Shunbei Oil and Gas Field has a special type of fault-controlled carbonate reservoir at depths of more than 7,000 m in Tarim Basin, China. The scale and distribution of faults determine the reservoir space distribution. The interaction among faults, geological fluid and carbonate rock and the overall impact towards the reservoir formation are hot issues of interest to scholars at home and abroad. In this study, we focused on the fractured carbonate reservoir of Yijianfang Formation in Shunbei area, and carried out dissolution experiments and 3D numerical calculations to mimic the interaction between CO2 brine fluid and fractured carbonate reservoir along the fracture. This study combines microscopy, scanning electron microscopy and XCMT scanning, aquous cation concentration analysis, numerical simulations together to compare the changes such as fracture surface area, fracture volume, and cations concentration after the reaction. In order to understand the effects of fluid transformation qualitatively and quantitatively. The research shows the main fracture is the dominant place of physical mass transfer and chemical reaction, and the overall reaction is mainly calcium carbonate dissolution. The sample physical heterogeneity and the hydraulic property jointly control the fracture and cation spatiotemporal evolution and affect the overall reservoir physical property finally. In this study, a three-factor coupled fracture-fluid-rock geological model for the fractured carbonate reservoirs is proposed, and the potential locations for the reservoir space are presented.
How to cite: Ding, Q.: Experiments and modeling of fracture evolution during percolation of CO2-acidified brine through fractured limestone samples, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19792, https://doi.org/10.5194/egusphere-egu25-19792, 2025.
Geological carbon sequestration is a critical step towards achieving Taiwan's net-zero emissions by 2050. The issues of induced seismicity and the reactivation of fractures as potential leakage paths due to the injection of supercritical CO2 into geological formations must be thoroughly investigated to gain public acceptance for carbon sequestration sites. This study uses the Changhua Coastal Park pilot site to establish two geological models and develop corresponding numerical simulation techniques. It examines whether CO2 injection impacts the stability of adjacent blind fault. The numerical simulations, conducted with three-dimensional distinct element method software, calculate the influence range of pressure increments and compare the differences between the two geological models.
How to cite: Chen, C.-J.: Preliminary research on safety of induced seismicity at carbon sequestration sites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5, https://doi.org/10.5194/egusphere-egu25-5, 2025.
This study proposes active learning-based artificial intelligence application to efficiently build a proxy model for carbon dioxide (CO2) injection scenarios in tight gas condensate reservoirs. In gas condensate reservoirs, as production progresses and reservoir pressure decreases, condensate accumulation in the reservoir pores leads to a relative reduction in gas permeability, thereby lowering gas productivity. Injecting CO2 into the target gas condensate reservoirs to maintain pressure can mitigate condensate banking while simultaneously enabling CO2 geological storage. However, multiple variables influence the performance of such CO2 injection strategies. In this research, proxy modeling for a tight gas condensate reservoir mimicking the Montney region in Canada was performed using active learning, which optimizes the acquirement of additional training data. The proxy model was constructed with a random forest algorithm trained on reservoir simulation results generated using Petrel, Eclipse, and MEPO software from SLB. Initially, simulations were conducted for a limited number of scenarios, and additional data were iteratively acquired by identifying input scenarios with high uncertainty in predictions from the previous proxy model. This active learning process improves the efficiency when adding extra training dataset, enhancing the model's performance while reducing the need for exhaustive simulations. The input parameters for CO2 injection included the timing of switching a production well to an injection well, the bottomhole pressure of an injection well, and the maximum production rate. Output parameters included CO2 molar injection and production rates, field gas and oil production totals, field oil saturation averages, field gas injection cumulative total, CO2 storage total, and field average pressure. Experiments analyzed the minimum additional data required to achieve an R2 score of 0.95, with initial datasets of 30, 40, 50, and 60 simulations. For these initial dataset sizes, the active learning method saved an average of 4, 6, 3, and 1 reservoir simulations, respectively. Considering that each reservoir simulation requires an average of 45 minutes, the computational cost savings are significant. This efficiency is expected to be even greater for more complex reservoir simulations.
How to cite: Kim, S., Kim, Y., and Lee, W.: Proxy modeling for CO2 injection in tight gas condensate reservoirs using active learning-based artificial intelligence, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2353, https://doi.org/10.5194/egusphere-egu25-2353, 2025.
Carbon capture, utilization and storage (CCUS) is a pivotal technology for reducing atmospheric CO2 and mitigating global warming to 1.5–2ºC. Deep geological storage plays a crucial role in this strategy, requiring a thorough understanding of the reservoir and seal rock properties before gas injection. Laboratory experiments simulating different conditions are essential to analyze how trapping mechanisms evolve over time.
This study examines the mineralogical and porous system evolution of detrital rocks from the Ebro Basin in Spain when exposed to dry CO2 and CO2-rich brine. Sandstones from the Lopin structure were subjected to supercritical CO2 in an autoclave under controlled batch conditions (8 MPa, 40ºC, 30 days). The samples were analyzed using optical microscopy, digital image analysis, and scanning electron microscopy to assess structural and compositional changes.
The results demonstrate striking differences between the two experimental conditions. Exposure to CO2-rich brine triggers significant grain detachment, mineral dissolution, and increased porosity, reflecting the high chemical reactivity of the system in the presence of fluids. Conversely, exposure to dry supercritical CO2 results in negligible changes, as the absence of fluids inhibits chemical reactions. These findings emphasize the critical role of fluid interactions and extended timescales in enhancing the security and efficiency of long-term CO2 storage.
