摘要：

针对致密碳酸盐岩储层“酸压+加砂”复合改造工艺面临的易砂堵问题，特别是酸性流体环境对压裂液携砂性能的破坏机制，本文构建了一套系统、精细化的实验评价方法与优化策略，分析了地层水、储层岩石矿物及酸岩反应残余酸对瓜胶压裂液流变性的影响规律。实验发现：前置酸与碳酸盐岩反应后的残余酸是导致压裂液破胶的首要因素，2%体积比的残余酸即可导致压裂液严重破胶；其次是地层水，10%体积比的地层水入侵即可引发压裂液的大幅破胶；碳酸盐岩的岩屑也能引发压裂液黏度大幅降低，在岩屑质量分数为10%时，压裂液黏度降低幅度约60%。基于实验结果，本文提出了包括液体化学改性与泵注程序物理隔离在内的综合优化方案，为致密碳酸盐岩的高效改造提供了坚实的实验依据。

关键词: 碳酸盐岩, 酸压, 加砂, 破胶, 实验评价

Abstract:

Addressing the issue of sand plugging susceptibility in the “acid fracturing + sand addition” composite stimulation technology applied to tight carbonate reservoir, particularly the degradation mechanism of fracturing fluid proppant-carrying performance under acidic fluid environments, this paper establishes a systematic and refined experimental evaluation methodology along with an optimization strategy. The effects of formation water, reservoir rock minerals, and residual acid from acid-rock reactions on the rheological properties of guar gum fracturing fluid were analyzed. Experimental results reveal that the residual acid following the reaction between the pre-flush acid and carbonate rocks is the primary factor causing fracturing fluid gel breaking; as little as 2 vol% residual acid leads to severe gel breaking. Formation water is the second most significant factor, with 10 vol% formation water intrusion inducing substantial gel breaking. Carbonate rock cuttings also cause a notable reduction in fluid viscosity: at a cuttings mass fraction of 10%, the viscosity decreases by approximately 60%. A comprehensive optimization strategy combining chemical modification of the fluid and physical isolation via pump sequencing is proposed, providing a solid experimental basis for the efficient stimulation of tight carbonate reservoirs.

Key words: carbonate reservoir, acid fracturing, propped fracturing, gel breaking, experimental evaluation

中图分类号: 

• TE357.2

• P618.13