed from T2 spectrum that the porethroat of cementationresidual intergranular pore facies reservoir is welldistributed, good connectivity, and percent of movable fluid saturation is high. The porethroat of feldspar corrosion facies reservoir is poorer than cementationresidual intergranular pore facies reservoir, and the percent of movable fluid saturation is middle. The porethroat of kaolinite cementation facies reservoir is simplification and small, and the percent of movable fluid saturation is the lowest of all. (3) The main controlling factors of movable fluid saturation in different diagenetic are porethroat radius, mainstream throat radius, porethroat radius ratio, significant porethroat volume, and permeability is one of important factors influencing movable fluid saturation. Another adverse factor is the increase content of kaolinite and illite

Key words: Jiyuan oilfield, Chang 6 reservoir, diagenetic facies, movable fluid, microscopic porethroat structure, throat