Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL 60616, United States; Schlumberger-Doll Research, 1 Hampshire St., Cambridge, MA 02139, United States.
Schlumberger-Doll Research, 1 Hampshire St., Cambridge, MA 02139, United States.
J Colloid Interface Sci. 2018 Feb 1;511:48-56. doi: 10.1016/j.jcis.2017.09.067. Epub 2017 Sep 19.
Nanofluids for improved oil recovery has been demonstrated through laboratory corefloods. Despite numerous experimental studies, little is known about the efficacy of nanofluids in fractured systems. Here, we present studies of nanofluid injection in fractured porous media (both water-wet and oil-wet) formed by sintering borosilicate glass-beads around a dissolvable substrate. The fracture inside the porous medium is characterized and visualized using a high resolution X-ray microtomography. Based on a simple displacement theory, the nanofluid injection is conducted at a rate where structural disjoining pressure driven oil recovery is operational. An additional 23.8% oil was displaced using nanofluid after brine injection with an overall recovery efficiency of 90.4% provided the matrix was in its native wettability state. But only 6% additional oil was displaced by nanofluid following brine injection when the bead-pack was rendered oil-wet. Nanofluids appear to be a good candidate for enhanced oil recovery (EOR) in fractured water-wet to weakly water-wet media but not necessarily for strongly oil-wet systems. Our laboratory studies enable us to understand limitations of nanofluids for improving oil recovery in fractured media.
通过实验室岩心驱替实验已经证明了纳米流体在提高石油采收率方面的有效性。尽管已经进行了大量的实验研究，但对于纳米流体在裂缝系统中的效果却知之甚少。在这里，我们研究了在由可溶解基底周围烧结硼硅酸盐玻璃珠形成的裂缝多孔介质（水湿和油湿）中注入纳米流体的情况。通过高分辨率 X 射线微断层扫描对多孔介质内部的裂缝进行了表征和可视化。基于简单的驱替理论，在结构离析压力驱动的采油操作可行的速率下进行纳米流体注入。在盐水注入后，使用纳米流体可额外驱替 23.8%的油，提供基质处于原生润湿性状态时，整体采收效率为 90.4%。但当珠包被油湿化后，在盐水注入后，仅能通过纳米流体驱替出 6%的额外油。纳米流体似乎是提高水湿至弱水湿裂缝介质中采收率的良好候选物，但对于强油湿系统则不一定。我们的实验室研究使我们能够了解纳米流体在提高裂缝介质中采收率方面的局限性。
