河南稠油油藏氮气辅助蒸汽吞吐机理及氮气添加量优化研究

针对河南稠油油藏"浅、薄、稠、散"的地质特征,利用数值模拟技术对1～3m、3～5m和5～10m三种薄层稠油油藏实施氮气辅助蒸汽吞吐的开发效果进行研究。通过对不同厚度稠油油藏分别实施氮气辅助普通湿蒸汽、高温湿蒸汽和过热蒸汽的增油能力、节约蒸汽效果及油藏特征进行对比和分析,总结了氮气辅助蒸汽吞吐提高采收率的机理。研究结果表明,由于氮气自身的压缩性、膨胀性、小热容、低粘度等特点,蒸汽吞吐添加氮气后有利于保持地层压力,延长吞吐周期,改善了蒸汽的波及体积,增加了近井地带的洗油效率。

Nitrogen auxiliary steam stimulation mechanism and the nitrogen additive quantity optimization research

Heavy oil reservoir in Henan oilfield has the geological features of "shallow,thin,heavy and bulk",numerical simulation technology is used to study the 1-3m,3-5m and 5-10 m three thin layer of heavy oil reservoirs nitrogen auxiliary steam stimulation development effect.Nitrogen auxiliary common wet stream,high temperature wet steam and over heat steam has been implemented in different thickness heavy oil reservoir to increase oil,reduce steam effect and compare and analyze reservoir features.Nitrogen auxiliary steam stimulation to enhance recovery has been summarized.The result shows that nitrogen is added to keep strata pressure,extend steam stimulation period because nitrogen has own characteristics of compressibility,expansibility,small thermal capacity and low viscosity.Meanwhile,nitrogen drainage and plugging improve the wave and volume of steam and increase the oil wash efficiency near the borehole zones.