New Viscoelastic Fluid for Chemical EOR

The viscoelastic fluid is induced by wormlike micelles formed by self-assembled surfactants. The phase<br>diagram of the surfactant in pure water was established using a pervaporation-based microfluidic device<br>(Leng et al., PRL, 96, 2006). Isotropic wormlike micelles have been observed up to 12 % w/w. In a second<br>step, Particle Tracking Microrheology (PTM) was used to investigate the rheological properties of the fluid<br>for surfactant concentrations below 2% w/w in water. Viscosity at low surfactant concentrations (0.1% to<br>0.3 % w/w), T= 80°C, in synthetic sea water (3.9 % w/w TDS) and in sodium chloride (2 % w/w TDS) has<br>been recorded. Data shows that the viscosity is weakly dependent on brine concentration and evolves<br>between 3 and 15 mPa.s (shear rate equal 10 s-1), for surfactant concentrations between respectively 0.1%<br>to 0.3 % w/w.