Geological Sequestration Research Articles

Formation characteristics and leakage termination effects of CO2 hydrate cap in case of geological sequestration leakage

Geological sequestration of carbon dioxide (CO2) has been considered one of the most effective strategies against global warming. The greatest concern on the stored CO2 in sub-seabed sediments is leakage risk and can be solved by the plugging effect of CO2 hydrate cap, which is derived from the capillary force change by hydrate crystal formation inside pores. This study experimentally simulated CO2 upward leakage process in water-containing sediments and investigated the plugging characteristics of formed hydrate cap via magnetic resonance imaging (MRI) and flow characteristic analysis. Different CO2 flow rates (0.3–4.0 ml/min) and initial pressures (1.8–3.0 MPa) were employed for experimental conditions, and the hydrate cap appeared with no CO2 efflux any longer after hydrate formation for several minutes. It is found that both slow flow of CO2 and high pressure are beneficial for the formation of hydrate cap, and the strength of hydrate caps formed in all cases is confirmed by 10.0 MPa pressure test without any CO2 leakage. In addition, the spatial water distribution and the hydrate cap location inside the sediments are analyzed by multi-level MRI images and pressure evolution calculation, respectively. Ultimately, this study conducted a CO2-water flow case and found that the strength of hydrate cap increases with the continuous formation of hydrates. Approximately 27.8% of hydrate saturation is a watershed of the plugging strength of CO2 hydrate cap. This study provides experimental evidences for the plugging effect of hydrate cap on terminating CO2 leakage and is of great significance for the scheme design and risk assessment of CO2 geological sequestration.

Chemical dissolution of minerals in anthracite after supercritical carbon dioxide immersion: Considering mechanical damage and enhanced porosity

Carbon dioxide injection into in-situ coal seams can effectively enhance coalbed methane recovery and promote carbon sequestration, increasing energy production while reducing greenhouse gas emissions. CO2 is prone to exist in a supercritical state in deep coal seams, so it is of great significance to quantitatively describe the mechanical properties damage of coal caused by supercritical carbon dioxide (SC–CO2). Based on the non-equilibrium thermodynamic framework, a nonlinear model of SC–CO2–coal interaction is developed using the special forms of Helmholtz free energy and energy dissipation. Two damage variables are employed to quantify the irreversible degradation induced by chemical reactions and mechanical loads, respectively. The results indicate that the long-term effect of SC-CO2 can increase the porosity of anthracite by approximately 5.49%, but reduce the elastic modulus and strength by about 58% and 56% respectively. The experimental data confirms that the damage model facilitates an analysis of the interplay among SC-CO2 absorption, porosity, elastic modulus and tensile strength of anthracite. The degradation of anthracite mechanical properties is time-dependent, which means that the risk of coal-rock dynamic disasters increases with the passage of CO2 injection time. This work is expected to study the complex multi-field coupling mechanism of SC-CO2 on in-situ coal seams, providing a theoretical basis for guiding CO2 geological sequestration and CO2 enhanced coalbed methane recovery.

Experimental study of influence of CO2 treatment on fracture toughness of tight sandstone

A large amount of CO2 will be emitted after the burning of fossil fuels, causing global warming and glacier melting which will bring a huge threat to the living environment. Atmospheric clearance through the capture, utilization or storage of CO2 is one of the technologies for dealing with global climate change. In order clarify the mechanization of supercritical CO2 fracturing, the tight sandstone cores in the Jinqiu Gas field, Sichuan Basin were used to carry out the effect research of supercritical CO2 on fracture toughness. The results show that after the treatment of tight sandstone on supercritical CO2, the degradation degree of I-type fracture toughness decreases by 23.6%−33.6% when the soaking days reach 15 days. At the same reaction time, the fracture toughness under 20 MPa and 60 ℃ is lower by 3∼11% than that under 10 MPa and 50 ℃. Meanwhile, the geometric fracture trajectories of sandstone samples before and after the treatment of supercritical CO2 treatment are observed. Before the treatment, the Smax was 1.46 mm and the fracture angle was 10.24°, but after the treatment, the parameters were 0.93 mm and 3.41°, respectively. The fracture trajectories after multiple polishing were observed by SEM imaging, which shows that the fractures can propagate directly through the mineral particles after the supercritical CO2 treatment, which causes the transcrystalline fracture. It is conducive to initiating, propagating, and destroying I-type fractures under smaller external loads. The results further improve the mechanism of CO2 on fracture toughness of tight sandstone, which is useful to explore the feasibility of CO2 fracturing of low-pressure tight sandstone, and provide theoretical support for the safety of CO2 fracturing and CO2 geological sequestration of tight sandstone.

