Hu Junjie, Yang Menglong, Yuan Meng, Jiang Ping, Bao Yan, Zhang Guicai
College of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China.
Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences; Shandong Energy Institute; Qingdao New Energy Shandong Laboratory, Qingdao 266101, China.
Langmuir. 2024 Sep 10;40(36):19008-19021. doi: 10.1021/acs.langmuir.4c01881. Epub 2024 Aug 26.
Pickering emulsions have promising applications in the development of unconventional oil and gas resources. However, the high-temperature environment of the reservoir is not conducive to the stabilization of Pickering emulsions. In addition, the preparation of Pickering emulsions under low-energy emulsification and low-concentration emulsifier conditions is a difficult challenge. Here, we report a high-temperature resistant water-in-paraffin oil Pickering emulsion, which is synergistically stabilized by polyglycerol ester (PGE) and nanoparticles with opposite wettability (lipophilic silica and hydrophilic alumina). This emulsion can be prepared under mild stirring (500 rpm) conditions and can be stable at 140 °C for at least 30 days. The synergistic effects of surfactant, silicon nanoparticles (MSNPs) with different wettability, and alumina nanoparticles (AONPs) on the stability of both emulsions and water-oil interfacial membranes were investigated through bottle experiments, cryogenic scanning electron microscopy (cryo-SEM), optical microscopy, fluorescence microscopy, etc. The results showed that both hydrophobic MSNPs and hydrophilic AONPs are adsorbed together at the water-oil interface to stabilize the W/O emulsion, which can be prepared by 500 rpm stirring. The stability of emulsions strongly depends on the wettability of MSNPs, and the MSNP with moderate hydrophobicity (for example, aqueous phase contact angle of 136°) makes the emulsion exhibit the highest stability against aggregation and settling at elevated temperatures. The emulsion stabilization mechanism was revealed in terms of the adsorption capacity of the surfactant by MSNPs, the adsorption morphology and desorption energy of nanoparticles at the water-oil interface adsorption layer, and emulsion rheology. These findings demonstrate a novel and simple strategy to prepare Pickering W/O emulsions with high-temperature stability at low shear strength.
皮克林乳液在非常规油气资源开发中具有广阔的应用前景。然而，储层的高温环境不利于皮克林乳液的稳定。此外，在低能量乳化和低浓度乳化剂条件下制备皮克林乳液是一项艰巨的挑战。在此，我们报道了一种耐高温的石蜡包水型皮克林乳液，它由聚甘油酯（PGE）和具有相反润湿性的纳米颗粒（亲脂性二氧化硅和亲水性氧化铝）协同稳定。该乳液可在温和搅拌（500转/分钟）条件下制备，并能在140℃下稳定至少30天。通过瓶试、低温扫描电子显微镜（cryo-SEM）、光学显微镜、荧光显微镜等手段，研究了表面活性剂、不同润湿性的硅纳米颗粒（MSNPs）和氧化铝纳米颗粒（AONPs）对乳液和水油界面膜稳定性的协同作用。结果表明，疏水性的MSNPs和亲水性的AONPs都在水油界面共同吸附，以稳定W/O乳液，该乳液可通过500转/分钟的搅拌制备。乳液的稳定性强烈依赖于MSNPs的润湿性，具有适度疏水性（例如水相接触角为136°）的MSNP使乳液在高温下表现出最高的抗聚集和沉降稳定性。从MSNPs对表面活性剂的吸附能力、纳米颗粒在水油界面吸附层的吸附形态和解吸能以及乳液流变学方面揭示了乳液稳定机制。这些发现展示了一种在低剪切强度下制备具有高温稳定性的皮克林W/O乳液的新颖且简单的策略。
