Abstract: This study comparatively analyzes the key differences in the development of tight oil reservoirs between China and the rest of the world, with a particular focus on the mechanisms, technological advancements, and limitations of CO₂ enhanced oil recovery (CO₂-EOR). The research indicates that compared to typical reservoirs in North America, tight reservoirs in China are generally characterized by low pressure, high viscosity, strong heterogeneity, and developed micron-to-nanoscale pore systems, which face dual challenges of poor injectivity and low recovery efficiency during hydrocarbon development. Although CO₂ injection can enhance permeability by mineral dissolution, the reaction byproducts, such as iron-bearing minerals, carbonates, and asphaltenes, are prone to plug pore throats, thereby affecting its practical application. At micro- and nano-scales, traditional methods such as the Peng-Robinson equation of state (PR-EOS) and Darcy’s law struggle to accurately capture the phase behavior and flow of multiphase fluids, which necessitates integrated approaches including nanochip experiments and fluid-solid coupling molecular simulations to deepen understandings of underlying mechanisms. CO₂ flooding primarily targets tight oil in meso- and macropores where gas channeling remains a critical challenge. CO₂ foam flooding can mitigate gas channeling, but it requires substantial amounts of surfactants for foam generation and stabilization. CO₂ nano-bubbles, boasting high stability, effective gas-channeling control, and superior oil-displacement performance, are recognized as one of the most promising research directions for future CO₂ flooding technologies. Additionally, further optimization of CO₂-responsive plugging systems is required in terms of plugging strength, manufacturability, and injectability to enhance their adaptability and practical application efficacy in tight reservoirs.

Key words: tight oil reservoirs, CO₂ enhanced oil recovery, CO₂ flooding, CO₂ huff and puff, phase behavior mechanisms, channeling control and plugging systems, microscale flow

摘要： 对比分析了国内外致密油藏开发的主要差异,并重点围绕CO₂提高采收率(CO₂-EOR)的作用机理、技术进展与面临局限展开探讨。研究表明,相较于北美地区典型储层,中国致密储层普遍具有低压、高黏、强非均质性及微米/纳米孔隙发育等特征,在开发过程中面临"注不进"与"采不出"的双重挑战。CO₂注入虽然可以通过溶蚀岩石矿物提升渗透率,但其反应生成的含铁矿物、碳酸盐及沥青质等产物易堵塞孔喉,影响实际效果。在微米/纳米尺度下,传统Peng-Robinson状态方程(PR-EOS)与达西定律难以准确刻画多相流体的相变与流动行为,需结合纳米芯片实验与流固耦合的分子模拟等方法深化机理认知。CO₂气驱主要作用于中孔和大孔中的致密油,但气窜问题突出;CO₂泡沫驱可改善气窜,但对发泡与稳泡表面活性剂的需求量较大。CO₂纳米气泡因兼具稳定性好、防窜能力强和驱油效果显著等优点,被认为是CO₂驱技术未来最具前景的研究方向之一。此外,CO₂响应性封堵体系在封堵强度、可制备性与注入能力等方面仍需进一步优化,以提升其在致密储层中的适应性与实际应用效果。

关键词: 致密油藏, CO₂提高采收率, CO₂驱, CO₂吞吐, 相变机理, 封窜体系, 微观流动