氮气泡沫剂性能评价及在大庆油田的应用

Application and Stability Evaluation of Nitrogen Foaming Agent Used in Daqing Oilfield

研制了适用于大庆油田的WT-1、WT-2、WT-3三套氮气泡沫剂体系。首先进行了静态评价实验,考察了温度、矿化度、含油饱和度等因素对三种氮气泡沫剂体系发泡体积、泡沫半衰期等性能的影响。实验结果表明:三种氮气泡沫剂体系适用于油藏温度小于55℃、矿化度小于5000mg/L、含油饱和度低于20%的油藏。然后,选用泡沫剂体系WT-1进行了动态评价实验,考察了发泡剂浓度、岩心渗透率、注入速度等因素对泡沫剂性能的影响。动态实验结果表明:气液比(氮气∶泡沫剂)介于1∶1～2∶1之间为最佳,注入速度对产生泡沫的质量没有明显影响,气液混注比气液交替注入效果好。大庆油田北2-丁2-59井组应用研制的氮气泡沫剂体系调剖后,启动压力平均升高0.7MPa,吸水剖面得到了有效调整,9口采油井中有6口井受效,整个井组累计增油3486t。

The systems of WT-1,WT-2,WT-3 nitrogen foaming agent suitable for Daqing oilfield were developed.Through a static evaluation experiment,the influence of the temperature,salinity and oil saturation on the performance of foam volume and half foam life period was researched for these three systems.The results show that these three systems can be available to the reservoirs with the temperature less than 55℃,salinity less than 500mg/L and oil saturation less than 20%.The system of WT-1 was selected for dynamic evaluation experiments.The influence of concentration of foaming agent,rock permeability and injection rate on the performance of the agent was researched.The results present that the best gas-liquid ratio is between 1 ∶1 and 2∶1,and the injection rate has few influence on the quality of the foam.The effect of gas-liquid mixed injection is better than gas-liquid alternative injection.After profile control of the developed agent in Bei2Ding2-59 well group,threshold pressure increased by 0.7MPa as average value and injectivity profile is improved.There are six ones have responses in nine production wells with 3486t of the cumulative incremental oil production in the whole well group.