Developments in Reservoir Characterization for Carbon Dioxide Sequestration

The pressing need to remove the increasing carbon dioxide (CO2) added in the atmosphere within the last century as a result of large-scale industrialization has motivated the geoscience community to look for opportunities for storing the captured and extracted atmospheric CO2 in the subsurface. This process is possible through a variety of trapping mechanisms in underground reservoirs. Yet, the scientific and engineering challenges to this achievement are substantial. At the core of the problem is defining the unique set of physical, chemical, mechanical and biological properties that ensure safe and long-term containment of CO2 in a given reservoir. For example, while four-way structural closures overlain by a tight-rock seal creates attractive CO₂ trapping in conventional sandstone reservoirs, the presence of abundant and interconnected fractures in basaltic reservoirs may be adequate to trap dissolved CO₂ as calcite precipitates for geological periods.

The last decade has seen significant advancements in subsurface characterization in terms of storage capacity (porosity), fluid-mobility (permeability), and reactive and non-reactive transport properties (dynamics) in time and space. These advancements are the result of recent developments in data acquisition and computation technology that have allowed the geoscience community to gather novel datasets and gain unprecedented insights into earth processes. Recent discoveries about the cause-and-effect cycles that correlate processes operating at nanometer to kilometer scale and nanosecond to millennium scale have significantly improved our understanding of how fluids accumulate, migrate and mineralize in the subsurface. The goal of this Research Topic is to explore the diversity of criteria that are required to answer the ultimate question of what makes a particular reservoir suitable for CO2 sequestration?

We welcome diverse studies on CO₂ sequestration that use real and simulated high-resolution geophysical, well and geochemical datasets to constrain the following aspects of a reservoir with special emphasis on the efficacy of storage and risk of leakage. In particular we are interested in high-quality contributions related to:

· Novel data analysis methods to define and detect facies and geobodies suitable for CO₂ storage;

· Reservoirs characterization for improved understanding of flow and storage of CO₂;

· Integrated laboratory-field studies to better understand fracture distribution and interconnectedness;

· Case studies related to CO₂ flooding in matured fields for enhance-oil-recovery (EOR);

· Use of inversion, big data and AI/ML techniques for reservoir characterization and risk analysis;

· Quantitative studies on storage capacity estimation and leakage probability assessment;

· Uncertainty quantification of reservoir rock and fluid properties; and

· Geophysical monitoring to understand fluid flow, dissolution, and trapping during injection and migration.

This Research Topic has been realized in collaboration with Prof. James Knapp, at Oklahoma State Univeristy and Dr. Eugene Holubnyak, at Kansas Geological Survey.