Reservoir rock type (RRT) classification is commonly used for the fine characterization of strongly heterogeneous reservoirs. Many research focused on proposing different RRT methods, while few studies focused on the relationship between micropore structure and macroscopic seepage law of fluid transporting through different types of formation. Considering the different diagenesis degrees of rock types in different sedimentary facies, the quadrant unit method and FZI method were applied to classify and evaluate the strongly heterogeneous reservoirs. The corresponding capillary pressure curves and relative permeability curves for different rock types could be obtained. A set of theoretical models that could describe the macroscopic seepage law are proposed, and numerical simulation case studies were carried out to explore the superimposed seepage law in reservoirs under different degrees of heterogeneity. Results show that water cut rises faster in poor-property RRT formation than in good-property RRT formation, with a lower recovery factor under the same conditions. The water cut rising rate increases firstly and then decreases with water cut and recovery degree increasing. The poorer the rock property is, the earlier and higher the peak value of water cut rising rate is. Also, based on numerical simulation case studies, the superimposed seepage law is close to that in the poor-property formation as the heterogeneity degree strengthens. The newly proposed method not only could provide a reference for rock type classification based on micropore structure but also could expound the influence of micropore structure on the change law of macroscopic water cut and elaborates the macroscopic change law after the superposition of different types of reservoirs. The conventional normalization of relative permeability curves is only applicable to relatively homogeneous reservoirs and not applicable to strongly heterogeneous reservoirs, especially when the permeability variation is higher than 0.7. The newly proposed approach is capable of analyzing the effect of micropore structure on macroscopic seepage law and improving the prediction accuracy of the production profile.

中文翻译：

---

微孔结构对强非均质油藏宏观含水率变化规律的影响

储层岩石类型 (RRT) 分类通常用于对强非均质储层进行精细表征。许多研究集中于提出不同的RRT方法，而很少有研究关注微孔结构与流体通过不同类型地层输运的宏观渗流规律之间的关系。针对不同沉积相岩石类型成岩程度不同，采用象限单元法和FZI法对强非均质储层进行分类评价。可以得到不同岩石类型对应的毛细管压力曲线和相对渗透率曲线。提出了一套可以描述宏观渗流规律的理论模型，并通过数值模拟实例研究不同非均质度下储层的叠加渗流规律。结果表明，在相同条件下，劣质 RRT 地层含水率上升速度快于性能良好的 RRT 地层，采收率较低。含水率上升率随着含水率和采收率的增加呈先增大后减小的趋势。岩石物性越差，含水上升率的峰值越早、越高。此外，基于数值模拟案例研究，随着非均质性程度的增强，叠加渗流规律与不良地层中的渗流规律接近。新提出的方法不仅可以为基于微孔结构的岩石类型分类提供参考，而且可以阐述微孔结构对宏观含水率变化规律的影响，阐述不同类型储层叠加后的宏观变化规律。相对渗透率曲线的常规归一化仅适用于相对均质储层，不适用于强非均质储层，尤其是渗透率变化大于0.7时。新提出的方法能够分析微孔结构对宏观渗流规律的影响，提高生产剖面的预测精度。