At present,carbon capture and storage(CCS)is the only mature and commercialized technology capable of effectively and economically reducing greenhouse gas emissions to achieve a significant and immedi-ate impact on th...At present,carbon capture and storage(CCS)is the only mature and commercialized technology capable of effectively and economically reducing greenhouse gas emissions to achieve a significant and immedi-ate impact on the CO_(2) level on Earth.Notably,long-term geological storage of captured CO_(2) has emerged as a primary storage method,given its minimal impact on surface ecological environments and high level of safety.The integrity of CO_(2) storage wellbores can be compromised by the corrosion of steel casings and degradation of cement in supercritical CO_(2) storage environments,potentially leading to the leakage of stored CO_(2) from the sites.This critical review endeavors to establish a knowledge foundation for the cor-rosion and materials degradation associated with geological CO_(2) storage through an in-depth examina-tion and analysis of the environments,operation,and the state-of-the-art progress in research pertaining to the topic.This article discusses the physical and chemical properties of CO_(2) in its supercrit-ical phase during injection and storage.It then introduces the principle of geological CO_(2) storage,consid-erations in the construction of storage systems,and the unique geo-bio-chemical environment involving aqueous media and microbial communities in CO_(2) storage.After a comprehensive analysis of existing knowledge on corrosion in CO_(2) storage,including corrosion mechanisms,parametric effects,and corro-sion rate measurements,this review identifies technical gaps and puts forward potential avenues for fur-ther research in steel corrosion within geological CO_(2) storage systems.展开更多
Saline aquifers are considered as highly favored reservoirs for CO_(2)sequestration due to their favorable properties.Understanding the impact of saline aquifer properties on the migration and distribution of CO_(2)pl...Saline aquifers are considered as highly favored reservoirs for CO_(2)sequestration due to their favorable properties.Understanding the impact of saline aquifer properties on the migration and distribution of CO_(2)plume is crucial.This study focuses on four key parameters-permeability,porosity,formation pressure,and temperature-to characterize the reservoir and analyse the petrophysical and elastic response of CO_(2).First,we performed reservoir simulations to simulate CO_(2)saturation,using multiple sets of these four parameters to examine their significance on CO_(2)saturation and the plume migration speed.Subsequently,the effect of these parameters on the elastic properties is tested using rock physics theory.We established a relationship of compressional wave velocity(V_(p))and quality factor(Q_(p))with the four key parameters,and conducted a sensitivity analysis to test their sensitivity to V_(p) and Q_(p).Finally,we utilized visco-acoustic wave equation simulated time-lapse seismic data based on the computed V_(p) and Q_(p) models,and analysed the impact of CO_(2) saturation changes on seismic data.As for the above nu-merical simulations and analysis,we conducted sensitivity analysis using both homogeneous and heterogeneous models.Consistent results are found between homogeneous and heterogeneous models.The permeability is the most sensitive parameter to the CO_(2)saturation,while porosity emerges as the primary factor affecting both Q_(p) and V_(p).Both Q_(p) and V_(p) increase with the porosity,which contradicts the observations in gas reservoirs.The seismic simulations highlight significant variations in the seismic response to different parameters.We provided analysis for these observations,which serves as a valuable reference for comprehensive CO_(2)integrity analysis,time-lapse monitoring,injection planning and site selection.展开更多
Understanding the storage mechanisms in CO_(2)flooding is crucial,as many carbon capture,utilization,and storage(CCUS)projects are related to enhanced oil recovery(EOR).CO_(2)storage in reservoirs across large timesca...Understanding the storage mechanisms in CO_(2)flooding is crucial,as many carbon capture,utilization,and storage(CCUS)projects are related to enhanced oil recovery(EOR).CO_(2)storage in reservoirs across large timescales undergoes the two storage stages of oil displacement and well shut-in,which cover mul-tiple replacement processes of injection-production synchronization,injection only with no production,and injection-production stoppage.Because the controlling mechanism of CO_(2)storage in different stages is unknown,the evolution of CO_(2)storage mechanisms over large timescales is not understood.A math-ematical model for the evaluation of CO_(2)storage,including stratigraphic,residual,solubility,and mineral trapping in low-permeability tight sandstone reservoirs,was established using experimental and theoret-ical analyses.Based on a detailed geological model of the Huaziping Oilfield,calibrated with reservoir permeability and fracture characteristic parameters obtained from well test results,a dynamic simulation of CO_(2)storage for the entire reservoir life cycle under two scenarios of continuous injection and water-gas alternation were considered.The results show that CO_(2)storage exhibits the significant stage charac-teristics of complete storage,dynamic storage,and stable storage.The CO_(2)storage capacity and storage rate under the continuous gas injection scenario(scenario 1)were 6.34×10^(4)t and 61%,while those under the water-gas alternation scenario(scenario 2)were 4.62×10^(4)t and 46%.The proportions of stor-age capacity under scenarios 1 and 2 for structural or stratigraphic,residual,solubility,and mineral trap-ping were 33.36%,33.96%,32.43%,and 0.25%;and 15.09%,38.65%,45.77%,and 0.49%,respectively.The evolution of the CO_(2)storage mechanism showed an overall trend:stratigraphic and residual trapping first increased and then decreased,whereas solubility trapping gradually decreased,and mineral trapping continuously increased.Based on these results,an evolution diagram of the CO_(2)storage mechanism of low-permeability tight sandstone reservoirs across large timescales was established.展开更多
Designing catalysts with high catalytic activity and stability is the key to achieve the commercial application of MgH_(2).Herein,the sulfur doped Ti_(3)C_(2)(S-Ti_(3)C_(2))was successfully prepared by heat treatment ...Designing catalysts with high catalytic activity and stability is the key to achieve the commercial application of MgH_(2).Herein,the sulfur doped Ti_(3)C_(2)(S-Ti_(3)C_(2))was successfully prepared by heat treatment of Ti_(3)C_(2)MXene under Ar/H_(2)S atmosphere to facilitate the hydrogen release and uptake from MgH_(2).The S-Ti_(3)C_(2)exhibited pleasant catalytic effect on the hydriding/dehydriding kinetics and cyclic stability of MgH_(2).The addition of 5 wt%S-Ti_(3)C_(2)into MgH_(2)resulted in a reduction of 114℃in the starting dehydriding temperature compared to pure MgH_(2).MgH_(2)+5 wt%S-Ti_(3)C_(2)sample could quickly release 6.6 wt%hydrogen in 17 min at 220℃,and 6.8 wt%H_(2)was absorbed in 25 min at 200℃.Cyclic testing revealed that MgH_(2)+5 wt%S-Ti_(3)C_(2)system achieved a reversible hydrogen capacity of 6.5 wt%.Characterization analysis demonstrated that Ti-species(Ti0,Ti^(2+),Ti-S,and Ti^(3+))as active species significantly lowered the dehydrogenation temperature and promoted the re-/dehydrogenation kinetics of MgH_(2),and sulfur doping can effectively improve the stability of Ti0 and Ti^(3+),contributing to the improvement of cyclic stability of MgH_(2).This study provides strategy for the construction of catalysts for hydrogen storage materials.展开更多