Ordoñez-Casado, B.; Mediato, J.; Kovacs, T.; Martínez-Martínez, J.; Fernández-Canteli, P., González-Menéndez, L.; Roces, S.; Caicedo-Potosí, J.; Berrezueta, E., Experimental geochemical assessment of a seal-reservoir system exposed to supercritical CO2: A case study from the Ebro Basin, Spain. International Journal of Greenhouse Gas Control 2024, 137, 104233. 10.1016/j.ijggc.2024.104233
How to cite: Roces, S., Fernández-Canteli, P., Ordóñez, B., Kovacs, T., Mediato, J., Baragaño, D., and Berrezueta, E.: Mineralogical and porous system evolution of reservoir and seal rocks: differences between wet and dry conditions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3174, https://doi.org/10.5194/egusphere-egu25-3174, 2025.
China 's energy structure is dominated by coal. The large amount of CO2 emissions leads to a deterioration of the environment. Sequestration of CO2 into coal seams will be an effective measure to reduce emissions. In order to evaluate the potential of CO2 sequestration in complex coal seams, taking the bifurcation and merging area of 15# coal seam in Xinjing mining area as an example, firstly, the spatial distribution characteristics of coal seams are finely characterized on the basis of logging constrained wave impedance inversion and time-depth conversion technology. Then, the intelligent ant body technology is used to realize the effective prediction of the fault system. On this basis, the influence of coal seam thickness, structure, sealing conditions and other factors on CO2 geological storage in the study area is discussed. The results show that the thickness of the bifurcation area of 15 # coal seam in Xinjing mining area is small and there is gangue, which is not conducive to CO2 storage; the thick coal seam in the combined area has large gas storage space, moderate burial, simple structure and good sealing conditions of surrounding rock, which is a good place for CO2 storage. Therefore, the 15 # coal merging area is selected as a favorable area for storage, which provides a reference for the storage and injection of CO2 in deep complex coal seams.
How to cite: Shi, S.: Discussion on the superiority of carbon dioxide geological storage between coal seam bifurcation and coalescence area, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8971, https://doi.org/10.5194/egusphere-egu25-8971, 2025.
Abstract. Geological structures play a critical role in carbon dioxide (CO₂) sequestration, providing natural barriers and spaces to trap CO₂ securely in subsurface formations. Modelling the dynamic behaviour of structural traps gives valuable insights into carbon dioxide (CO₂) storage capacity and plume evolution. This helps identify the optimal injection strategies, understand the effect of CO₂ plume migration, and predict the long-term containment of CO₂. This study analyses the effect of cap rock architecture in the CO₂ plume migration and estimates the CO₂ trapping capacity for different geological structures. Using the MATLAB Reservoir Simulation Toolbox (MRST-co2lab), theoretical models comprising anticlines and anticlines with varying dips were used to simulate CO₂ injection and migration using the spill point analysis. For the study, a three-dimensional corner point grid was constructed to represent structural features over an area of 60 square kilometres. The model incorporates a porosity range between 7% and 35%. The results from spill-point analysis indicate that the anticline structures with a dipping angle of 0.3 degrees and 0.4 degrees exhibit a capacity of 55.87% and 22.36% compared to the anticline structure without any dip. It was observed that the plume direction was oriented towards the top of the dipping direction. That is, the fluid migration is along the slope of the dip. The findings emphasise that a steeper dip results in lower storage capacity due to faster plume migration and reduced CO₂ trapping. These results highlight the variability in percentages of the CO₂ trapping efficiency and emphasise the importance of both geological structure and fluid properties in determining storage capacity. The insights obtained from spill point analysis can contribute to better planning and optimisation of carbon sequestration strategies by highlighting the influence of cap rock architecture on storage potential.
Keywords: Geological carbon sequestration; CO2 trapping mechanisms; Spill point analysis
How to cite: Priya P B, L., Katre, S., and Nair, A. M.: Modelling the Dynamic Behaviour of Structural Traps for Carbon Sequestration, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9216, https://doi.org/10.5194/egusphere-egu25-9216, 2025.
Saline aquifers possess significant storage capacity for CO2, offering a potential resource for mitigating anthropogenic climate change due to CO2 emissions. However, identifying suitable storage sites across regions that may be several tens or hundreds kmacross can be extremely time consuming both computationally and in terms of human resources. This study introduces a Dynamic Common Risk Segment (D-CRS) workflow to efficiently screen large-scale saline aquifers and rapidly pinpoint promising locations for further detailed study. This technique relies on generating maps related to storage capacity, storage security, and fluid flow, while also estimating the risks and hazards associated with each potential site.
A 3D static model in Southeast Asia was used to evaluate the applicability of D-CRS in a geologically complex region characterized by multiple faults, existing hydrocarbon reservoirs, and legacy wells. The region of interest is approximately 50km by 30km across containing saline aquifers in nine intervals of generally low net-to-gross fluvial reservoirs together with three hydrocarbon fields. Maps of CO2 injection rate, pressure propagation time, and storage capacity were generated for each potential storage zone within this region. These maps were then translated into a traffic light format using threshold values derived from other Carbon Capture and Storage (CCS) projects or specific to the region of study. For each zone, a composite D-CRS map was created by overlaying the previously generated maps of storage capacity, pressure propagation time, and injection rate. This composite map facilitated the identification of the most promising storage sites for subsequent detailed studies and analysis.
