Abstract:

Single phase micro-emulsified acid was studied in laboratory aimed at reducing its corrosion on pipes in the process of acidizing and increasing the penetration range of the layer. Micro-emulsified acid were prepared by mixing cationic surfactant with nonionic surfactant and other additives. The laboratory formation of the single phase micro-emulsified mud acid were as following(mass ratio):2.5% A-126, 2.5% CHJ-100, 1.2% n-butanol, 2.3% n-octanol, 0.5% W-221, 67.0% mud acid, 24.0% diesel oil. The result shows that its thermal stability can reach 81 ℃ with the suitable amount of additive of anionic surfactant W-221. The reactions between the micro-emulsified acid and P110S steel under both room temperature and 70 ℃ showed that the ratio of inhibiting corrosion has reached to 90.57% compared with mud acid of the same concentrations. Finally, the reaction between the acid and manmade rock core under 70 ℃ shows that the corrosion rate reduce to 0.5%.

Key words: micro-emulsified acid, surfactant, corrosion inhibiting, temperature resistance