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Abstract
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Electric field application has become an emerging strategy in enhanced oil recovery (EOR) because of environmental and economic benefits. This study elucidates the extent of interfacial tension (IFT) reduction for the crude oil water system by applying very low-voltage direct and pulsed electric fields with square and sinusoidal waveforms. For this aim, IFTs were measured using a set-up in which pendant drops were formed in a waterfilled cell equipped with parallel electrodes. Various direct and pulsed electric field strengths within (1–3) V/ cm and frequencies within (100 1000) Hz were applied. By stimulating indigenous natural surfactants, their adsorption at the interface is facilitated and that interface instabilities would be governed due to switching poles and the induced electro-hydrodynamic (EHD) patterns. This situation brings about IFT reduction from 32.0 to 8.1 mN/m by applying 3 V/cm electric field strength with an optimum frequency of 600 Hz. Temperature could further reduce the IFT to 4.9 mN/m (84.7 % reduction). Applying direct electric fields could reduce the IFT but to a lesser extent. Besides, the effects of asphaltene removal from crude oil were examined to clarify the mechanisms. The Young Laplace equation for no electric field, accompanied with the corrections due to electric field strength and frequency, could precisely reproduce the IFT data with a maximum deviation of ±7 %. The Findings highlight new advances in EOR to be extended for potentially efficient solutions.
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