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/min^0.5, 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.