Mg-based hydrogen storage materials have attracted much attention due to their high hydrogen content,abundant resources,and environmental friendliness.However,the high dehydrogenation temperature,slow kinetics and poo...Mg-based hydrogen storage materials have attracted much attention due to their high hydrogen content,abundant resources,and environmental friendliness.However,the high dehydrogenation temperature,slow kinetics and poor cycling stability are limiting its practical application.This work demonstrates the improved dehydrogenation kinetics and cycling stability of MgH_(2) modified by a hybrid of metallic Ni and layered MoS_(2)(denoted as“Ni-MoS_(2)”)introduced by ball milling,with Ni as the catalyst for MgH_(2) and MoS_(2) as the support for both Ni and MgH_(2).The onset dehydrogenation temperature of MgH_(2) is reduced to 198℃,and the rehydrogenation begins at a low temperature of 50℃.The MgH_(2)+10 wt%Ni-MoS_(2) composite has a fast dehydrogenation kinetics and can release 6.1 wt% hydrogen in 10 min at a constant temperature of 300℃,with the dehydrogenation activation energy significantly reduced from 151 to 85 kJ mol^(-1).During the cycling,the reversible capacity of the composite first exhibits a gradual increase for the initial 22 cycles and then maintains at 6.1 wt% from the 23th cycle to the 50th cycle.The Ni/MoS_(2) addition does not change the overall thermodynamic properties of MgH_(2) but can weaken the Mg-H bonds in the local regions as evident by theoretical calculation.Microstructure studies reveal that the metallic Ni will react with MgH_(2) to form Mg_(2)NiH_(0.3),which can act as a hydrogen pump,while the layered MoS_(2) serves as a support for the well dispersion of MgH_(2) and Ni.It is believed that the synergy of Mg_(2)NiH_(0.3) and layered MoS_(2) contributes to the significantly enhanced hydrogen storage of MgH_(2).This work provides a promising and simple strategy for enhancing the Mg-based hydrogen storage materials by combination of transition metals and layered materials introduced via simple ball milling.展开更多
Magnesium hydride(MgH_(2))has garnered significant attention as a promising material for high-capacity hydrogen storage.However,its commercial application remains challenging due to the high operating temperature and ...Magnesium hydride(MgH_(2))has garnered significant attention as a promising material for high-capacity hydrogen storage.However,its commercial application remains challenging due to the high operating temperature and slow reaction kinetics.In this study,melt-spun Ti_(45)Cr_(40)Nb_(15)(with a BCC phase)hydride(designated as TiCrNbH_(x-)MS)was synthesized and used to form a nano-multiphase composite to improve the de-/rehydrogenation properties of MgH_(2) through ball milling.The incorporation of TiCrNbH_(x-)MS was shown to significantly enhance the hydrogen de-/rehydrogenation properties of MgH_(2).The MgH_(2)+20 wt%TiCrNbH_(x-)MS composite exhibits an appealing initial dehydrogenation temperature of 163℃ and can absorb hydrogen at room temperature.Notably,it releases 5.8 wt% hydrogen in 700 s at 230℃ and recharges 4.3 wt%hydrogen in just 2 mins at 150℃.Even after 100 cycles,it retains a reversible hydrogen capacity of 4.98 wt%.Kinetic analysis revealed that the dehydrogenation rate follows the Chou surface penetration model.Microstructural analysis showed that the FCC phase of the melt-spun TiCrNbH_(x-)MS hydride reversibly transformed into the BCC phase during the de-/rehydrogenation process in the composite.Numerous phase interfaces were generated and uniformly dispersed on the MgH_(2) surface,providing additional hydrogen diffusion pathways and heterogeneous nucleation sites for Mg/MgH_(2),thereby further improving the hydrogen de-/rehydrogenation kinetics of the system.This study offers valuable insights into the use of multiphase composites to enhance MgH_(2) performance.展开更多
Magnesium-based materials are considered as among the most promising candidates for hydrogen storage,owing to their high storage capacity,safety,and reliability.However,a passivation layer easily forms on the surface ...Magnesium-based materials are considered as among the most promising candidates for hydrogen storage,owing to their high storage capacity,safety,and reliability.However,a passivation layer easily forms on the surface of magnesium,which hinders the dissociation and diffusion of hydrogen.High dehydrogenation temperature,sluggish kinetics and activation difficulties hinder their commercial application.Herein,dual-strategy regulation through nickel microalloying and surface catalysis of TiO_(2/)MnO_(2)catalysts has been proposed to obtain more active sites and diffusion channels that promote hydrogen dissociation and transport.Mg8Ni-X(X=None,TiO_(2),and TiO_(2/)MnO_(2))can achieve more than 80%hydrogen absorption without activation.Mg8Ni-5 wt%TiO_(2)/MnO_(2)absorbs hydrogen 5.27 wt%in 30 s at 200℃and desorbs 5.15 wt%in 20 min at 325℃.The activation energy(E_(a))of hydrogen absorption is 52.04kJ/mol.These results are significantly better than those of Mg8Ni and MgH_(2)under the same conditions.The NiTi phase is generated in the course of hydrogenation,and the coexistence of multiple phases and multivalent Ti facilitates the transport of electrons and H.The dual-strategy regulation means of surface catalysis and microalloying is promising for the design of high-capacity fast hydrogen absorbed and desorbed materials without activation.展开更多
Carbon dioxide-enhanced oil recovery(CO_(2)-EOR)and storage is recognized as an economically feasible technique if used in suitable reservoirs.The type or form and capacity of this CO_(2) sequestration technique is sy...Carbon dioxide-enhanced oil recovery(CO_(2)-EOR)and storage is recognized as an economically feasible technique if used in suitable reservoirs.The type or form and capacity of this CO_(2) sequestration technique is synergistically affected by heat,flow,stress,and chemical reactions.Aimed at addressing the technological issues in applying CO_(2)-EOR and storage in a high water-cut reservoir in Xinjiang,China,this paper proposes a thermo-hydro-mechanical-chemical coupling method during CO_(2) flooding.The potential of CO_(2) sequestration and EOR in the target reservoir is discussed in combination with the surrogate optimization method.This method works better as it considers the evolution of structural trapping,capillary trapping,solubility trapping,and mineral trapping during CO_(2) injection as well as the influence the physical field has on the sequestration capacity for different forms of CO_(2) sequestration.The main mechanisms of CO_(2) sequestration in the high water-cut reservoir is structural trapping,followed by capillary trapping.Solubility trapping and mineral trapping have less contribution to the total sequestration capacity of CO_(2).After optimization,the cumulative oil production was 2.36×10^(6)m^(3),an increase of 0.25×10^(6)m3or 11.9%compared to the pre-optimization value.The CO_(2) sequestration capacity after optimization was 1.39×10^(6)t,which is an increase of 0.23×10^(6)t compared to values obtained before optimization;this effectively increases the area affected by CO_(2) by 24.4%.Of the four trapping mechanisms,capillary trapping and structural trapping showed a high increase of 32.5%and17.28%,respectively,while solubility trapping and mineral trapping only led to an increase of 5.1%and0.43%,respectively.This research could provide theoretical support for fully utilizing the potential of CO_(2)-EOR and sequestration technology.展开更多
