小直径管在含油气井泡沫排水采气中的应用研究

Application of Small Diameter Pipe in Foam Drainage Gas Recovery of Oil and Gas Well

针对川西气区含油气井泡排低效的问题,通过物理实验模拟发现,含油气井中油套环空存在油水分层,且油套环空内流体搅动较弱,起泡剂扩散速度慢,这是导致泡排效果不佳的主要原因。采用小直径管将起泡剂加注到油水界面以下,使起泡剂直接与地层水作用,提高了药剂的利用率,具有加快气井排液、提高起泡剂携液量、降低井筒回压的作用。实验结果显示,小直径管加注起泡剂较环空加注气井泡排出液时间提前了52%,泡排携液量提高了73%,且加注位置越深、加注频率越高,泡排效果越好。为此,本文提出了深注剂、勤加注的含油气井起泡剂加注技术措施,在川西气区开展了两口井的现场试验,气井平均产气量提高了24%,产液量提高了52%,累计增产天然气82×10^(4)m^(3),经济效益显著,有效解决了含油气井泡排低效的问题。

Aiming at the issue of low efficiency of foam drainage in oil and gas wells in western Sichuan gas area,physical simulation experiment found that oil and water are in different layers in the casing annulus of oil and gas wells,and the fluid in the casing annulus is stirred weakly,and the diffusion rate of foaming agent is slow,which are the main reasons of poor effect during foam drainage.The foaming agent is injected below the oil-water interface through a small diameter pipe,so that the foaming agent can directly interact with the formation water and the utilization rate of the agent may be improved.It has the role of accelerating the drainage in the gas well,increasing the carrying capacity of the foaming agent and reducing the wellbore back pressure.The experimental results show that the fluid may be discharged earlier by 52%and more by 73%in the small diameter tube than that in the annulus,and the deeper the injection position and the higher the injection frequency,the better the effect of the foam discharge.For this reason,the technical measures of deep injection and frequent injection of the foaming agent in oil and gas wells are put forward in this paper.Field tests were carried out on two wells in the western Sichuan gas area.For the gas wells,the average gas production increased by 24%,the fluid production increased by 52%,and the accumulative increase of gas production was 82×10^(4)m^(3).Remarkable economic results have been achieved,and the low efficiency in the foam drainage may be improved effectively.