Role of Rock Wettability on Relative Permeability and Capillary Pressure Behavior

Rock wettability is one of the factors that affecting flow mechanism of reservoir, such as relative permeability and capillary pressure. These properties are important to determine the effective production and choose the suitable recovery methods of the reservoir. This paper will discuss the studies done on wettability of carbonate rocks, in order to differentiate and analyze the flow properties hysteresis when the wetting phase of the rocks are different.
Analysis on capillary pressure for different wetting phase shows different hysteresis on the curve and wettability index, which ranged between -0.85 to +0.35. Observation of Lambda from the graphs, also show the irreducible water saturation values and can identified the type of the sand reservoir and permeability. Moreover for relative permeability curve, it shows also different trend for different wetting phase, although the hysteresis did not satisfy all Craig’s rule of thumbs. The difference of hysteresis in different cores samples show that for improvement of production, water-flooding is better to be used in water wet condition and in order to have better accuracy, measurement with solely method is not sufficient.