Nwufoh Phillip, Hu Zhongliang, Wen Dongsheng, Wang Mi
School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, UK.
Sensors (Basel). 2019 Jul 10;19(14):3036. doi: 10.3390/s19143036.
Silica nanoparticles have been shown to exhibit many characteristics that allow for additional oil to be recovered during sand-pack flooding experiments. Additionally various imaging techniques have been employed in the past to visually compare flooding procedures including x-ray computed tomography and magnetic resonance imaging; however, these techniques require the sample to be destroyed or sliced after the flooding experiment finishes. Electrical resistance tomography (ERT) overcomes these limitations by offering a non-destructive visualization method allowing for online images to be taken during the flooding process by the determination of spatial distribution of electrical resistivity, thus making it suitable for sand-packs. During the scope of this research a new sand-pack system and methodology was created which utilized ERT as a monitoring tool. Two concentrations, 0.5 wt% and 1.0 wt%, of SiO nanoparticles were compared with runs using only brine to compare the recovery efficiency and explore the ability of ERT to monitor the flooding process. Electrical resistance tomography was found to be an effective tool in monitoring local recovery efficiency revealing 1.0 wt% SiO to be more effective than 0.5 wt% and brine only runs during the scope of this research. A new method involving the slope function in excel was used to compare the effects of nanofluids on resistivity trends also revealing information about the rate of recovery against time. SiO nanofluid recovery mechanisms such interfacial tension reduction and viscosity enhancement were then considered to explain why the nanofluids resulted in greater oil recovery.
二氧化硅纳米颗粒已被证明具有许多特性，使得在填砂驱油实验中能够采收更多的原油。此外，过去还采用了各种成像技术来直观比较驱油过程，包括X射线计算机断层扫描和磁共振成像；然而，这些技术要求在驱油实验结束后对样品进行破坏或切片。电阻层析成像（ERT）通过提供一种非破坏性的可视化方法克服了这些局限性，该方法通过确定电阻率的空间分布，在驱油过程中获取在线图像，因此适用于填砂模型。在本研究范围内，创建了一种新的填砂系统和方法，该方法利用ERT作为监测工具。将两种浓度（0.5 wt%和1.0 wt%）的SiO纳米颗粒与仅使用盐水的实验进行比较，以比较采收效率，并探索ERT监测驱油过程的能力。结果发现，电阻层析成像在监测局部采收效率方面是一种有效的工具，在本研究范围内，显示1.0 wt%的SiO比0.5 wt%和仅使用盐水的实验更有效。一种涉及Excel中斜率函数的新方法被用来比较纳米流体对电阻率趋势的影响，同时也揭示了采收率随时间变化的信息。然后考虑了SiO纳米流体的采收机理，如界面张力降低和粘度增加，以解释为什么纳米流体能实现更高的原油采收率。
