Abstract: By the analysis of large number of sample mercury injection capillary pressure data, it is found that capillary pressure curve shows distinct hyperbola characteristics under log-log coordination, and any capillary pressure can only be determined by three parameters, Ps, S and Fg. The apex of hyperbola shows the situation where non-wetting phase completely occupy the effective pore volume controlling fluid flow. The absolute permeability of reservoir rock is determined by the parameters about position and shape and apex of hyperbola. The estimating model of rock absolute permeability is established successfully by position-shape and apex parameters respectively, and its reliability has been proved by plenty of measured data.

Key words: reservoir, absolute permeability, capillary pressure, estimate, model