Metallic single-atom catalysts(SACs)have demonstrated high activity and potential in enhancing the hydrogen storage properties of MgH_(2).However,previous reports primarily focus on supported SACs,which often suffer f...Metallic single-atom catalysts(SACs)have demonstrated high activity and potential in enhancing the hydrogen storage properties of MgH_(2).However,previous reports primarily focus on supported SACs,which often suffer from insufficient co ntact between single-atom active sites and hydrogen storage materials.In this study,the precursor Mo(CO)_(6)is uniformly dispersed on the surface of MgH_(2)via impregnation adsorption,leading to the formation of alloy-type Mo single atoms after hydrogenation/dehydrogenation activation.This alloy structure enables zero-distance contact between catalytic sites and the hydrogen storage material,facilitating electron exchange and hydrogen transfer between the Mo sites and MgH_(2).The MgH_(2)loaded with Mo single atoms(Mo_(1)-MgH_(2))exhibits excellent hydrogen absorption and desorption properties,with the initial hydrogen release temperature lowered from 323 to 218℃.At 250℃,Mo_(1)-MgH_(2)absorbs over 6.77 wt% of hydrogen within 1 min and releases over 5.85 wt% within 4 h.During 10 cycles of hydrogenation and dehydrogenation reactions,Mo_(1)-MgH_(2)maintains nearly 100% capacity and shows stable kinetics.This work provides new insights into the design and fabrication of catalysts for hydrogen storage materials.展开更多
Gas channeling in fractures during CO_(2) injection into the deep coal seam seriously reduces the CO_(2) storage efficiency after the development of coalbed methane.The generation and migration of coal fines causes bl...Gas channeling in fractures during CO_(2) injection into the deep coal seam seriously reduces the CO_(2) storage efficiency after the development of coalbed methane.The generation and migration of coal fines causes blockages in the fractures in the stage of drainage and gas production,reducing the gas channeling effect of injected CO_(2) caused by the heterogeneity of the coal seam.To explore the impact of coal fines within coal seam fractures on the efficacy of CO_(2) storage,experiments on the production stage and CO_(2) injection for storage were conducted on coal combinations containing propped fractures,fractures,and matrix.The CO_(2) storage characteristics of coal at the constraint of coal fines,as well as the influence of multiple rounds of intermittent CO_(2) injection and different injection parameters on the CO_(2) storage effect,were analyzed.The research results show that blockage by coal fines increases the resistance to fluid flow in the fractures by 71.2%.The CO_(2) storage capacity and storage potential of coal with coal fines are 6.5 cm^(3)/g and 8.8%higher than those of coal without coal fines,while the CO_(2) storage capacity of fractured coal under the influence of coal fines has the largest increase of 9.4 cm^(3)/g.The CO_(2) storage of coal containing coal fines is significantly higher(6.6%)than that of the coal without coal fines.The CO_(2) storage effect of the coal with coal fines is improved with the increase in injection rate,whereas the CO_(2) storage effect of the coal without coal fines decreases significantly(by 7.8%).Multiple rounds of intermittent injection increases the CO_(2) storage volume of coal by 20.4%(with coal fines)and 17.1%(without coal fines).The presence of coal fines in fractures also slows down the downward trend of CO_(2) storage fraction after multiple rounds of CO_(2) injection.The blockage in fractures significantly increases the CO_(2) injection time and difficulty,but can increase the CO_(2) storage fraction by 4.7%-17.1%,and the storage volume by 1.9%-14%,increasing the feasibility of CO_(2) storage in fractured coal seams that have previously been exploited for methane production.The multiple rounds of intermittent CO_(2) injection and shut-in periods has shown potential for greater CO_(2) storage and injection efficiency.展开更多
The increasing atmospheric CO_(2)concentration linked to human activity results in global warming by the greenhouse effect.This anthropogenic CO_(2)may be sequestrated into geological formations,e.g.,porous basalts,sa...The increasing atmospheric CO_(2)concentration linked to human activity results in global warming by the greenhouse effect.This anthropogenic CO_(2)may be sequestrated into geological formations,e.g.,porous basalts,saline aquifers,depleted oil or gas reservoirs,and unmineable coal seams.Furthermore,carbon capture,utilization,and storage(CCUS)methods are an acceptable and sustainable technology to meet the goals of the Paris Agreement,in which Kazakhstan is expected to reduce greenhouse gas emissions by 25%compared with the 1990 level.Unmineable coal seams are an attractive option among all geostorage solutions,as CO_(2)sequestration in coal comes with an income stream via enhanced coalbed methane(ECBM)recovery.This paper identifies four carboniferous coal formations,namely Karagandy,Teniz-Korzhinkol,Ekibustuz,and Chu coal basins of Kazakhstan,as CO_(2)geostorage solutions for their unmineable coal seams.The ideal depth of CO_(2)storage is identified as 800 m to ensure the supercritical state of CO_(2).However,the Ekibustuz coal basin fails to meet the required depth of 800 m in its unmineable coal seams.The conventional formula for calculating CO_(2)storage in coal basins has been modified,and a new formula has been proposed for assessing the CO_(2)storage potential in a coal seam.The CO_(2)storage capacities of unmineable coal seam of these coal basins are 24.60 Bt,0.61 Bt,14.02 Bt,and 5.42 Bt,respectively.The Langmuir volume of the coal fields was calculated using the proximate analysis of coalfields and found to vary between 36.42 and 98.90 m3/ton.This paper is the first to outline CO_(2)storage potential in Kazakhstani coal basins,albeit with limited data,along with a detailed geological and paleographic review of the carboniferous coalfields of Kazakhstan.A short overview of the CO_(2)-ECBM process was also included in the paper.Instead of any experimental work for CO_(2)storage,this paper attempts to present the CO_(2)storage capacity of carboniferous coal formation using the modified version of previously determined formulas for CO_(2)storage.展开更多
The long-term stability of CO_(2) storage represents a pivotal challenge in geological CO_(2) storage(CGS),particularly within deep saline aquifers characterized by complex fault-block systems.While the injection site...The long-term stability of CO_(2) storage represents a pivotal challenge in geological CO_(2) storage(CGS),particularly within deep saline aquifers characterized by complex fault-block systems.While the injection sites and rate under different fault structures will directly affect the CO_(2) storage effect and the risk of leakage.This study investigates the Gaoyou Sag in the Subei Basin,a representative fault-block reservoir,through an integrated numerical-experimental approach.A three-dimensional simulation model incorporating multiphase flow dynamics was developed to characterize subsurface CO_(2) transport and dissolution processes.A novel fault seal capacity evaluation framework was proposed,integrating three critical geological indices(fault throw/reservoir thickness/caprock thicknesses)with the coupling of formation physical properties,temperature,and pressure for the rational selection of injection sites and rates.The results show that Optimal storage performance is observed when the fault throw is lower than the reservoir and caprock thicknesses.Furthermore,higher temperature and pressure promote the dissolution and diffusion of CO_(2),while compared to the structural form of faults,the physical properties of faults have a more significant effect on CO_(2) leakage.The larger reservoir space and the presence of an interlayer reduce the risk of CO_(2) leakage,and augmenting storage potential.Decreasing the injection rate increases the proportion of dissolved CO_(2),thereby enhancing the safety of CO_(2) storage.展开更多
