自生酸酸液体系评价实验研究

自生酸也叫潜在酸,可以在地层中发生化学反应就地生酸,且生酸是逐步进行的,使得酸岩反应速度会大大减慢。以高温下能生酸的体系乙酸甲酯(A剂)与氯化铵盐(B剂)为母体调配出一种酯类自生酸,对其性能进行研究表明:当A剂与B剂比例为3:2时,生酸能力最强。这种自生酸在90℃释放出的有效H^+浓度可达3.78 mol/L,在140℃释放出的H^+浓度可达4.26 mol/L,满足对储层的溶蚀要求。这种酸液与地层水及各种工作液体系的配伍性能均较好,对钢片的腐蚀速率小于60 g/(m^2·h),满足酸液施工行业的一级标准。针对此类自生酸,宜采用乙二胺四乙酸二钠对其进行破胶,破胶效果良好。相较于转向酸、交联酸,自生酸形成的酸蚀裂缝导流能力更好。通过对自生酸封堵能力进行测试,发现在18 MPa左右会形成有效封堵。

Experimental study on evaluation of authigenic acid system

The Self-generated acid, also known as the latent acid, can be chemically reacted in the formation to produce acid in situ, and the acid is gradually carried out, so that the reaction speed of the acid rock is greatly slowed down. A kind of ester auto-acid was prepared by using methyl acetate(A agent) and ammonium chloride salt(B agent) as the precursor of the acid-producing system at high temperature. The performance of the product was as follows: when the ratio of agent A to agent B was 3 to 2, the acidity is the strongest. The effective H^+ concentration of this phthalic acid released at 90 ℃ can reach 3.78 mol/L, and the H^+ concentration released at 140 ℃ can reach 4.26 mol/L, which satisfies the corrosion requirements of the reservoir. The compatibility of the acid solution with the formation water and various working fluid systems is good, and the corrosion rate of the steel sheet is less than 60 g/(m^2·h), which satisfies the first-class standard of the acid liquid construction industry. For such autogenous acid, it is preferable to use disodium edetate acid disodium to break the gel, and the gel breaking effect is good. Compared with the steering acid and the cross-linked acid, the acid-etching crack formed by the self-generated acid has better conductivity.By testing the self-generated acid blocking ability, it was found that effective sealing was formed at around 18 MPa.