School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom; Department of Mining and Petroleum Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand; Center of Excellence in Natural Disaster Management (CENDiM), Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand.
School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom.
J Colloid Interface Sci. 2021 Aug 15;596:420-430. doi: 10.1016/j.jcis.2021.03.130. Epub 2021 Mar 26.
Improved oil recovery by low-salinity injection correlates to the optimal brine concentration to achieve maximum dewetting of oil droplets on rock surfaces. While interfacial tension and electrical double layer forces are often cited as being determinant properties, we hypothesize that other structural/interfacial forces are more prominent in governing the system behavior.
The sessile droplet technique was used to study the receding dynamics of oil droplets from flat hydrophilic substrates in brines of different salt type (NaCl and CaCl) and concentration, and were studied at both low and elevated temperatures (60 and 140 °C) and pressures (1, 10, 100 and 200 bar).
At 1 bar and 60 °C, the minimum oil droplet-substrate adhesion force (F) was determined at 34 mM NaCl and 225 mM CaCl. For NaCl this strongly correlated to strengthening hydration forces, which for CaCl were diminished by long-range hydrophobic forces. These results highlight the importance of other non-DLVO forces governing the dewetting dynamics of heavy crude oil droplets. At 140 °C and 200 bar, the optimal brine concentrations were found to be much higher (1027 mM NaCl and 541 mM CaCl), with higher concentrations likely attributed to weakening hydration forces at elevated temperatures.
低盐度注入可提高采油量，这与实现岩石表面油滴最大去湿的最佳盐水浓度有关。尽管界面张力和双电层力通常被认为是决定性的性质，但我们假设其他结构/界面力在控制系统行为方面更为突出。
使用静态液滴技术研究了不同盐类型（NaCl 和 CaCl）和浓度的盐水在不同温度（60 和 140°C）和压力（1、10、100 和 200 巴）下从亲水平板上油滴的后退动力学。
在 1 巴和 60°C 下，在 34 mM NaCl 和 225 mM CaCl 下确定了最小油滴-基底粘附力（F）。对于 NaCl，这与增强的水化力强烈相关，而对于 CaCl，长程疏水力减弱了水化力。这些结果强调了其他非 DLVO 力在控制重质原油滴去湿动力学方面的重要性。在 140°C 和 200 巴下，发现最佳盐水浓度要高得多（1027 mM NaCl 和 541 mM CaCl），高温下可能归因于水化力减弱。
