Progress and perspectives on pore-scale flow in methane hydrate reservoirs: Microfluidic and numerical strategies for synergistic CH4 recovery and CO2 sequestration.

DUST: A framework for quantifying dugong-seagrass interactions using low-cost UAVs.

Upcycling steel slag into carbon-negative magnesium oxychloride cement: A novel strategy for enhanced water durability and CO2 sequestration

The acclimating mechanisms of Nannochloropsis sp. In response to long-term high CO2 stress-the important role of active cytoplasmic pH regulation.

Multi-parameter kinetic optimization of Chlorella vulgaris for enhanced CO₂ sequestration and biomass production

Simplified theoretical bounds of thermal expansion coefficients for coal: Implications for CO2 sequestration in coals

From green waste to horticultural resources: A novel approach to quantifying greenhouse gas emission factors for decision-making.

The solubility of water in liquid CO2 coexisting with CO2 hydrate or liquid water is evaluated in order to investigate the thermodynamic conditions to avoid the formation of CO2 hydrate in the transportation processes of liquid CO2. To this end, theoretical calculations have been carried out to obtain the chemical potentials of water and CO2 in all the phases involved in their coexistence. The solubility of water in liquid CO2 coexisting with liquid water decreases with decreasing temperature over a wide range of temperature and pressure, except for in the vicinity of the critical point of CO2. The decrease in the solubility is further enhanced by the formation of hydrate. We estimate the Gibbs energy of hydrate formation, which is an important property for sequestration of CO2, for cases where the temperature or pressure of water-saturated liquid CO2 decreases. We also estimate the amount of water precipitated as hydrate during these processes, which has a direct bearing on flow assurance in CO2 transportation. The present study will contribute to the development of a low-energy, safe CO2 transport network aiming at achieving large-scale carbon neutrality.

Glauconite-bearing sandstone reservoirs represent promising targets for potential subsurface CO2 storage via mineral trapping. Nevertheless, previous studies commonly indicate that substantial CO2 sequestration through glauconite carbonation occurs on a geological timescale. In this study, we present results of a controlled experimental assessment of CO2 mineral trapping in Albian glauconite-bearing sandstones from the Mangyshlak Basin (southwestern Kazakhstan). The studied unit, composed of very fine to fine-grained sandstones, is commonly 30-40 m thick and extends hundreds of kilometers laterally. A 30-day CO2 injection batch experiment was performed at 100°C and 150 bar using a brine/rock ratio of 20. The aqueous phase exhibited a sustained increase in Fe, Na, K, Mg, and Si ions, followed by a modest late-stage decline in Mg, Fe, and Si ions, implying mineral dissolution followed by ion consumption through formation of secondary minerals. These results are supported by petrographic comparison of pre- and post-experiment mineral assemblages, which confirm the dissolution of glauconite clasts, feldspars, albite, and K-feldspar overgrowths, with minor precipitation of ankerite. Although the experiments clearly demonstrate significant dissolution of glauconite, the precise mechanisms governing the partitioning and incorporation of Fe and Mg into newly formed carbonate and/or secondary phyllosilicate phases require further mineralogical and geochemical investigations. The current results demonstrate that nascent laboratory scale glauconite carbonation can be feasible under high temperature-pressure conditions and significant concentration of Fe2+.

Physiological responses of Chlorella sp. To high CO2 stress and effective alleviation strategies.

