低渗透油藏化学复合驱提高采收率技术研究进展与展望

Advances and Perspectives in Chemical Combined Flooding for EOR in Low-Permeability Reservoirs

摘要: 低渗透油藏孔喉半径小、连通性差且非均质性强，渗流受启动压力梯度与低速非达西效应影响，导致水驱早期难以形成有效驱替前缘，且易在裂缝/高渗条带发生优势通道窜流，造成剩余油滞留于微细孔喉、弱连通区及裂缝–基质系统。化学复合驱通过聚合物/调驱体系改善流度比和剖面，扩大波及；表面活性剂与醇、纳米、或生物活性组分复配，能降低界面张力、调控润湿性并增溶乳化，形成宏观–微观协同增效。低渗条件下，工程可行性依赖“可注入性–有效黏度”匹配及吸附保留、剪切降解等全过程约束，评价体系需在目标温度、矿化度与孔喉尺度条件下开展全链路校核。建议沿低伤害材料、耐盐温体系、段塞组合与动态调控等方向协同推进。

Abstract: Low-permeability oil reservoirs are characterized by small pore-throat radii, poor connectivity, and strong heterogeneity. Flow behavior is influenced by threshold pressure gradients and low-velocity non-Darcy effects, making it difficult to establish an effective displacement front during the early stage of waterflooding and promoting preferential channeling along fractures or high-permeability streaks. As a result, substantial residual oil remains trapped within micro-scale pore throats, weakly connected zones, and fracture-matrix systems. Chemical combined flooding improves recovery by enhancing the mobility ratio and conformance through polymer or profile-control systems to expand sweep efficiency, while surfactants formulated with alcohols, nanoparticles, or bio-active components reduce interfacial tension, modify wettability, and promote solubilization and emulsification, thereby achieving macro-micro synergistic enhancement. Under low-permeability conditions, engineering feasibility depends on the matching between injectivity and effective viscosity, as well as the comprehensive control of adsorption/retention and shear degradation. Accordingly, evaluation systems should conduct integrated, full-chain verification under target temperature, salinity, and pore-throat scale constraints. Future development should advance synergistically toward low-damage materials, salinity- and temperature-tolerant systems, optimized slug design, and dynamic process control.