Quantifying Wetted Area during Multiphase Flow in an Oil Reservoir

Wettability of reservoir sediments is generally quantified using contact angle, which is importnt for reservoir characterization for enhanced oil recovery. Contact angle measurement, Amott Harvey index and USBM method are used to quantifying wettability. These methods does not account for heterogeneity of an oil reservoir and are performed at much smaller scale than an oil reservoir. In this work, we develop a method of quantifying wettability in a heterogeneous, large scale porous medium. We use dual tracer experiments to quantify the water and oil wetted surface area of a porous medium. We use two tracers for phase, one tracer being an ideal tracer and follows oil or water flow in the reservoir. Another tracer we use is an adsorbing tracer, which dynamically adsorbs and desorbs on the porous surface surface. We conduct the experiments at various saturations of the liquid and various wettability conditions. Using the contact area with the sediments vs. saturation curves we develop a method to quantify wettability in terms of the wetted area. The new quantification of wettability compares well with other quantification methods. This method can be done during the ongoing production from the reservoir and takes into account the heterogeneity of the porous surface.