Hu Zhongliang, Al-Ameri Layth, Gardy Jabbar, Alhreez Mahmoud, Wen Dongsheng
School of Chemical and Process Engineering, University of Leeds, LeedsLS2 9JT, U.K.
Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing, Yantai264006, China.
Energy Fuels. 2022 Nov 3;36(21):12986-12996. doi: 10.1021/acs.energyfuels.2c01800. Epub 2022 Oct 14.
Nanoparticle-assisted enhanced oil recovery (Nano-EOR) has attracted intensive interest in the laboratory as a promising oil recovery technology. However, the nanoparticles' stability and long-distance delivery of nanoparticles (NPs) in large-scale reservoirs are two main challenges. In this work, we developed a novel concept of synthesizing NPs at the oil-water interface inside the reservoir for EOR instead of injecting presynthesized NPs from outside. The pore-scale flooding experiments show that EOR efficiencies for tertiary flooding were 6.3% without reaction (Case 3), 14.6% for slow reaction (Case 1), and 25.4% for relatively quick reaction (Case 4). Examination of the EOR mechanism shows that produced SiO NPs in microchannels could alter the substrate wettability toward neutral wetting. Moreover, the produced NPs tended to assemble on the immiscible oil-water interface, forming a barrier toward interface deformation. As the reaction continued, excessive surface-modified NPs could also diffuse into aqueous brine and accumulate as a soft gel in the flowing path swept by brine. Collectively, these processes induced a "shut-off" effect and diverted displacing fluids to unswept areas, which consequently increased the sweep efficiency and improved the oil recovery efficiency. Auxiliary bulk-scale experiments also showed that the reaction-induced nanoparticle synthesis and assembly at an immiscible interface reduced the interfacial tension and generated an elastic oil-water interface.
纳米颗粒辅助强化采油（Nano-EOR）作为一种很有前景的采油技术，在实验室中引起了广泛关注。然而，纳米颗粒的稳定性以及纳米颗粒（NPs）在大规模油藏中的长距离输送是两个主要挑战。在这项工作中，我们提出了一种新颖的概念，即在油藏内部的油水界面处合成纳米颗粒用于强化采油，而不是从外部注入预先合成的纳米颗粒。孔隙尺度驱替实验表明，三次采油的强化采油效率在无反应时（情况3）为6.3%，慢反应时（情况1）为14.6%，相对快反应时（情况4）为25.4%。对强化采油机理的研究表明，微通道中生成的SiO纳米颗粒可使基质润湿性转变为中性润湿。此外，生成的纳米颗粒倾向于在不混溶的油水界面上聚集，形成一道阻止界面变形的屏障。随着反应的持续进行，过量的表面改性纳米颗粒也会扩散到盐水相中，并在盐水扫过的流动路径中积聚成软凝胶。总的来说，这些过程引发了一种“封堵”效应，并将驱替流体转向未波及区域，从而提高了波及效率并改善了采油效率。辅助的宏观尺度实验还表明，在不混溶界面处反应诱导的纳米颗粒合成与聚集降低了界面张力，并产生了一个弹性油水界面。
