孤东油田九区稠油油藏化学蒸汽驱提高采收率技术

Study on chemical steam flood to enhance recovery ratio of ninth block of Gudong oilfield

稠油油藏在经历了蒸汽吞吐和蒸汽驱开发后，随着注蒸汽井吞吐次数和开采时间的增加，产量递减快、汽窜严重等现象成为开发中后期面临的共性问题，同时也严重制约了该类油藏采收率的大幅提高。化学蒸汽驱在注入蒸汽或热水的同时，加入泡沫体系，利用泡沫体系“堵水不堵油”和“堵低更堵高”的特点，改变注入介质的流动方向，抑制蒸汽超覆和汽窜，补充地层能量，可达到提高稠油油藏采收率和经济效益的目的。根据数值模拟研究和开发实际，设计了孤东油田九区化学蒸汽驱注采参数：泡沫驱后平均注汽速度为3．9t／h，采注比为1．3，泡沫剂质量分数为0．5％，段塞长度为氮气与泡沫剂段塞注30d停60d，在整个过程中蒸汽连续注入。研究结果表明，与未调整的老井相比，调整后泡沫辅助蒸汽驱可生产11a，新增产能为1．15×10^4t，提高采收率为14．63％。

With steam injection times and production time of steamed well increasing,the problem that production declines quickly and serious steam channels become very common,and recovery enhancing of this kind of reservoir become more difficult after the viscous oil reservoir undergoes steam soak and steam flood.Thermal chemical flood is the foam system that is acceded to steam and thermal water which is injected to reservoir,distinguishing feature of foam system that 'water shutoff and not oil shutoff' and ' low shutoff and more high shutoff' can change flow direction of medium,repress steam overlapping and steam channeling and supply producing energy,so that it can get the performance of enhancing recovery and economic benefit.According to numerical simulation and production reality of reservoir,injection and production parameters are designed:equally steam injection rate after foam flooding is 3.9 t/h,production/injection ratio is 1.3,quality fraction of foam is 0.5%,length of slug flow is injection 30 d and stop 60 d,and steam is injected in all process.The result indicates that,compared with old unregulated well,the ninth block can produce more 11 years and increment of productive capacity is 1.15x10 t after foam steam injection is designed,meanwhile, the recovery ratio of block can be enhanced by 14.63%.