Phase behaviour and thermodynamic properties of lamellar liquid crystal developed for viscoelastic surfactant based fracturing fluid

Phase behaviour of SDS/iso-amyl alcohol/pine oil/water and SDS/tert-amyl alcohol/pine oil/water systems were investigated for the development of viscoelastic surfactant (VES) based fracturing fluids having lamellar structures. The effects of co-surfactant, alkali, salt and nano-particle on rheology and thermodynamics of the lamellar liquid crystals were investigated. In contrast to tert-amyl alcohol, the use of iso-amyl alcohol as en surfactant facilitated the formation of water based gels. However, with subsequent addition of alkali, salt and nano particles, VES fluid indicated an improvement in viscoelastic properties. Decrease in viscosity was observed with increase in temperature and shear rate. The developed VES fluids were miscible in water and nano particle induced VES fluid exhibited satisfactory proppant suspension capability. (C) 2015 Elsevier Ltd. All rights reserved.