Deng Xiao, Kamal Muhammad Shahzad, Patil Shirish, Hussain Syed Muhammad Shakil, Mahmoud Mohamed, Al-Shehri Dhafer, Al-Shalabi Emad W
Department of Petroleum Engineering, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Saudi Arabia.
Center for Integrative Petroleum Research, King Fahd University of Petroleum & Minerals, 31261 Dhahran, Saudi Arabia.
ACS Omega. 2023 Mar 22;8(13):12069-12078. doi: 10.1021/acsomega.2c07906. eCollection 2023 Apr 4.
Interfacial tension (IFT) reduction and wettability alteration (WA) are both important enhanced oil recovery (EOR) mechanisms. In oil-wet formations, IFT reduction reduces the magnitude of negative capillary pressure, releasing trapped oil. WA changes the negative capillary pressure to positive conditions, helping the entrance of the aqueous phase, and the displacement of the oil phase. In most cases, IFT reduction and WA happen at the same time. However, studies regarding the coupled effect provided different, sometimes conflicting observations. It requires further study and better understanding. In our study, oil-aged Indiana limestone samples were chosen to represent oil-wet carbonate rocks. Static contact angle and spinning drop method were adopted for wettability assessment and IFT measurement, respectively. Spontaneous imbibition was adopted to reflect on the oil recovery mechanisms in different cases. The impact of IFT reduction, WA, and permeability on the coupled effect was discussed by choosing four pairs of comparison tests. Results showed that when the coupled effect took place, both a higher IFT value and a stronger WA performance resulted in faster and higher oil recoveries. The importance of IFT reduction was enhanced in the higher-permeability condition, while the importance of WA was enhanced in the lower-permeability condition.
界面张力降低和润湿性改变都是重要的提高采收率（EOR）机制。在油湿地层中，界面张力降低会减小负毛细管压力的大小，从而释放被困油。润湿性改变将负毛细管压力转变为正毛细管压力，有助于水相的进入和油相的驱替。在大多数情况下，界面张力降低和润湿性改变同时发生。然而，关于耦合效应的研究给出了不同的、有时甚至相互矛盾的观察结果。这需要进一步研究并更好地理解。在我们的研究中，选择了被油老化的印第安纳石灰岩样品来代表油湿碳酸盐岩。分别采用静态接触角和旋滴法进行润湿性评估和界面张力测量。采用自吸法来反映不同情况下的采收率机制。通过选择四组对比试验，讨论了界面张力降低、润湿性改变和渗透率对耦合效应的影响。结果表明，当耦合效应发生时，较高的界面张力值和较强的润湿性改变性能都会导致更快、更高的采收率。在高渗透率条件下，界面张力降低的重要性增强，而在低渗透率条件下，润湿性改变的重要性增强。
