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碳酸盐岩油藏作为全球的主力油气储集层,在微观尺度上分布有大量发育的大孔隙和微孔隙,研究不同孔隙对其微观渗流特征的影响具有重要意义.本文基于碳酸盐岩中分别描述大孔隙和微孔隙特征的单一尺度孔隙网络模型,利用整合法构建出能够同时描述大孔隙和微孔隙特征的双孔隙网络模型,最后模拟各网络模型的渗流过程,计算相应的渗流特征参数并同岩心实验室渗透率进行了对比.结果表明,基于整合法构建的双孔隙网络模型可根据区间域随机产生任意大小的网络尺寸,不仅同时包含大孔隙和微孔隙的几何拓扑结构信息,而且可同时描述大孔隙和微孔隙的渗流特征,能够较好描述真实碳酸盐岩油藏中多尺度孔隙特征.双孔隙网络模型的绝对渗透率和实验室岩心结果基本一致,水湿油藏条件下对比各网络模型的相对渗透率曲线发现,双孔隙网络模型的等渗点含水饱和度均大于大孔隙和微孔隙网络,其残余油饱和度明显减少,这是由于大孔隙和微孔隙的整合极大地提高了双孔隙网络的连通性,进而大幅度提高网络的渗流能力,本研究为碳酸盐岩微观渗流研究提供了重要的理论基础.
Carbonate reservoirs, as the main oil and gas reservoirs in the world, have a large number of macropores and micropores distributed on the microscopic scale, and it is of great significance to study the influence of different pores on the microscopic seepage characteristics.Based on the carbonate rocks , A single-scale pore network model describing the characteristics of macropores and micropores is described respectively. A dual-porosity network model that can simultaneously describe the characteristics of macropores and micropores is constructed by using the integration method. Finally, the percolation process of each network model is simulated and the corresponding seepage characteristics The results show that the dual-aperture network model based on the integration method can randomly generate any size of network according to the interval domain, including not only the geometric topological information of macropores and micropores, But also describes the seepage characteristics of macropores and micropores, which can describe the characteristics of multi-scale pores in real carbonate reservoirs well.The absolute permeability of the dual-porosity network model is basically the same as that of the laboratory core, Comparing the relative permeability curves of various network models under the conditions, we found that the isotonic point of the two-pore network model contains Saturation is greater than the macropores and microporous networks, the residual oil saturation decreased significantly, this is because the integration of macropores and micropores greatly improve the connectivity of the two-pore network, and thus greatly improve the network’s seepage capacity, the The study provides an important theoretical basis for the study of carbonate micro-seepage.