Geological storage and utilization of CO_(2)involve complex interactions among Thermo-hydromechanical-chemical(THMC)coupling processes,which significantly affect storage integrity and efficiency.To address the challen...Geological storage and utilization of CO_(2)involve complex interactions among Thermo-hydromechanical-chemical(THMC)coupling processes,which significantly affect storage integrity and efficiency.To address the challenges in accurately simulating these coupled phenomena,this paper systematically reviews recent advances in the mathematical modeling and numerical solution of THMC coupling in CO_(2)geological storage.The study focuses on the derivation and structure of governing and constitutive equations,the classification and comparative performance of fully coupled,iteratively coupled,and explicitly coupled solution methods,and the modeling of dynamic changes in porosity,permeability,and fracture evolution induced by multi-field interactions.Furthermore,the paper evaluates the capabilities,application scenarios,and limitations of major simulation platforms,including TOUGH,CMG-GEM,and COMSOL.By establishing a comparative framework integrating model formulations and solver strategies,this work clarifies the strengths and gaps of current approaches and contributes to the development of robust,scalable,and mechanism-oriented numerical models for long-term prediction of CO_(2)behavior in geological formations.展开更多
Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative...Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.展开更多
Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments...Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments,and high-temperature,high-pressure online nuclear magnetic resonance(NMR)displacement experiments,are conducted to reveal the oil/gas mass transfer pattern and oil production mechanisms during CO_(2) flooding in ultra-low permeability reservoirs.The impacts of CO_(2) storage pore range and miscibility on oil production and CO_(2) storage characteristics during CO_(2) flooding are clarified.The CO_(2) flooding process is divided into three stages:oil displacement stage by CO_(2),CO_(2) breakthrough stage,CO_(2) extraction stage.Crude oil expansion and viscosity reduction are the main mechanisms for improving recovery in the CO_(2) displacement stage.After CO_(2) breakthrough,the extraction of light components from the crude oil further enhances oil recovery.During CO_(2) flooding,the contribution of crude oil in large pores to the enhanced recovery exceeds 46%,while crude oil in medium pores serves as a reserve for incremental recovery.After CO_(2) breakthrough,a small portion of the crude oil is extracted and carried into nano-scale pores by CO_(2),becoming residual oil that is hard to recover.As the miscibility increases,the CO_(2) front moves more stably and sweeps a larger area,leading to increased CO_(2) storage range and volume.The CO_(2) full-storage stage contributes the most to the overall CO_(2) storage volume.In the CO_(2) escape stage,the storage mechanism involves partial in-situ storage of crude oil within the initial pore range and the CO_(2) carrying crude oil into smaller pores to increase the volume of stored CO_(2).In the CO_(2) leakage stage,as crude oil is produced,a significant amount of CO_(2) leaks out,causing a sharp decline in the storage efficiency.展开更多
We study CO_(2) injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks.The simulation approach integrates the reservoir and mechanic...We study CO_(2) injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks.The simulation approach integrates the reservoir and mechanical simulators through a data transfer algorithm.MUFITS simulates non-isothermal multiphase flow in the reservoir,while FLAC3D calculates its mechanical equilibrium state.We accurately describe the tectonic fault,which consists of damage and core zones,and derive novel analytical closure relations governing the permeability alteration in the fault zone.We estimate the permeability of the activated fracture network in the damage zone and calculate the permeability of the main crack in the fault core,which opens on asperities due to slip.The coupled model is applied to simulate CO_(2) injection into synthetic and realistic reservoirs.In the synthetic reservoir model,we examine the impact of formation depth and initial tectonic stresses on geomechanical risks.Pronounced tectonic stresses lead to inelastic deformations in the fault zone.Regardless of the magnitude of tectonic stress,slip along the fault plane occurs,and the main crack in the fault core opens on asperities,causing CO_(2) leakage out of the storage aquifer.In the realistic reservoir model,we demonstrate that sufficiently high bottomhole pressure induces plastic deformations in the near-wellbore zone,interpreted as rock fracturing,without slippage along the fault plane.We perform a sensitivity analysis of the coupled model,varying the mechanical and flow properties of the storage layers and fault zone to assess fault stability and associated geomechanical risks.展开更多
The construction and operation of sulfur-containing gas storage are often more difficult than a non-sulfur storage facility due to the need to prevent environmental contamination from H_(2)S leaks,as well as the corro...The construction and operation of sulfur-containing gas storage are often more difficult than a non-sulfur storage facility due to the need to prevent environmental contamination from H_(2)S leaks,as well as the corrosive effects of H_(2)S on production facilities.Rapid elutriation of H_(2)S from the reservoir during the construction of the gas storage is an effective way to avoid these problems.However,the existing H_(2)S elutriation method has low efficiency and high economic cost,which limits the development of reconstructed gas storage of sulfur-containing gas reservoirs.To improve the efficiency of H_(2)S elutriation in sulfur-containing gas reservoirs and enhance the economic benefits,a numerical simulation model of multiphase flow components was established to study the migration law of H_(2)S in the multi-cycle operation of gas storage.Based on the H_(2)S migrate law,the displacement H_(2)S elutriation method was developed,and the elutriation mechanism and elutriation efficiency of the two methods were compared and analyzed.In addition,the main controlling factors affecting the H_(2)S elutriation efficiency were investigated,and the H_(2)S elutriation scheme of H gas storage was optimized.The results indicate that H_(2)S migrates between near-well and far-well regions under pressure differentials.The traditional H_(2)S elutriation method relies on concentration gradient diffusion,whereas the displacement elutriation approach leverages pressure differentials with higher H_(2)S elutriation efficiency.For the displacement elutriation method,higher reservoir permeability enhances the peak-shaving capacity of the gas storage but has a minor impact on H_(2)S elutriation when the formation permeability is between 30 and 100 mD.The elutriation efficiency is significantly higher when wells are drilled in the high structural parts of the reservoir compared to the low structural parts.Longer displacement elutriation time within a cycle improves H_(2)S elutriation efficiency but reduces the working gas volume of the storage.Therefore,the optimal displacement time for H gas storage is 60 days.An optimized H_(2)S elutriation scheme enabled the working gas to meet the national first-class natural gas standard within 10 cycles.This study elucidates H_(2)S migration patterns,H_(2)S elutriation mechanisms,and key influence factors on H_(2)S elutriation efficiency,offering valuable technical insights for sour gas storage operations.展开更多
