The invention provides a method for determining the
pore diameter lower limit and the effective pore volume ratio of movable fluid. The method comprises the steps that the temperature of each sample under the stratum in-situ condition is calculated according to the
ground temperature gradient and the burial depth; correcting the
surface tension coefficient of the water by using the calculated temperature; determining an average
contact angle of water and shale; calculating capillary force, enabling the capillary force to be equal to
reservoir fluid pressure, and calculating the
lower limit of the aperture of the movable water; carrying out
carbon dioxide adsorption,
liquid nitrogen adsorption and mercury injection experiments on the sample to obtain
connectivity pore volume-pore size distribution, and calculating effective pore volume in combination with a movable water pore size
lower limit; carrying out a low-field
nuclear magnetic resonance experiment, calculating the total pore volume of macropores, obtaining the total pore volume of small pores in combination with a
carbon dioxide experiment, and finally calculating the total pore volume; and calculating the pore volume ratio of the effective pores by using the pore volume of the effective pores and the total pore volume. According to the method, the evaluation precision of the lower limit of the
pore diameter of the shale reservoir movable fluid and the pore volume ratio of the effective pores is effectively improved, and the test cost is reduced.