Storage capacity maps indicated that nearly 40% of the region exhibited low storage potential, while approximately 30% demonstrated favorable storage capacity. Injection rates varied significantly, ranging from less than 0.01 Mt/yr to 2 Mt/yr across different locations, influenced by factors such as permeability, thickness, and maximum allowable pressure. Notably, almost 20% of the region displayed acceptable potential injection rates exceeding 0.2 Mt/yr, whereas over 40% exhibited rates below 0.04 Mt/yr. Furthermore, maps illustrating the pressure propagation time from potential CO2 injection sites to the nearest hazardous areas were analyzed for each prospective storage interval. These maps revealed a wide range of propagation times, from less than a day to several years. Approximately 30% of the grid cells demonstrated propagation times under a month, while over 50% exceeded a year. These results were validated through comparison with full reservoir simulations conducted at selected sites. The implementation of the D-CRS workflow facilitates a more efficient allocation of resources by concentrating characterization and study efforts on the sites with the highest potential and lowest risk.
D-CRS is a robust and powerful tool for rapid screening, enabling efficient exploration of prospective basins. It delivers a comprehensive set of dynamic maps that represent storage capacity and security, guiding engineers towards informed decisions. By integrating these maps into a single, color-coded composite, D-CRS provides a valuable insight for selecting the most promising sites for further characterization and detailed study.
How to cite: Darvish Sarvestani, A., Muggeridge, A., Smalley, P. C., Lonergan, L., Widyanita, A., Rahayu Razali, N. M., and Wen Pin, Y.: Rapid Screening of Basins for Geological CO2 Storage Using Dynamic Common Risk Segment Mapping, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18835, https://doi.org/10.5194/egusphere-egu25-18835, 2025.
The time window, in which global warming can be limited to the 2° target without large-scale carbon dioxide removal (CDR) narrows down quickly. All CDR methods require energy as an input, which translates to land requirements for energy harvesting and potential land-use conflicts.1(Photo-)electrochemical methods for CDR aim to convert CO2 to storage products that broaden potential storage reservoirs when compared to direct CO2 injection.
Here, graphitic carbon from a process where CO2 is split into elemental C and O is a highly promising sink product, enabling straightforward, near-surface long-term storage. While natural photosynthesis can also produce solid, carbon rich products using solar energy, the artificial photosynthesis route promises solar-to-carbon conversion efficiencies at least one order of magnitude higher than natural photosynthesis, which accordingly translates to a significantly reduced land footprint for a given CDR target.2 Yet, to realize these efficiencies and make the process scalable, the catalysts and the overall, solar-driven electrochemical process need to be developed.
In our work we aim to deconvolute the reaction mechanism of the GaInSn/Ce – system, which is a liquid metal at ambient conditions and allows electrocatalytic splitting of CO2 to graphitic carbon.3 Herein, we identify CO as the main intermediate, as well as the addition of alkaline H2O to the non-aqueous electrolyte solution as beneficial to the carbon yield, likely due to the formation of OH – terminated surface species like Ce(OH)3. Furthermore, we show the importance of the liquid metal matrix not only as a co-catalyst for CO2 reduction itself, but also as the reason for an interfacial restructuring and optimization process.4
This shows that the electrochemical conversion of CO2 to graphite on the liquid-metal surface does not only provide stable long-term performance due it’s non-coking behavior but also promises an accessible way for further optimization of its catalytic activity and selectivity. Due to its stable intermediate state (CO) it even offers an alternative approach of breaking down the process of CO2 and CO reduction in a cascaded process. While this study clearly shows the potential of electrocatalytic CO2 splitting as a CDR technology, we also identify current bottlenecks on the way to large-scale, competitive implementation.
1: Adam, M., Kleinen, T., May, M.M., Rehfeld, K., Land conversions not climate effects are the dominant indirect consequence of sun-driven CO2 capture, conversion, and sequestration, Environmental Research Letters, in print (2025)
2: May, M. M. and Rehfeld, K.: ESD Ideas: Photoelectrochemical carbon removal as negative emission technology, Earth System Dynamics, 10, 1–7, 2019
3: Esrafilzadeh, D., Zavabeti, A., Jalili, R. et al. Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces. Nat Commun 10, 865 (2019)
4: Lörch, D., et al., From CO 2 to Solid Carbon: Reaction Mechanism, Active Species, and Conditioning the Ce-Alloyed GaInSn Catalyst, Journal of Physical Chemistry C 128 (49)
How to cite: Lörch, D., Euchner, H., Mohamed, A., Übele, M., Bogdanoff, P., and May, M.: From CO2 to Solid Carbon – Realizing Carbon Dioxide Removal with Liquid Metal-Based Electrocatalysis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19630, https://doi.org/10.5194/egusphere-egu25-19630, 2025.