Dissolution-driven convection of low solubility fluids in porous media

Geological sequestration represents a promising strategy for storing CO2. In order to further elucidate this process, we simulated the dissolution-driven convection of a CO2-brine system with a free interface in a porous medium, based on a novel Darcy-Cahn-Hilliard model that accounts for the low solubility of CO2 with brine. We consider a range of unstable Rayleigh numbers Ra, and we derive a quantitative relationship for the dimensionless solute flux. This flux exhibits distinctly different behaviors during the various stages of the flow. In particular, during the free convection stage, larger Ra-values result in a moderate decrease of the solute flux, while the solute flux is approximately independent of Ra during the constant flux stage. In order to evaluate the solute flux during the shutdown stage, we employ simulations in the two-sided Rayleigh-Bénard cell configuration. With a correction factor a=0.67 to account for the damping effect of the bottom boundary, the model can reproduce the solute flux during the shutdown stage. By accounting for the effects of partial miscibility, the simulation approach developed here holds the potential to yield more accurate estimates of the solute flux in the context of CO2 sequestration and related applications.

CO2 geological sequestration potential of the low-rank coals in the southern margin of the Junggar Basin

CO2 geological sequestration potential of the low-rank coals in the southern margin of the Junggar Basin

A molecular insight into the mechanism of organic molecule detachment by supercritical CO2 from a water invasion calcite surface: Effect of water film and molecular absorbability

Understanding the mechanism of organic molecule detachment by supercritical CO2 (scCO2) from a water-invaded calcite surface is crucial for CO2 enhanced oil recovery (EOR) and geological sequestration. In this study, a series of MD simulations were conducted to investigate the detachment performance of organic molecules from a water-invaded calcite surface under different reservoir conditions. The molecular configuration, relative concentration, interaction energy, H-bond number, COM distance and absorbed number were calculated to analyze the effect of water film and molecular absorbability on the detachment phenomenon at different pressure and temperature. The molecular configuration and relative concentration results manifest that scCO2 could break the water film and channel out a CO2 path to detach the organic molecules. The water molecules absorbed to the surface and dissociated in the CO2 phase simultaneously. High temperature and pressure could help the water molecules absorb on the surface and reduce the dissociative molecule number. The organics could be miscible with the CO2 molecules and escape from the surface through the CO2 channel. The COM distance results show that the detachment level of the organic molecules increased with pressure and temperature while decreased with water film thickness. The interaction energy results reveal that the toluene-calcite interaction and C8H18-calcite interaction are higher than the toluene-scCO2 interaction and C8H18-scCO2 interaction. In contrast, the pyridine-calcite and acetic acid-calcite interaction are weaker than the pyridine-scCO2 and acetic acid-scCO2 interaction. Thus, the scCO2 could detach the toluene and C8H18 while could not detach the pyridine and acetic acid.These findings can strengthen our understanding about some details of calcite-organics-water-CO2 interaction under reservoir conditions, which may provide some inspiration for CO2 EOR and CO2 geological sequestration.

Investment feasibilities of CCUS technology retrofitting China's coal chemical enterprises with different CO2 geological sequestration and utilization approaches

CO2 capture, utilization, and storage (CCUS) technology provides an efficient alternative for decarbonizing the coal chemical industry under China's carbon neutrality goal. However, uncertainties such as geological conditions, technology level, carbon markets, subsidy policies, etc., will greatly affect investor confidence in the CCUS applicability in this industry. This study develops a trinomial tree real options based CCUS investment decision model to explore CCUS investment feasibilities for China's coal chemical enterprises with different CO2 geological sequestration and utilization approaches, i.e., CO2 enhanced oil recovery (CO2-EOR) projects, CO2 enhanced coalbed methane (CO2-ECBM) projects, and deep saline aquifer (DSA) projects. The findings show that 1) CO2-ECBM projects have a larger investment benefit compared to CO2-EOR and DSA projects, with a critical coalbed methane (CBM) price for the immediate investment of 1.3 CNY/m³ under the current technology and carbon price level. 2) CO2-EOR projects are immediately investable at a critical oil price of 200 CNY/BBL; DSA projects require the execution of a delayed option with a critical carbon price of 361.8 CNY/t. 3) Provincial investment benefits vary substantially depending on CO2 transport distance and product revenue, particularly for CO2-ECBM projects in Henan and Guizhou, which have significant investment benefits due to high local CBM prices and short CO2 transport distances.

