弱边水普通稠油油藏蒸汽吞吐转氮气泡沫辅助蒸汽驱技术界限——以孤岛油田中二北Ng5为例

Technology limit when steam stimulation changes into nitrogen foam assisted steam flooding in heavy oil reservoirs with inactive edge water—a case study of Zhongerbei Ng5 in Gudao Oilfleld.

通过分析胜利油区弱边水普通稠油油藏处于蒸汽吞吐中后期所面临的问题及转常规蒸汽驱的不利因素,着重剖析了氮气泡沫辅助蒸汽驱的驱油机理,即泡沫不仅能够封堵蒸汽窜流通道,抑制蒸汽超覆,还能提高洗油效率。以孤岛油田中二北Ng5为例,利用CMG数值模拟软件,在室内物理实验的基础上,优化了在井距分别为141m×200m和100m×141m反九点井网的条件下,转氮气泡沫辅助蒸汽驱的时机、气液比、高温泡沫剂质量分数及注入方式的界限。模拟结果表明,对于吞吐转氮气泡沫辅助蒸汽驱,大、小井距关键参数的技术界限相近,采收率均有大幅度提高,比吞吐提高采收率15%以上。

The problems in the heavy oil reservoir with inactive edge water at middle-late stage of steam soaking were analyzed,and disadvantageous factors of changing into regular steam-flooding as well as.The oil displacement mechanism for enhancing recovery by using N_2 steam-foam flooding was analyzed deeply. The foam can not only block off steam channeling way and control steam overlapping,but also enhance oil displacement efficiency.Zhongerbei Ng5 was taken as an example,technology limits were optimized in different well-spacing(141m×200m and 100m×141m) by means of CMG numerical simulation, namely N_2 foam injection timing,gas-liquid ratio,high-temperature foaming agent concentration and the injection way based on the laboratory physical experiment.The result of the numerical simulation shows that the technology limits of the key parameters are similar at different well spacing,and the recovery efficiency of nitrogen steam assisted-foam flooding is higher 20%than that of steam stimulation.