Basalt mineralization storage technology represents a pivotal approach in CO₂ geological sequestration, offering a promising pathway for safe and long-term carbon storage. This study focuses on the "water-CO₂-basalt" mineralization reaction, leveraging natural basalt samples from Yangpu, Haikou, and Zhangzhou in Hainan Province, China. Through high-temperature and high-pressure mineralization experiments, the effects of varying temperatures and reaction times on mineralization efficiency were systematically investigated. Pre- and post-reaction rock and solution samples were analyzed using advanced characterization techniques, including XRD, XRF and CT-scan. Results demonstrate that mineralization efficiency increases with higher temperatures and extended reaction durations, following a dissolution-precipitation mechanism. Notably, basalt samples from Hainan exhibited superior mineralization performance, highlighting their suitability for large-scale storage applications. Furthermore, a robust formula for assessing CO₂ storage potential was developed based on experimental data, with Hainan serving as a case study. The findings reveal significant carbon sequestration potential in Hainan's basalt formations, underscoring the credibility and applicability of the proposed evaluation method. This research provides critical theoretical insights to advance basalt mineralization storage projects, contributing to the broader development of CO₂ mineralization and storage technologies.
How to cite: Liu, Q., Tiong, M., Wang, C., Bao, Q., Wu, S., and Ye, H.: Enhancing CO₂ Geological Sequestration through Basalt Mineralization: Experimental Insights and Storage Potential Evaluation in Hainan, China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14721, https://doi.org/10.5194/egusphere-egu25-14721, 2025.
Gas field produced water reinjection is similar to CO2 geological storage in terms of site selection, well construction, injection and environmental monitoring. The co-storage of gas field produced water and CO2 could maximize the use of stratum space, injection wells, environmental monitoring technologies, and promote efficient disposal of gas field produced water and large-scale development of CO2 geological storage. Under the background of synergistic reduction of pollution and carbon emissions, the coordination of gas field produced water reinjection and CO2 geological storage could provide a potential way to promote the synergistic reduction of pollution and carbon emissions and expand the efficiency path of CO2 geological storage.
The CO2 injected into the reservoir would be presented in dissolution-mineralization phase and free phase, which changes with time. The evolution of the CO2 occurrence state in the gas field produced water reinjection formation will directly affect the storage efficiency and long-term safety of the reservoir. Based on the interaction mechanism of CO2-gas field produced water-reservoir rock, the effects of CO2 pressure, produced water salinity, reservoir rock type and formation temperature on the dissolution-mineralization phase CO2 and gas phase CO2 were systematically investigated by using PHREEQC program. PHREEQC is currently the most commonly used fluid rock geochemical reaction simulation software, which can simulate processes such as ion exchange, oxidation-reduction, mineral dissolution and precipitation. It has been widely used in the simulation of long-term complex hydrogeochemical reaction processes in fields such as CO2+O2 in-situ leaching of uranium, CO2 geological storage, shale hydraulic fracturing, and groundwater remediation.
Combined with the changes of mineral composition of the reaction process and the dissolution-mineralization phase CO2 proportion, the main controlling factors affecting the occurrence state of CO2 in the gas field produced water reinjection formation were analyzed. The results show that (1) feldspar and chlorite are the main minerals to promote CO2 mineralization reaction, while illite and calcite are the main carbon fixation minerals in the process of CO2 geological storage. (2) CO2 pressure is the main controlling factor affecting the CO2 occurrence state in the gas field produced water reinjection formation, followed by the reservoir rock type and the gas field produced water salinity, and the formation temperature has the least influence on the change of CO2 occurrence state. Under the simulated conditions, the change of CO2 pressure leads to the change of proportion of dissolution-mineralization phase CO2 in the sandstone and limestone system range from 47% to 72%, the variation of the proportion of dissolution-mineralization phase CO2 caused by the difference of rock type range from 10% to 45%, the change of the proportion caused by the produced water salinity and formation temperature fall 2% ~ 30 % and 1 % ~ 15 %, respectively. The study shows that in the practice of gas field produced water reinjection combining with CO2 geological storage, the corresponding injection volume and pressure should be adjusted in time according to the salinity of reinjection water, reservoir physical properties and temperature, so as to reduce the increase of leakage risk caused by gas phase CO2 accumulation in the early stage of storage.
How to cite: Yang, S., Liu, S., Cai, M., Xue, M., Li, X., and Zhang, K.: Geochemical modeling of CO2 occurrence state in gas field produced water reinjection reservoir, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7576, https://doi.org/10.5194/egusphere-egu25-7576, 2025.
For tight reservoirs dominated by micro- and nanopores, the confined phase behavior of CO2 and in-situ fluids significantly impacts multicomponent diffusion and underground multiphase flow. To address the challenge of measuring effective multicomponent diffusion coefficients under high-temperature and high-pressure conditions in tight porous media, this study proposes a fractal-based theoretical model. The model is integrated into compositional simulations to predict multiphase flow and analyze the impact of multicomponent diffusion on CO2 flooding and storage. The Volume Translated Peng-Robinson Equation of State (VTPR-EOS) is modified to include criticality shifts and capillary forces, accurately capturing CO2 and in-situ fluid phase behavior under tight reservoir conditions. Multicomponent diffusion is described using Fick’s and Maxwell-Stefan’s laws, while the effective diffusion coefficients are derived based on fractal theory. A heterogeneous 2D model (50×20 grid) is constructed with porosity distribution generated by a stochastic Gaussian method, and the effective diffusion coefficient correlation terms are validated against empirical models. Simulation results show that the inclusion of confined phase behavior enhances molecular diffusion, increasing CO2 mole fractions by up to 46.8% within the sweep area. Multicomponent diffusion expands the CO2 sweep area and improves concentration uniformity along the displacement direction for both miscible and immiscible simulations, with minimal impact on pressure distribution. In immiscible simulations, CO2 injection extracts lighter components, leading to higher residual fluid density in the sweep area. This fractal-based model reduces uncertainties associated with empirical models by incorporating reservoir-specific pore structures and properties. It can be integrated into compositional simulation codes for large-scale and long-term reservoir simulations, providing valuable insights into CO2 utilization and storage in tight and shale reservoirs.
