Understanding Wettability of SiO2-Brine-CO2 System Using Modified DLVO Theory and its Applications in Carbon Geo-Sequestration Processes

Abstract

Abstract The reduction of Carbon footprints without hindering the evolution of the fossil fuel industry is the subject of prominent attention and research these days. In multi-phase rock-fluid systems, the wettability characteristics play a substantial role in determining the trustworthiness of underground reservoir formations for holding CO2 in situ for Carbon Geo-sequestration applications. Despite several struggles over the modern years in recognizing the aspects such as the information on the wettability of systems comprising CO2 under supercritical conditions and the zeta potential over the brine- CO2 film interfaces, inferring the wettability of the complete arrangement are crucial uncertainties and voids in our existing knowledge. Again, one needs to deal with the concepts of wettability and capillary pressures to understand the suitability of a formation for carbon sequestration. This study focuses on the sequestration of carbon in deep saline brine reservoirs. Under the intense pressure and temperature situations in these formations, CO2 can exist in a supercritical state and thus have a liquid-like density, enabling efficient utilization of the pore spaces in those formations. In this research, a mathematical model based on the modified DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory is designed to provide a better insight into the wettability of supercritical CO2 systems by utilizing fundamental principles to evaluate contact angles. The base model has been modified in the course of the study to accommodate for the properties of supercritical CO2. This model can also take up the experimental contact angle measurements as an input to anticipate values of critical properties that are presently unfamiliar, as they are challenging to analyze, such as the zeta potential on brine- CO2 interfaces. This model could also predict the suitability of geological reservoirs for carbon sequestration by evaluating the wettability under known conditions.