Previously proposed models of wettability change have not been tied to the chemistry that controls wettability but instead were driven by simplistic criteria such as salinity level or concentration of an adsorbed species. In this paper, after testing proposed models in the literature on sandstones and carbonates, the authors propose a mechanistic surface-complexation-based model that describes observations quantitatively for ionically treated waterfloods. To the best of the authors’ knowledge, this is the first surface-complexation-based model that describes fully ionic compositional dependence observed in ionically treated waterfloods in both sandstones and carbonates.
Introduction
While some debate remains about the underlying mechanisms of ionically tuned waterflooding, the geochemical reactions that control the wetting of crude oil on the rock surface are likely to be central to a detailed description of the process. Models of wettability change often have been simplistic and not tied to the chemistry that controls wettability, instead driven by a simplistic criterion such as salinity level or concentration of an adsorbed species.
