Abstract

In order to discuss the influence of microheterogeneity on oil displacement and residue distribution, the parallel capillary model is established, and the forming and finally distribution of remaining oil after water flooding is analyzed. To verify the theoretical model and to discuss the remaining oil further, two experimental models with the property of microheterogeneity are designed, which are the visual sand-packed model visual model and the man-made sandstone core slab model, according to the similarity principle. And the video observation method is used during the oil displacement experiments in visual sand-packed model visual model, while the resistivity test is taken in the sandstone core slab model experiments. The results show that the microheterogeneity can cause the different oil seepage ability between low permeability area and high permeability area relatively. It also makes the instability oil–water front and the heavy fingering during oil displacement in microheterogeneity reservoir. The remaining oil is formed and mostly located in the low permeability area and the hydrodynamic retention places among them., which is consistent with the theoretical model. Long-term water flooding can only reduce the saturation of remaining oil nearby the water injection inlet. So the main direction to enhance oil recovery in microheterogeneity reservoir is to improve the microsweep efficiency.

摘要

为探讨微观非均质性对驱油及残油分布的影响，建立平行毛细管模型，分析注水后剩余油的形成及最终分布。为验证理论模型并进一步讨论剩余油，根据相似性原理，设计了可视化充砂模型可视化模型和人造砂岩岩心板模型两个具有微观非均质性的实验模型。并且在可视化充砂模型视觉模型的驱油实验中采用视频观察方法，而在砂岩芯板模型实验中采用电阻率测试。结果表明，微观非均质性会导致低渗透区和高渗透区的渗油能力相对不同。也造成了微非均质油藏驱油过程中的不稳定油水锋和重指进。剩余油的形成主要位于低渗透区和其中的水动力滞留区，与理论模型一致。长期注水只能降低注水口附近剩余油的饱和度。因此提高微非均质油藏采收率的主要方向是提高微波及效率。剩余油的形成主要位于低渗透区和其中的水动力滞留区，与理论模型一致。长期注水只能降低注水口附近剩余油的饱和度。因此提高微非均质油藏采收率的主要方向是提高微波及效率。剩余油的形成主要位于低渗透区和其中的水动力滞留区，与理论模型一致。长期注水只能降低注水口附近剩余油的饱和度。因此提高微非均质油藏采收率的主要方向是提高微波及效率。