Abstract
The wettability characteristics of a porous medium play a major role in a diverse range of measurements including: capillary pressure data, relative ^rmeability curves, electrical conductivity, waterflred recovery efficiency and residual oil saturation. This study descritos the development and implementation of a pore-scale simulator capable of modelling multiphase flow in porous media of nonuniform wettability. By explicitly incorçxrating pore wettability effects into a steady-state mtoel, it has toen ^ssible to explain many experimental observations from a microscopic standpoint.
Results are presented which show how a (the fracrion of pores which are assigned oil-wet characteristics) affects resulting capillary pressure and relative Jtermeability curves. Simulated capillary pressure data demonstrate that some standard wettability tests (such as Amott-Harvey and free imbibirion) may give spurious results when the sample is fractionally-wet in nature. The corresponding relative pemeability curves have been used to calculate waterflood displacement efficiencies for a range of wettability conditions, and recovery, is shown to to maximum when the oil-wet pore fraction approaclies 0.5.
Furthermore, a novel test is promised which could to used to determine the wettability of both fractionally-wet and mixed-wet jxrrous media. To date, no such satisfactory test exists.
