微观物理模拟水驱油实验及残余油分布分形特征研究

研究制作了能真实反映岩石孔隙结构的微观仿真孔隙模型，应用微观渗流物理实验模拟技术和图像分析技术，开展了微观模型水驱油物理模拟实验，对水驱油过程及微观物理模型中残余油的形成和分布进行了观察，模拟了不同驱替速度、孔隙结构、粘度比等条件下的水驱过程。应用分形几何学的基本理论，给出了数盒子法和R／S分析法定量研究微观残余油分形特征的关系式，结合水驱油残余油分布图像，建立了用分形维数定量表征残余油及空间分布的测定方法。研究结果表明，随驱替速度增大，形成的残余油量减少；随原油粘度增大，形成的残余油量增多。容量维数表征了残余油的多少，它与残余油饱和度、孔隙结构有关；分形维数则表征了残余油空间分布的非均质性，分形维数越大，残余油空间分布的非均质性越强。

Physical simulation experiment of water driving by micro-model and fractal features of residual oil distribution

By manufacturing an emulation porous micro-model and applying the simulation technology of micro-flow physical experiment and image analysis technology, the physical simulation experiment of water driving micro-flow was developed. The process of water driving as well as the form and distribution of residual oil in the physical micro-model was investigated, and water driving processes under different displacement rate, porous structure and viscosity ratio were simulated. With the help of the basic theory of fractal geometry, the box algorithm and R/S analysis relationship formula were deduced, which are used to quantitatively study residual oil microscopic fractal characteristics. Combined with the figures of water driving residual oil distribution, the quantitatively measuring method of figuring the size and spatial distribution of the residual oil .saturation was established. The results show that the residual oil decreases with the enhancement of displacement rate, and the residual oil increases with the increase of viscosity of crude oil. The volume dimension figures the quantity of residual oil and is related to the residual oil saturation and pore structure, while fractal dimension shows the homogeneity degree of the residual oil spatial distribution which becomes strong when the fractal dimension expands.