甲酸盐完井液泥饼清除室内实验研究

Experimental Investigation on Formate Completion Fluid Mud Cake Cleaning

含碳酸钙颗粒的甲酸盐完井液体系常在裸眼砾石填充完井过程中使用,充填过程中会在井壁上形成泥饼。为了提高产能,该泥饼需要用一种合适的清除体系去掉。无机、有机酸和泥饼反应速度过快,造成泥饼清除不完全。原酸酯能在盐水溶液中水解并形成缓释酸,但由于甲酸盐体系较高的p H值,甲酸盐溶液体系对于原酸酯来说并非合适的基液。提出一种方法来解决这个问题:向甲酸盐体系中加入Na Br溶液后,原酸酯体系能用于甲酸盐体系的泥饼破胶。最后提出了一种螯合剂破胶体系,能够高效清除泥饼,并且满足缓速要求。

Formate completion fluid system with calcium carbonate particles is always used in open-hole gravel packing process. The mud cake is often formed in the packing process. It is important to clear the mud cake on the wellbore for restoring the productivity. Because of excessive high reacting rate with inorganic and organic acids, the mud cake can not be cleared adequately. Ortho ester can dissolve in the brine to produce sustained-release acid. But formate brine is not suitable base fluid for the ortho ester because of its high pH value. By adding sodium bromide solution to formate system, the ortho ester can be used to clear the mud cake. Another chelating agent system which can clear the mud cake efficiently was proposed in this paper. This system can meet the requirement of sustained-release.