Geological Storage Research Articles

Defining CO2 Geological Storage Capacity in Unmineable Coal Seams Through Adsorption Data in 3D: Case Study of the Chico Lomã Deposit, Southern Brazil

The concentration of greenhouse gases in the atmosphere has led to irreversible climate changes, emphasizing the need for effective strategies to mitigate emissions. Carbon capture, utilization, and storage (CCUS) technologies, including geological CO2 storage, have gained recognition worldwide due to their potential for CO2 emissions abatement. Among potential geological reservoirs, coal seams are significant due to their efficiency in securing CO2 storage, through their adsorption storage capacity. This study presents an innovative methodology for estimating the theoretical CO2 storage capacity in unmineable coal seams, focusing on the Chico Lomã deposit in southern Brazil. The methodology integrates a comprehensive drillhole database and adsorption isotherm data to define the coal reservoir zone and calculate its CO2 storage capacity. The results indicate a total theoretical CO2 storage capacity of 47.8 Gt in the Chico Lomã deposit, with the potential to mitigate emissions from local thermoelectric plants for over 500 years. The study encourages the application of the proposed methodology to assess CO2 storage capacity in other unmineable coal deposits worldwide.

Molecular Insight Into the Replacement Behavior of CO2CH4 Hydrate in Porous Media: Implications for CH4 Recovery and CO2 Storage

ABSTRACTCO2 replacement method is an auspicious method for the CH4 extraction from gas hydrate and the CO2 geological storage into sediments. The replacement of CO2CH4 hydrate in porous medium system is jointly affected by many factors such as heat transfer, mass transfer, and reaction. It is of great significance to deeply understand the mechanism and dynamics of different factors influencing the replacement characteristics of CO2CH4 hydrate in porous media. In this study, the molecular dynamics simulation method was employed to study the replacement characteristics and kinetic process of CO2CH4 hydrate in porous medium system with varying conditions expecting to offer significant theoretical direction and a point of reference for the CO2 replacement method of natural gas hydrate extraction in permafrost regions in reality. The quantitative influence and internal mechanism of different factors on the replacement process of CO2CH4 hydrate were revealed. The results show that, in the porous medium system, when the temperature was ranged of 265–270 K and the pressure was ranged of 10–20 MPa, the replacement effect of CO2CH4 hydrate is the best under the initial concentration of CO2 of 100%. It was further indicated that the replacement effect is appropriate when the initial concentration of CO2 was ranged of 40%–60% under the case of 265 K and 10 MPa. Moreover, the result also indicated that the effects of some certain factors, including temperature, pressure, and initial concentration of CO2 on the replacement process of CO2CH4 hydrate, exist slightly different. Owing to the adsorption effect of porous media on CO2 molecules, it reduced the replacement efficiency between CO2CH4 hydrate. Additionally, the initial concentration of CO2 imposed a more significant influence on the replacement of CO2CH4 hydrate in porous medium system considering the adsorption effect of porous. It does not mean that the higher the initial concentration of CO2, the better the replacement effect of hydrate. The diffusion capacity of CO2 depends on the concentration of H2O molecules and the adsorption effect of porous media.

Study on CCS source-sink matching and its cluster deployment in multi-type geological bodies in Anhui Province of China

Scientific and reasonable source-sink matching is an important basis for the site selection of CCUS (i.e., Carbon capture, utilization and storage) cluster deployment project. In this study, deep saltwater layer, depleted oil and gas reservoir and unrecoverable coal field in Anhui province are the research objects. Firstly, the evaluation methods of CO2 storage potential of multi-type geological bodies are discussed, respectively. Secondly, the methods of source-sink matching of CCS and its pipe network optimization are discussed. Then the application schemes of CCS source-sink matching and its cluster deployment are established. The results show that the cumulative CO2 emissions of 27 active coal-fired power plants in Anhui province are nearly one trillion tons during the 30-year planning period. The geological storage potential of CO2 is 899.08 × 108 t, and the deep saltwater layer has absolute storage advantage. After the optimization, the total amount of CO2 stored in saltwater layer is 9198.72 million tons, and the cumulative planning pipeline is 684.37 km, which requires a cumulative capital of 5.20*1011 $, and pipeline planning and accumulated capital can save 67.19% of pipeline length and 26.01% of total capital, respectively. The CCS cluster deployment in Anhui province can focus on Huaibei coalfield, Huainan coalfield, Hefei metropolitan area, and Yangtze River Economic Belt, and should give full play to the advantages of saltwater layer layout. Demonstration projects should be built in clusters to simplify the overall layout of CCS pipe network. Connecting C23 and C25, C27 and C10, and C18 and C13 can connect the four CCS cluster deployment areas in Anhui province into a whole. This study can provide theoretical support for the cluster deployment and demonstration project implementation of CCS in Anhui province.