An experimental and numerical investigation on mechanical behavior of sandstone specimens saturated in brine

The mechanical behavior of reservoir rock saturated in brine is of great interest to scientists and engineers for geological CO2 sequestration in deep saline aquifers. However, the mechanical behavior of brine-saturated sandstone under triaxial compression has not been fully investigated, particularly with numerical simulations. In this study, an experimental study and numerical simulation were carried out on brine-saturated sandstone specimens to explore the mechanical properties in sandstones subjected to various brine salinities. Laboratory uniaxial compression tests were conducted on the brine-saturated sandstone specimens, and enhancements in strength and elastic modulus were observed with increasing brine salinity. Scanning electron microscopy results showed NaCl crystals deposited in the pore spaces, which provides evidence of strength and modulus variation in sandstone after brine saturation. Microparameters in a PFC3D numerical model were calibrated for each brine salinity condition, and the numerically simulated results were compared with the experimental results. The numerical results agreed well with the triaxial compression test results, indicating the appropriateness and reasonability of the calibrated models.

Subcritical CO2 adsorption on geomaterials of coal-bearing strata in the context of geological carbon sequestration

This paper explores the adsorption behaviour of geomaterials in the framework of CO2 sequestration in shallow level coal seams. Manometric adsorption experiments were carried out on two anthracite coal samples, two rock samples from East Irish Sea, MX80-bentonite, Speswhite kaolinite, dry, wet and biofilm-laden (Bascillus mojavensis-laden) sand at subcritical pressure range (up to 6.4 MPa) of isothermal condition at 298.15 K. The experiments were aimed to investigate the influence of the biogeological conditions of coal and caprock constitutions on CO2 adsorption. At lower pressures, the moisture had an influence on the CO2 adsorption on coal resulted in reduced adsorption capacity. At elevated pressures, the volume expulsion behaviour and coal-water interaction had an influence on the adsorption capacities of moist coal sample and resulted in comparable adsorption capacities to dry sample. The disparity in the adsorption capacities between the wet powdered and wet intact core samples showed that the results obtained with powder samples may not reflect the field conditions. Wet conditions and Bascillus mojavensis bacteria influenced the adsorption capacity of sand and showed CO2 chemisorption capacity. The desorption isotherm pattern of wet and biofilm sand showed that the CO2 was continuously adsorbed independent of the gas phase pressure. Among the clay minerals, bentonite had greater affinity towards CO2. Despite the fact that the adsorption capacity of the cap rock is smaller than that of the coal samples, the experimental investigation with constituents of the cap rock provides insights into the effect of biogeological conditions of coal and rock sample constituents on CO2 storage in coal seams.

Optimizing a monitoring scheme for CO2 geological sequestration: An environmentally sustainable and cost-efficient approach

CO2 geological storage in depleted oil and gas reservoirs is recognized as a vital approach to combat anthropogenic CO2 emissions. However, the associated challenges of high operational costs and potential CO2 leakage necessitate the development of a cost-effective and environmentally sustainable monitoring program. This study presents a multi-objective optimization model aimed at designing an efficient CO2 monitoring program that meets both economic and environmental requirements. The model is applied to a case study of a Carbon Capture and Storage project in Shaanxi, utilizing an enhanced strengthen elitist genetic algorithm to solve the model under various scenarios. The analysis results demonstrate that in any scenario, a 10 % increase in the required monitoring technology precision leads to an average 1 % rise in monitoring costs, highlighting the cost-effectiveness of the CO2 monitoring scheme developed using our model. Furthermore, when environmental targets are raised by 10 times, monitoring costs show an average increase of 0.92 times, further illustrating the environmentally sustainable nature of our proposed CO2 monitoring scheme. In conclusion, this study provides a cost-effective and environmentally sustainable method framework for the development of CO2 geologic sequestration monitoring scheme, which can contribute to the practical implementation of Carbon Capture and Storage projects to a certain extent.

Development of Empirical and Artificial Neural Network Model for the Prediction of Sorption Time to Assess the Potential of CO2 Sequestration in Coal.

