多氢酸体系酸化效果的室内试验研究

针对渤海辽东湾某区域油井采用常规酸液体系进行酸化处理效果不佳的现状,开展了多氢酸氢离子浓度测定以及多氢酸体系的溶蚀率、润湿性、流动效果等室内试验研究。结果表明:多氢酸原液的氢离子浓度较高,可以保证酸液体系中具有充足的氢离子与氟盐反应生成氢氟酸;多氢酸体系对石英的溶蚀率大大高于土酸和氟硼酸体系,而且对粘土矿物具有抑制反应速度的作用;多氢酸体系可以保持地层的水湿性质,不会对储层的油气渗流产生不利影响;多氢酸体系对砂岩储层的酸化效果要好于土酸和氟硼酸等常规酸液体系,应用多氢酸体系进行酸化处理后的岩心渗透率比可达3.0。采用本次试验研制的新型多氢酸体系对渤海辽东湾3口油井进行酸化处理,单井增油效果明显。

Lab experimental study on the acidizing effect of multi-hydrogen acid system

In order to resolve the problem of bad acidizing effect of the conventional acid systems applied in Liaodong Bay in Bohai Sea, the Lab experiments and studies have been conducted for the multi-hydrogen acid system (MH acid system), including the experiments of hydrogen concentration, solubility, wettability and core flow effect. The study results show that MH acid system has many advantages over the mud acid and fluorboric acid systems. For example, it contains enough hydrogen ion to react with villiaumite to generate fluorboric acid;it can improve the solubility of quartz greatly; it can retard reaction rate with clays; it can keep the formation water wetting property and the production of oil and gas would not be detrimentally affected; especially it can give better acidizing effect for the sandstone reservoir than the conventional acid systems. The core acidizing test indicates that MH acid system can improve the formation permeability and core permeability ratio (K/K0 ) up to 3.0. The MH acid system developed in the lab experiments has been successfully applied in 3 oil wells in Bohai Bay and single well stimulation effect is quite well.