Analysis of pore size distribution and fractal dimension in tight sandstone with mercury intrusion porosimetry

Abstract

The pore size distribution (PSD) and fractal dimension of tight sandstone are studied with mercury intrusion porosimetry (MIP). Four different fractal models are used to calculate fractal dimensions from mercury intrusion capillary pressure (MICP) and mercury extrusion capillary pressure (MECP) respectively, and the physical meanings of the fractal dimensions calculated from different fractal models are discussed. The fractal characteristics of tight sandstone pore spaces with unimodal and bimodal PSD are compared. The correlations between fractal dimensions and tight sandstone petrophysical properties are researched, and the optimal fractal model for formation evaluation is recommended. Finally, the key parameters influencing tight sandstone permeability are investigated. Keywords: Tight sandstone, Pore size distribution, Fractal dimension, Permeability, Mercury intrusion, Capillary pressure