An introductory investigation of a polymeric surfactant from a new natural source in chemical enhanced oil recovery (CEOR)

Greater than 50% of the original oil in place turns into immobile or trapped oil because of unfavored mobility and capillary forces problems. More efficient methods should be introduced in the tertiary oil recovery section as a scheme of Enhanced Oil Recovery (EOR). Surface-active-agents presented as surfactants play an important role in chemical EOR by their ability to optimize the operative parameters of interfacial/surface tension, wettability state, and modify the mobility of fluids in EOR processes. Beside all these optimizations induced to the fluid and rock of the reservoir, surfactants like other materials experience molecule losses by adsorption of solid/liquid interface. Great loss of surfactant molecules causes expensive materials cost and ineffectiveness of the benefits of these surface-active agents. Also, as literature reported, natural surfactants possess lower production costs, lower adsorption capacity, and environmentally friendly. This study introduces a new natural polymeric surfactant governed from the Acanthephyllum plant. Aqueous extraction process conducted and the extract was characterized by Fourier Transform Infrared spectroscopy (FTIR), Thermo-Gravimetric Analysis (TGA), and Proton Nuclear Magnetic Resonance spectroscopy (H-NMR). Characterization tests confirmed the polymeric state of the extract and the existence of surface-active functional groups in the extract. Interfacial tension (IFT) and surface tension (ST) between water-oil and water-air was measured respectively and showed a 92.6 and 61.6 percent optimization in their initial values in turn. Wettability alteration evaluated on a carbonate rock/crude oil/natural surfactant solution system and changed the oil wetness state of the initial oil-wet carbonate rock to a water wetness state because the wettability alteration measurements showed a reduction of the contact angle from 146 degrees to 64 degrees for only 80 min as the equilibrium time. Adsorption experiments conducted as adsorption isotherms and kinetic models. Freundlich isotherm fitted as the best model, and comparison of kinetic adsorption models for Acanthephyllum plant root extract as polymeric surfactant uptake shows that the pseudo-second-order model has the best accuracy and the pseudo-first-order model has the lowest accuracy.