低渗储层高效返排酸的性能评价及现场应用

Performance evaluation and field application of an acid system with high efficiency flowback in low permeability reservoirs

针对低压低渗储层酸化后残酸返排困难问题,在分析研究低渗条件下流体吸附滞留机理的基础上,研究开发了一种高效返排酸。室内研究结果表明:该酸液在盐酸质量分数低至5%时,溶蚀率高达97. 15%;表面张力为23. 09 mN/m,界面张力低至0. 83 mN/m;在温度60℃及90℃下的腐蚀速率仅为1. 29 g/(m^2·h)和4. 11 g/(m^2·h)。现场试验结果表明:C_1井解堵后产油量由3. 54 m^3/d增至136 m^3/d,酸化有效期长达184 d。该技术能有效解决低渗油气田酸化后残酸返排难的技术难题,有效保证酸化增产效果,具有较好的应用前景。

In order to solve the problem of flowback in reacted acid in the reservoirs with low permeability, an acid system with high efficient flowback is developed based on the analysis of the mechanism of fluid adsorption and retention under low permeability. The laboratory results show that with the concentration of hydrochloric acid as low as 5%, the dissolution rate of the system is still as high as 97.15 %, and surface tension is 23.09 raN/m, interfacial tension is 0. 83 mN/m, the corrosion rate is 1.29 g/（m^2·h ） and 4. 11 g/（m^2·h） at the temperature of 60℃ and 90 ℃ , respectively. Field test results show that the oil production increases from 3.54 m^3/d to 136 m^3/d after plugging measures, while the period of validity is up to 184 days. The technology can solve the technical problem of difficult flowback in reacted acid, effectively ensure the effect of acidification and increase production, which has good application prospects.