The effects of rock/pore characteristics such as porosity, permeability, tortuosity, formation factor, wettability index, irreducible water saturation, and mercury porosimetry properties, on oil recovery (at breakthrough and floodout) have been investigated in linearcores. Berea sandstone cores were placed in horizontal position with their flood planes parallel to their bedding planes and oil displaced from them by brine at injection rate ranging from 1.20 cc/min to 7.90 cc/min. A scaling-coefficient (product of core length in cm, water velocity in cm/min and water viscosity in cp) of about 5.0 was maintained in each of the waterfloods.

A 10 cp (at 35°C) binary mixture of refined oils, and twenty-one sandstone linear-cores ranging in length from 7.3 to 52.1 cm and diameter ranging from 3.79 to 3.88 cm were used for the study. For the waterfloods, the investigation was conducted at a temperature of 35°C and confining pressure of 500 psi. Six to fifty-four core plugs were extracted from each of the waterflooded cores for a total of 580 core plugs. The core plugs were further analyzed by conducting wettability and mercury porosimetry tests.

The results of the tests show that the core samples investigated were all water-wet and they all exhibited steep-concave unimodal pore-size distribution. Furthermore, the results show good correlations between waterflood sandstone oil recovery (at breakthrough and floodout) and porosity, permeability, formation factor, irreducible water saturation, pore intrusion volume, pore surface area, pore specific surface area, apparent (skeletal) density and mercury recovery efficiency. The accuracy of the oil recovery predictions by these newly proposed empirical models show encouraging results.

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