Given the environmental hazards posed by CO2 emissions, carbon sequestration represents a key approach to reducing emissions. CO2 flooding serves the dual purpose of improving oil recovery and facilitating underground CO2 sequestration. Changes in crude oil mobility following CO2 dissolution warrant a thorough investigation of the gas dissolution behavior. A multicomponent model of crude oil, comprising its fundamental components, was constructed. Molecular dynamics simulations were then applied to investigate CO2 dissolution within this system. The simulation data show that the pressure dependence of CO2 solubility follows the Langmuir adsorption model, this indicates that the Langmuir equation can serve as an empirical fitting relationship to describe CO2 solubility. The dissolution mechanism of CO2 in crude oil was analyzed using microscopic characteristics such as the conformational distribution of dissolved CO2, isosteric heat of dissolution, and changes in CO2 molecular bond lengths and angles. Furthermore, by comparing the intermolecular interaction energies in gas-free and CO2-saturated crude oil systems, this provides molecular-level insights into the variation of CO2 solubility in crude oil. The results of this work analyze the molecular-scale mechanisms underlying CO2 dissolution in crude oil, providing a theoretical basis for the implementation of CO2 flooding technology.

Improved rangeland grazing could mitigate climate change through carbon dioxide (CO2) sequestration in soils and vegetation. However, altering grazing practices to increase ecosystem carbon storage may also decrease livestock production and/or increase greenhouse gas emissions through the supply chain, such that the net emissions impacts remain unclear. Here, we assess the global net mitigation potential of improving grazing intensity by quantifying potential CO2 sequestration alongside systems-level impacts of plant productivity changes, livestock emissions, feed requirements, and production constraints. Improving grazing intensity in global rangelands could sequester 2.2 ± 0.43 gigatons of carbon dioxide equivalent (Gt/CO2eq) per year in the near term, but maintaining livestock production through supplemental feeding would reduce net mitigation by 2 to 31% (to 1.8 ± 0.45 GT/CO2eq per year). Our results suggest that neglecting systems-level emissions impacts may substantially overestimate the global climate benefits of improved grazing.

Hydrate-based carbon sequestration offers a promising pathway for offshore CCS by exploiting the complementary properties of structure I (sI) and structure II (sII) hydrates in different sedimentary domains. Here, we employed Diffuse Reflectance Infrared Fourier Transformations Spectroscopy (DRIFTS) and chemical potential calculations to quantify cage occupancies in binary 1,3-dioxane/CO2 hydrates. At 8.5 °C and 3.6 MPa with 5.56 mol % dioxane, the large (51264) and small (512) cage occupancies by CO2 were determined to be 0.0810 and 0.7696, respectively. A numerical program was developed to calculate gas uptake, hydration number, density, and hydrate molar mass by incorporating cage occupancies and CO2 solubility in saltwater. Stirring speed and gas-water ratio were optimized for hydrate formation in seamud, yielding an optimal stirring rate of 800 rpm and a gas-liquid ratio of 5. Kinetic experiments across 1,3-dioxane concentrations (5.56 and 2.86 mol %) and diverse kinetic promoters (SL-Na, l-Trp, l-Lys; 300-2000 ppm) reveal that 5.56 mol % 1,3-dioxane/CO2 hydrate achieves a t90 of 2.44 min and a gas uptake of 73.526 mmol/mol (millimoles of gas/mol of saltwater), while the optimal sI hydrate pathway was identified as 800 ppm of SL-Na, with a corresponding t90 and uptake of 18.78 min and 53.719 mmol/mol, respectively. These findings highlight the potential of integrating cage occupancy insights with promoter optimization to design stratified sealing strategies, advancing safe and efficient offshore CO2 sequestration.

Understanding fluid-driven fracture propagation in anisotropic, layered geological formations is critical for optimizing resource recovery in unconventional reservoirs. In this study, we present a novel experimental and numerical investigation into fluid flow-induced deformation dynamics under biaxial loading using analogue models of shale and reservoir rock. A custom-designed low-pressure biaxial compression system is developed to simulate realistic subsurface conditions while allowing real-time, high-resolution visualization of fracture evolution in low-modulus elastic and viscoelastic materials. Gelatin-based analogues, representing both isotropic and anisotropic formations, are employed to mimic geological heterogeneity and elasticity. Fracturing experiments are conducted using water, SAE 140 oil, and oil-toluene mixtures injected at a constant rate of 1ml/min under controlled loading conditions (confining load: 1.23bar; top load: 0.52bar). The evolving fracture geometries are analysed using ImageJ, focusing on metrics such as aspect ratio and fracture length. Numerical simulations based on a phase field damage model are performed to predict fracture initiation and propagation, showing strong agreement with experimental results and qualitative consistency with the analytical Khristianovic-Geertsma-de Klerk (KGD) model. Our integrated approach provides critical insights into the role of fluid viscosity, heterogeneity and loading conditions on fracture dynamics. The experimental setup also supports studies relevant to CO₂ sequestration and gas hydrate dissociation. This work advances the mechanistic understanding of fracture processes in layered formations, offering insights for field-scale hydraulic fracturing and sustainable subsurface resource management.