How to cite: Cai, M., Li, X., Liu, S., Yang, S., Xue, M., and Zhang, K.: A fractal model for predicting multicomponent effective diffusion coefficients with application to CCUS in tight reservoir, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14012, https://doi.org/10.5194/egusphere-egu25-14012, 2025.
CO2 storage efficiency refers to the amount of CO2 storage in a certain volume of underground space, which is directly affected by CO2 sweeping volume. Besides, the balance between vertical and horizontal migration of CO2 is the key to increase the sweeping volume. This study focused on the influence of foam fluid on the fluidity and percolation characteristics of CO2 in porous media. The rheological properties, percolation characteristics and maximum injection volume of pure CO2 and CO2 foam were investigated by rheometer, percolation performance test and CO2 storage simulation experiment, respectively.
As the experimental results shown, the apparent viscosity of CO2 foam reached 6000 mPa·s at 85℃, and the viscosity of pure CO2 was below 0.1 mPa·s at the same temperature; the resistance factor (the ratio of the pressure difference between the two ends of the core during foam injection and the pressure difference between the two ends of the core during water injection) of foam was over 500 times that of pure CO2 in 10mD core, and the difference in resistance factors was more significant in cores with lower permeability; in a core with a pore volume of 127 ml, the CO2 storage amount of foam injection was 136% that of pure CO2 injection. Meanwhile, the impact of foam`s property, such as diameter distribution, gas-liquid ratio, on the storage efficiency was investigated by a series experiments. Firstly, the resistance factor and residual resistance factor of CO2 foam reached the highest in the cores with permeability of 110 mD class, and the second in the cores with 1 mD class. Secondly, under the condition of the same permeability, the larger the gas-liquid ratio is, the better the blocking effect is. Thirdly, under all three permeability conditions, the residual resistance factor showed a decreasing and then increasing trend at the beginning of injection.
According the results and analysis, foam injection can effectively improve the CO2 storage efficiency. The key parameters affecting the effectiveness of storage efficiency improvement are as follows. Firstly, matching of foam particle size to formation pore size. Bubbles shown a higher probability of entering narrow pore channels with pore diameters smaller than their particle sizes, resulting in a more frequent occurrence of the Jarman effect, which manifested in the increase of sweeping volume and fluidity control capacity in macroscale. Secondly, the larger the gas ratio, the more frequently the foam system is generated, and the greater the density of bubbles in the system, giving the foam system a higher chance of blocking when passing through pores and pore throats.
Although the global CO2 storage potential is more than 4 trillion tonnes, if geological sequestration becomes a routine method to reduce CO2 emissions, underground space will be used up. Therefore, improving the CO2 storage efficiency is a key choice to enhance the CO2 storage potential and extend the life of CCUS technology. This study proposed a method to improve the CO2 storage potential by changing the fluid form, which can provide a new idea for the better utilization of underground space.
How to cite: Liu, S., Cai, M., Yang, S., Xue, M., Li, X., Zhang, K., and Wu, J.: Improvement on CO2 Storage Efficiency by Foam Fluid, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15012, https://doi.org/10.5194/egusphere-egu25-15012, 2025.
The Krishna-Godavari (KG) Basin, a prolific hydrocarbon province in eastern India, offers promising potential for geological carbon dioxide (CO2 ) sequestration. CO2 storage in the KG Basin is crucial due to its potential to mitigate climate change by safely sequestering industrial CO2 emissions. The basin's geological formations, characterized by high porosity and the presence of structural traps, provide ideal conditions for long-term CO2 storage, supporting India's transition to a low-carbon economy and enhancing energy sustainability. This study integrates advanced seismic and well log analyses to evaluate the basin’s subsurface characteristics and estimate its CO2 storage capacity. Key petrophysical properties such as pay zone thickness, porosity, and water saturation were derived from well log data to delineate reservoirs suitable for CO2 injection. Additionally, model-based seismic inversion techniques were utilized to construct a high-resolution 3D impedance model, identifying low-impedance zones indicative of high porosity and enhanced storage potential. To further improve porosity predictionfrom seismic attributes, a Probabilistic Neural Network (PNN) was employed, enabling precise characterization of favorable injection sites. The theoretical storage capacity of the KG Basin is estimated based on integrated analyses of petrophysical and seismic data. This study emphasizes the importance of identifying stratigraphic and structural traps in the G-1 Structure block of the KG Basin to ensure secure and efficient CO2 storage. The findings highlight the KG Basin’s suitability for long-term sequestration, contributing to India’s carbon management goals and broader efforts to mitigate climate change through the sustainable utilization of subsurface geological formations. These insights provide a robust framework for optimizing CO2 storage strategies in similar hydrocarbon-rich basins worldwide.
