天然气井用纳米高效泡沫排水采气技术研究

Study on nano and high efficient foam drainage gas recovery technology for natural gas well

为了使泡沫排水采气技术更有效地提高气田采收率,考察了二氧化硅纳米流体对表面活性剂基二氧化碳泡沫流变行为的影响,结果表明:纳米颗粒粒径的增大对泡沫稳定性有不利影响,而质量分数的增大会提高泡沫的稳定性。在90℃以上,泡沫表现出较高的泡沫降解率。当纳米颗粒质量分数增大时,泡沫黏度随之增大,表现出非牛顿剪切稀化行为。滞后分析表明,纳米流体泡沫S1在不同剪切速率下具有最小的滞后损失,加载和卸载循环后的滞后损失为5%。加入二氧化硅纳米流体可以改善常规CO_(2)泡沫的稳定性和流变性,进而提高采收率。

In order to make the foam drainage gas recovery technology more effective in improving gas field recovery,the influence of silica nanofluid on the rheological behavior of surfactant-based carbon dioxide foam is investigated.The results show that the increase of particle size of nanoparticles has a negative effect on the stability of foam,while the increase of mass fraction can improve the stability of foam.Above 90℃,the foam has a high degradation rate.When the mass fraction of nanoparticles increases,the foam viscosity increases,which shows non-Newtonian shear thinning behavior.Hysteresis analysis shows that the nanofluid foam S1 has the smallest hysteresis loss at different shear rates,and the hysteresis loss after loading and unloading cycles is 5%.Adding silica nanofluid can improve the stability and rheology of conventional CO_(2) foam,and then enhance the oil recovery.