Abstract: The Kuqa Piedmont Block in Tarim is an ultra-deep high temperature and high pressure block with the characteristics of deep burial, high temperature and high formation pressure, so conventional fracturing fluids are not favoralole for the construction requirements of this block. To this end, acrylamide (AM), trimethyl (3-acrylamidopropyl) ammonium chloride (APTAC), 3-acryloylethanol-3-methylpropanesulfonic acid (AEMS) were used as monomers to synthesize the polymer thickener JAS-3 with temperature resistance, salt resistance and low damage through the optimization of additives dosage and reaction parameters, and the properties of such polymer thickener were evaluated. The research shows: The polymer fracturing fluid prepared with JAS-3 has good temperature and shear resistance, sand-carrying performance and low damage to the reservoir. After adding NaBr with a mass fraction of 30% to 40%, its viscosity can still be maintained above 85 mPa·s at a temperature of 180 ℃ and a rotation speed of 170 r/s. The polymer fracturing fluid has a large elastic modulus, a small viscosity modulus, a larger rigidity, good sand-carrying performance, and meanwhile it has low residue content after gelout, causing small damage to the reservoir. The fracturing fluid has been tested in 6 wells in the Kuqa Piedmont Block in Tarim, and has achieved good stimulation effects. The development of the thickener has important reference significance for the fracturing of ultra-deep high temperature and high pressure blocks.

Key words: fracturing fluid, polymer thickener, temperature resistance, salt resistance, low damage, Tarim