pH值对硅酸盐钻井液性能的影响

Effect of pH on properties of silicate drilling fluids

蓝强 邱正松 王毅 张妍

LAN Qiang QIU Zheng-song WANG Yi ZHANG Yan

中国石油大学泥浆研究室, 山东东营 257061 山东大学化学与化工学院, 山东济南 250100 胜利石油管理局钻井工艺研究院, 山东东营 257017

硅酸盐钻井液体系的流变性能、防塌性能以及油层保护性能受pH值影响最甚。采用常规方法研究了不同pH值下硅酸盐钻井液体系的性能,采用动态光散射技术研究了聚硅酸粒子的粒径分布和表面电荷。研究表明:pH值对体系的失水影响最大;对黏度影响则不同,在低浓度(1.0%)时pH值对体系的黏度影响不大,在高浓度(5.0%)时黏度随着pH值增加迅速下降;而防塌性能随着pH值增加先增强后减弱,在pH=8.0处达到最强;pH值通过控制聚硅酸粒子的粒径分布和表面电荷控制聚硅酸粒子的絮凝程度,从而影响到聚硅酸/造浆黏土和聚硅酸/井壁黏土之间的作用。该研究结果有利于人们从本质上认识硅酸盐钻井液体系的宏观性能,进一步促进硅酸盐钻井液体系的应用。

The theological property,hole-stability property,and reservoir protection performance of silicate drilling fluids are greatly influenced by pH.The properties of silicate drilling fluids of various pH are analyzed based on conventional methods,as well as the size distribution and surface charges of polysilicic particles are examined on the basis of the dynamic light scattering technology.Research results show that pH exerts the greatest effect on the water loss of silicate drilling fluids.However,the effect of pH on the viscosity of silicate drilling fluids varies a lot.When the silicate concentration is as low as 1.0%,the viscosity changes little with pH.But when the silicate concentration is as high as 5.0%,the viscosity decreases quickly as the pH increases.When the pH increases,the hole-stability property increases initially and then decreases,being the strongest when the pH is 8.0.Since the pH controls the size distribution and surface charges of polysilicic particles,so it determines the flocculation of them and it has effect on the interaction of poly-silicate particles/wellbore clay particles and poly-silicate particles/slurry clay particles.These results are helpful to recognize the properties of silicate drilling fluids in essential,and further to promote its application.

10.3969/j.issn.1000-7393.2007.03.025