The Study About A Novel Supramolecular Viscoelastic Surfactant Fracturing Fluid And Performance Evaluation

Hydraulic fracturing of oil and gas wells is one of effective method for increasing production of oil and gas reservoir. Fracturing fluids are very important in hydraulic fracturing operations. The fracturing fluids property is essential to fracturing operations success and plays an important role in increasing production of low permeability reservoir. Among various fracturing fluids, water-based fracturing fluids is the most widely used. Viscoelastic surfactant(VES) fracturing fluids have properties of high viscoelasticity and low formation damage, and is easy to prepare with no breaker and chemical crosslinkers needed.Extensive research on the viscoelastic surfactant fracturing fluids have been done, however the various factors affecting high temperature fracturing fluid system have not been systemically studied.The properties of a novel supramolecular complex fracturing fluid consisting of worm-like micelle and associative polyacrylamide copolymer were investigated. The studied properties include rheology, viscoelasticity, temperature stability, shear recovery, sand suspension, fluid conductivity and gel breaking. The results showed that the viscosity of fracturing fluid is 40 m Pa·s at a shear rate of 100s-1 and 90℃. The viscosity of fracturing fluid is stable for over 90 min at 90℃. The fracturing fluid is shear thinning from 40s-1 to 1000s-1, and viscosity can be instantly recoveried from high shear 1000s-1 to low shear 40s-1. Static sedimentation rate of proppant in fracturing fluid is less than 0.054mm·s-1 in various oilfield water at 80℃.The results show that fluids have good suspension, short gel breaking time, and high conductivity. The fluid meets the requirements for field application.