The establishment of correlations between the continuous phase change saturation interval (ds) and Archie variables "m" and "n" allow for a cost effective and quick method of obtaining critical data used in the formation evaluation of oil reservoirs. This is significant since the direct electrical measurements conventionally used to obtain these variables is both time consuming and expensive. Conventional mercury injection tests can be utilized to predict electrical parameters based on the porosity/permeability ratio of the rock sample.

The measurement of electrical properties were performed with a true four pole configuration at five different frequencies ranging from 0.5 kHz to 10 kHz. Continuous Resistivity and Capacitance Measurements have been accomplished under simulated net overburden pressure. Following the measurement of the fully brine saturated sample, the desaturation was initiated through a semi-permeable membrane without removing the sample. The Rock/Fluid equilibrium at each capillary pressure was determined based on a continuous resistance measurement and corresponding volume of expelled brine. Completing the resistivity measurements, samples were extracted and mercury was injected from low vacuum, 20 microns of mercury pressure, up to 4500 psi. Following the first injection cycle, mercury was ejected down to atmospheric pressure and then second injection cycle performed up to 4500 psi. The transient saturation between mercury and mercury vapor, where continuous phase changes take place, has been succesfully correlated with the electrical parameters.

The correlation developed between continuous phase change saturation interval (ds), and Archie's parameters exhibit two opposite trends based on the permeability/porosity ratio of the samples: (1) Both cementation factor and saturation exponent, for the group of samples with (k/ø) less than one are directly proportional with the continuous phase change saturation interval. (2) The group of samples having (k/ø) more than one display an inverse proportion between (ds) and Archie's Parameters.

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