Co2 Miscible Flooding Overview

Principles

Definition

Co2 miscible flooding is an advanced enhanced oil recovery (EOR) technique predicated on injecting carbon dioxide into hydrocarbon reservoirs under conditions that achieve miscibility with the crude oil, fundamentally altering fluid properties to facilitate more efficient displacement. As an academic concept and research field, it investigates the complex phase behavior, dynamic flow mechanisms at multiple scales, and the impact of reservoir heterogeneity on achieving and maintaining miscibility, aiming to optimize oil recovery efficiency and explore synergies with carbon sequestration objectives. Its significance lies in providing a highly effective method for mobilizing otherwise unrecoverable oil resources while potentially contributing to greenhouse gas mitigation.

Ontological type

Phase Behavior

Displacement Mechanisms

Process Design and Optimization

Key developments

Key Figures

Compositional Controls on Miscibility era

Franklin M. Orr [1] was a leading figure at Stanford University [3] and The University of Texas at Austin [4] during the Compositional Controls on Miscibility era (1982-1996). His interpretation of 'Interpretation of Pressure-Composition Phase Diagrams for CO2/Crude-Oil Systems' [7], 'Flow Visualization for CO2/Crude-Oil Displacements' [8], and 'Effect of Oil Composition on Minimum Miscibility Pressure—Part 2: Correlation' [9] advanced the thermodynamic and experimental framework that underpinned screening and informed early mobility-mitigation design in this era. J.P. Heller [2] was affiliated with New Mexico Institute of Mining and Technology [5] and Morgantown High School [6] during this era. His work on CO2-foam mobility includes Laboratory Measurements of CO2-Foam Mobility [10], Foamlike Dispersions for Mobility Control in CO2 Floods [11], and Laboratory Investigation of Parameters Affecting CO2-Foam Mobility in Sandstone at Reservoir Conditions [12], which together provided practical guidance for foam deployment and mobility-control strategies in CO2 floods.

Conformance-Driven Mobility Control era

Stefan Bachu [1] from University of Bergen [3] emerged as a leading figure in CO2 storage and conformance-related research during the Conformance-Driven Mobility Control era. His work highlighted key mechanisms through papers such as Injection and Storage of CO2 in Deep Saline Aquifers: Analytical Solution for CO2 Plume Evolution During Injection [6], Drainage and Imbibition Relative Permeability Relationships for Supercritical CO2/Brine and H2S/Brine Systems in Intergranular Sandstone, Carbonate, Shale, and Anhydrite Rocks [7], and The role of hydrogeological and geochemical trapping in sedimentary basins for secure geological storage of carbon dioxide [8]. Martin J. Blunt [2] of Stanford University [4] and Imperial College London [5] contributed foundational insights into multiphase flow that underpinned mobility-control strategies. His papers, Network Modeling of Three-Phase Flow in Porous Media [10] and Impact of relative permeability hysteresis on geological CO2 storage [9], quantified three-phase flow behavior and hysteresis effects that underpinned conformance-control designs and screening for CO2 floods.

Integrated Mobility-Control and Storage era

Samuel Krevor[1], whose work spans Stanford University[3] and Columbia University[4], is a leading figure in the Integrated Mobility-Control and Storage era. His key contributions include advancing understanding of relative permeability and trapping in reservoir conditions as presented in Relative permeability and trapping of CO2 and water in sandstone rocks at reservoir conditions[6], Capillary trapping for geologic carbon dioxide storage – From pore scale physics to field scale implications[7], and Capillary heterogeneity trapping of CO2 in a sandstone rock at reservoir conditions[8], which collectively clarified the link between pore-scale capillary processes and field-scale storage security and informed decisions on when and how to mobilize CO2 for integrated EOR and storage. Sally M. Benson[2], affiliated with Stanford University[3] and University of California, Berkeley[5], has contributed to the era through capillary trapping research spanning pore-scale physics to field-scale implications as captured in Relative permeability and trapping of CO2 and water in sandstone rocks at reservoir conditions[6], Capillary trapping for geologic carbon dioxide storage – From pore scale physics to field scale implications[7], and Capillary heterogeneity trapping of CO2 in a sandstone rock at reservoir conditions[8]. These contributions advanced imaging-guided mobility optimization, risk-aware planning, and integrated project design for CO2-EOR and storage under supercritical CO2 conditions.