Study On Rheological Properties And Reaction Kinetics Of Ground Crosslinking Acid

Acid fracturing technology is an important means to exploit carbonate reservoirs,and fracturing fluid is the key to achieve sand carrying.Ground crosslinking acid is widely used in fracturing construction due to its low friction,high viscosity and low filtration.In view of the problems of ground crosslinking acid,the formulation of ground crosslinking acid was optimized in this thesis.Performance evaluation experiments and acid rock reaction kinetics experiments were carried out at 90 °C,120 °C and 150 °C,respectively,and optimized a high temperature ground crosslinking acid system.The ground crosslinking acid fracturing fluid system suitable for 150 °C is: 0.8 %thickener + 0.4 % crosslinking agent + 0.4 % conditioner + 20 % HCl + 7.5 % FL-C +1.0 % CA + 1.0 % DL-8 + 1.5 % A-25.The performance evaluation of the fracturing fluid showed that the fracturing fluid has good gel breaking and sand suspension.Under the condition of 150 °C,the apparent viscosity is stable at 40 ～ 50 m Pa·s after shearing for 2 hours,which meets the requirements of sand carrying.The acid-rock reaction kinetics experiments of ground crosslinking acid were carried out at 90 °C,120 °C and 150 °C,respectively.The results showed that it has better corrosion resistance than ordinary cementitious acid at the same temperature.At the same time,the performance of the residual acid after acid rock reaction was tested.The results showed that the surface tension of the ground crosslinking acid residue was about 29 m N/m,and the interfacial tension was about 3 m N/m,which was lower than that of the gelled acid.The flow resistance of ground crosslinking acid is low,which is conducive to the reverse flow of fracturing fluid.This fracturing fluid system has good comprehensive new energy,which has guiding significance for the development and field construction of carbonate oil and gas fields.