【摘要】 为优化CO₂驱油技术,采用5组平行驱油实验探索研究两种不同性能凝胶对CO₂驱的增油效果及作用机理,通过采收率、气油比以及提出的冲刷系数综合分析CO₂凝胶复合驱的驱替特征。结果表明:注入段塞越大驱油效果越好,复合驱最终采收率比CO₂驱提升8.31～19.87个百分点;CO₂驱至气窜注入量约为0.3PV,而复合驱驱至气窜注入量需0.64～0.73PV,有效延缓了气窜时间;CO₂驱平均冲刷系数见气前为0.35cm³·（cm²·s·MPa）^-1,见气后为0.75cm³·（cm²·s·MPa）^-1,复合驱组注凝胶前平均冲刷系数为0.36cm³·（cm²·s·MPa）^-1,后续CO₂驱降至0.092～0.188cm³·（cm²·s·MPa）^-1,说明凝胶段塞封堵效果显著;复合驱机理分析表明:凝胶段塞赋予CO₂足够的液流转向能力是复合驱增油机理;凝胶在储层内的可动程度是调控液流转向能力的关键。更多还原

【Abstract】 In order to optimize CO₂ flooding technology that 5 groups of contrast flooding experiments were conducted to investigate the effect and mechanism of two different properties of gel on CO₂ flooding. Then, the displacement characteristics of CO₂ gel composite flooding were analyzed by recovery, gas oil ratio and dynamic scour capacity. The results showed that with the increase of injection slug, the better the oil displacement effect, and the final recovery of composite flooding is 8.31～19.87 percentage points higher than that of CO₂ flooding;CO₂ flooding to gas channeling need injection CO₂ about 0.3 Pore Volume, but composite flooding needs 0.64～0.73 PV, so the gas channeling time was effectively delayed;The average scour capacity of CO₂ flooding is 0.35 cm³·（cm²·s·MPa）^-1 before gas breakthrough, but 0.75 cm³·（cm²·s·MPa）^-1 after gas breakthrough; the average scour capacity of composite flooding group is 0.36 cm³·（cm2·s·MPa）-1 before injection gel, and the subsequent CO₂ flooding rapidly to0.092-0.188 cm³·（cm²·s·MPa）^-1, It shows that the effect of gel plugging is remarkable. The mechanism analysis of composite flooding shows that the change of CO₂ flow direction by gel slug is the mechanism of compound flooding for increasing oil production; And the mobility of gel in reservoir is the key to control fluid diverting ability of CO₂.更多还原