页岩储层新型清洁滑溜水压裂液体系

NEW CLEAN SLICK WATER FRACTURING FLUID SYSTEM FOR SHALE RESERVOIR

滑溜水压裂液体系以其低摩阻、低伤害等特点,在页岩气储层压裂施工过程中得到了广泛的应用,而由于其自身黏度较低导致携砂能力较差,为达到施工设计的加砂量就需要大幅增加滑溜水压裂液的用量,从而增大了压裂施工的成本。为解决滑溜水压裂液携砂能力差的问题,开发出一套新型清洁滑溜水压裂液体系,该体系主要由高效低分子量减阻剂FJZ-2和新型聚合物乳液增黏剂FZN-1组成,体系综合性能评价结果表明,无论在室温还是80℃条件下,体系均具有良好的降阻效果;在80℃、170 s^(-1)条件下剪切90 min后,体系的黏度仍在20 m Pa·s以上,具有良好的耐温抗剪切能力;在一定的应力和频率扫描范围内,体系的储能模量G'一直高于耗能模量G",说明该压裂液体系具有良好的黏弹性能;支撑剂在该压裂液体系中的沉降速度明显低于常规滑溜水压裂液,而不同砂比条件下支撑剂的沉降时间均远远高于常规滑溜水压裂液,说明该压裂液体系具有良好的携砂能力;另外,该压裂液体系的其他性能指标均能满足滑溜水压裂液的技术指标要求。矿场应用效果表明,S-1井压裂施工过程顺利,最高砂比可达25%以上,最大降阻率达到70%以上,压裂施工效果明显。

Slick water fracturing fluid system has been widely used in shale gas reservoir fracturing because of its low friction and low damage.However,because of its low viscosity,the sand carrying capacity is poor.In order to achieve the sand loading amount of construction design,it is necessary to increase the amount of slip-water fracturing fluid substantially,thus,the cost of fracturing construction is increased.In order to solve the problem of poor sand carrying capacity of slick water fracturing fluid,a new clean and slick water fracturing fluid system has been developed.The system is mainly composed of an efficient low molecular weight drag reducer FJZ-2 and a new polymer emulsion tackifier FZN-1.The comprehensive performance evaluation results show that the system has both room temperature and80℃temperature.After shearing for 90 minutes at 80℃and170 s-1,the viscosity of the system is still above 20 m Pa.s,which has good resistance to temperature and shearing.In a certain range of stress and frequency scanning,the energy storage modulus G’of the system is always higher than the energy dissipation modulus G″,which indicates that the fracturing fluid system has good viscoelastic properties;the settling velocity of proppant in the fracturing fluid system is lower than that of conventional slick water fracturing fluid,and the settling time of proppant is much higher under different sand ratio conditions.The conventional slick water fracturing fluid shows that the fracturing fluid system has good sand carrying capacity.In addition,other performance indicators of the fracturing fluid system can meet the technical requirements of slick water fracturing fluid.The results of field application show that the fracturing process of Well S-1 is smooth,the maximum sand ratio can reach more than 25%,the maximum resistance reduction rate can reach more than 70%,and the fracturing effect is obvious.