稠油油藏氮气泡沫辅助蒸汽驱驱油效率实验及参数优化

Oil sweeping efficiency experiment and parameter optimization of nitrogen foam-assisted steam flooding in heavy oil reservoir

蒸汽驱能大幅度提高稠油油藏采收率,但对于单一蒸汽驱而言,由于受边底水及储层非均质性等因素的影响,易发生汽窜,降低了蒸汽的波及体积,开发效果不理想。为此,设计了氮气泡沫辅助蒸汽驱驱油实验,对单一蒸汽驱和氮气泡沫辅助蒸汽驱的驱油效率进行了对比,并对氮气泡沫辅助蒸汽驱注入参数进行了优化研究。实验结果表明,单一蒸汽驱综合驱油效率为63.52%,氮气泡沫辅助蒸汽驱综合驱油效率为69.95%,比单一蒸汽驱提高了6.43%。当气液比为1∶1,发泡剂质量分数为0.5%,含水率较低时,进行氮气泡沫辅助蒸汽驱开发效果较好。通过室内实验证实,氮气泡沫辅助蒸汽驱能够有效封堵高渗透条带,提高驱油效率,改善稠油油藏的开发效果。

Steam flooding can enhance greatly the heavy oil recovery. However, for single steam flooding, it is possible to decrease the steam sweep efficiency resulted by poor heavy oil development efficiency due to steam channeling and heterogeneity. This paper has designed an experiment of nitrogen foam-assisted steam flooding and studied the oil displacement efficiency of single steam flooding and foam-assisted steam flooding. The experiment result shows that the oil displacement efficiency of single steam flooding is 63.52%, while the foam-assisted steam flooding is 69.65%, which is higher than that of former. And, it is testified that the nitrogen foam-assisted steam flooding can dramatically improve the oil displacement efficiency. In addition, we have studied the injection parameter optimization of nitrogen foam-assisted steam flooding. The result is that 1:1 of gas-liquid ratio, 0.5% of foam agent concentration and lower water cut of foam injection time. This experiment demonstrates that nitrogen foam-assisted steam flooding can be used in high permeability formation to enhance oil displacement efficient, and obtain good heavy oil reservoir development.