微通道中油水两相的渗流特性研究

Percolation Characteristics of Oil-Water Two-Phase Fluids in Micro Channels

摘要: 微通道渗流是多孔介质渗流的微观基础。以微通道渗流为前提，建立了油水两相渗流的单元模型，该模型表明油水两相的相对渗透率与多孔介质的孔隙度无关，相对渗透率只与微通道中相态分布的几何尺度以及流体饱和度等参数有关。采用微流控技术加工了不同尺寸的微通道，以去离子水和白油为两相流体，实验研究了油水两相在不同尺寸微通道中的渗流特性。实验数据表明，对于相同尺度等级的微通道，油水两相渗流的平均相对渗透率曲线类似；对于尺度等级明显不同的微通道，油水两相渗流的平均相对渗透率曲线有显著差异。体积含油率或者流体饱和度不是影响相对渗透率的唯一因素，相对渗透率还与两相渗流的总体积流量等参数有关。实验所得结论与渗流单元模型的推论相符。

Abstract: The flow in micro channels is the microscopic foundation of the flow in porous media. Based on the flow in micro channels, the percolation unit model was developed for the oil-water two-phase flow in a porous medium. This model indicates that the relative permeabilities of oil-water two-phase flow in a porous medium are related to the phase geometry distribution and fluid saturation in micro channels, but have nothing to do with the porosity of the porous medium. An experimental device is designed in which the micro channels are fabricated by microfluidic technology. The percolation characteristics of two-phase flow in the micro channels are experimentally investigated in such device with immiscible oil and water as fluids. The experimental data show that the relative permeability curves of oil-water two-phase flow are approximately the same for the micro channels with similar geometry sizes, but obviously different for the micro channels with distinct geometry sizes. In addition to the fluid saturation and the pressure drop, the total volume flow rate is discovered to be a parameter affecting the relative permeability of oil-water two-phase flow. The experimental results are consistent with the inferences drawn from the percolation unit model developed.