极限体积压裂技术是深层煤岩气获得高产工业气流的有效手段，而压裂液是在该技术基础上充分“打碎”煤层、形成饱填砂复杂裂缝网络、实现煤岩增渗—促解吸的关键，充分满足现场工况、施工工艺和煤岩物性特征要求是煤岩气压裂液研究的重点。以高稳定性、速溶、低剂高效能和在线变黏一体化的减阻剂研发为着力点，通过无机盐刺激响应材料引入、开关型反相乳液聚合技术设计、多元共聚条件控制和促解吸剂复配等制备得到开关型乳液减阻剂。结合基础性能表征及评价，厘清了乳液减阻剂重要参数对压裂液性能的影响规律，确定水解度50%～55%、分子量1 800万左右、有效质量分数29%～34%的优化条件，得到预期的煤岩气专用减阻剂SFY-2，稳定性提高至50 d以上，抗低温−15 ℃以下，溶解时间降低至10 s，3 min增黏率达90%以上且增黏能力强，解决了常规乳液减阻剂稳定性和速溶性之间的突出矛盾，也为深层煤岩气极限体积压裂在线一体化施工提供了保障。借助SFY-2优势，契合煤岩气极限体积压裂设计思路构建了高效能变黏压裂液体系，制定变黏控制方案和施工工艺优化，实现充分“打碎”煤岩，造复杂缝网并饱填砂有效支撑的目标。对压裂液性能评价表明：高黏液、中黏液在70 ℃、170 s⁻¹～1 500 s⁻¹～100 s⁻¹ 模拟变剪切后黏度分别保持在35、20 mPa·s左右；高黏液、中黏液、低黏液降阻率分别可达66%、72 %、77 %以上，得益于压裂液良好的剪切稀释性，高剪切状态下高黏液、中黏液降阻率保持率超过100%；建立了压裂液悬砂性能与黏弹性参数tan δ的对应关系，当SFY-2体积分数超过0.2%(tan δ=0.84)后压裂液沉砂速度明显降低，体积分数达到0.4%(tan δ=0.395)后黏弹性显著，具有良好的携砂性能，利于高强度连续加砂进行缝网饱和支撑，并增大缝网有效改造体积；压裂液破胶后几乎无残渣，表面张力低至26 mN/m以下，破胶液可以有效改善煤岩表面润湿性，将接触角最高增大到108.2°，降低煤岩解吸伤害率最低至13%。该技术已在鄂尔多斯盆地深层煤储层累计施工超350井次(共2 000余段/次)，液体性能稳定，施工效率高，实时降阻率可达84.4%，加砂完成率高，增产效果显著，为实现深层煤岩气压裂技术进步及规模效益开发提供了强有力的支撑。

Limit volume Fracturing Technology is the effective means to achieve high yield industrial flow for deep coal rock gas, on the basis of this technique,fracturing fluid is the key to fully "Breaking" coal seam, establish filling sand complex crack network, realize Anatonosising-Desorption promote for coal rock,therefore, the focus of coal rock gas fracturing fluid research is fully meet the field condition, construction technology and physical characteristics of coal rock.Focus on the research of the friction reducer with high stability, instant, low dosage but high efficiency and on-line viscosity change integration,a switch-type emulsion resistance reducer was prepared by introducing inorganic salt stimulation response material,designing switch reverse phase emulsion polymerization technology, condition controling of Multicomponent copolymerization and compounding desorption promote agent.The influence law on fracturing fluid performance by important parameters of emulsion resistance reducer was clarified by combining Characterization and Evaluation of basic performance, the expected coal rock gas special resistance reducing agent SFY-2 was obtained with the optimization conditions of hydrolysis ratio for 50%～55%, molecular weight for about 18 million and effective content for 29%～34%, the stability is improved to over 50 day, the low temperature resistance is below﹣15 ℃, the dissolution time is reduced to 10 s, the viscosity increasing rate is over 90% in 3 min, and the viscosity increasing ability is strong,the highlight contradiction of convention emulsion friction reducer between stability and instant solubility was resolved,as well as provided a guarantee for the online integrated construction of deep coal rock gas Ultimate volume Fracturing.By taking the advantage of SFY-2, a efficient and variable viscosity fracturing fluid is constructed to fit the design idea of coal rock gas Ultimate volume Fracturing, the variable viscosity control scheme is formulated and the construction technology is optimizated to achieve the goal of "Breaking" the coal rock sufficiently, creating complex sewing nets, filling sands fully and supporting effective.Performance evaluation of fracturing fluid indicated that: after simulate variable shearing of 170 s⁻¹～1 500 s⁻¹～100 s⁻¹ at 70 ℃, the viscosities of high viscosity fluid and middle viscosity fluid were kept 35 and 20 mPa·s respectively; The drag reduction rates of high viscosity fluid,middle viscosity fluid and low viscosity fluid can respectively reachs more than 66%, 72%, 77%, furthermore, the resistance retention rate of high viscosity fluid and middle viscosity fluid is over 100% under high shear conditions, thanks to the good shear dilution of fracturing fluid.The corresponding relationship between the suspended sand performance and the viscoelastic parameter tanδfor the fracturing fluid has been established, when the dosage of SFY-2 exceeds 0.2% (tanδ=0.84), the settling speed of fracturing fluid is obviously reduced, When the dosage reaches 0.4% (tanδ=0.395), the viscoelasticity of fracturing fluid is significant, which is conducive to high strength continuous sand adding for seam mesh saturation support, and increases the effective transformation volume of seam mesh.There is almost no residue in fracturing fluid gel breaker,the surface tension is as low as 26 mN/m or below, the gel breaker can effectively improve the wettability of coal rock surface, increase the contact angle up to 108.2°, reduce the desorption damage rate of coal rock as low as 13%. This technology has been applied more than 350 Wells (more than 2 000 stages/times in total) in the deep coal reservoir of Ordos Basin, with the advantages such as stable liquid performance, high construction efficiency, the real-time Drag reduction rate reachs 84.4%, highly sand completion rate, remarkable effect of increasing production,and so on,which provided power for realizing the scale benefit development of deep coal rock gas.