砂岩油藏海水基酸液二次伤害的影响因素分析

Analysis on the influencing factors of secondary damage of seawater-based acid on sandstone reservoir

使用X射线衍射技术分析海水基酸液中的伤害类型,利用浊度法研究酸液类型、pH值、海水稀释倍数以及电解质对二次伤害的影响。结果表明:海水基酸液配制及反应中的二次伤害以MgF_2、CaF_2为主;相比土酸体系,多氢酸具有更好的抑制二次伤害的性能;增大酸液中HCl的用量、对海水进行稀释以及使用合适的电解质都可以抑制沉淀的生成。在酸效应、络合效应和一种特殊的反常同离子效应的基础上,研制出能够有效抑制酸液配制及反应中二次伤害的海水基酸液体系。

The damage type of seawater -base acid was analyzed by X- ray diffract ion technology. And the ef fects of acid types,pH value,dilution ratio of seawater and electrolytes on the secondar damage were studied by the turbidity method. It is found that the damage in seawater-based acid preparation and reaction is mainly formed by MgF2 and CaF2. C om p ared with mud acid system ,multi -hydrogen acid is better in mitig ating the secondary damage. Inc reasing the amo unt of HCl ,diluting seawater and using appropriate electrolytes can also effectively inhibit the precipitations. Based on the analysis of the acid effects,the complexation effect,and a special kind of abnormal common-ion effect,one seawater-based acid system that can eliminate the secondary damage in sandstone matrix treatmentis developed.