The study on the adsorption characteristics of anthracite under different temperature and pressure conditions.

The study of the adsorption characteristics of coal is of great significance to gas prevention and CO2 geological storage. To explore the adsorption mechanism of coal, this study focuses on columnar anthracite. Adsorption tests on coal rock under a range of physical field conditions were conducted using the volumetric method. The adsorption characteristics of anthracite for CO2, CH4, and N2 gases under different conditions were investigated using Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) methods. The results showed that the adsorption capacities of anthracite for these three gases are in the order of CO2 > CH4 > N2, and that the adsorption capacity increases with increasing gas injection pressure. The CO2/CH4/N2 gas molecule adsorption capacity of the anthracite macromolecular structure model decreases with increasing temperature. The increase in temperature has the greatest influence on the CO2 absorption capacity, followed by the CH4 and N2 adsorption capacities. The research offers a theoretical basis for the control of coal mine gas and the geological storage of CO2.

Laboratory Sand Tank Modeling of the Brumbys Fault CO2 Controlled Release Field Experiment

AbstractFaults present potential leakage risks for geological CO2 storage. To de‐risk a field test injecting CO2 into a shallow fault, laboratory sand tank fluid flow experiments were conducted prior to field injection. The vertical 2.5D sand tank analog models were constructed with different grain sizes of glass beads to represent the permeability contrast between formation layers. A variety of analog fluids were also used to represent both the injection of gaseous and supercritical CO2. Experimental results have validated the simulation results in terms of fluid migration pathways. In addition, results with different analog fluids show that CO2 migration along faults is likely to have similar overall flow paths both near the surface and at depth, but different plume sizes and saturation. Finally, based on an inspectional scaling analysis, we were able to estimate field‐scale CO2 plume migration time, which has been validated by real field observations for the first time.

Effects of Hydrogenated and De-Hydrogenated Organic Hydrogen Carriers on Carbonate Wettability for Hydrogen Geological Storage

Effects of Hydrogenated and De-Hydrogenated Organic Hydrogen Carriers on Carbonate Wettability for Hydrogen Geological Storage

Geological and Petrophysical Properties of Underground Gas Storage Facilities in Ukraine and Their Potential for Hydrogen and CO2 Storage

This article provides detailed geological and reservoir data on the existing underground gas storage (UGS) facilities in Ukraine and their prospects for hydrogen (H2) and carbon dioxide (CO2) storage. The H2 and CO2 storage issue is an integral part of the decarbonisation of Ukraine and Europe as a whole. A detailed assessment of UGS in Ukraine was carried out in the framework of the EU Horizon 2020 project Hystories, which is about the possibility of the geological storage of H2. A database of the available geological data on reservoir and caprock properties was compiled and standardised (reservoir geometry, petrophysics, tectonics, and reservoir fluids). General environmental criteria were defined in terms of geology and surface context. The total estimated H2 energy storage capacity in 13 studied UGS facilities is about 89.8 TWh, with 459.6 and 228.2 Mt of H2 using the total (cushion and working gas) and working gas volumes, respectively. The estimated optimistic and conservative CO2 storage capacities in the 13 studied UGS facilities are about 37.6/18.8 Gt, respectively. The largest and deepest UGS facilities are favourable for H2 and CO2 storage, while shallower UGS facilities are suitable only for H2 storage. Studies could be conducted to determine if CO2 and H2 storage could be applied in synergy with CO2 being used as a cushion gas for H2 storage. The underground storage of H2 and CO2 plays key roles in reducing greenhouse gas emissions and supporting clean energy while enhancing energy security. Increasing the share of renewable energy and integrating sustainable development across various sectors of the economy is crucial for achieving climate goals.

