Effect of silicone oil contamination on imbibition characteristics of liquid through porous media

Spontaneous imbibition is a common phenomenon in oil and gas reservoir extraction, environmental engineering and biomedicine. Studies generally assume that solid matrices possess smooth and clean surfaces. However, in most practical research scenarios, solid surfaces become contaminated, obscuring their inherent wettability. This research investigates the impact of silicone oil contamination on spontaneous imbibition characteristics. Spontaneous imbibition experiments were conducted using microporous filter membranes under silicone oil contamination. The results indicate that silicone oil contamination significantly prolongs the complete saturation time. Compared to uncontaminated membranes, contamination for 5, 10 and 15 days results in an increase in saturation time of 37.5%, 68.75% and 112.5% respectively. The spontaneous imbibition dynamics under silicone oil contamination still follow the form of the classical Lucas-Washburn equation. Calculations show that the contact angle increases with the duration of contamination, indicating a decrease in wettability. A novel theoretical model based on the Lucas-Washburn equation is established to describe the imbibition dynamics under silicone oil contamination. The conclusions drawn from this study are of significant importance for understanding and improving the performance of paper-based microfluidic devices in contaminated environments, enhancing the efficiency of oil and gas reservoir recovery, and assessing the accuracy of groundwater monitoring under contaminated conditions.