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通过一维水平砂柱试验,结合多孔介质传质理论,从孔隙尺度探索含水层中微纳米颗粒形貌特征与其释放、运移、沉积过程的内在关联,揭示颗粒重组的力学诱导机制。研究结果表明,在渗流溶液水动力作用与物化性质相同,并且含水介质机械组成相近的条件下,球形硅微粉释放率最高,试验过程中累计释放颗粒质量达93.74 mg;咸水层原砂释放率最低,仅为0.62%。依据试验结果,利用双沉积位动力学模型进行反演,计算得到咸水层原砂在受运移距离控制点位沉积系数最大,高于人工制备砂样2个量级。结合电镜扫描与颗粒表面ζ电位测试结果,基于颗粒受力平衡分析,渗流剪切应力与颗粒法向截面面积成正比;同时伴随微纳米颗粒形貌、构成的变化,扩散双电层排斥力存在显著差异。因此,球状硅微粉颗粒通常以单体形式脱离多孔介质表面;片状次生黏土矿物颗粒多以大体积粒团形式释放,出现再次沉积或被孔喉捕获的机率提高。
Based on the one-dimensional horizontal sand column test and the mass transfer theory of porous media, the intrinsic relationship between the morphology of micro-nano-particles in aquifer and their release, migration and deposition process was explored from the pore scale, and the mechanical induction mechanism of particle recombination was revealed. The results show that under the same hydrodynamic and physicochemical properties of percolation solution and the similar mechanical composition of aqueous medium, the release rate of spherical silica powder is the highest, and the mass of particles released during the experiment reaches 93.74 mg. The release rate of raw sand The lowest, only 0.62%. According to the experimental results, the inversion of the dynamic model of double sedimentation was used to calculate the sedimentation coefficient of the raw sand in the saline water layer at the control point of the migration distance was the highest, which was two orders of magnitude higher than that of the artificial sand sample. Based on the results of electron microscopy and zeta potential measurements, the seepage shear stress is proportional to the normal cross-sectional area of the particles based on the force balance analysis of the particles. At the same time, with the changes of the morphology and composition of the micro-nano particles, Significant differences. Therefore, the spherical silica powder particles are usually separated from the surface of the porous medium as monomers; the secondary clay mineral particles are mostly released in the form of bulky particles and the probability of re-deposition or pore-throat capture is increased.