碳酸盐岩储层酸基压裂液体系性能研究

Research on the performance of acid-based fracturing fluid system in carbonate reservoirs

伊拉克米桑油田主力产层均为碳酸盐岩储层,具有岩性复杂、埋藏较深、地层温度较高以及非均质性强等特征,需要通过酸压技术开发储层。针对储层温度90℃酸压开采,通过实验室研究,优选出了适用于90~100℃碳酸盐岩储层酸基压裂液体系,盐酸浓度为20%,岩心溶蚀率为83.6%。在20%盐酸中,加入质量分数为1.0%稠化剂,耐温耐剪切评价后黏度保持61mPa·s;加入质量分数为1.0%酸化缓蚀剂,缓蚀率为2.61g/(m^(2)·h);加入质量分数为1.4%助排剂,表面张力为30.4mN/m,界面张力为1.8mN/m;加入质量分数为1.5%黏土稳定剂,防膨率为92.6%,各项指标均满足行业标准要求。

The main production layers of the Missan oilfield in Iraq were all carbonate reservoirs,which have complex lithology,deep burial,high formation temperature,and strong heterogeneity.Therefore,acid fracturing technology was needed to develop reservoirs.Based on laboratory research,an acid based fracturing fluid system suitable for 90~100℃ carbonate rock reservoirs was selected for acid fracturing at a reservoir temperature of 90℃,the hydrochloric acid concentration was 20%and the core dissolution rate was 83.6%.In 20% hydrochloric acid,a thickening agent with a mass fraction of 1.0%was added,and the viscosity remained at 6lmPa·s after temperature and shear resistance evaluation.Add a 1.0% mass fraction acid corrosion inhibitor with a corrosion inhibition rate of 2.61g/(m^(2)·h).Add a mass fraction of 1.4% drainage aid,with a surface tension of 30.4mN/m and an interface tension of 1.8mN/m.Adding an anti swelling agent with a quality score of 1.5% and an anti swelling rate of 92.6%,all indicators met the industry standard requirements.