The reservoir's wettability can be determined in the displacement experiment of oil and water with the natural sandstone micromodels.A lot of information is used in the experiment.Some details should be noticed:1.the reliability of the natural sandstone micromodels and the experimental fluid should be noticed

and various factors that may probably effect the reservoir's wettability should be considered in making the model;2.the wettability determining methods should be correct.When using the distribution state of oil and gas to determine reservoir wettability in displacing oil by water or after the displacement

other methods should be synthesized;when using the interface of oil and water to determine reservoir wettability

the interface in thick and thin pore passages should be observed together

and the affection of wettability hysteresis should be avoided;when using the automatic suction quantity of oil and water to determine reservoir's wettability

it should be carried out under the similar fluid state in pore space.