How to cite: Sharma, A. and Mohanty, W. K.: Evaluating CO2 Storage Potential in Krishna Godavari Basin: An Integrated Seismic and Well Log Approach, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1004, https://doi.org/10.5194/egusphere-egu25-1004, 2025.
Carbon capture and storage (CCS) is a critical technology for mitigating climate change, requiring accurate predictions of storage potential in subsurface reservoirs. This study introduces a novel multimodal machine learning framework to predict the carbon storage potential using geological, geophysical, and simulation data from the Sleipner 2019 Benchmark dataset. The proposed method integrates convolutional neural networks (CNNs) to analyze 3D seismic data, transformers to model temporal injection dynamics, and fully connected layers to synthesize spatial and temporal features. Physics-informed constraints, including mass conservation and pressure limits, are embedded into the training process to ensure physically consistent predictions.
The framework outputs key metrics, including CO₂ storage capacity, retention efficiency, and risk indicators, with high accuracy and interpretability. Validation on Sleipner data demonstrates the ability to predict CO₂ plume migration and assess seal integrity under varying injection scenarios. By reducing computational costs and enhancing predictive reliability, this approach provides a scalable tool for CCS site screening, operational planning, and risk assessment. The results underscore the transformative potential of integrating machine learning with geophysical datasets to advance CCS technologies.
How to cite: Ali, J., Mohanty, W. K., and Sarkar, S.: Integrating Multimodal Machine Learning for Predicting Carbon Storage Potential: A Case Study Using Sleipner Benchmark Data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3803, https://doi.org/10.5194/egusphere-egu25-3803, 2025.
Carbon capture, storage, and utilization (CCSU) is regarded by scientists and industries as one of the most effective methods for large-scale reduction of atmospheric CO2 levels and is an essential tool in achieving global net-zero targets. However, the feasibility of CO2 storage in Taiwan's environment and its potential for effective storage capacity are contingent upon the region's geological characteristics. Several years ago, the Taiwanese government and state-owned enterprises conducted investigations to assess the possibility of implementing CO2 storage domestically. Preliminary estimates suggested that the potential storage capacity could reach up to 40 billion tons, significantly reducing Taiwan's carbon footprint. However, the actual storage areas and methods are still under investigation and research.
Considering Taiwan's location in an active orogenic zone and its dense population, extensive surveys and evaluations have identified that the most suitable storage methods would involve injecting CO2 into offshore regions or beneath the uncompressed layers of coastal plain areas along Taiwan's western shoreline.
This study employs the numerical multiphase reactive-transport simulator TOUGHREACT with the ECO2N module, incorporating data from selected areas along the northwestern coastal region of Taiwan. Stratigraphic layering is derived from processed subsurface data, while reservoir permeability is determined from 3D core scans, with limited experimental measurements conducted on a single core sample for validation. A geological model was constructed to evaluate potential storage formations, including the depth, thickness, permeability, and porosity of both reservoir and caprock layers. CO₂ migration, pressure buildup, and various trapping mechanisms—structural, residual, and solubility trapping—are further investigate to assess the long-term feasibility of CO₂ storage. The storage capacity is quantified in terms of total storage volume and the percentage contribution of each mechanism, with a focus on identifying potential leakage risks based on a realistic geological framework.
Numerical simulations are conducted to analyze the influence of key parameters such as porosity, permeability, relative permeability curves, and capillary pressure curves on CO₂ plume migration and storage efficiency. The study also examines the impact of geological heterogeneities, including layered structures and fault systems, incorporating field survey data to evaluate their role in storage performance and leakage risks.
The research focuses on two key objectives: 1) analyze the impact of rock permeability on storage performance, and 2) evaluating CO2 physical storage performance and potential leakage risks in the selected area of the northwest coast of Taiwan. The findings highlight the critical role of geological heterogeneities in influencing storage capacity and leakage risks, providing valuable insights for optimizing CO₂ storage strategies in complex subsurface environments.
How to cite: Yang, Y.-C.: The prospective research of CO2 storage in northwestern Taiwan － Assessment and Simulation of CO2 Storage in Selected Coastal Regions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10189, https://doi.org/10.5194/egusphere-egu25-10189, 2025.
Abstract
The rapid increase in global warming due to greenhouse gas emission, accompanying the development of human civilization, has led to the establishment of the global common goal of achieving called Net-zero, by 2050. To reach this goal, several efforts are being made through the expansion of renewable energy and methods such as CCS (Carbon Capture and Storage). This study describes a simulation study aimed at improving the efficiency of CO2 storage using the CO2-EWR (Enhanced Water Recovery) technology, as well as an evaluation of its feasibility in the field, through indirect comparative analysis with pilot data.
