关键词: 低渗透, 多元复合酸, 酸化, 降压, 增注, 应用

Abstract: Weicheng Oilfield is a typical rock sandstone oil reservoir.The result of acidizing is comparatively poor in recent years.Based on physical phenomenon of Weicheng Oilfield reservoir, influence factors of acidizing: influence of acid sludge, secondary precipitation of iron ion and influence of acid liquid discharged, were analyzed. Aimed at these problems, polyatomic-recombination acid was brought under research and application.Negative pressure extrusion acid and discharged acid integrated pipe string were used of this technology. This acid liquid having distinguishing feature as: ability to prevent secondary precipitation of iron ion effectively,ability to prevent acid sludge coming into being effectively,fine compatibility with formation water and fine ability to antiswelling.All these were proved in the lab.This technology was used in seven high pressure water wells and injection pressure decreases 12.8 MPa on average,cumulative increase water injected 27652m³. Comparatively fine result of decreasing injection pressure and increasing water injected are obtained.

Key words: polyatomic-recombination acid, acidizing, depressurization, augmented injection