Prediction of CO2/water/quartz wettability behavior during CO2 storage in deep saline aquifers

In the context of geological CO2 sequestration projects, CO2/water/rock wettability directly affects the capacities of residual and structural trapping mechanisms. Therefore, presenting an accurate model that can simulate the wettability behavior of CO2/water/rock under different environmental conditions is necessary. In this study, a new model based on adaptive neuro-fuzzy interference system (ANFIS) was developed for estimation of CO2/water/quartz contact angle as a function of influencing parameters, such as pressure, temperature, salinity, and salt type. Results of the proposed model were compared to the actual data and it was found that the presented model has immense potential with high correlation coefficient (R-2) of 0.991 and average absolute relative error (AARE) of 2.010 for predicting the CO2/water/quartz contact angle. Finally, a sensitivity analysis was performed on the influencing factors. Results of this analysis demonstrated that salinity and pressure have the highest impact on the wettability of CO2/water/quartz.