Pore characteristic was drawn from thin sections of dye casted sandstone samples using an image analyzer. Pore size distribution of the sample and its characteristic values were obtained with section-chord technique.
The following items have been obtained from the samples studied:
The same core sample may have different curves of throat size distribution and the pore size distribution. For the two samples with basically identical throat size distribution curves, their pore size distribution curves may be different. And for the two samples with basically identical pore size distribution curves, a large difference between the two throat size distribution curves may occur. Therefore, pore size, throat size and their distributions must be studied simultaneously in order to have a complete study on pore structures.
The throat diameters have a larger effect on permeability than those of pores. Pore and throat sizes as well as their sortings almost have no effect on porosity.
Water displacement recovery efficiency is affected by both pore and throat sortings, however, pore-to-throat size ratio has even larger effects on the recovery efficiency. The smaller the pore-to-throat size ratio is the better the pore and throat sortings, and the higher the recovery efficiency will be; and vice versa.