The CO2-EWR technology takes advantage of the concept that the pressure in the aquifer decreases due to the extraction of produced water, allowing for additional CO2 injection into the aquifer due to the reduced pressure. In the field experiment, a steel pipe with a diameter of 0.2 m and a length of 5 m was filled with glass beads (70-110 µm) to simulate aquifer conditions. In the experiments, absolute permeability was measured, and 85 Bar of supercritical CO2 was injected into the pipe, simulating aquifer conditions of 35°C and 80 Bar. And supercritical CO2 flow rate at the breakthrough point at the back end of the pipe was measured. The absolute permeability, measured using Darcy’s law, was found to be approximately 6548 mD and CO2 flow rate at the breakthrough point was 5.46 kg. The simulation modeling conditions involved filling a pipe of the same size with small size glass beads (40-70 µm) and injecting 40°C, 84 Bar supercritical CO2 into a simulated environment of 40°C and 80 Bar, with a breakthrough point of supercritical CO2 flow rate measured at 3.69 kg. Although a direct comparison between the field data and the modeling conditions is difficult due to differences in conditions, the higher permeability and injection pressure in the field data suggest meaningful results. Near future, direct comparisons of modeling results under identical conditions as the field site, along with additional CO2-EWR tests, simulating various conditions, are expected to provide reasonable data. This data will contribute to optimizing the CO2 injection efficiency and storage capacity, offering a guideline for field application.
Acknowledgement
This work was supported by Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government (MOTIE) (20212010200010, Technical development of enhancing CO2 injection efficiency and increase in storage capacity)
How to cite: Um, K., Yi, M.-J., Park, K., and Ahn, J.-Y.: Feasibility and Performance Evaluation of CO2-EWR Systems: The Simulation Study on CO2 Injectivity and Storage Capacity Enhancement, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14563, https://doi.org/10.5194/egusphere-egu25-14563, 2025.
Posters virtual: Thu, 1 May, 14:00–15:45 | vPoster spot 4
EGU25-4956 | ECS | Posters virtual | VPS17
Influence of capillary force heterogeneity and geochemical raction on CO2 flow and trappingThu, 01 May, 14:00–15:45 (CEST) | vP4.10
To safely store CO2, it is necessary to accurately predict the behaviors and trapping evolution of CO2 in saline aquifers. However, due to the heterogeneity of actual saline aquifers, the evolution of CO2 plume and accompanying trapping are still unclear during and after injection. Although prior studies have highlighted the impact of capillary entry pressure heterogeneity on CO2 plume and trapping, the role and influence of CO2-induced geochemical reactions are still not fully understood. Therefore, the main objectives of this work are to study the evolution of CO2 plume and storage under heterogeneous capillary entry pressure and geochemical reactions. To illustrate the evolution, a comprehensive CO2 migration and storage model under heterogeneous capillary entry pressure and geochemical reactions is done to study CO2 behavior in detail. The results showed that heterogeneous capillary entry pressure in the saline aquifer can hinder the upward migration of CO2, causing it to redirect and increase its lateral volume. The geochemical reactions can reduce porosity by 10-4 and permeability by 1 mD within 100 years and hinder CO2 migration in all directions. The capillary entry pressure magnitude, its heterogeneity, and lateral correlation length are the main parameters affecting the evolution of CO2 storage. Their increase can greatly limit CO2 vertical migration rates and decrease dissolution and mineral trapping amount but may double local capillary trapping amount. In contrast, the increase in temperature and the ratio of vertical/horizontal permeability favors CO2 vertical migration, dissolution, and mineral trapping amount. Therefore, to ensure the long-term safety of CO2 storage, it is necessary to select a suitable heterogeneous reservoir.
How to cite: Cui, G., Hu, Z., Chen, X., Liu, Z., and Lian, Y.: Influence of capillary force heterogeneity and geochemical raction on CO2 flow and trapping, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4956, https://doi.org/10.5194/egusphere-egu25-4956, 2025.
EGU25-21409 | ECS | Posters virtual | VPS17 | Highlight
Study on the response of formation fluid during geological storage of impure carbon dioxideThu, 01 May, 14:00–15:45 (CEST) | vP4.11
With the increasing urgency of global climate change and rising energy demand, carbon dioxide (CO2) geological storage has garnered significant attention as an effective method for mitigating greenhouse gas emissions. In the CO2 geological storage process, understanding the behavior of formation fluids is crucial to ensuring both the safety and long-term stability of storage. However, in actual storage operations, industrial CO2 emissions are rarely pure and typically contain a variety of impurity gases. As a result, CO2 must undergo purification prior to injection, a process that is not only time-consuming but also adds substantial costs. When considering the entire carbon capture and storage (CCS) chain, including capture, transportation, and purification, the total cost of operating current and future CCS projects can reach nearly one billion dollars. According to recent literature, the transportation and storage costs for CO2 can be as high as 45 USD per ton. In China, where cost sensitivity is especially high, these elevated expenses could significantly hinder the implementation of CO2 storage projects. Industrial CO2 emissions often contain not only CO2 but also other gases such as N2, O2, H2S, H2, and SO2. Direct injection of these gas mixtures into subsurface storage sites has the potential to reduce the overall cost of a CO2 geological storage project. However, the effects of impurity gases on storage mechanisms and long-term safety remain insufficiently understood and require further investigation. This study explores the response mechanisms of formation fluids in the context of non-pure CO2 geological storage, focusing on the influence of water-rock reactions, water-rock-gas interactions, permeability, solubility, and changes in the ionic composition of formation waters.
Keywords: water-rock reactions; impure CO2; permeability; solubility; formation water ionic changes
How to cite: liu, S. and Peng, B.: Study on the response of formation fluid during geological storage of impure carbon dioxide, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21409, https://doi.org/10.5194/egusphere-egu25-21409, 2025.
