胜利油田超稠油蒸汽驱汽窜控制技术

Steam channeling control in the steam flooding of super heavy oil reservoirs,Shengli Oilfield

针对超稠油油藏蒸汽驱过程中汽窜严重的问题,开展室内蒸汽驱汽窜控制技术研究,将氮气泡沫与热固性堵剂相结合封堵汽窜,热固性堵剂封堵大孔道,氮气泡沫调整蒸汽的吸汽剖面。优化后的泡沫剂体系300℃阻力因子达到30以上,且对低含油饱和度区域具有选择性封堵作用,适用于超稠油油藏条件下高渗透带的封堵;热固性堵剂在静态120℃可4 h形成固结,150℃可2h有效固结,在蒸汽动态驱替过程中可形成有效封堵。利用双岩心管开展堵调工艺评价研究,结果表明,采用热固性堵剂和氮气泡沫相结合的封堵汽窜方式比单纯应用氮气泡沫提高采收率5.7%,驱替效率整体达到60.8%。2011年在单56超稠油藏进行现场实施,措施后综合含水下降10.2%,生产井井口温度下降15℃,井组日产油量增加28 t以上,单轮次措施有效期198 d,措施增油2 562 t,效果明显。

In view of the severe steam channeling in the steam flooding of super heavy reservoir,lab experiment on steam channeling control were carried out.The combination of nitrogen foam and thermoset blocking agent was tested to seal steam channeling,in which thermoset blocking agent plugs big pore throats,while nitrogen foam adjusts steam absorption profile.The optimized foam formulation has a resistance factor of over 30 at 300 ℃,can plug low oil saturation areas selectively,and applies to the plugging of high permeability zones in super-heavy oil reservoirs.Thermoset blocking agent,which would consolidate at 120 ℃ in 4 h and consolidate at 150℃in 2 h,can provide effective plugging during dynamic steam flooding.The best steam channeling control mode was determined using parallel tube model.By the combination of nitrogen foam and thermoset blocking agent,the recovery rate is 5.7% higher than the application of nitrogen foam only,with the overall sweeping efficiency reaching up to 60.8%.In 2011,the mode was used in the steam flooding in Shan-56 reservoir.The water cut drops 10.2%,the wellhead temperature of producer drops more than 15 ℃,the oil production of the well group increases over 28 tons per day,the valid period of a single cycle is up to 198 days,and the oil production increases 2 562 t,showing significant improvement in steam flooding.