Development and performance evaluation of high temperature resistant clean fracturing fluids

Aiming at the problem of high temperature failure of fracturing fluid in the process of high temperature deep well reservoir stimulation, an aqueous solution polymerization method was used to optimize the synthesis conditions to develop a fracturing thickener with a temperature resistance of 180 degrees C. The optimal preparation process is AM: DMDAAC: AMPS=1:0.1:0.1, the reaction temperature is 40 degrees C, the reaction time is 60min, and the initiator dosage is 0.2%. Based on the anti-high temperature thickener, the anti-high temperature surfactant, anti-swelling agent and gel breaker were further optimized, to optimize and construct a set of water-based fracturing fluid formula with temperature resistance up to 180 degrees C. The comprehensive performance evaluation results of the optimized formula of anti-high temperature clean fracturing fluid show that the optimized formula of water-based clean fracturing fluid can resist temperature up to 180 degrees C and can withstand temperature up to 10h at 180 degrees C. Under the condition of 180 degrees C, the viscosity has good stability within 60min. In addition, the settling speed of the steel ball at 180 degrees C is only 1/6 of the traditional fracturing fluid, showing good sand-carrying performance. The gel breaking performance is excellent, and the viscosity can be less than 5mPa.s after adding the gel breaker for 20min. In addition, the optimized fracturing fluid formula also has excellent reservoir protection effect, and the permeability recovery value is as high as 87%.