Herein is presented a new methodology to determine the static adsorption of a zwitterionic surfactant on limestone in three different aqueous media [high-performance liquid chromatography (HPLC) water, seawater, and connate water] with the use of HPLC at room temperature and 70 °C. The results showed that, in both HPLC water and seawater, the surfactant adsorption followed a monolayer Langmuir tendency. In contrast, for connate water, the surfactant presented a new adsorption profile, characterized by two regions: (i) At surfactant concentrations below 1500 mg L(-1), an increase of adsorption is observed as the amount of divalent cations increases in the aqueous media. (ii) At surfactant concentrations above 1500 mg L(-1), the adsorption decreases because the equilibrium, monomer ⇆ micelle ⇆ vesicle, is shifted to the formation of vesicles, giving as a result a decrease in the concentration of monomers, thus reducing the interaction between the surfactant and the rock, and therefore, lower adsorption values were obtained. The behavior of the surfactant adsorption under different concentrations of divalent cations was well-described by the use of a new modified Langmuir model: (dΓ/dt)ads = k(ads)c(Γ∞ - Γ) - k(cmc)(c - c(cmc))(n)ΓH(c - c(cmc)). It was also observed that, as the temperature increases, the adsorption is reduced because of the exothermic nature of the adsorption processes.

Herein, the synthesis of three zwitterionic compounds (GZC-8, GZC-12, and GZC-18) derived from β-amino acids was carried out in good yield (>97%) through an ecofriendly, zero-waste synthesis procedure, starting from alkylamines (octylamine, dodecylamine, octadecylamine) and acrylic acid, under solventless conditions at ambient pressure and temperature. These compounds were characterized by Fourier transform infrared, two-dimensional nuclear magnetic resonance, electrospray ionization mass spectrometry, and elemental analyses and then evaluated as potential corrosion inhibitors for CO2 acidic environments characteristic of enhanced oil recovery (EOR) processes of the petroleum industry through electrochemical techniques such as open circuit potential (OCP), lineal polarization resistance (LRP), electrochemical impedance spectroscopy (EIS) at different immersion times, and potentiodynamic polarization after 24 h of immersion. From experimental measurements, inhibition efficiencies of 60, 89, and 90% were obtained for GZC-8, GZC-12, and GZC-18, respectively at a concentration of 25 ppm. In addition, acute toxicity of GZCs was evaluated on Photobacterium phosphoreum (Vibrio fischeri) by Microtox testing from which an EC50 value of 209, 188, and 43 ppm was obtained for GZC-8, GZC-12, and GZC-18, respectively, i.e., 2 orders of magnitude lower than typical ionic liquid inhibitors. From experimental results, it was found that the GZC-12 compound presented an adequate balance between inhibition efficiency and toxicity with maximum efficiency of 98.9% at a concentration of 75 ppm. Accordingly, GZC-12 can be classified as well-suited to human health and the environment and thus as a greener production alternative for oil and gas industry operations.

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Dynamic adsorption of a zwitterionic-type surfactant cocamidopropyl hydroxysultaine on limestone cores at oil reservoir conditions, i.e., under 2000 psi pressure, 130 °C temperature, and in the presence of seawater with 30 800 ppm NaCl, has been studied through core-flood displacement tests and in the absence of oil, at an injection rate of 120 cm3·h–1 up to 60 pore volumes (PV). The amount of adsorbed surfactant has been determined from mass balance by calculating its concentration through high performance liquid chromatography (HPLC). The normalized surfactant concentrations (NSC) have been used in terms of the PV, and then they are obtained the corresponding dynamic adsorption curves. Dynamic adsorption isotherm curves of the zwitterionic surfactant diluted in seawater showed a steep rise between 1 and 3 pore volumes (PV), and the saturation conditions were kept up to 60 PV. An average surfactant adsorption of 0.1138 ± 0.0126 mg·g–1 was determined. Quantum theoretical studies show that the electronic energy gap of (104) the limestone is electrically neutral, preferably acquiring a negative charge tendency, these results imply that the calcite surface will preferentially interact with positive ions, so that the cations present in the solution interacting in the limestone, resulting in a positive charge in the rock that implies that the surfactant cocamidopropyl hydroxysultaine interacts in the rock by the anionic group.