微泡沫体系直径影响因素及微观稳定性

Bubble size influence factors and microscopic stability of microfoam system

针对普通泡沫稳定性差问题,通过玻璃珠填制的填砂管制备一种稳定性好、均匀度高且直径细小的微泡沫体系,用显微镜对微泡沫的微观形态进行观察,研究不同影响因素对微泡沫直径的影响,分析黄原胶稳定的微泡沫与普通微泡沫稳定性的差异。结果表明：气、液同时注入玻璃珠填制的填砂管时,可形成直径为10~100μm、变异因数小于10%的微泡沫体系。可通过改变溶液黏度、起泡剂质量浓度、两相流速、温度和回压等影响因素调节微泡沫的直径大小。随着溶液黏度、两相流速、回压的增大,微泡沫平均气泡直径减小,均匀性变好;温度升高导致微泡沫直径增大,均匀性变差。当起泡剂质量浓度高于5g/L时,起泡剂质量浓度增加对微泡沫直径影响不明显。由于溶液中的黄原胶增加液膜黏度和厚度,减缓微泡沫液膜排液过程,促使黄原胶稳定的微泡沫具有优越的稳定性,并在160g/L矿化度、90℃温度、6 MPa回压条件下,其稳定时间长达2h,而普通微泡沫的稳定时间少于20min。

In view of the poor stability of regular foam,we come up with a new method to realize good stability,high uniformity and small size of microfoam by using aglass beads sandpack.The micromorphology of microfoam were observed by microscope,the effect of different factors on bubble size of microfoam were investigated,and the stability of xanthan gum-stabilized microfoam and common microfoam at the pore scale were also compared.The results showed that highly uniform microbubbles from 10 to 100μm in diameter with a variable coefficient less than 10% were successfully prepared.The bubble size of microfoam could be adjusted by solution viscosity,foaming agent concentration,gas and liquid flow rate,temperature and back pressure.The bubble size of microfoam decreased and became uniformed increased with increasing solution viscosity,total flow rate,as well as the back pressure.The bubble size increased slightly and become nonuniformed with the increase of temperature,while the amount foaming agent had little effect on bubble size when its concentration was above 5g/L.The xanthan gum in the solution that increased liquid membrane viscosity and thickness,and drainage speed of liquid film was decreased,so xanthan gum-stabilized microfoam maintained excellent stability and continue to be stable for 2 hours under 160g/L salinity,90℃ and 6MPa back-pressure condition,as compared to less than 20 minutes for common microfoam.