Mixing and finger morphologies in miscible non-Newtonian solution displacement
Mixing and finger morphologies in miscible non-Newtonian solution displacement
复制标题
DOI：
10.1007/s00348-020-2932-x
复制
发表时间：
2020-03-16
影响因子：
2.4
通讯作者：
Selker, John S.
中科院分区：
文献类型：
--
作者：
Mehr, Nicole;Roques, Clement;Selker, John S.
意想不到的界面复杂性，发现从盐水的混溶位移的混溶剪切稀化溶液（黄原胶）在径向Hele-Shaw细胞，收敛和发散流。这种复杂的模式以前没有描述过，无论是牛顿或非牛顿的解决方案。将更粘稠的溶液注入池中以置换较不粘稠的溶液（发散流），然后在注射部位取出（收敛流）。在注射阶段，溶液之间形成了杂色混合边缘，对抗稳定粘性效应，这将倾向于促进稳定的活塞式位移。该界面几何形状明显不同于在其它类似粘度对比和流动条件下用甘油进行的驱替实验中所见的。浓度场的不均匀性产生的边缘的存在下，量化使用空间自相关措施，主要是由所施加的剪切速率，或等效地，由体积流量的流动池的孔径的比率控制。它与混合区的径向宽度显著相关。除了在进样阶段产生大量混合溶液外，混合边缘还影响了抽取阶段粘性指状物（VF）的形成。这样的VF是预期的，由于粘度比，但从他们开发的界面的初始粗糙度，因此，他们后来的动态控制的几何形状的混合边缘在注射结束。我们的动态特性作为施加的流速和细胞厚度的函数。所观察到的复杂性的混相驱替涉及剪切稀化解决方案的地下工程应用，如石油开采和地下水修复的影响。[图形摘要]我们探索了将剪切稀化流体注入到充满水的腔体中的几何形状。孔径为2.54 mm（A和B）和0.762 mm（C和D）的两个黄原胶注入/取出实验的浓度图显示，在窄裂缝中，水的驱替具有不规则的界面，这是预料不到的。这种不规则的界面导致了完全不同的取出几何形状（右图）。这些结果表明，使用这样的流体追逐碳氢化合物，或测试含水层的属性，将不遵循标准的理论，采取较低的粘性流体的位移更粘性的流体有稳定的界面。[图形]。
Unexpected interface complexities were found resulting from the miscible displacement of saltwater by a miscible shear-thinning solution (xanthan gum) in a radial Hele-Shaw cell, for both convergent and divergent flow. Such complex patterns have not been described before for either Newtonian or non-Newtonian solutions. A more viscous solution was injected into the cell to displace a less viscous solution (divergent flow) and then withdrawn at the injection site (convergent flow). A variegated mixing fringe between the solutions developed during the injection phase, against the stabilizing viscous effects, which would tend to promote a stable piston-like displacement. This interface geometry is markedly different from what is seen in displacement experiments performed with glycerol under otherwise similar viscosity contrast and flow conditions. The concentration field heterogeneity resulting from the presence of the fringe, quantified using a spatial autocorrelation measure, is mostly controlled by the applied shear rate, or equivalently, by the ratio of the volumetric flow rate to the flow cell's aperture. It is significantly correlated with the radial width of the mixing zone. In addition to producing a large volume of blended solution during the injection phase, the mixing fringe impacted the development of viscous fingers (VFs) during the withdrawal phase. Such VFs are expected due to the viscosity ratio, but the initial roughness of the interface from which they develop and, hence, their later dynamics are controlled by the geometry of the mixing fringe at the end of the injection. We characterize the dynamics as a function of the imposed flow rate and cell thickness. The observed complexities of miscible displacement involving shear-thinning solutions have implications for subsurface engineering applications such as oil recovery and groundwater remediation.[Graphic abstract]We explore the geometry of injection of shear-thinning fluid into a water-filled cavity. Concentration maps for two xanthan gum injection/withdrawal experiments with apertures of 2.54 mm (A and B) and 0.762 mm (C and D) show that in narrow fissures, the displacement of water has a ragged interface, which was not expected. This irregular interface gave rise to radically different withdrawal geometries (right frames). These results suggest that the use of such fluids for chasing hydrocarbons, or for testing aquifer properties, will not follow standard theories which take displacement of less viscous fluids by more viscous fluids to have stable interfaces.[GRAPHICS].