Polymer-Free Fluid for Frocturing Applications

Polymer residues that slay in the fracture after fracturing can limit the treatment effectiveness. A new and easy-to-prepare, surfactant-hased polymer-free fluid, ClearFRAC(tm), that consists of a quaternary ammonium salt derived from a long-chain fatty acid is described. In brine, it builds fluid viscosity and viscoelasticity due lo the formation of highly entangled worm-like micelles. The micelles have a gross structure similar to a polymer chain. Since the viscosity of the fluid depends on the nature of micelles, the fluid can be broken by changing this micellar structure. The breaking occurs when the fluid is exposed to hydrocarbons or diluted with formation water. Therefore, conventional breakers are not required, and the produced oil or gas can act as breakers for this fluid system. The structural characteristics of this viscoelastic surfaclantbased fluid to its chemical and physical properties are correlated in this article. Structure, rheology, fluid loss, and conductivity of this surfactant fluid together with its case histories are presented.