Geological sequestration of CO2 in a coal seam is considered an attractive option to reduce the carbon footprint. It has an additional advantage of enhancing the recovery of coalbed methane, which has less sorption affinity toward coal in comparison to CO2. Desorption of gases from coal is controlled by various parameters, including reservoir depth and coal rank. A representative factor for desorption and diffusion in coal is the sorption time. It is an indicator which helps in estimation and evaluation of gas movement in the coal seam. Coals exhibiting high sorption time allow greater quantities of CO2 injection and hold potential for CO2 sequestration. Therefore, reliable and cost-effective estimation of sorption time is very important prior to investment in projects related to CO2 sequestration. Generally, proximate and gas content analyses are part of the preliminary analysis of coal for the assessment of its potential as a coal-bed methane reservoir. In this study, data generated using these analyses were found very useful for estimating the sorption time and CO2 sequestration potential of coal. The coal samples were collected from different depths of the Mand Raigarh coalfield for testing, and an empirical equation and artificial neural network (ANN)-based model have been developed to predict the sorption time of coal. The developed empirical equation predicts the sorption time with a coefficient of determination value of 0.88 and a root mean squared error value of ±1.07 days. Furthermore, the developed ANN model has been found to be very efficient in prediction with a correlation coefficient value of 0.97.

New insights into the dolomitization and dissolution mechanisms of dolomite-calcite (104)/(110) crystal boundary: An implication to geologic carbon sequestration process

Geologic carbon sequestration (GCS) is a promising strategy to reduce the harm of CO2 due to the rapidly increased fossil fuel combustion. Dolomitization and dissolution processes of deeply buried carbonate reservoirs significantly impact the potential of GCS. However, previous investigations mainly focus on the macroscopic batch experiments, the mechanisms at atomic level are still unclear especially for crystal boundary, but urgently required. Herein, the GCS potential and the effects of boundary dissolution on calcite and dolomite were investigated based on both analytical and simulation methods such as molecular dynamics simulation (MDS) and density functional theory (DFT) calculations, to deeply unveil the mechanisms of dolomitization and formation of intergranular secondary pores from the atomic perspective. The morphology results indicated that the dissolution of calcite and dolomite in carbonic acid solution started via the edges and corners. In addition, the simulated results showed that the carbon sequestration potential presented an order in dolomite (PMg50%) > PMg40% > PMg30% > PMg20% > PMg10% > calcite by dolomitization due to the reduced bulk volume but increased lattice stress. Furthermore, both electrons transfer and diffusion coefficients results suggested that the (104)/(110) boundary was preferentially dissolved as compared to the (104) and (110) planes, indicating that crystal boundary was beneficial to the formation of pores for the oil and gas storage, but harmful to the stability of long-term GCS. Therefore, this study, for the first time, provides new insights into uncovering the mechanisms of the GCS process in depth, from an atomic level focusing on the crystal boundary, thereby promoting the understand of the long-term evolution for both calcite and dolomite in deep reservoirs.

Numerical simulation of the impact of different cushion gases on underground hydrogen storage in aquifers based on an experimentally-benchmarked equation-of-state

Underground hydrogen storage (UHS) in geological formations is a promising technology for large-scale hydrogen energy storage. In this study we focus on UHS in saline aquifers. Although lessons were learned from similar studies, including geological carbon sequestration and underground gas storage, the unique thermodynamic and physical properties of hydrogen distinguish UHS from the other subsurface storage projects. We developed a two-phase, three-component reservoir simulator, which incorporated essential physics based on the fully coupled multi-physics framework of the Delft Advanced Reservoir Simulation (DARSim). Properties of fluid mixtures were computed using the GERG-2008 equation of state (EoS), in which the parameters were determined by fitting laboratory data. The simulation results demonstrated the impact of different cushion gases (CO2, CH4, and N2) on UHS. Most hydrogen stayed in the gaseous phase at the top of the aquifer when CH4 and N2 were used as the cushion gas. Conversely, hydrogen-rich fingers were observed in the aqueous phase when CO2 was used as the cushion gas, because dissolved CO2 increased brine density, leading to density-driven downward convection which was favorable for hydrogen dissolution into the aqueous phase. The highest purity of produced hydrogen was observed when CO2 was used as the cushion gas, whereas using CH4 and N2 as the cushion gas was favorable for the hydrogen production rate and mobility. This work is the first study that utilizes an EoS-based reservoir simulator to investigate hydrogen's flow patterns and interactions with cushion gases in an underground storage system. Specifically, the productivity and retrievability of hydrogen in a two-phase, three-component UHS system were analyzed in detail. The developed reservoir simulation tool and research findings from this study will be valuable to support decision making in practical UHS projects.

