Advances in Geoelectrical and Electromagnetic Methods for Hydrocarbon Reservoir Characterization: A Critical Review and Future Outlook

Geoelectrical and electromagnetic (EM) methods have emerged as powerful tools in hydrocarbon exploration, complementing conventional seismic techniques by offering direct sensitivity to subsurface electrical properties. This review synthesizes the fundamental principles, applications, and recent innovations in applying geoelectrical and EM approaches for oil and gas reservoir characterization. Key applications include near-surface structural mapping, lithological discrimination, and hydrocarbon fluid detection, with case studies demonstrating their utility in both onshore and offshore settings. Advances in instrumentation, data acquisition, and AI-driven inversion are enabling higher-resolution imaging and integration with seismic and well logging data, enhancing reservoir interpretation workflows. The review also highlights the role of these techniques in emerging energy transition applications, such as monitoring CO۲-enhanced oil recovery (CO۲-EOR) and underground hydrogen storage. Despite notable progress, challenges remain in terms of depth penetration, resolution trade-offs, and field-scale validation. Future research directions emphasize hybrid geophysical workflows, real-time reservoir monitoring, and the use of digital twins for predictive modeling. Overall, geoelectrical and EM methods are poised to play an increasingly critical role in sustainable exploration and subsurface monitoring as the oil and gas industry adapts to global energy transition goals.

Keywords:

Geoelectrical methods , Electromagnetic surveys , Hydrocarbon exploration , Reservoir characterization , Seismic integration , Energy transition