EGU25-21370 | ECS | Posters virtual | VPS17
Experimental study on the influence of CO2 adsorption on the mechanical properties of anisotropic coalThu, 01 May, 14:00–15:45 (CEST) | vP4.12
In the project focused on CO2-enhanced coalbed methane exploitation and geological storage, the seam network structure of coal seams serves as a conduit for gas migration, diffusion, displacement, and storage. The mechanical properties of these coal seams are intrinsically linked to the propagation and evolution of cracks. Prolonged exposure of coal seams to CO2 adsorption environments inevitably alters their structure and mechanical properties. Consequently, experimental research has been conducted on the microstructure and mechanical properties of coal seams with potential for CO2 geological storage in China. The results indicate that, under varying CO2 adsorption pressures and durations: The relative contents of calcite, chlorite, and kaolinite in coal decrease, while the relative content of quartz increases significantly. Notably, the influence of supercritical CO2 on mineral composition and relative content changes is the most pronounced. Long-term CO2 adsorption accelerates mineral dissolution and ion exchange rates in coal, resulting in a rougher surface of coal mineral particles. Numerous secondary pores and fractures emerge and coalesce to form dissolution pits and grooves. Some mineral particle structures transition from intact to fragmented, severely weakening the skeleton particles and mineral bonding strength. Significant transformations occur in pores and fractures of different scales, with CO2 adsorption causing a mutual transformation of mesopores and micropores in coal, albeit without altering the pore type. The uniaxial compressive strength, Brazilian splitting strength, and fracture toughness of coal exhibit a similar trend with increasing CO2 pressure: an initial rapid decrease followed by a gradual, more gradual decrease. The mechanical strength/fracture toughness of coal samples with three different bedding types follows the order: Diverder type > Arrester type > Short transverse type. As CO2 pressure increases, the destructive characteristics of coal transition from sudden instability to gradual instability, and then back to sudden instability. Under CO2 adsorption, coal fracture trajectories can be classified into three types and 12 subtypes: single destruction, multi-source destruction, and fragmentation destruction trajectories. The interaction between CO2 and coal alters the specific surface area, total pore volume, and uniformity of pore size distribution of coal, significantly impacting its composition. These microstructural changes underpin the macroscopic mechanical properties of coal, which in turn affect its mechanical properties and failure characteristics. The research findings have significant implications for evaluating the efficiency and stability of CO2-enhanced coalbed methane mining and CO2 geological storage.
How to cite: Feng, G., Xie, H., Wu, F., Xiao, M., Sun, Z., Liu, H., Jin, P., Wang, G., Meng, T., and Hu, Y.: Experimental study on the influence of CO2 adsorption on the mechanical properties of anisotropic coal, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-21370, https://doi.org/10.5194/egusphere-egu25-21370, 2025.
EGU25-18282 | Posters virtual | VPS17
Preliminary assessment of CO2 storage potential of deep saline aquifers in the Lusitanian Basin, (Portugal): mineralogical and chemical constrainsThu, 01 May, 14:00–15:45 (CEST) | vP4.17
The reduction of atmospheric CO2 through its safe geological storage, as CCUS techniques is one of the goals to achieve the 2050 commitment. Within the scope of the PILOTSTRATEGY project, two sedimentary sequences Triassic (on-shore) and Cretaceous (offshore) were object of a detailed study in order to evaluate their potential as CO2 storage complexes in the Lusitanian basin (west Portuguese margin).
A multi-disciplinary, multi-analytical approach was applied to the potential reservoirs and caprock samples to their characterization. The obtained results (XRD, TGA, petrography) reflect the predominance of siliciclastic composition of the reservoirs (mainly quartz and K-feldspar) whereas the caprock exhibit a carbonate (mainly calcite) (Cretaceous) or gypsum (Triassic) composition.
Several batch reaction experiments were carried out at Edinburgh University (UEDIN). Samples from the Cretaceous storage complex reacted with a NaCl brine injected with CO2 at controlled P=100bar, T=40°C conditions for 30days during which the chemical composition of the brine was regularly analysed. The elemental variations of the brine reacting with the reservoir samples reflect the dissolution of the present mineralogical phases, namely the K-feldspar, pyrite and clay minerals, and in some cases the precipitation of new phases, such as opaline silica.
The composition of the brine reacting with the caprock, registered an increase in Ca content at the first 2 days, interpreted as being the result of the limestone dissolution, without further variation throughout the experiment with a constant pH (6.36-6.57).
The identification of newly formed phases and evidence of dissolution as future and ongoing work are fundamental in understanding the entire process and predictability of the reservoir and sealant.
The work is funded by H2020 – STRATEGY CCUS (grant No. 837754)and national funds through FCT – Fundação para a Ciência e Tecnologia, I.P., in the framework of the UIDB/04449/2020 and UIDP/04449/2020 – Laboratório Hercules; UID/04292 - MARE-Centro de Ciências do Mar e do Ambiente and; UIDB/04683 and UIDP/04683 – Instituto de Ciências da Terra program.
How to cite: Jorge, P., Patrícia, M., Carlos, R., Andrew, K., Katriona, E., Mark, W., Paula, A., João, B., and Júlio, C.: Preliminary assessment of CO2 storage potential of deep saline aquifers in the Lusitanian Basin, (Portugal): mineralogical and chemical constrains, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18282, https://doi.org/10.5194/egusphere-egu25-18282, 2025.