Public Acceptance of the Underground Storage of Hydrogen: Lessons Learned from the Geological Storage of CO2

The successful commercialisation of underground hydrogen storage (UHS) is contingent upon technological readiness and social acceptance. A lack of social acceptance, inadequate policies/regulations, an unreliable business case, and environmental uncertainty have the potential to delay or prevent UHS commercialisation, even in cases where it is ready. The technologies utilised for underground hydrogen and carbon dioxide storage are analogous. The differences lie in the types of gases stored and the purpose of their storage. It is anticipated that the challenges related to public acceptance will be analogous in both cases. An assessment was made of the possibility of transferring experiences related to the social acceptance of CO2 sequestration to UHS based on an analysis of relevant articles from indexed journals. The analysis enabled the identification of elements that can be used and incorporated into the social acceptance of UHS. A framework was identified that supports the assessment and implementation of factors determining social acceptance, ranging from conception to demonstration to implementation. These factors include education, communication, stakeholder involvement, risk assessment, policy and regulation, public trust, benefits, research and demonstration programmes, and social embedding. Implementing these measures has the potential to increase acceptance and facilitate faster implementation of this technology.

Geological potential of hydrogen storage in the Pannonian Basin complex

Hydrogen has a growing importance in the global energy market, as hydrogen technologies are foreseen as the leaders of the energy transition. Its large-scale storage is the most practical manner to balance the weather dependency of renewable energy production and the daily (seasonal) energy demand. The large-scale storage of gases in geological formations is currently implemented for natural gas and carbon dioxide. Owing to technological developments, underground hydrogen storage (UHS) has emerged as an option providing seasonal storage capability. Nevertheless, UHS can be challenging from several aspects, including environmental and economics. Geochemical and biochemical reactions can occur leading to hydrogen loss in the subsurface space. Hence the geological potential of the UHS sites needs to be estimated. This study focuses on the geological resources of the Carpathian–Pannonian region, where two promising rock types are available, including porous sandstones and evaporites. The geological risk of hydrogen loss is discussed, and a site-selection method is introduced with respect of the regional geological storage types.

Technology Focus: CO2, Natural Gas, and Hydrogen Storage (March 2025)

Two significant trends currently shaping the industry are transitioning to a low-carbon economy and integrating artificial intelligence (AI) and machine learning (ML) to revolutionize design and operational processes. Transitioning to a low-carbon economy demands large-scale CO2, natural gas, and hydrogen storage. In this context, the application of AI/ML technology to uncover geochemical, microbial, geomechanical, and hydraulic mechanisms related to storage and solve complicated history-matching and optimization problems, thereby enhancing storage efficiency, has been prominently featured in recent publications. Although still in the infancy stage, hydrogen is expected to play a pivotal role in the transition to a low-carbon economy. Thanks to its abundant storage capacity and widespread distribution, subsurface hydrogen storage, especially in porous media, is crucial for addressing the spatial and temporal imbalances between supply and demand. By optimizing storage-development plans with technical and economical efficiency, AI/ML is becoming a catalyst for scaling up subsurface hydrogen storage. Carbon storage is relatively mature, with substantial knowledge gained from numerous pilot projects and ongoing commercial-scale projects worldwide. Its primary focus is leveraging the latest technologies, particularly AI and ML, to enhance performance and reduce cost through a smarter and more-automatic way of geological modeling, numerical simulation, and history-matching. Furthermore, to cope efficiently with the dynamic demand of a low-carbon energy mix and improve overall economics, an emphasis on repurposing and multipurposing storage sites (for example, converting natural gas storage to hydrogen storage) is emerging, blurring the boundary of storage sites with different storage media. Looking forward, it is clear that the storage operations of carbon, hydrogen, and natural gas, the so-called “warehouse business” in the low-carbon era, will become an important pillar for the global energy transition, with AI/ML accelerating the process. Recommended additional reading at OnePetro: www.onepetro.org. SPE 220865 - Optimizing Hydrogen Storage in the Subsurface Using a Reservoir-Simulation-Based and Deep-Learning-Accelerated Optimization Method by Esmail Eltahan, The University of Texas at Austin, et al. SPE 220026 - Performance Comparison of Gradient-Free Optimization Methods for Well Placement and Well-Control Optimization for Geologic CO2 Storage by Imaobong Tom, University of Tulsa, et al. SPE 222120 - MAGCS: Machine-Assisted Geologic Carbon Storage by H.M. Alqassab, ExxonMobil, et al.

