**Abstract**

 Traditional wettability measurement practices, introduced as early as the late 1950s, are still perceived as reliable industrial methods for characterizing wettability. These techniques, in contrast to the contact angle method, provide indices that can quantitatively describe the degree of wetting state. Nevertheless, these approaches can determine the current state of wettability, subject to limitations. By employing the zeta potential measurements technique, a complete wettability profile is derived. In this chapter, the theory behind this technique is discussed. A case study is presented where the wettability of limestone rock is investigated, as crude oil and asphaltenic solutions of varying concentration are added to the limestonewater suspension. Findings of this study are discussed with the possible mechanism in effect when wettability alteration is observed.

**Keywords:** zeta potential, water-wet, oil-wet interfaces, calcium carbonate, asphaltene
