氮气泡沫辅助蒸汽吞吐提高采收率机理研究

Mechanism of Enhanced Oil Recovery by Nitrogen Foam Assisted Steam Huff and Puff

边底水稠油油藏注蒸汽热采开发中,水体和蒸汽容易沿大孔道发生窜流,引起含水上升,热采开发效果变差。通过开展注蒸汽后氮气泡沫封堵实验,研究泡沫封堵机理,分析氮气泡沫的增产效果。结果表明:注入氮气泡沫后,改变了底水水侵流动方向,促使底水向水平段两端运移,扩大了水驱波及范围,有效抑制了水淹。注入氮气泡沫能够实现增压、降水、增油的效果,实验生产压差从350 kPa增至390 kPa,含水率从90%降至80%,产油量从0.02 mL·min^(-1)增至0.05 mL·min^(-1),最终采出程度接近60.0%,比单纯蒸汽驱提高11.5%。此研究成果对于边底水热采稠油油藏水平井开发过程中实现抑水增油,具有参考价值和指导意义。

During the thermal recovery of heavy oil reservoir with edge-bottom water by steam injection,water and steam flow easily along the large channels,resulting in the increase of water cut and poor thermal recovery effect.Through the experiment of nitrogen foam plugging after steam injection,the foam plugging mechanism was studied,and the effect of nitrogen foam production was analyzed.The experimental results showed that after injecting nitrogen foam,the flow direction of bottom water was changed,and the bottom water moved to both ends of the horizontal section,which expanded the range of water flooding and effectively suppressed the water flooding.The injection of nitrogen foam could achieve the effect of increasing the pressure difference,reducing water cut and increasing oil production.The experimental production pressure difference increased from 350 kPa to 390 kPa,the water cut decreased from 90%to 80%,the oil production increased from 0.02 mL·min^(-1)to 0.05 mL·min^(-1),and the final recovery degree was close to 60%,which was 11.5%higher than that of pure steam flooding.This research result has reference value and guiding significance for the realization of water suppression and oil increase in the development of horizontal wells in the thermal recovery of heavy oil reservoirs with edge-bottom water.