Micro-sized anatase TiO_(2) displays inferior capacity as cathode material for magnesium ion batteries because of the higher diffusion energy barrier of Mg^(2+)in anatase TiO_(2) lattice.Herein,we report that nanosize...Micro-sized anatase TiO_(2) displays inferior capacity as cathode material for magnesium ion batteries because of the higher diffusion energy barrier of Mg^(2+)in anatase TiO_(2) lattice.Herein,we report that nanosized anatase TiO_(2) exposed(001)facet doubles the capacity compared to the micro-sized sample ascribed to the interfacial Mg^(2+)ion storage.First-principles calculations reveal that the diffusion energy barrier of Mg^(2+)on the(001)facet is significantly lower than those in the bulk phase and on(100)facet,and the adsorption energy of Mg^(2+)on the(001)facet is also considerably lower than that on(100)facet,which guarantees superior interfacial Mg^(2+)storage of(001)facet.Moreover,anatase TiO_(2) exposed(001)facet displays a significantly higher capacity of 312.9 mAh g^(−1) in Mg-Li dual-salt electrolyte compared to 234.3 mAh g^(−1) in Li salt electrolyte.The adsorption energies of Mg^(2+)on(001)facet are much lower than the adsorption energies of Li+on(001)facet,implying that the Mg^(2+)ion interfacial storage is more favorable.These results highlight that controlling the crystal facet of the nanocrystals effectively enhances the interfacial storage of multivalent ions.This work offers valuable guidance for the rational design of high-capacity storage systems.展开更多
The objective of this study is to investigate the potential of the microbially induced carbonate precipitation(MICP)method for leakage control in geological CO_(2) storage.It is crucial to understand the influence of ...The objective of this study is to investigate the potential of the microbially induced carbonate precipitation(MICP)method for leakage control in geological CO_(2) storage.It is crucial to understand the influence of supercritical environmental factors on the MICP,as this is directly related to the safety of geological storage systems.This paper analyzes the impact of four key factors on the MICP process and the resulting CaCO_(3) precipitation.These factors are temperature,CO_(2) pressure,bacterial suspension(BS),and cementation solution(CS)concentration.The influence of the above four factors on the MICP process and the resulting CaCO_(3) precipitation is investigated by solution tests,scanning electron microscopy(SEM)tests,X-ray diffraction(XRD)tests,and ultrasonic oscillation tests.The results indicate that the MICP process is inhibited in high temperature and CO_(2) pressure environments.Under supercritical CO_(2)(SC-CO_(2))conditions,the quantity of CaCO_(3) precipitation formed is reduced by approximately 35%compared to that produced under normal temperature and pressure conditions.The morphology and mineral composition of CaCO_(3) crystals are influenced by temperature and CO_(2) pressure,which in turn control their cementitious properties.The optimal concentration of CS is 0.5-0.75 mol/L,with a temperature of 45℃ and a CO_(2) pressure of 7.5 MPa.Furthermore,increasing the BS concentration can mitigate the inhibition of SC-CO_(2) in the MICP process.The findings of this study are significant for the application of the MICP method in geological CO_(2) storage.展开更多
As a promising cathode material for aqueous zinc-ion batteries,1T-MoS_(2)has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity.However,the limi...As a promising cathode material for aqueous zinc-ion batteries,1T-MoS_(2)has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity.However,the limited number of available Zn storage sites,i.e.,limited capacity,hinders its application because the inserted Zn^(2+),which form strong electrostatic interactions with 1T-MoS_(2),preventing subsequent Zn^(2+)insertion.Currently,the approach of enlarging the interlayer distance to reduce electrostatic interactions has been commonly used to enhance the capacity and reduce Zn^(2+)migration barriers.However,an enlarged interlayer spacing can weaken the van der Waals force between 1T-MoS_(2)monolayers,easily disrupting the structural stability.Herein,to address this issue,an effective strategy based on Fe doping is proposed for 1T-MoS_(2)(Fe-1T-MoS_(2)).The theoretical calculations reveal that Fe doping can simultaneously moderate the rate of decrease in the adsorption energy after gradually increasing the number of stored atoms,and enhance the electron delocalization on metal-O bonds.Therefore,the experiment results show that Fe doping can simultaneously activate more Zn storage sites,thus enhancing the capacity,and stabilize the structural stability for improved cycling performance.Consequently,Fe-1T-MoS_(2)exhibits a larger capacity(189 mAh·g^(-1)at 0.1 A·g^(-1))and superior cycling stability(78%capacity retention after 400 cycles at 2 A·g^(-1))than pure 1T-MoS_(2).This work may open up a new avenue for constructing high-performance MoS_(2)-based cathodes.展开更多
文摘At present,carbon capture and storage(CCS)is the only mature and commercialized technology capable of effectively and economically reducing greenhouse gas emissions to achieve a significant and immedi-ate impact on the CO_(2) level on Earth.Notably,long-term geological storage of captured CO_(2) has emerged as a primary storage method,given its minimal impact on surface ecological environments and high level of safety.The integrity of CO_(2) storage wellbores can be compromised by the corrosion of steel casings and degradation of cement in supercritical CO_(2) storage environments,potentially leading to the leakage of stored CO_(2) from the sites.This critical review endeavors to establish a knowledge foundation for the cor-rosion and materials degradation associated with geological CO_(2) storage through an in-depth examina-tion and analysis of the environments,operation,and the state-of-the-art progress in research pertaining to the topic.This article discusses the physical and chemical properties of CO_(2) in its supercrit-ical phase during injection and storage.It then introduces the principle of geological CO_(2) storage,consid-erations in the construction of storage systems,and the unique geo-bio-chemical environment involving aqueous media and microbial communities in CO_(2) storage.After a comprehensive analysis of existing knowledge on corrosion in CO_(2) storage,including corrosion mechanisms,parametric effects,and corro-sion rate measurements,this review identifies technical gaps and puts forward potential avenues for fur-ther research in steel corrosion within geological CO_(2) storage systems.
