Evaluation And Analysis Of Low Friction,high Density And High Temperature Fracturing Fluid

The Shunbei block of the Tarim Basin in Xinjiang has the characteristics of high reservoir temperature?180??,deep burial depth?8600m?and dense lithology.The common silicone fracturing fluid has poor temperature resistance,fast gelation speed,it has high friction and greatly increase wellhead pressure,which will improve fracturing cost and construction difficulty,so it needs to be developed.A low friction,high density and high temperature fracturing fluid system is available to meet the needs of on-site construction.Firstly,a polyacrylamide polymer GS-100 was selected as a thickening agent for the fracturing fluid system based on literature research results and laboratory conditions;Three kinds of organic zirconium crosslinkers ZJ-60,ZJ-55,ZJ-125 were synthesized in the chamber by using zirconium oxychloride,glycerol,lactic acid,sodium hydroxide,ethylene glycol and triethanolamine as raw materials.The most suitable product ZJ-60was screened by orthogonal experiment as the crosslinking agent of the fracturing fluid system,the optimal addition is 0.65%.At the same time,the p H regulator was determined to be 1mol/L hydrochloric acid,the optimal addition is 2.5%;among the five common inorganic salts of Na Cl,KCl,Na Br,Ca Cl₂,and Na NO₃,KCl was preferred as a weighting agent for the fracturing fluid system in consideration of fracturing cost and temperature resistance test,the density of the fracturing fluid can be increased to 1.1 g/cm³by adding 20%KCl.Then,we used polymer GS-100,organic zirconium crosslinker ZJ-60 and weighting agent KCI to form a gelatin fracturing fluid under acidic conditions,the optimum thickener addition amount determined by the rheological experiment was0.5%.The formula was:0.5%GS-100+0.65%ZJ-60+2.5%hydrochloric acid+20%KCI was obtained.The polymer fracturing fluid was then prepared according to the above formula to evaluate the comprehensive performance of the fracturing fluid.The final evaluation result was that the new low friction,high specific gravity and high temperature fracturing fluid system had a good temperature resistance and shear resistance,and it could be increased to a density of 1.1 g/cm³.After being sheared at180?,170 s^-1for 90 min,the viscosity of the fracturing fluid was always above 50m Pa·s.After the addition of the anti-panning agent,the demulsifier and the drainage aid,the compatibility between the respective additives in the fracturing fluid was still good.The viscosity after breaking the gel was less than 5 m Pa·s,and the residue content was340.25 mg/L.The filtrate of the system broke the core matrix.The average penetration rate of penetration rate was 26.94%,the resistance reduction rate exceeded 75%.It had a certain delayed cross-linking characteristics,which could meet the on-site construction requirements.