Experimental investigation of electric field-assisted in-situ conditioning of shale oil for reducing CO₂ minimum miscibility pressure
Abstract
Electric‑field‑assisted conditioning constitutes a promising approach for improving carbon dioxide‑oil miscibility during carbon dioxide flooding. However, studies to date have mainly focused on simplified model oils, and the miscibility behavior of real shale oil remains insufficiently understood. In this work, a custom‑designed electric‑field conditioning system was developed to investigate the physicochemical evolution of real shale oil and its subsequent carbon dioxide miscibility. While current and temperature were monitored during conditioning, viscosity, carbon number distribution and carbon dioxide minimum miscibility pressure were systematically characterized. The results show that current and temperature initially increased and subsequently declined with the attenuation of electrochemical reactions. Dark brown deposits accumulated on the electrode surfaces, which were likely associated with heavy polar components, accompanied by a progressive weakening of the electrochemical process. Electric‑field conditioning induced hydrocarbon redistribution, characterized by decreases in light and heavy fractions and the enrichment of medium fractions, together with reduced shale oil viscosity. The conditioned shale oil exhibited a lower carbon dioxide minimum miscibility pressure, while excessively strong electric fields provided less pronounced miscibility enhancement, indicating the existence of an optimal conditioning intensity. These findings underscore that electric‑field‑induced electrochemical conditioning can regulate shale oil composition and physicochemical properties, thereby favoring carbon dioxide‑oil miscibility and providing a potential strategy for coupling enhanced shale oil recovery with carbon storage.
Document Type: Original article
Cited as: Zhang, W., Jia, Q., Huang, H., Shi, J., Li, Q., Li, H. A. Experimental investigation of electric field‑assisted in‑situ conditioning of shale oil for reducing CO₂ minimum miscibility pressure. Advances in Geo‑Energy Research, 2026, 22(1): 1‑10. https://doi.org/10.46690/ager.2026.10.01
DOI:
https://doi.org/10.46690/ager.2026.10.01Keywords:
Electric ffeld, shale oil, carbon number distribution, minimum miscibility pressure, CO₂ miscibilityReferences
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