Study And Application Performance Evaluation On High Temperature Fracturing Fluid System

In this paper,the fracturing fluid in the low-permeability and deep-high-temperature reservoirs can not guarantee the sufficient sand viscosity and the fracturing construction in the process of fracturing cracking under high temperature shear conditions.In order to solve this problem,through the screening of mesons,ligands,catalysts and so on,it was confirmed that boron,zirconium oxychloride,citric acid and triethanolamine were used as raw materials to synthesize OBZC-6 as a composite crosslinking agent for high temperature fracturing fluid methods and conditions to optimize.The cross-linking agent OBZC-6 is light yellow transparent liquid,the long-term preservation state is stable,the crosslinking time is adjustable,the temperature and shear resistance is good,which can reach 151?.At 150?,170 s-1 shear 1h,the viscosity remained at 65.4 mPa·s.The reaction conditions of the intermediates were optimized by the orthogonal experiment method.The modified guanidine gelatin GHPG was obtained by infrared spectroscopy,the structures of the intermediates and modified guanidine were characterized by1H-NMR and their properties were evaluated.The results showed that the properties of the modified carbamate GHPG were improved,the viscosity of 0.6% base was 95.31 mPa·s,the initial viscosity of crosslinked jelly was 1782.3 mPa·s,and the viscoelasticity was good.The formula of the high temperature fracturing fluid system was obtained by screening the thickener,crosslinking agent,temperature stabilizer,bactericide,crosslinking accelerator,auxiliary agent,viscosity stabilizer and breaker.The base solution is 0.6% thickener + 0.2%temperature stabilizer + 0.2% crosslinking accelerator + 0.1% fungicide + 0.06% dispatching agent + 1.0% clay stabilizer;The crosslinking agent is Organic boron zirconium crosslinking agent OBZC-6,crosslinking ratio is 100:0.3;the amount of breaking agent JN-160 is 0.2%.The properties of the high temperature fracturing fluid system were evaluated by temperature performance,shear resistance,filtration loss,rheology,viscoelasticity,breaking performance,residue content and damage to the core.The experimental results show that the performance indexes of the high temperature fracturing fluid system meet the relevant requirements of the oil and gas industry standard SY/T 6376-2008 "General technical requirements for fracturing fluid",the temperature is 163.8?,the shear resistance is good,Suitable for 160? fracturing needs.