Role of the process conditions on three-dimensional viscous fingering: Impact on enhanced oil recovery and geological storage

Role of the process conditions on three-dimensional viscous fingering: Impact on enhanced oil recovery and geological storage

SO2 ad-/desorption performance on shale matrix: New insights into SO mitigation via geologic storage in unconventional natural gas reservoir

SO2 ad-/desorption performance on shale matrix: New insights into SO mitigation via geologic storage in unconventional natural gas reservoir

Strain analysis for early leakage detection and geomechanical monitoring at CO2 storage sites using distributed fiber optic strain sensing

Strain analysis for early leakage detection and geomechanical monitoring at CO2 storage sites using distributed fiber optic strain sensing

Unleashing tomorrow’s potential: A comprehensive exploration of risks in carbon capture and storage

Unleashing tomorrow’s potential: A comprehensive exploration of risks in carbon capture and storage

An integrated approach for optimizing geological hydrogen storage

An integrated approach for optimizing geological hydrogen storage

Phase transition kinetics and mass transfer characteristics of CO2 hydrate formation process under geological storage conditions: A comprehensive review

Phase transition kinetics and mass transfer characteristics of CO2 hydrate formation process under geological storage conditions: A comprehensive review

Gas transport in shales with applications to geological storage of H2 and CO2

Gas transport in shales with applications to geological storage of H2 and CO2

Techno-Economic Evaluation of CO2-EOR and Carbon Storage in a Shallow Incised Fluvial Reservoir using Captured-CO2 from An Ethanol Plant

Techno-Economic Evaluation of CO2-EOR and Carbon Storage in a Shallow Incised Fluvial Reservoir using Captured-CO2 from An Ethanol Plant

Optimisation study of carbon dioxide geological storage sites based on GIS and machine learning algorithms

Comparison is a crucial stage of site-level selection process. This study integrates the geographic information system (GIS) techniques and analyses the stability of predictions based on five machine learning models to identify key indices for site selection. The study results reveal that: (1) the relevant site selection index system was improved. The precision of predictions using the five machine learning models all reached 95%, with the deep neural networks (DNN) model achieving the highest precision at 96.4%, indicating its broader applicability for site selection. (2) A machine learning index optimisation process is proposed. Based on the results of index importance, indices are categorised as important, less important, and general. Using only the important indices yields satisfactory evaluation results. (3) A rapid assessment model was developed. In the DNN model, the results could be predicted more accurately by using approximately 25% of the data and 50% of the indices. This provides a reference for subsequent site selection for difficult-to-obtain data. This study aims to accumulate extensive data via future research to establish a model database. The database will help refine geological models for different types and stages of engineering projects and incorporate more site-specific models. The ultimate goal is to provide more convenient theoretical guidance and recommendations for subsequent site selection processes.

Development of carbon capture and storage technologies in natural gas facilities for clean energy production

Carbon capture and storage (CCS) technologies represent a critical strategic intervention in addressing global climate change challenges while maintaining energy security in natural gas infrastructure. This comprehensive review explores the multifaceted landscape of CCS technologies, examining technological innovations, economic frameworks, and environmental implications for clean energy production. By synthesizing current research and emerging approaches, the study provides a holistic assessment of CCS potential in mitigating carbon emissions from natural gas facilities. The review critically analyzes existing capture technologies, including post-combustion, pre-combustion, and oxy-fuel combustion methods, highlighting recent advances in material sciences and technological innovations. Economic considerations are examined through the lens of investment strategies, policy frameworks, and long-term viability. Environmental performance evaluation encompasses comprehensive emissions assessment, geological storage risks, and broader ecosystem implications. Key findings underscore the complexity of CCS implementation, revealing both significant challenges and promising opportunities for transforming natural gas infrastructure. The study emphasizes the need for interdisciplinary approaches, robust policy support, and continued technological innovation to realize the full potential of carbon capture technologies in achieving sustainable energy transitions.