基金supported by the State Key Laboratory of Offshore Oil and Gas Exploitation, Open Fund Project (No. CCL2023RCPS0162RQN)the primary funding, National Natural Science Foundation of China (No. ZX20230400)
文摘Saline aquifers are considered as highly favored reservoirs for CO_(2)sequestration due to their favorable properties.Understanding the impact of saline aquifer properties on the migration and distribution of CO_(2)plume is crucial.This study focuses on four key parameters-permeability,porosity,formation pressure,and temperature-to characterize the reservoir and analyse the petrophysical and elastic response of CO_(2).First,we performed reservoir simulations to simulate CO_(2)saturation,using multiple sets of these four parameters to examine their significance on CO_(2)saturation and the plume migration speed.Subsequently,the effect of these parameters on the elastic properties is tested using rock physics theory.We established a relationship of compressional wave velocity(V_(p))and quality factor(Q_(p))with the four key parameters,and conducted a sensitivity analysis to test their sensitivity to V_(p) and Q_(p).Finally,we utilized visco-acoustic wave equation simulated time-lapse seismic data based on the computed V_(p) and Q_(p) models,and analysed the impact of CO_(2) saturation changes on seismic data.As for the above nu-merical simulations and analysis,we conducted sensitivity analysis using both homogeneous and heterogeneous models.Consistent results are found between homogeneous and heterogeneous models.The permeability is the most sensitive parameter to the CO_(2)saturation,while porosity emerges as the primary factor affecting both Q_(p) and V_(p).Both Q_(p) and V_(p) increase with the porosity,which contradicts the observations in gas reservoirs.The seismic simulations highlight significant variations in the seismic response to different parameters.We provided analysis for these observations,which serves as a valuable reference for comprehensive CO_(2)integrity analysis,time-lapse monitoring,injection planning and site selection.
基金supported by the National Key Research and Development Program of China(2022YFE0206700).
文摘Understanding the storage mechanisms in CO_(2)flooding is crucial,as many carbon capture,utilization,and storage(CCUS)projects are related to enhanced oil recovery(EOR).CO_(2)storage in reservoirs across large timescales undergoes the two storage stages of oil displacement and well shut-in,which cover mul-tiple replacement processes of injection-production synchronization,injection only with no production,and injection-production stoppage.Because the controlling mechanism of CO_(2)storage in different stages is unknown,the evolution of CO_(2)storage mechanisms over large timescales is not understood.A math-ematical model for the evaluation of CO_(2)storage,including stratigraphic,residual,solubility,and mineral trapping in low-permeability tight sandstone reservoirs,was established using experimental and theoret-ical analyses.Based on a detailed geological model of the Huaziping Oilfield,calibrated with reservoir permeability and fracture characteristic parameters obtained from well test results,a dynamic simulation of CO_(2)storage for the entire reservoir life cycle under two scenarios of continuous injection and water-gas alternation were considered.The results show that CO_(2)storage exhibits the significant stage charac-teristics of complete storage,dynamic storage,and stable storage.The CO_(2)storage capacity and storage rate under the continuous gas injection scenario(scenario 1)were 6.34×10^(4)t and 61%,while those under the water-gas alternation scenario(scenario 2)were 4.62×10^(4)t and 46%.The proportions of stor-age capacity under scenarios 1 and 2 for structural or stratigraphic,residual,solubility,and mineral trap-ping were 33.36%,33.96%,32.43%,and 0.25%;and 15.09%,38.65%,45.77%,and 0.49%,respectively.The evolution of the CO_(2)storage mechanism showed an overall trend:stratigraphic and residual trapping first increased and then decreased,whereas solubility trapping gradually decreased,and mineral trapping continuously increased.Based on these results,an evolution diagram of the CO_(2)storage mechanism of low-permeability tight sandstone reservoirs across large timescales was established.
基金supported by the National Natural Science Foundation of China(U22A20120,52071135,51871090,U1804135,and 52301269)the Natural Science Foundation of Hebei Province for Innovation Groups Program(C2022203003)Fundamental Research Funds for the Universities of Henan Province(NSFRF220201).
文摘Designing catalysts with high catalytic activity and stability is the key to achieve the commercial application of MgH_(2).Herein,the sulfur doped Ti_(3)C_(2)(S-Ti_(3)C_(2))was successfully prepared by heat treatment of Ti_(3)C_(2)MXene under Ar/H_(2)S atmosphere to facilitate the hydrogen release and uptake from MgH_(2).The S-Ti_(3)C_(2)exhibited pleasant catalytic effect on the hydriding/dehydriding kinetics and cyclic stability of MgH_(2).The addition of 5 wt%S-Ti_(3)C_(2)into MgH_(2)resulted in a reduction of 114℃in the starting dehydriding temperature compared to pure MgH_(2).MgH_(2)+5 wt%S-Ti_(3)C_(2)sample could quickly release 6.6 wt%hydrogen in 17 min at 220℃,and 6.8 wt%H_(2)was absorbed in 25 min at 200℃.Cyclic testing revealed that MgH_(2)+5 wt%S-Ti_(3)C_(2)system achieved a reversible hydrogen capacity of 6.5 wt%.Characterization analysis demonstrated that Ti-species(Ti0,Ti^(2+),Ti-S,and Ti^(3+))as active species significantly lowered the dehydrogenation temperature and promoted the re-/dehydrogenation kinetics of MgH_(2),and sulfur doping can effectively improve the stability of Ti0 and Ti^(3+),contributing to the improvement of cyclic stability of MgH_(2).This study provides strategy for the construction of catalysts for hydrogen storage materials.
基金supported by the Science and Technology Department of Guangxi Zhuang Autonomous[grant numbers 2025GXNSFFA069003]the National Natural Science Foundation of China[grant numbers 22379030]+1 种基金Bagui Young Scholars Program of Guangxi Zhuang Autonomous Regionthe high-performance computing platform of Guangxi University.
文摘Mg-based hydrogen storage materials have attracted much attention due to their high hydrogen content,abundant resources,and environmental friendliness.However,the high dehydrogenation temperature,slow kinetics and poor cycling stability are limiting its practical application.This work demonstrates the improved dehydrogenation kinetics and cycling stability of MgH_(2) modified by a hybrid of metallic Ni and layered MoS_(2)(denoted as“Ni-MoS_(2)”)introduced by ball milling,with Ni as the catalyst for MgH_(2) and MoS_(2) as the support for both Ni and MgH_(2).The onset dehydrogenation temperature of MgH_(2) is reduced to 198℃,and the rehydrogenation begins at a low temperature of 50℃.The MgH_(2)+10 wt%Ni-MoS_(2) composite has a fast dehydrogenation kinetics and can release 6.1 wt% hydrogen in 10 min at a constant temperature of 300℃,with the dehydrogenation activation energy significantly reduced from 151 to 85 kJ mol^(-1).During the cycling,the reversible capacity of the composite first exhibits a gradual increase for the initial 22 cycles and then maintains at 6.1 wt% from the 23th cycle to the 50th cycle.The Ni/MoS_(2) addition does not change the overall thermodynamic properties of MgH_(2) but can weaken the Mg-H bonds in the local regions as evident by theoretical calculation.Microstructure studies reveal that the metallic Ni will react with MgH_(2) to form Mg_(2)NiH_(0.3),which can act as a hydrogen pump,while the layered MoS_(2) serves as a support for the well dispersion of MgH_(2) and Ni.It is believed that the synergy of Mg_(2)NiH_(0.3) and layered MoS_(2) contributes to the significantly enhanced hydrogen storage of MgH_(2).This work provides a promising and simple strategy for enhancing the Mg-based hydrogen storage materials by combination of transition metals and layered materials introduced via simple ball milling.
