Abstract

Surfactants are considered as beneficial chemical additives in enhanced oil recovery due to their capability of reducing the interfacial tension and altering the wettability. However, the loss of surfactant by adsorption on the surface of the porous rock is one of the significant drawbacks of surfactant flooding. The mechanism, equilibrium, and kinetics of adsorption of a natural surfactant derived from the weed, Eichhornia crassipes, on sandstone and sand surfaces have been investigated through batch experiments at different concentrations (i.e., 1000–5000 mg dm⁻³), temperatures (i.e., 298–333 K), and a fixed salinity [NaCl (76.2%), CaCl₂ (3.7%), MgCl₂ (1.5%), and Na₂SO₄ (18.6%)]. The mineralogy and morphology of the adsorbent samples were examined by the XRD and SEM analyses. The mechanism of surfactant adsorption and maximum adsorption were determined by various isotherms and kinetic models. $\Delta G^{\mathrm{o}}$ for adsorption on sandstone and sand was found to be −21.48 and −20.80 kJ mol⁻¹, respectively.

摘要

表面活性剂被认为是提高石油采收率的有益化学添加剂，因为它们具有降低界面张力和改变润湿性的能力。然而，表面活性剂在多孔岩石表面的吸附损失是表面活性剂驱的显着缺点之一。通过在不同浓度（即 1000-5000 mg dm -3 ）^、温度（即, 298–333 K) 和固定盐度 [NaCl (76.2%)、CaCl ₂ (3.7%)、MgCl ₂ (1.5%) 和 Na ₂ SO ₄(18.6%)]。通过 XRD 和 SEM 分析检查了吸附剂样品的矿物学和形态。表面活性剂吸附和最大吸附的机理由各种等温线和动力学模型确定。$\Delta G^{\mathrm{○}}$在砂岩和沙子上的吸附量分别为 -21.48 和 -20.80 kJ mol ^-1。