Research on the Pore Structure Fractals of Capillary Pressure Curve of He8 Zone in Sulige

This paper discusses the fractal feature of pore structure based on the capillary pressure data of mercury withdrawal and mercury injection. Also, the paper calculates the fractal dimension of pore structure of He8 zone in Sulige gas field. The study results show that fractal feature of mercury injection capillary pressure curve has a property of two-stage with an obvious bend, which shows the double-porosity fractal. The fractal feature of mercury withdrawal of capillary pressure curve is single-stage. The measuring scale and measuring object have a good correlation property; Mercury injection fractal dimension De1, is closely related to slanting degrees and median radius. Mercury injection fractal dimension De2 doesn´t have any relation to other basic parameters. Mercury withdrawal fractal dimension Dr relates to permeability and mercury withdrawal efficiency. The study shows that, by the analysis of De1 and Dr which can have a good reflection of microscopic pore structure, a convenient and effective way is obtained for the research on the microscopic heterogeneity of reservoir pore structure.