Wettability of rock/fluid systems is an important physicochemical parameter that significantly influences the fluid distribution and flow behavior in hydrocarbon reservoirs. A precise characterization of rock wettability at the relevant thermophysical conditions is thus essential for important subsurface applications including enhanced oil recovery and CO2-geoseuqestration. Wettability of rock/fluids systems is a function of operating conditions, such as pressure, temperature, and salinity. Furthermore, wettability is also strongly influenced by rock surface roughness and mineralogical heterogeneity of the sample surface. While a notable literature has investigated the wettability dependence on operating conditions (e.g., pressure and temperature), the dependence of wettability on rock surface roughness and mineral heterogeneity has not received much attention and thus remain poorly understood. In this context, there are preliminary investigations that suggest an increase in surface hydrophilicity with increasing roughness; however, the current available literature is limited to pure mineral samples only.
Furthermore, and importantly, the carbonate family of rocks are typically:
We hypothesize that such wide variations of wetting behavior in carbonate rocks may be related to the millimeter-to-micrometer-scale surface roughness and the hectometer-scale mineralogical heterogeneity. To this end, rock surface roughness will be characterized by the in-house available atomic force microscopy measurements, and wetting will be characterized by experimental contact angle measurements on carbonate rock surfaces. It is expected that this research will significantly enhance our scientific understanding of the rock wettability variations and the associated multiphase flow mechanism in the porous medium; and the results of the study will be of interest to a broader scientific community.