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Reservoir Characterization |
Amoco Exploration and Production Technology Group, 4502 East 41 Street, Tulsa, OK 74135-2500, USA
Knowledge of three-phase relative permeability is important to the successful design of many types of improved oil recovery projects. An extensive experimental study was made of three-phase relative permeability in water-wet, intermediate-wet and oil-wet rock. The data obtained in this study are the only complete relative permeability data set for rocks which are not water-wet.
The study confirms the commonly held assumptions about the relative permeability behaviour of wetting and non-wetting phases. Phase saturation and the saturation history (the path by which a particular saturation condition is reached) are major factors in determining relative permeability. In general, the more wetting a phase is, the more nearly the relative permeability of the phase depends only on the saturation of that phase (regardless of saturation history). The relative permeability of the non-wetting phase depends largely (but not entirely) on the saturation of the phase and on the saturation history. The relative permeability surface of an intermediate-wetting phase is affected by the saturations of all phases, particularly when one of the phases is strongly wetting.
Three-dimensional plots of the phase relative permeability surfaces show smooth variation of relative permeability with saturation and with saturation history.
The study provides much new data and guidance for developing and testing theoretical models of three-phase relative permeability. Examples of currently used correlations (Stone’s methods 1 and 2) and a linear interpolation relative permeability correlation are compared to the experimental results.