基金financially supported by the National Key Research and Development program of China(2022YFB3504700)the National Natural Science Foundation of China(U23A20128)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0400304)the Research Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(No.E355B0020).
文摘Magnesium hydride(MgH_(2))has garnered significant attention as a promising material for high-capacity hydrogen storage.However,its commercial application remains challenging due to the high operating temperature and slow reaction kinetics.In this study,melt-spun Ti_(45)Cr_(40)Nb_(15)(with a BCC phase)hydride(designated as TiCrNbH_(x-)MS)was synthesized and used to form a nano-multiphase composite to improve the de-/rehydrogenation properties of MgH_(2) through ball milling.The incorporation of TiCrNbH_(x-)MS was shown to significantly enhance the hydrogen de-/rehydrogenation properties of MgH_(2).The MgH_(2)+20 wt%TiCrNbH_(x-)MS composite exhibits an appealing initial dehydrogenation temperature of 163℃ and can absorb hydrogen at room temperature.Notably,it releases 5.8 wt% hydrogen in 700 s at 230℃ and recharges 4.3 wt%hydrogen in just 2 mins at 150℃.Even after 100 cycles,it retains a reversible hydrogen capacity of 4.98 wt%.Kinetic analysis revealed that the dehydrogenation rate follows the Chou surface penetration model.Microstructural analysis showed that the FCC phase of the melt-spun TiCrNbH_(x-)MS hydride reversibly transformed into the BCC phase during the de-/rehydrogenation process in the composite.Numerous phase interfaces were generated and uniformly dispersed on the MgH_(2) surface,providing additional hydrogen diffusion pathways and heterogeneous nucleation sites for Mg/MgH_(2),thereby further improving the hydrogen de-/rehydrogenation kinetics of the system.This study offers valuable insights into the use of multiphase composites to enhance MgH_(2) performance.
基金financially supported by the Yulin Science and Technology Bureau(Grant No.2023-CXY-202)Scientific Research Program Funded by Shaanxi Provincial Education Department(Grant No.23JP008)+1 种基金Key Research and Development Projects of Shaanxi Province(Grant No.2024GX-YBXM-213)National Natural Science Foundation of China(Grant No.52102109)。
文摘Magnesium-based materials are considered as among the most promising candidates for hydrogen storage,owing to their high storage capacity,safety,and reliability.However,a passivation layer easily forms on the surface of magnesium,which hinders the dissociation and diffusion of hydrogen.High dehydrogenation temperature,sluggish kinetics and activation difficulties hinder their commercial application.Herein,dual-strategy regulation through nickel microalloying and surface catalysis of TiO_(2/)MnO_(2)catalysts has been proposed to obtain more active sites and diffusion channels that promote hydrogen dissociation and transport.Mg8Ni-X(X=None,TiO_(2),and TiO_(2/)MnO_(2))can achieve more than 80%hydrogen absorption without activation.Mg8Ni-5 wt%TiO_(2)/MnO_(2)absorbs hydrogen 5.27 wt%in 30 s at 200℃and desorbs 5.15 wt%in 20 min at 325℃.The activation energy(E_(a))of hydrogen absorption is 52.04kJ/mol.These results are significantly better than those of Mg8Ni and MgH_(2)under the same conditions.The NiTi phase is generated in the course of hydrogenation,and the coexistence of multiple phases and multivalent Ti facilitates the transport of electrons and H.The dual-strategy regulation means of surface catalysis and microalloying is promising for the design of high-capacity fast hydrogen absorbed and desorbed materials without activation.
文摘Carbon dioxide-enhanced oil recovery(CO_(2)-EOR)and storage is recognized as an economically feasible technique if used in suitable reservoirs.The type or form and capacity of this CO_(2) sequestration technique is synergistically affected by heat,flow,stress,and chemical reactions.Aimed at addressing the technological issues in applying CO_(2)-EOR and storage in a high water-cut reservoir in Xinjiang,China,this paper proposes a thermo-hydro-mechanical-chemical coupling method during CO_(2) flooding.The potential of CO_(2) sequestration and EOR in the target reservoir is discussed in combination with the surrogate optimization method.This method works better as it considers the evolution of structural trapping,capillary trapping,solubility trapping,and mineral trapping during CO_(2) injection as well as the influence the physical field has on the sequestration capacity for different forms of CO_(2) sequestration.The main mechanisms of CO_(2) sequestration in the high water-cut reservoir is structural trapping,followed by capillary trapping.Solubility trapping and mineral trapping have less contribution to the total sequestration capacity of CO_(2).After optimization,the cumulative oil production was 2.36×10^(6)m^(3),an increase of 0.25×10^(6)m3or 11.9%compared to the pre-optimization value.The CO_(2) sequestration capacity after optimization was 1.39×10^(6)t,which is an increase of 0.23×10^(6)t compared to values obtained before optimization;this effectively increases the area affected by CO_(2) by 24.4%.Of the four trapping mechanisms,capillary trapping and structural trapping showed a high increase of 32.5%and17.28%,respectively,while solubility trapping and mineral trapping only led to an increase of 5.1%and0.43%,respectively.This research could provide theoretical support for fully utilizing the potential of CO_(2)-EOR and sequestration technology.
基金supported by the Science and Technology Foundation of China Electric Power Research Institute(Development of high-energy-density alloy solid hydrogen storage materials,DG8323-002)。
文摘Metallic single-atom catalysts(SACs)have demonstrated high activity and potential in enhancing the hydrogen storage properties of MgH_(2).However,previous reports primarily focus on supported SACs,which often suffer from insufficient co ntact between single-atom active sites and hydrogen storage materials.In this study,the precursor Mo(CO)_(6)is uniformly dispersed on the surface of MgH_(2)via impregnation adsorption,leading to the formation of alloy-type Mo single atoms after hydrogenation/dehydrogenation activation.This alloy structure enables zero-distance contact between catalytic sites and the hydrogen storage material,facilitating electron exchange and hydrogen transfer between the Mo sites and MgH_(2).The MgH_(2)loaded with Mo single atoms(Mo_(1)-MgH_(2))exhibits excellent hydrogen absorption and desorption properties,with the initial hydrogen release temperature lowered from 323 to 218℃.At 250℃,Mo_(1)-MgH_(2)absorbs over 6.77 wt% of hydrogen within 1 min and releases over 5.85 wt% within 4 h.During 10 cycles of hydrogenation and dehydrogenation reactions,Mo_(1)-MgH_(2)maintains nearly 100% capacity and shows stable kinetics.This work provides new insights into the design and fabrication of catalysts for hydrogen storage materials.
