酸敏研究进展

酸化也会产生某些不溶性物质堵孔喉,给储层带来新的损害,即产生所谓酸敏反应。综述了有关酸敏的研究进展。盐酸引起的酸敏及其防止对策为：石膏的二次沉淀,防止对策为在酸化液中加入CaCl2,但只要酸化液进入储层后不是优先与石膏接触,酸溶解碳酸盐矿物生成的钙离子就足以抑制石膏溶解,而无需外加钙离子;氢氧化钱沉淀,应用EDTA和NTA络合剂,并与乙酸复配,可有效抑制酸化液残液中析出氢氧化钱沉淀,由于亚铁离子生成氢氧化亚铁沉淀的pH值远大于残酸的pH值,所以应用抗坏血酸等还原剂将铁离子还原为亚铁离子也是抑制氢氧化铁沉淀的有效方法;水合二氧化硅,在储层中占优势的铝硅酸盐矿物的T50低于储层温度时,用醋酸代替盐酸可以防止生成水合二氧化硅。土酸引起的酸敏及其防止对策为：碱金属的氟硅酸盐沉淀,降低氢氟酸的浓度;铝垢,增大盐酸的浓度;氟化钙沉淀,用盐酸作前置液除去钙质。

Progress on the study of acid sensitivity

Acidizing may also produce some insoluble matters that plug the pore throats, causing further damages to the formation, i. e. , acid sensitive reaction. Progress on the study of it is reviewed in this paper. Acid sensitive phenomena caused by hydrochloric acid and the preventing solutions include: Secondary precipitation of gypsum, which may be ceased by adding CaCl2; precipitation of iron hydroxide, and it can be effectively inhibited by using the complexing agent of EDTA and NTA combined with acetic acid, or by using the reducing agent to reduce the iron ions back to the ferrous ions, as the pH value of iron hydroxide precipitation is remarkably over that of the residue acid; the formation of silica hydrate, when the temperature of T50 of the silicon a-luminate mineral is lower than the formation temperature, the hydrochloric acid may be replaced by acetic acid. Acid sensitive phenomena caused by hydrofluoric acid and the preventing solutions include: precipitation of silicate fluorine of basic metal, this can be minimized by lower the concentration of hydrofluoric acid; aluminum scale, which can be inhibited by raising the concentration of hydrochloric acid; precipitation of calcium fluorine, and by using the hydrochloride acid as flushing fluid, the calcium may be removed.