泡沫酸化技术研究及其在低渗非均质油藏中应用

Research of Foamed Acid System and it's Application in Low Permeability Reservoirs

本文针对华池油田长3油层在常规酸化过程中因非均质原因存在酸化效果差的实际状况,提出了在常规酸液中加入起泡剂和稳泡剂的氮气泡沫酸化法。室内研制出抗温性和抗盐性能较好的泡沫酸化液,并进行了泡沫封堵能力评价、泡沫岩心分流实验和现场泡沫酸化试验。得到泡沫酸化液配方为:1%十六烷基三甲基溴化铵和烷基酚聚氧乙烯醚的复配物EL-23(Ⅱ)+0.3%三聚磷酸钠STPP+12%HCl+3%HF+0.5%缓蚀剂EL-10+0.3%铁离子稳定剂EL-4。该泡沫酸化液耐热性达90℃,耐盐性能达80 g/L。驱替实验结果表明,泡沫驱封堵能力明显强于水驱,岩心分流量由注泡沫前的9.7∶5.5∶1变为最终的1.7∶1.5∶1。现场泡沫酸化1口井,酸化措施前日产油1.09 t,目前日产油3.14 t,日增油2.05 t,有效期4个月以上,取得了较好的效果。

In view of actual state of unsatisfactory acid effect of the heterogeneity formation,in the ordinary acid process,in Huaqing oil field,the nitrogen foam acidizing method was propounded through adding foam agent and stabilizer to the ordinary acid.The optimized foamed acid fluid with good heat resistance and salt resistance,heat resistance being up to 90℃,salinity resistance being up to 80 g/L,was obtained and the formulation was as follows：1% complex EL-23（Ⅱ）（a mixture of hexadecyl trimethyl ammonium bromide（CTAB） and nonionic surfactant）＋0.3% sodium polyphosphate＋12%HCl＋3%HF＋0.5%corrosion inhibitor EL-10＋0.3% ferric ion stabilizer EL-4.The results of core displacement experiment showed that the shutoff capacity of foam flooding was better than that of water flooding,the fractional flow of core turned from 9.7∶5.5∶1 before infusing foam,into 1.7∶1.5∶1.The system had been applied on one well with good acidizing result.The average daily oil production increased from 1.09 t,before acidizing,to 3.14 t,and the period of validity was four months above.