Abstract: Pore structures in reservoir rocks possess good fractal characters. The fractal dimension of pore structure can be used to qnantitatively describe its complexity and variation. Its distribution accords with its log normal distribution. This paper establishes a fractal characterization method of probability density function of pore size distribution by applying fractal geometry principle, according to the fractal geometry model of pore distribution and capillary pressure curves,which allows the conventional qualitative description to tnrn into quantitative estimation of the pore sized distribution. The estimation shows that this method is easier for use and higher in accuracy.

Key words: reservoir, pore structnre, fractal geometry, rock, probability, distribution