The geological conditions of marine fluvial sedimentary reservoir are very complex.In the process of water flooding development

the remaining oil distribution is dispersed and it is difficult to develop due to different water absorption in the same permeability reservoir.In order to guide the exploration direction of remaining oil

in the later stage of each reservoir

the pore throat distribution characteristics and micro percolation characteristics of different permeability reservoirs are studied based on the micro pore throat scale by the mercury injection experiment and micro water drive visualization experiment.The results show that there is a good logarithmic correlation between the average pore throat radius and permeability

and the correlation coefficient is 0.963 5.With the increase of the reservoir permeability

the mean pore throat radius increases gradually

whereas the micro fingering phenomenon of water drive is reduced

and the water flooding process is gradually changing to finger-network-uniform displacement.Both the sweep efficiency and recovery efficiency of each model show an increasing tendency

and the proportion of continuous remaining oil is gradually decreasing.When the permeability increases to 2 228.7×10

-3

μm

2

both the sweep efficiency and recovery efficiency reach their maximum value

the for is 82.97%

the latter is 66.1%

and the proportion of continuous remaining oil reaches the minimum value of 45.82%.For the reservoirs with permeability of（73.1～1 005.2）×10

-3

μm

2

the main direction of potential tapping in the later period should be to increase the viscosity of displacement fluid and increase sweep.For reservoirs with permeability of（1 005.2～3 509.6）×10

-3

μm

2

it turns to be improving oil displacement efficiency.For reservoirs with permeability of（3 509.6～4 040.6）×10

-3

μm

2

it is appropriate to increase water injection pressure or block large water breakthrough channels to change the direction of injected water

so as to improve the conformance as the main direction of the potential tapping.