The complexity of the pore throat structures of heterogeneous low-permeability reservoirs causes uneven water flooding, resulting in the retention of a considerable amount of residual oil. Therefore, it is necessary to characterize pore throat structures and the effects of these structures on water flooding. Such structures and effects were investigated using scanning electron microscopy (SEM), cast thin sections (CTS), high-pressure mercury intrusion (HPMI) and microvisualization seepage experimentations. In the fractal dimension curves, there were two relatively close inflection points, corresponding to pore throat radii of approximately 3 µm and 0.02 µm. On this basis, the pore throat structures of all the samples were categorized into macrothroats, mesothroats and microthroats. All the samples contained these three types of pore throat structures. The heterogeneity of the pore throat structure was caused by the varying proportions of the different pore throat structure types. This was the first analysis of the effects of these varying proportions of pore throat structure types in one sample on water flooding. The influences of the proportions and pore throat radii of the different pore throat structures on water flooding were notable. Through this study, the effects of the pore throat structures on water flooding were found to be controlled by the proportions of the different pore throat structure types. This finding is of great significance to the efficient development of heterogeneous low-permeability reservoirs.

非均质低渗透油藏孔喉结构复杂，造成水驱不均匀，滞留大量剩余油。因此，有必要表征孔喉结构以及这些结构对水驱的影响。使用扫描电子显微镜 (SEM)、铸造薄片 (CTS)、高压压汞 (HPMI) 和显微渗漏实验研究了这种结构和效应。在分形维数曲线中，有两个相对较近的拐点，对应的孔喉半径约为 3 µm 和 0.02 µm。在此基础上，将所有样品的孔喉结构分为大喉管、中喉管和小喉管。所有样品均含有这三种类型的孔喉结构。孔喉结构的非均质性是由不同类型的孔喉结构比例不同造成的。这是对一个样品中这些不同比例的孔喉结构类型对水驱的影响的首次分析。不同孔喉结构的比例和孔喉半径对水驱的影响显着。通过本研究，发现孔喉结构对水驱的影响受不同孔喉结构类型的比例控制。这一发现对非均质低渗透油藏的高效开发具有重要意义。孔喉结构的非均质性是由不同类型的孔喉结构比例不同造成的。这是对一个样品中这些不同比例的孔喉结构类型对水驱的影响的首次分析。不同孔喉结构的比例和孔喉半径对水驱的影响显着。通过本研究，发现孔喉结构对水驱的影响受不同孔喉结构类型的比例控制。这一发现对非均质低渗透油藏的高效开发具有重要意义。孔喉结构的非均质性是由不同孔喉结构类型的比例不同造成的。这是对一个样品中这些不同比例的孔喉结构类型对水驱的影响的首次分析。不同孔喉结构的比例和孔喉半径对水驱的影响显着。通过本研究，发现孔喉结构对水驱的影响受不同孔喉结构类型的比例控制。这一发现对非均质低渗透油藏的高效开发具有重要意义。不同孔喉结构的比例和孔喉半径对水驱的影响显着。通过本研究，发现孔喉结构对水驱的影响受不同孔喉结构类型的比例控制。这一发现对非均质低渗透油藏的高效开发具有重要意义。不同孔喉结构的比例和孔喉半径对水驱的影响显着。通过本研究，发现孔喉结构对水驱的影响受不同孔喉结构类型的比例控制。这一发现对非均质低渗透油藏的高效开发具有重要意义。