Phase Behavior And Rheology Of Viscoelastic Surfactant Fracturing Fluid

Hydraulic fracturing of oil and gas wells are one of effective method for increasingproduction of oil and gas reservoir. Fracturing fluids are very important in hydraulic fracturingoperations. The fracturing fluids property is essential to fracturing operations success andplays an important role in increasing production of low permeability reservoir. Among variousfracturing fluids, water-based fracturing fluids is the most widely used. Viscoelastic surfactant(VES) fracturing fluids have properties of high viscoelasticity and low formation damage, andis easy to prepare with no breaker and chemical crosslinkers needed.Extensive research on the viscoelastic surfactant fracturing fluids have been done, howeverthe various factors affecting high temperature fracturing fluid system and phase behavior ofthe concentrated fracturing fluid rheology have not been systemically studied.We hereby synthesized an environmental friendly zwitterionic surfactants, oleylamidopropyl betaine in laboratory, and studied the impact of co-surfactant, temperature,solvents, salts and small organic molecules on the system for oil field application. In addition,the proppant suspension, gel breaking and other relevant properties of the fluids were studied.In addition, for faster dissolution of VES fluid in the field, factors affecting the dissolutionrate of viscoelastic surfactant fracturing fluid concentrates are investigated, and providesguidance for oil field application.