Abstract: CO₂ flooding, as a strategic pathway integrating both hydrocarbon reserves and production enhancement and carbon capture, utilization, and storage, and its displacement effectiveness relies on the swept volume and CO₂ channeling control. During petroleum reservoir exploitation, displacement front advancement directly determines the swept volume and the spatiotemporal distribution characteristics of CO₂. Systematically revealing its dynamic pattern provides a theoretical foundation for front control and displacement efficiency improvement. This paper elaborates on the characterization of CO₂ flooding front and its influencing factors, while analyzing the significance and distinctions among different types of CO₂ flooding fronts. It highlights that the dynamic changes of CO₂ flooding fronts are under the coupled control of multiple physical fields. Physical simulations have evolved from one-dimensional phase front studies to two-dimensional visual dynamic characterization, revealing the front advancement patterns under various heterogeneous reservoir conditions. Existing CO₂ flooding front prediction models are generally based on Darcy flow theory and are gradually developing into coupled models that incorporate factors such as reservoir heterogeneity and phase behavior transitions. Different factors have varying impacts on the migration velocity and morphology of the front during reservoir exploitation. Future research should focus on the multi-front synergistic characterization theory, aiming to clarify the mechanisms and key factors of interlayer heterogeneity on front migration. Additionally, an emphasis should be given to high-precision numerical simulations on low-permeability, highly heterogeneous reservoirs, as well as intelligent injection and production strategies based on front control. These provide theoretical and technical support for the efficient development by CO₂ flooding.

Key words: CO₂ flooding front characterization, multi-scale physical simulation, CO₂ flooding front characterization model, CO₂ flooding influencing factors, sweep efficiency

摘要： CO₂驱油气作为 实现油气增储上产与二氧化碳捕集利用封存协同发展的战略路径,其驱替效果取决于CO₂驱的波及体积及对CO₂气窜的控制。在油藏开发中,前缘运移直接决定波及体积与CO₂的时空分布特征,系统揭示其动态规律可为前缘调控与提高驱替效果提供理论基础。围绕CO₂驱前缘表征及影响因素进行阐述,剖析不同类型CO₂驱前缘的意义及其相互区别,指出其动态变化受到多物理场耦合控制。物理模拟从一维相前缘研究逐步发展为二维可视化动态表征,揭示多种非均质储层条件下的前缘运移规律。现有CO₂驱前缘预测模型普遍基于达西渗流理论,逐步向考虑储层非均质性、相态转变等多因素耦合模型发展。开发过程中不同因素对前缘运移速度、形态的影响程度各异。未来研究应聚焦于多前缘协同表征理论、揭示层间非均质性对前缘运移的影响机制及主控因素、低渗—强非均质储层中的高精度数值模拟以及基于前缘调控的智能注采策略,为实现CO₂驱高效开发提供理论与技术依据。

关键词: CO₂驱前缘表征, 多尺度物理模拟, CO₂驱前缘表征模型, CO₂驱影响因素, 波及效率