携砂酸压已经成为碳酸盐岩地层储层改造的重要措施之一,而实现携砂酸压的关键问题是选择性能良好的耐高温可携砂酸液体系。针对目前国内外交联酸液体系剪切变碎、脱酸严重、交联剂用量大、成本高等问题,通过设计合成了新型酸用疏水缔合稠化剂和高效交联剂,优选出了最佳交联酸体系配方,并对该体系进行综合性能评价室内实验。具体配方为20%盐酸+0.8%稠化剂SRAP-1+0.8%交联剂SRACL(2∶10)+2%高温缓蚀剂SRAC-1+0.2%铁离子稳定剂DF-1+1.0%助排剂SRCU-1+0.05%胶囊破胶剂JSP-8。综合性能评价结果表明,在大幅度降低交联剂用量的同时,该体系交联时间为89s左右,具有良好的延迟交联特性;在140℃、170s-1条件下恒温剪切2h后黏度仍大于60mPa·s,且交联状态仍然良好,无脱酸现象,完全满足现场施工要求,有很好的推广意义。
Acid fracturing with sand carrying acid has become one of the important measures in carbonate reservoir stimulation.The key to the success of acid fracturing with sand carrying acid is the selection of a high temperature sand carrying acid with good performance.To deal with problems encountered in fracturing,such as shear-breaking of the crosslinked acid by shearing,serious deacidification,high crosslinking agent consumption and high job cost etc.,a new hydrophobically associating thickener(used in acid)and a high performance crosslinking agent have been synthesized,and an optimum crosslinked acid formulation developed with the following composition:20%HCl+0.8%SRAP-1(thickener)+0.8%SRACL(2∶10,crosslinking agent)+2%SRAC-1(high temperature corrosion inhibitor)+0.2%DF-1(iron ion stabilizer)+1.0%SRCU-1(cleanup additive)+0.05%JSP-8(capsule gel breaker).Laboratory evaluation showed that the crosslinking time of the acid formulation was about89s even after substantial decrease in the amount of crosslinking agent,indicating that the acid formulation has good delayed crosslinking ability.After shearing for2h at140℃and170s-1,the viscosity of the acid was still greater than60mPa·s,and the state of the crosslinking remained stable,no de-acidification was found of the acid.The acid formulation has satisfied the need of field operation,and is worth popularizing.