Research on correlation between capillary pressure and resistivity index based on fractal theory

Key words:  pore struclure  fractal theory  semi-permeable plate  capillary pressure  resistivity index  con etation theory

Abstract:

The theoretical model of capillary pressure and resistivity index was established based on fractal theory of por? structure. The semi-pertneable plate resistivity-capillary pressure experiments were conducted to verify the relationship between capillary pressure and resistivity index. The results show that the capillary pressure and resistivity index has a power function relationship and the fitting exponent between capillary pressure and resistivity index has a nice coherence with pore structure index for shaly saild cores studied in the experiment when its porosity ranges from 12. 9% 1o IB. 1% and permeability ranges from 0. 313xlO_3(jLm2 to 21. 196xl0"3|xm2. The correlation chart between water saturation variation ratio and resistivity index is similar with pore throat radius distribution histogram. Capillary pressure is one of the most important parameters for pore slruclure characterization. The impact of pore structure on conductivity property should bs considered when using litho-electrical experiments .data for well logging analysis and formation evaluation.