Hydraulic fracturing is an important technical means to improve the development effect of low-permeability oil and gas reservoirs. However, for low pressure, low-permeability, tight, and high-clay sandstone gas reservoirs, conventional propped fracturing can cause serious damage to the reservoir and restrict the fracturing effect. The pre-acid fracturing technology combines acid treatment technology with sand-fracturing technology. A pre-acid system that meets special performance requirements is injected before fracturing. The pre-acid reduces the formation fracture pressure and removes clay damage. During acid flowback, the fracturing fluid is promoted to break the gel, dissolve the fracturing fluid residue and polymer filter cake, clean the supporting cracks, and effectively improve the fracturing effect. This study analyzes the process principle and technical advantages of the pre-acid fracturing technology based on the laboratory evaluation of the fracturing damage mechanism of low-permeability tight gas reservoirs. To meet the performance requirements of low-permeability tight gas reservoirs and pre-acid fracturing technology, a set of polyhydrogen acid system with long-lasting slow reactivity, low damage, and low corrosion was developed and used as the pre-fracturing acid. The acid system is mainly composed of the main agent SA601 and the auxiliary agent SA701. Then, on the basis of laboratory experiments, this acid system is used as the fracturing pre-acid to evaluate the fracturing improvement effect. The results show that the fracturing fluid system can better dissolve the fracturing fluid filter cake and remove the fracturing fluid damage.

水力压裂是提高低渗油气藏开发效果的重要技术手段。但是，对于低压，低渗，致密，高黏土的砂岩气藏，常规的支撑压裂会严重损害储层，限制压裂效果。预酸压裂技术将酸处理技术与砂压裂技术相结合。满足特殊性能要求的预酸系统在压裂之前被注入。该预酸降低了地层破裂压力并消除了粘土破坏。在酸回流过程中，促进了压裂液的破碎，溶解了压裂液的残留物和聚合物滤饼，清理了支撑裂缝，有效提高了压裂效果。本文通过对低渗透致密气藏压裂破坏机理的实验室评价，分析了预酸压裂技术的工艺原理和技术优势。为满足低渗致密气藏的性能要求和预酸压裂技术，开发了一套反应时间长，反应寿命长，损伤小，腐蚀低的多氢酸体系，并将其用作预压裂酸。酸体系主要由主剂SA601和辅助剂SA701组成。然后，在实验室实验的基础上，将该酸体系用作压裂预酸，以评价压裂改善效果。结果表明，压裂液体系能较好地溶解压裂液滤饼，消除压裂液的破坏。