An investigation into the electrical behavior of oil/water/reservoir rock interfaces: The implication for improvement in wettability prediction

• A simple method is proposed for prediction of wettability and contact angle.
• ​Electrical nature of oil/water and rock/water interfaces significantly impact the wetting behavior.
• ​Constant electrical potential at rock/water interface resulted in the best predictions.
• ​Constant electrical charge at oil/water interface resulted in the best prediction.

Wettability and contact angle are crucial factors in oil and gas industries. They have essential influences on oil recoveries and fine migration. Therefore, their reliable predictions are of great importance. We have designed a set of experiments to measure different properties of oil/water and sand/water interfaces at different pHs and salinities. Zeta potentials of the both interfaces as well as interfacial tensions of oil/water interface have been measured using electrophoresis and Du Noüy ring methods, respectively, at different aqueous solutions. Disjoining pressure (sum of double layer, van der Waals, and structural forces) between the interfaces was calculated for each aqueous solution. Contact angle and wettability of each aqueous solution were calculated using augmented Laplace–Young equation. Adhesion tests and contact angle measurements were used to check the validity of the results. Comparing experimental and predicted values indicated the poor capability of simple DLVO model in prediction of contact angle. We thoroughly investigated different factors and assessed their importance in improving the predicted data. Considering effective factors, a new model was proposed. The results show noticeable enhancements in wettability, contact angle, and adhesion predictions.

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