An Overview of Recent Advances in Viscoelastic Surfactant based Fracturing Fluid Technology

Abstract

High percentages of oil and gas wells are hydraulically fractured worldwide in order to make economically producible at an efficient production rate. Cross-linked polymer fluids are in use for decades to stimulate oil and gas wells. Even though these fluids exhibit exceptional viscosity, thermal stability, proppant transportability and fluid leak-off control; extensive formation damage by polymer residues demanded a clean fracturing fluid technology. New generation of fracturing fluids based upon viscoelastic surfactants (VES) has recently been introduced which attempts to address this problem. Their gel rheology is caused by worm-like cylindrical micelles. The paper discusses about microstructure and rheology of model worm-like micelle forming systems, molecular – bulk property relationships, and unique rheological, functional treatments for efficient fracturing fluid design. Prospective application of viscoelastic synergy observed in mixed surfactant, mixed surfactant-polymer systems and its advantages over classical VES (c VES) technology is also discussed. The paper also deals with new adaptations in fracturing sector like foam fracturing, pseudo-cross linked VES technology, and its merits with respect to reservoir characteristics of different oil fields.
Keywords: Worm-like micelle, Rheology, Fluid-loss, Proppant suspension, Viscoelastic synergy