ABSTRACT
Viscoelastic surfactant (VES) systems based on wormlike micelles have generated considerable scientific interest and have been used in applications ranging from industrial cleaning, detergents, hydraulic fluids, and slurry transport fluids. The oil and gas industry has also employed VES fluids in a variety of well completion and stimulation applications. This chapter deals with brief discussion of applications and requirements of fluids used in oilfield operations. It describes the self-assembly process of VES fluids and some of the surfactant chemistries used in oilfield operations. The chapter provides key properties of a successful VES fluid are explained, and important advantages of VES gels. Traditionally, polymers such as guar or hydroxyethyl cellulose have been used as fluid thickeners in oilfield applications. Three classes of VESs are useful in oilfield applications— cationic, anionic, and zwitterionic. Each has advantages and disadvantages that influence the manner in which they are used.