ABSTRACT During CO₂ sequestration in abandoned mines, concrete isolation walls or lining layers and surrounding rock may suffer damage or failure during CO₂ injection and long-term storage, increasing leakage risk. To investigate the damage–failure behaviour, crack evolution and sequestration prediction of sandstone–concrete composites under Sc-CO₂ conditions, specimens with interface inclinations of 0°, 30°, 45°, 60° and 90° were immersed in Sc-CO₂ for 0, 12 and 24 h. Uniaxial compression and acoustic emission (AE) tests were conducted, and constitutive and sequestration prediction models were established. Results show that: (1) at the same immersion time, specimens with a 60° interface inclination exhibited the lowest peak strength (15.82–18.53 MPa) and cumulative AE ringing counts (1.8×10³–4.1×10³); (2) for a given inclination, peak strength increased while cumulative AE ringing counts decreased with immersion time; (3) permeability first decreased and then increased with interface inclination, reaching a minimum at 60°, which was 31.2%–69.9% lower than that of other inclinations; and (4) CO₂ sequestration states were classified into steady, controllable, warning and critical levels. Based on strain and cumulative AE ringing counts, crack constitutive and sequestration prediction models were developed, with prediction errors within ±8%. These findings provide theoretical guidance for safe CO₂ sequestration in abandoned mines.

Subsurface gas storage, particularly the sequestration of CO2, continues to remain an active area of research for mitigating atmospheric CO2 concentrations. However, experimental datasets providing direct, high-resolution measurements of CO2 transport, saturation, and pore-scale dynamics under realistic reservoir conditions remain limited, due primarily to experimental complexity. In this study, we present a comprehensive dataset from supercritical CO2 (scCO2)-brine core-flooding experiments conducted at relevant subsurface conditions, employing a sophisticated core holder system capable of sustaining high-pressure and high-temperature environments within an X-ray microcomputed tomography (µCT) setup. Continuous monitoring of flow rates and system pressures accompanied X-ray imaging performed at equilibrium conditions, capturing fluid saturations with a high spatial resolution of 25 µm. scCO2-equilibrated brine was utilized to minimize mass-transfer effects, and both drainage and imbibition scenarios are thoroughly documented. The unique dataset includes high-resolution 3D raw and segmented X-ray images detailing the dry and fluid-saturated conditions, complemented by quantitative metrics of fluid saturation, morphological descriptors, and phase connectivity. In addition, dual-quality X-ray image sets of high- and low-noise scans captured at residual scCO2 saturation after imbibition are provided, enabling comparative analysis and advancements in rapid image-acquisition techniques. The detailed pressure histories and segmented morphological data facilitate advanced numerical model validation and serve as a benchmark dataset for image segmentation algorithm development. All data have been curated and uploaded to an open-access repository, promoting broad usability and fostering innovation in subsurface gas storage research.

Seismic reflections induced by two-phase fluids during CO2 sequestration in saline aquifers

Gas adsorption behavior in organic-rich carbonate source rocks: Insights into hydrogen storage, methane recovery, and CO2 sequestration in oil shales

Synergistic effects of Albizia Procera leaf-derived activated carbon and curing regimes on CO2 sequestration and hardened properties of cementitious systems

Microstructural insights into CO2 sequestration in metakaolin-blended recycled cement: mechanism and performance