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鄂尔多斯盆地延长组储层非均质性对石油采收率的影响研究

Study on the Influence of Reservoir Heterogeneity on Oil Recovery Factor in Yanchang Formation of Ordos Basin

Environment and Resource / 2026,8(1): 18-23 / 2026-02-06 49 31

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• Authors: 吴昊 赵东方
• Information:

  西南石油大学地球科学与技术学院，成都

• Keywords:
  Reservoir heterogeneity; Oil recovery factor; Seepage characteristics; Development optimization
  储层非均质性; 石油采收率; 渗流特征; 开发优化
• Abstract: The reservoirs of Yanchang Formation in Ordos Basin are typical tight sandstone reservoirs with low porosity and ultra-low permeability, and reservoir heterogeneity is the core factor restricting the improvement of oil recovery factor. To clarify the influence law and mechanism of heterogeneity on oil recovery factor, taking the Chang 6 and Chang 8 oil-bearing intervals of Yanchang Formation as the research objects, this paper systematically characterized the reservoir heterogeneity characteristics from four dimensions, namely plane, interlayer, intralayer and microcosm, by comprehensively using methods such as core analysis, thin section identification, well logging interpretation and numerical simulation. The influence of reservoir heterogeneity on oil recovery factor was quantified through laboratory experiments and field dynamic data, and targeted development optimization strategies were put forward. The results show that the porosity of Yanchang Formation reservoirs ranges from 7.8% to 14.1%, the permeability is concentrated in 0.05×10⁻³μm² to 9.1×10⁻³μm², and the permeability ratio varies from 1.03 to 43.7. The plane heterogeneity is characterized by the interbedded distribution of channel sand bodies and flood plains, the thickness of interlayer barriers and intercalations is 0.6-2.4 m, and the micro-pore-throat ratio is 5-25. Experimental and simulation results indicate that the water flooding recovery factor decreases by 4.2%-6.8% with every 10 increase in permeability ratio, the water flooding recovery factor of reservoirs with strong heterogeneity is only 20.3%, and air foam flooding can increase the recovery factor by 28%. Reservoir heterogeneity restricts oil recovery factor by controlling fluid seepage paths, affecting displacement efficiency and residual oil distribution. The research results provide theoretical basis and practical reference for the efficient development and residual oil tapping of Yanchang Formation reservoirs. 鄂尔多斯盆地延长组储层为典型低孔特低渗致密砂岩储层，储层非均质性是制约石油采收率提升的核心因素。为明确非均质性对采收率的影响规律与机制，以延长组长6、长8油层组为研究对象，综合运用岩心分析、薄片鉴定、测井解释及数值模拟等方法，从平面、层间、层内及微观四个维度系统表征储层非均质性特征，通过室内实验与矿场动态数据量化其对采收率的影响，并提出针对性开发优化策略。研究表明，延长组储层孔隙度介于7.8%～14.1%，渗透率集中在0.05×10⁻³μm²～9.1×10⁻³μm²，渗透率级差为1.03～43.7；平面非均质性表现为河道砂体与泛滥平原相间分布，层间隔夹层厚度0.6～2.4m，微观孔喉比5～25。实验与模拟结果显示，渗透率级差每增加10，水驱采收率下降4.2%～6.8%，强非均质性储层水驱采收率仅20.3%，空气泡沫驱可使采收率提升28%。储层非均质性通过控制流体渗流路径、影响驱替效率及剩余油分布制约采收率，研究成果为延长组储层高效开发及剩余油挖潜提供了理论依据与实践参考。
• DOI: https://doi.org/10.35534/er.0801003 (registering DOI)
• Cite: 吴昊，赵东方．鄂尔多斯盆地延长组储层非均质性对石油采收率的影响研究［J］．环境与资源，2026，8（1）：18-23.