Integrated Subsurface Energy Systems and Secure CO₂ Sequestration: From Characterization to Monitoring

Dear Colleagues,

The urgent need for anthropogenic carbon dioxide (CO₂) management has made geological sequestration a cornerstone of the global energy transition. Primary considerations in subsurface sequestration are the storability of the geological formation, the definition of the area of review, and comprehensive post-injection site care to address risks associated with CO₂ leakage and fault reactivation. Crucially, not all high-porosity formations are suitable for permanent storage, as many lack the requisite storage environment to foster effective physical and geochemical trapping mechanisms.

Secure, long-term storage relies on a combination of trapping mechanisms—structural/stratigraphic, residual, solubility, and mineral trapping—all driven by complex fluid–fluid and fluid–solid interactions in porous media. These include dissolution, physical adsorption, homogeneous reactions in the aqueous phase, and heterogeneous reactions at the fluid-rock interface. The dissolved CO₂ promotes density-driven natural convection and hydrodynamic instabilities, while the free-phase CO₂ plume can migrate over large distances depending on reservoir boundary conditions. These dynamics underscore potential risks, such as leakage through wells or thief zones and fault reactivation due to pressure changes, highlighting the necessity of robust characterization and monitoring.

This Special Issue seeks to highlight recent advances in science and engineering that integrate CO₂ sequestration with energy systems, spanning from pre-injection site characterization to long-term monitoring and real-field validation. We invite original research and review articles that address the multi-scale challenges of secure carbon storage.

Topics of interest include, but are not limited to:

• Advanced Reservoir Characterization & Monitoring:
  • Seismic (4D/time-lapse) and geophysical methods for mapping CO₂ plumes, detecting leakage, and monitoring fault integrity.
  • Integrated geochemical studies of rock-fluid interactions, including aqueous reactions, mineral dissolution/precipitation, and their impact on porosity and permeability.
  • Geochemical and isotopic tracing for monitoring fluid evolution and verifying containment.
• Novel Storage Formations and Trapping Mechanisms:
  • Potential of ultramafic rocks (e.g., basalts, peridotites) for CO₂ mineralization and secure mineral trapping.
  • Experimental and modeling studies of geochemical trapping kinetics, including in saline aquifers and depleted reservoirs.
• Energy-Integrated Systems:
  • Synergistic energy production: CO₂ storage in depleted oil/gas fields for enhanced recovery (EOR/EGR) and subsurface hydrogen production or storage.
  • Energy storage integration: Use of salt caverns for compressed air energy storage (CAES) coupled with CO₂ storage.
• Engineering for Efficiency and Integrity:
  • Drilling and completion design optimized for CO₂ injection wells, focusing on long-term integrity, energy efficiency, and cost reduction.
  • Geomechanical evaluation of caprock integrity, fault reactivation potential, and impacts on existing energy infrastructure during and after injection.
• Modeling, Risk, & Real-Field Validation:
  • Real-field case studies providing lessons learned from pilot and commercial-scale injection projects.
  • Simulation of reservoir dynamics: Modeling pressure evolution, CO₂ plume migration, and solubility trapping to support storage security and energy grid stability.
  • Risk assessment frameworks for the Area of Review (AoR) definition and Post-Injection Site Care (PISC) planning.

Prof. Dr. Ebrahim Fathi
Guest Editor

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• CO₂ sequestration
• petrophysics
• petrochemsitry
• geomechanics
• seismic
• reservoir simulation
• artificial intelligence
• monitoring and leak detection
• economic and societal analysis