鄂尔多斯盆地合水南地区长7段储层地层水矿化度高、泥质含量非均质性强，导致油水分布规律及主控因素不清，严重制约了油田的高效开发。为提高油水层识别效率、精度，明确油水分布规律，以测井、试油、试采等数据为基础，利用随机森林智能方法对单井油水层进行了解释，明确了合水南地区长7段的油水分布规律。结合恒速压汞、CT（computerized tomography）扫描、核磁共振等实验，从多角度分析油水分布的控制因素。结果表明：应用随机森林方法解释合水南地区长7段油水层，精度可达到78.9%；垂向上长7₁砂组油层发育优于长7₂砂组，油水同层和水层主要发育在长7₂砂组；在平面上，东部油层厚度较大且分布连续，西南部B60井区附近含水程度较高；储层中泥质含量、孔隙结构与原油黏度共同控制了储层内部流体性质，泥质含量的高低影响了储层孔径大小和孔喉连通性，储层孔隙结构与原油黏度影响流体可动性，从而控制研究区油水的空间分布。

The reservoir of Chang 7 in Heshuinan area of Ordos Basin has high salinity of formation water and strong heterogeneity of mud content, which leads to unclear understanding of oil-water distribution and main controlling factors. It seriously restricts the efficient development of the oilfield. In order to improve the efficiency and accuracy of the identification of oil-water layer and clarify the distribution law of oil and water, the intelligent random forest method was used to interpret the fluid properties on the basis of logging, oil test and production test data, and defined the distribution law of oil and water in Chang 7 in Heshuinan area. In addition, the controlling factors of oil and water distribution were analyzed from various angles by combining the experiments of constant rate mercury injection, CT (computerized tomography) and nuclear magnetic resonance. The results show that the accuracy of the fluid properties interpretation can reach 78.9% by using random forest method. In the vertical direction, the oil layer developed in Chang 7₁ is better than that in Chang 7₂, and the oil-water layer and water layer are mainly developed in Chang 7₂. In the plane direction, the eastern oil layer is thicker and distributed more continuously, and the southwest oil layer near the B60 well area has higher water content. The fluid properties inside the reservoir are controlled by the shale content, the pore structure and the viscosity of crude oil. The pore size and the connectivity of pore throat of the reservoir are affected by the content of mud. The pore structure of the reservoir and the viscosity of crude oil together control the fluid mobility, thus affecting the spatial distribution of oil and water in Heshuinan area.