Synthesis And Evaluation Of Hydrophobically Associating Polymer Thickener For Fracturing Fluid

In developing low permeability reservoirs,the performance of fracturing fluid directly affects the effect of hydraulic fracturing,and the performance of thickener is very important for fracturing fluid.In this paper,according to the requirement of water soluble thickener in fracturing fluid,the long chain quaternary ammonium salt with hydrophobic properties were selected as hydrophobic monomer to synthesize and evaluate.The synthesized hydrophobic monomer was copolymerized with acrylamide,acrylic acid and N-vinylpyrrolidone,and the hydrophobically associating polymer?AACV?was formed as a thickener.The optimum conditions were determined by the single factor analysis:monomer ratio is 62:26.5:10:1.5,monomer concentration is 20%,pH=7,the dosage of initiator is0.3%,and reacting 8 h at 30?.Under this condition,the apparent viscosity of thickener at the rate of 170 s^-1 is 162 mPa·s.The structure of the product is confirmed by the IR and¹H-NMR.The thickener was evaluated from the performance of the thickener solution and the properties of thickener in fracturing fluid.Results show that the AACV thickener has better temperature resistance and salt resistance,and the addition of the surfactant can increase the viscosity of the polymer solution in a certain range.AACV fracturing fluid is a typical power-law fluid.It has good heat and shear resistance performances and sand-carrying performance.Meanwhile,it has good gel breaking,and less damage to the reservoirs,which can meet the requirements of construction site.