Wettability is an indication of relative adhesion of fluids to a solid surface. In a system including several fluids, the fluid with less contact angle, spreading more on the surface, is considered as the wetting phase of the system. In pore system the wetting phase occupies the small pores and coats the surface of the larger pores with a thin film. Ultimate recovery and relative permeabilities of a reservoir greatly depend on the wetting behavior of the rocks. Modifying the wettability of a reservoir affects the production rates, production fluid ratios and the residual saturations. By adjusting the wettability of a system, a higher recovery factor can be achieved. Wettability alteration is necessary for preparing the cores and samples for experimental studies as well. There are several methods for wettability alteration among which, some are applicable only in laboratory scales while some are feasible in large scales as well. Using nano-materials for alteration of wettability is a new method which is focused on, after the development of the techniques for synthesizing nano sized particles in late 1980s. In this paper, after mentioning the fundamentals of wettability alteration, a review study is done on the nano materials which are used for wettability alteration. Among these nano-materials nano particles of silica and polysilicone indicated better results, in terms of efficiency on incremental oil recovery in water flooding, and therefore a more detailed description on these materials is mentioned in this paper.

You can access this article if you purchase or spend a download.