铁对酸化效果的影响探讨及控制铁酸液配方研究

Influence of iron on acidizing effect and formula research of iron precipitation control acid

关键词:  高温碳酸岩  酸化  铁沉淀

Key words:  high temperature carbonate reservoir  acidizing  iron precipitation

摘要:

针对高温碳酸岩储层酸化后返排液中铁离子含量较高的问题,建立了铁对酸化效果影响模拟评价方法,探索了铁离子对酸化效果的影响关系,注入铁离子质量浓度为1 500～5 000 mg/L的酸液后,岩心渗透率降至初始渗透率的60%～67%。根据多基团桥接铁离子成为稳定物质的机理,研发了控制铁沉淀酸液体系,150 ℃、ρ(Fe)为5 000 mg/L时,酸反应至残酸(pH值＞3)后稳定铁4 650 mg/L,残酸对岩心的伤害＜20%。

Abstract:

Aiming at the problem of high iron concentration existing in the flowback fluid for acidizing the high temperature carbonate reservoir, simulation evaluation methods of iron on aciding effects are established, the influence relation of iron on the acidizing effects are discussed. After injecting acid with iron content of 1 500～5 000 mg/L, the core permeability reduced to 60%~67% of the initial permeability. According to the mechanism of multi-groups bridging iron becoming stable materials, acidizing fluid system of controlling iron precipitation was developed. Stable iron concentration in reacted acid(pH＞3) reduced to 4 650 mg/L from 5 000 mg/L at 150℃, the damage of reacted acid on core permeability was less than 20%.