New Viscoelastic Fluid for Chemical EOR

Abstract

This work aims at evaluating a new surfactant based viscoelastic fluid for Chemical EOR applications. The surfactant based fluid exhibits a viscous phase at low concentration and high temperature, useful for improving oil recovery.The viscoelastic fluid is induced by wormlike micelles formed by self-assembled surfactants. The phase diagram of the surfactant in pure water was established using a pervaporation-based microfluidic device (Leng et al., PRL, 96, 2006). Isotropic wormlike micelles have been observed up to 12 % w/w. In a second step, Particle Tracking Microrheology (PTM) was used to investigate the rheological properties of the fluid for surfactant concentrations below 2% w/w in water. Viscosity at low surfactant concentrations (0.1% to 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 been recorded. Data shows that the viscosity is weakly dependent on brine concentration and evolves between 3 and 15 mPa.s (γ=10 s -1 ), for surfactant concentrations between respectively 0.1% to 0.3 % w/w.The second series of tests consisted of core-flood experiments at 80°C in Clashach sandstone with brine solution (NaCl 2% w/w) containing surfactant concentrations between 0.1 %w/w and 0.3 %w/w. The surfactant is shown to adsorb moderately on the sandstone (50 μg/g) and displace a great fraction of residual oil (from Sor=0.49 to Sor=0.20).These preliminary results show a strong potential for this new surfactant based viscoelastic fluid in chemical EOR. Compared to other viscoelastic fluids this product shows the following advantages:Superior viscosity, at low surfactant concentration, in hard brine and at high temperature Better displacement of residual oil in core-flood with moderate adsorption

Viscoelastic Surfactants with High Salt Tolerance, Fast‐Dissolving Property, and Ultralow Interfacial Tension for Chemical Flooding in Offshore Oilfields

“…In previous research on chemical flooding, the viscosity of polymer or VES solution was measured at a fixed shear rate in the range of 1–10 s −1 (Azad & Sultan, ; Dai et al, ; Kumar et al, ; Lakatos et al, ; Li et al, , ; Morvan et al, ; Santvoort & Golombok, ; Sultan et al, ; Zhu et al, ). Thus, the viscosities of HDPS/SDS and ODPS/SDS solutions as a function of total surfactant concentration are summarized in Fig.…”

“…When the concentration of micelles is above the threshold point, those micelles can overlap and entangle to form three‐dimensional network structures, exhibiting remarkable viscoelastic properties. The fascinating properties of the worm‐like micelles render them extremely useful in many applications, for example, as templates for nanomaterial synthesis (Qiao et al, ), carriers for drug release and delivery (Afifi et al, ), clean fracturing fluid for oil production (Lu et al, ; Samuel et al, ), and mobility‐control agents for chemical‐EOR (Azad & Sultan, ; Dai et al, ; Kumar, Awang, Abbas, & Kalwar, ; Lakatos et al, ; Li, Jing, He, Ren, & Wei, ; Li et al, ; Morvan et al, ; Santvoort & Golombok, ; Sultan, Azad, Hussein, & Mahmoud, ; Zhu, Fan, Liu, & Li, ). Morvan et al () found that the surfactant‐based viscoelastic fluid shows superior thickening ability at a low surfactant concentration ( e.g ., 0.5 wt.%), high‐salinity brine, and high temperature.…”

Enhanced Oil Recovery: An Update Review

“…Therefore and despite the volatility of oil prices, it is fair to conclude that operators and surfactant manufacturers are showing a growing interest in EOR chemical flooding [132,133]. This trend is also noticed with an increase of screening and lab studies to evaluate or re-estimate EOR potential of chemical flooding in different basins [134][135][136][137][138][139][140][141].…”

Development of a Stimuli‐Responsive Gemini Zwitterionic Viscoelastic Surfactant for Self‐Diverting Acid

“…In the oil and gas industry, smart surfactant micelle materials, also named viscoelastic surfactants (VES), have been successfully applied as clean working fluid thickeners in enhanced oil recovery and reservoir stimulation (fracturing and acidizing) (Degre et al, ; Mao et al, , ; Morvan et al, ). According to field practices, salinity, temperature, pH, and acid concentration are the main response conditions that can be adjusted to control micelle structures and rheological properties.…”

“…The conditions that control formation of wormlike micelles and rheological properties have been described, including temperature, pH, salinity, light, electricity, and CO 2 levels (Chu et al, 2010;Chu and Feng, 2011;Weiss and Terech, 2006). In the oil and gas industry, smart surfactant micelle materials, also named viscoelastic surfactants (VES), have been successfully applied as clean working fluid thickeners in enhanced oil recovery and reservoir stimulation (fracturing and acidizing) (Degre et al, 2012;Mao et al, 2016Mao et al, , 2018Morvan et al, 2009). According to field practices, salinity, temperature, pH, and acid concentration are the main response conditions that can be adjusted to control micelle structures and rheological properties.…”