Performance evaluation of a high temperature-resistant & low damage nano-VES fluids

Aiming at the problems of clean fracture fluids with low temperature-resistant and high fluid loss, a novel high temperature-resistant and low damage nano-VES fluids was developed. The results show that the tighter three-dimensional network which formed by MWNT and zwitterionic surfactant BET-12 can enhance viscosity when the concentration of MWNT is appropriate. The added MWNT concentration for 3% BET-12 was optimized to be 0.3% by rheological measurements. The results of performance evaluation of the nano-VES fluids indicate its viscosity is more than 20 mPa·s at 170 s^-1 and 150 ℃.The volume of fluid-loss of nano-VES fluids is obviously lower than base fluids at 70 ℃, the system with excellent shear restoration and proppant suspension capability. When the nano-VES fluids contact with formation water or hydrocarbon substance, the gel can be quickly broken down. The damage rate of fracture flowed conductivity of the fluid is 8.9%, showing a less formation damage compared with polymer fluids. Research result shows that the nano-VES fluids can be applied to middle and high temperature reservoir development.