Pore-scale modeling of thermal-hydro-mechanical-chemical coupled rock dissolution and fracturing process

Acid fracturing can effectively improve the connectivity inside underground reservoirs, which is of significance for geothermal exploitation and geological carbon sequestration. It involves a complex thermal-hydro-mechanical-chemical (THMC) coupled process. This work first develops a pore-scale THMC coupled model combining the lattice Boltzmann method (LBM) and the discrete element method (DEM) to describe the acid fracturing process, particularly covering chemical damage, rock dissolution, and solute transport. A chemical damage variable based on the cohesive bond is proposed to characterize the alteration of mechanical parameters caused by local rock dissolution. The change of fluid pathway due to rock dissolution is handled by the lattice Boltzmann solute transport model combined with the volume of pixel method. Based on the proposed model, the influence of injection pressure and Damkohler number (Da) on the THMC coupled rock dissolution and fracturing process is analyzed. Results indicate three types according to dissolution morphologies, i.e., permeation, cavity, and permeation-cavity. The first and second types are related to the reaction-controlled and diffusion-controlled processes, respectively. Particularly, the permeation-cavity type occurs at conditions with high injection pressure and high Da and is the combination of the first two types, where the dissolution around the main fracture presents the cavity type but converts into the permeation type around secondary fractures. Additionally, the evolution patterns of reactive surface area and dissolution rate with time differ significantly with rock dissolution types. In particular, for the permeation type, the aperture of fracture far away from the injection hole could be larger than that near the injection hole under the THMC coupling, which is quite different from HM and THM coupling.

Geomechanical risk and mechanism analysis of CO2 sequestration in unconventional coal seams and shale gas reservoirs

With global greenhouse gas emissions hitting record highs in 2021, CO2 geological sequestration (CGS) is the most realistic and feasible technology to ensure large-scale carbon reduction to achieve global carbon capping and carbon neutrality goals. Both coalbed methane and shale gas have the characteristics of self-generation and self-storage, which is considered to be a valuable target reservoir for geological sequestration of CO2. After a high volume of CO2 is injected into unconventional coal seams and shale gas reservoirs, many geomechanical issues may be induced, resulting in leakage. Therefore, it is crucial to evaluate the geomechanical risks of CO2 geological sequestration. In this article, global CO2 emissions and geological resources available for sequestration are teased out. The effects of coupled CO2-water-rock-driven geomechanical, geophysical, and geochemical interactions on the evolution of rock physical properties and pore characteristics, as well as caprock sealing, are discussed. The caprock failure and its inducing mechanism are analyzed, and the criteria for predicting the occurrence of risk are summarized, which is necessary for pressure management and risk prevention. To serve as a benchmark for CO2 sequestration in unconventional coal seams and shale gas reservoirs.

Wettability alteration and dynamic wetting behavior of coal during geologic CO2 sequestration using LF-NMR technology

As CO2 has a strong affinity to coal surface, coal seams are considered as an attractive geological formation for CO2 sequestration. Naturally occurring coal seams are often saturated with free water in the cleats as well as moisture. Hence, the wetting behavior of coal by water is an important aspect in the study of coal properties. However, carbon dioxide, which replaces methane on the surface of coal, interacts with water and coal for a long time. Geochemical reactions of CO2-H2O-coal system can change the surface properties and pore structure of coal. Studies on wettability of coal altered by CO2-H2O-coal interaction are rare. This paper explored the wettability alteration and wetting dynamic behavior of two bituminous coals in Huainan and Huaibei coalfield using low-field nuclear magnetic resonance (LF-NMR) combined with CO2-H2O-coal interaction experiments. The results show that dynamic wetting of water in the coal mainly depends on the pores structure. The geochemical reaction changed the pore structure of coal reservoir, further promoted the hydrophobicity of coal surface, and thereby affected the dynamic wetting process of water. Moreover, the wetting of large pores in coal is not significantly affected by the weakening of hydrophilicity, whereas wetting in small pores is obviously affected by the enhanced hydrophobicity, which may be beneficial to the adsorption and storage of CO2 in the coal.

