Comparison Between SCAL Measurements and Pore-Scale Network Models for Neutrally Wet Sandstone on Two-Phase Oil-Water Empirical Correlations and Petrophysical Properties

Secondary oil recovery by waterflooding is usually achieved in neutrally and water wet reservoirs. Special core analysis (SCAL) data are difficult to obtain and expensive, we therefore generate experimentally-derived petrophysical correlations based on SCAL experiments conducted on neutrally wet sandstone in order to further understand maximizing oil recovery. The key objectives of the present study are to obtain and analyze the possible relationships between the reservoir petrophysical properties that are essential for reservoir simulations. The experimentally obtained petrophysical parameters and generated relationships are compared versus the prevailing initial water saturation, absolute permeability and wettability. Experimental results are then compared with network modeling results from the literature. Network modeling is a promising tool that has many usages including the convenient estimation of capillary pressure, relative permeability and residual oil saturation that would otherwise be obtained through lengthy and expensive SCAL experiments. However, network modeling predictively has been questioned in terms of making a full priori prediction of multiphase flow properties in mixed and neutrally wet systems as true representation of pore geometry and wettability are most challenging. Scaled, two-phase oil-water system, endpoint relative permeability was found to be linearly and strongly correlated to wettability. Residual oil saturation, however, was found to be curvilinear upward correlated to Amott-Harvey wettability. Comparing the experimental results of the present study with previous network model results, limited agreement was observed. Disagreement was mainly due to pore space wettability misrepresentation in network models. The representation of neutral wettability is the path towards more realistic physical description of pore-scale multiphase flow since most reservoirs tend to show some degree of neutral wettability.