超分子压裂液体系的研制及评价

为解决现有交联压裂液抗剪切稀释性差、仅靠高黏度携砂,且残渣含量高易造成储层损害等问题,利用超分子聚合物化学原理,设计和制备出了一种超分子聚合物稠化剂,并研制出了配方简单、无需交联的超分子聚合物压裂液,并对其流变性、静态悬砂性、破胶性、静态滤失性和岩心基质伤害率进行了评价。结果表明,该压裂液体系在130℃、170 s-1剪切2 h后黏度可保持在140 m Pa·s;支撑剂的24 h和48 h沉降速率分别为3.7×10-4 mm/s和5.6×10-4mm/s;在80℃时加入0.05%的破胶剂过硫酸钾,2 h破胶后,破胶液黏度为1.32 m Pa·s,破胶液表面张力为25.23 m N/m,破胶液透明、基本无残渣;初滤失量为2.32×10-3 m3/m2,滤失系数为1.86×10-4 m3/min0.5,滤失速率为3.23×10-5 m/min,压裂液滤液对岩心基质的伤害率为10.8%。室内评价结果证明,该超分子聚合物压裂液体系满足致密气藏使用要求。

Development and Evaluation of Supramolecular Fracturing Fluid

Crosslinking polymer fracturing fluids presently used have poor shear-thinning performance, therefore relying on high viscosity forsand carrying. Moreover, these fracturing fluids, because of their high residue contents, have been causing reservoir damage. A supramolecular polymer has recently been developed and a fracturing fluid of simple formulation has been prepared. Laboratory studies show that this fracturing fluid has viscosity of 140 mPa·s after shearing at 130℃ and 170 s-1 for 2 h. Settling velocities of a proppant in this fracturing fluid at 24 h and 48 h are 3.7×10-4 mm/s and 5.6×10-4 mm/s, respectively. At 80℃, this fracturing fluid, 2 h after treatment with potassium persulfate at a concentration of 0.05%, has a viscosity of 1.32 mPa·s and a surface tension of 25.23 mN/m. The fracturing fluid, with gel broken, is transparent, and has almost no residues. It has an initial filtration volume of 2.32×10-3 m3/m2, a filtration coefficient of 1.86×10-4 m3/min0.5, and a filtration rate of 3.23×10-5 m/min. Damage of the filtrate of the fracturing fluid to the matrix of cores is 10.8%. These properties make this fracturing fluid suitable for use in the fracturing of tight gas reservoirs.