Effect of temperature on convective-reactive transport of CO2 in geological formations

Geological CO2 sequestration (GCS) remains the main promising solution to mitigate global warming. Understating the fate of CO2 behavior is crucial for securing its containment in the reservoir and predicting the impact of dissolved CO2 on the host formation. Most modeling-based studies in the literature investigated the convective-reactive transport of CO2 by assuming isothermal conditions. The effect of temperature on the convective-reactive transport of CO2 is still poorly understood, particularly at the field scale. The objective of this study is to provide an in-depth understanding of CO2-related reactive thermohaline convection (RTHC) processes at field scale. Thus, a new numerical model based on advanced finite element formulations is developed. The new model incorporates an accurate time integration scheme with error control. Numerical experiments confirm high accuracy and efficiency of the newly developed model. The effect of temperature on CO2 transport is investigated for a field case in the Viking reservoir in the North Sea. Results show that including the temperature effect intensifies the fingering processes and, consequently, CO2 dissolution. Neglecting the thermal convection processes and the impact of temperature on the dissolution rate can significantly impact the model predictions. A sensitivity analysis is developed to understand the effect of parameters governing the dissolution rate on the fingering phenomenon and the total CO2 flux.

Facile Metal Release from Pore-Lining Phases Enables Unique Carbonate Zonation in a Basalt Carbon Mineralization Demonstration.

Carbon-negative strategies such as geologic carbon sequestration in continental flood basalts offers a promising route to the removal of greenhouse gases, such as CO2, via safe and permanent storage as stable carbonates. This potential has been successfully demonstrated at a field scale at the Wallula Basalt Carbon Storage Pilot Project where supercritical CO2 was injected into the Columbia River Basalt Group (CRBG). Here, we analyze recovered post-injection sidewall core cross-sections containing carbonate nodules using μ-XRF chemical mapping techniques that revealed compositional zonation within the nodules. The unique nature of the subsurface anthropogenic carbonates is highlighted by the near absence of Mg in an ankerite-like composition. Furthermore, a comparison between pre- and post-injection sidewall cores along with an in-depth chemical mapping of basalt pore lining cements provides a better understanding into the source and fate of critical cationic species involved in the precipitation of carbon mineralization products. Collectively, these results provide crucial insights into carbonate growth mechanisms under a time-dependent pore fluid composition. As such, these findings will enable parameterization of predictive models for future CO2 sequestration efforts in reactive reservoirs around the world.

Limiting pathways and breakthrough pressure for CO2 flow in mudstones

The sealing and integrity of caprocks is a critical issue in the geological sequestration of CO2. In this work, we integrate multiscale pore-size measurements and imaging techniques, to characterize macropores, microporosity, and their spatial connectivity of intact mudstone cores from an Enping oilfield in the South China Sea. Together with the information on mineral compositions, we propose clay regions in the absence of organic matter as limiting pathways for supercritical CO2 flows in the cores, which primarily consist of nanopores ranging from tens to hundred nm in diameter. The FIB-SEM tomography is used to obtain nanoporous structures of a representative domain of those limiting pathways. We simulate the primary drainage of supercritical CO2 displacing brine in the domain by using an in-house quasi-static pore-network model. The numerical predictions of capillary breakthrough pressure match the experimental data well. Our proposed method of determining capillary breakthrough pressure can substantially complement experimental measurements. Moreover, it has the potential to quantitatively link the multiscale porous structures of mudstone to its CO2 sealing.

Potential for permanent CO2 sequestration in depleted volcanic reservoirs in the offshore Campos Basin, Brazil

The pre-salt oil and gas production in Brazil faces a significant challenge due to the high CO2 content in these reservoirs. Approximately 600,000 t of CO2 are reinjected monthly in the reservoirs, but the increased production of CO2 will demand alternatives for sequestration. Experiments and pilot projects have demonstrated the viability of CO2 sequestration through the mineralization method in basaltic rocks. Here, we present a study aimed at demonstrating the feasibility of using the volcanic rocks of the Cabiúnas Formation, located at the base of the pre-salt section in shallow waters of the Campos Basin, for CCS projects. We used legacy data to determine the regional characteristics and porosity distribution of the volcanic sequence to assess the feasibility of geological sequestration in this region. Our estimates demonstrated that the Cabiúnas flood basalts have a good to excellent storage capacity. The modeling of a 31km2 hypothetical reservoir with a thickness of 300 m in the upper part of the sequence above the Badejo Field revealed a storage estimate of 16–47 Mt. The technical aspects discussed in this study provide valuable insights that can help with the development of future CCS projects in the volcanic rocks of this petroleum province.