Abstract In this study, experimental and numerical simulation studies were conducted to enhance oil production in a tight oil reservoir using CO 2 injection processes. In experimental studies, three types of CO 2 injection experiments—CO 2 flooding (continuous CO 2 injection process), CO 2 flooding coupled with a soaking period, and CO 2 flooding coupled with pressure maintenance—were carried out in one-meter-long core plugs to investigate the effect of CO 2 flooding schemes on production performance. The properties of light oil–CO 2 systems with different CO 2 concentrations under different pressures were measured to study the phase behaviors of light oil–CO 2 systems. Test results indicate that the CO 2 flooding process is the best method to enhance oil recovery in tight formations, showing an oil recovery factor of 38.96% and a CO 2 utilization of 10.41 Mscf/STB. In numerical simulation study, the properties of light oil–CO 2 systems first were simulated using the WinProp module. Next, the GEM module was applied to implement history-matching studies on experimental results, and good agreement was achieved. Third, a sensitivity analysis was carried out to investigate the effect of parameters on the CO 2 flooding process. Finally, upscaling simulation studies were conducted at the field scale to optimize the well pattern and CO 2 injection rate to enhance oil recovery in the target reservoir. Important correlations on the effect parameters were generated for predicting the oil production performance in the reservoir with different operations. Among the studied well patterns, the inverted seven-spot well pattern with a CO 2 injection rate of 44.28 t/day/well achieved the best production performance in the field study. In the optimized case, the oil recovery factor reached 30.89% with a low CO 2 utilization of 5.69 Mscf/STB.

中文翻译：

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基于实验和数值模拟研究的致密油油藏 CO2 驱油过程性能评价

摘要 在这项研究中，进行了实验和数值模拟研究，以使用 CO 2 注入工艺提高致密油储层的石油产量。在实验研究中，进行了CO 2 驱（连续CO 2 注入工艺）、CO 2 驱加浸泡期和CO 2 驱加保压三种类型的CO 2 注入实验，在1米长的范围内进行。岩心塞以研究 CO 2 驱油方案对生产性能的影响。通过测量不同压力下不同CO 2 浓度的轻油-CO 2 体系的性质，研究轻油-CO 2 体系的相行为。试验结果表明，CO 2 驱油工艺是提高致密地层原油采收率的最佳方法，采收率为38。96% 和 10.41 Mscf/STB 的 CO 2 利用率。在数值模拟研究中，首先使用 WinProp 模块模拟了轻油-CO 2 系统的性质。接下来，应用GEM模块对实验结果进行历史匹配研究，取得了良好的一致性。第三，进行敏感性分析以研究参数对CO 2 驱油过程的影响。最后，在现场规模上进行了放大模拟研究，以优化井网和 CO 2 注入率，以提高目标油藏的石油采收率。生成了关于影响参数的重要相关性，用于预测具有不同操作的油藏中的石油生产性能。研究井网中，CO 2 注入量为44的倒置七点井网。28 t/day/well 在现场研究中实现了最佳生产性能。在优化的情况下，采油率达到 30.89%，CO 2 利用率低，为 5.69 Mscf/STB。