基金supported by National Natural Science Foundation of China(52104048,42272198)。
文摘Gas channeling in fractures during CO_(2) injection into the deep coal seam seriously reduces the CO_(2) storage efficiency after the development of coalbed methane.The generation and migration of coal fines causes blockages in the fractures in the stage of drainage and gas production,reducing the gas channeling effect of injected CO_(2) caused by the heterogeneity of the coal seam.To explore the impact of coal fines within coal seam fractures on the efficacy of CO_(2) storage,experiments on the production stage and CO_(2) injection for storage were conducted on coal combinations containing propped fractures,fractures,and matrix.The CO_(2) storage characteristics of coal at the constraint of coal fines,as well as the influence of multiple rounds of intermittent CO_(2) injection and different injection parameters on the CO_(2) storage effect,were analyzed.The research results show that blockage by coal fines increases the resistance to fluid flow in the fractures by 71.2%.The CO_(2) storage capacity and storage potential of coal with coal fines are 6.5 cm^(3)/g and 8.8%higher than those of coal without coal fines,while the CO_(2) storage capacity of fractured coal under the influence of coal fines has the largest increase of 9.4 cm^(3)/g.The CO_(2) storage of coal containing coal fines is significantly higher(6.6%)than that of the coal without coal fines.The CO_(2) storage effect of the coal with coal fines is improved with the increase in injection rate,whereas the CO_(2) storage effect of the coal without coal fines decreases significantly(by 7.8%).Multiple rounds of intermittent injection increases the CO_(2) storage volume of coal by 20.4%(with coal fines)and 17.1%(without coal fines).The presence of coal fines in fractures also slows down the downward trend of CO_(2) storage fraction after multiple rounds of CO_(2) injection.The blockage in fractures significantly increases the CO_(2) injection time and difficulty,but can increase the CO_(2) storage fraction by 4.7%-17.1%,and the storage volume by 1.9%-14%,increasing the feasibility of CO_(2) storage in fractured coal seams that have previously been exploited for methane production.The multiple rounds of intermittent CO_(2) injection and shut-in periods has shown potential for greater CO_(2) storage and injection efficiency.
文摘The increasing atmospheric CO_(2)concentration linked to human activity results in global warming by the greenhouse effect.This anthropogenic CO_(2)may be sequestrated into geological formations,e.g.,porous basalts,saline aquifers,depleted oil or gas reservoirs,and unmineable coal seams.Furthermore,carbon capture,utilization,and storage(CCUS)methods are an acceptable and sustainable technology to meet the goals of the Paris Agreement,in which Kazakhstan is expected to reduce greenhouse gas emissions by 25%compared with the 1990 level.Unmineable coal seams are an attractive option among all geostorage solutions,as CO_(2)sequestration in coal comes with an income stream via enhanced coalbed methane(ECBM)recovery.This paper identifies four carboniferous coal formations,namely Karagandy,Teniz-Korzhinkol,Ekibustuz,and Chu coal basins of Kazakhstan,as CO_(2)geostorage solutions for their unmineable coal seams.The ideal depth of CO_(2)storage is identified as 800 m to ensure the supercritical state of CO_(2).However,the Ekibustuz coal basin fails to meet the required depth of 800 m in its unmineable coal seams.The conventional formula for calculating CO_(2)storage in coal basins has been modified,and a new formula has been proposed for assessing the CO_(2)storage potential in a coal seam.The CO_(2)storage capacities of unmineable coal seam of these coal basins are 24.60 Bt,0.61 Bt,14.02 Bt,and 5.42 Bt,respectively.The Langmuir volume of the coal fields was calculated using the proximate analysis of coalfields and found to vary between 36.42 and 98.90 m3/ton.This paper is the first to outline CO_(2)storage potential in Kazakhstani coal basins,albeit with limited data,along with a detailed geological and paleographic review of the carboniferous coalfields of Kazakhstan.A short overview of the CO_(2)-ECBM process was also included in the paper.Instead of any experimental work for CO_(2)storage,this paper attempts to present the CO_(2)storage capacity of carboniferous coal formation using the modified version of previously determined formulas for CO_(2)storage.
基金the Beijing Natural Science Foundation(No.8232044)the Science Foundation of China University of Petroleum,Beijing(No.2462023BJRC030).
文摘The long-term stability of CO_(2) storage represents a pivotal challenge in geological CO_(2) storage(CGS),particularly within deep saline aquifers characterized by complex fault-block systems.While the injection sites and rate under different fault structures will directly affect the CO_(2) storage effect and the risk of leakage.This study investigates the Gaoyou Sag in the Subei Basin,a representative fault-block reservoir,through an integrated numerical-experimental approach.A three-dimensional simulation model incorporating multiphase flow dynamics was developed to characterize subsurface CO_(2) transport and dissolution processes.A novel fault seal capacity evaluation framework was proposed,integrating three critical geological indices(fault throw/reservoir thickness/caprock thicknesses)with the coupling of formation physical properties,temperature,and pressure for the rational selection of injection sites and rates.The results show that Optimal storage performance is observed when the fault throw is lower than the reservoir and caprock thicknesses.Furthermore,higher temperature and pressure promote the dissolution and diffusion of CO_(2),while compared to the structural form of faults,the physical properties of faults have a more significant effect on CO_(2) leakage.The larger reservoir space and the presence of an interlayer reduce the risk of CO_(2) leakage,and augmenting storage potential.Decreasing the injection rate increases the proportion of dissolved CO_(2),thereby enhancing the safety of CO_(2) storage.
基金supported by the China Postdoctoral Science Foundation(No.2024M752803)the National Natural Science Foundation of China(No.52179112)the Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)(No.PLN2023-02)。
文摘Geological storage and utilization of CO_(2)involve complex interactions among Thermo-hydromechanical-chemical(THMC)coupling processes,which significantly affect storage integrity and efficiency.To address the challenges in accurately simulating these coupled phenomena,this paper systematically reviews recent advances in the mathematical modeling and numerical solution of THMC coupling in CO_(2)geological storage.The study focuses on the derivation and structure of governing and constitutive equations,the classification and comparative performance of fully coupled,iteratively coupled,and explicitly coupled solution methods,and the modeling of dynamic changes in porosity,permeability,and fracture evolution induced by multi-field interactions.Furthermore,the paper evaluates the capabilities,application scenarios,and limitations of major simulation platforms,including TOUGH,CMG-GEM,and COMSOL.By establishing a comparative framework integrating model formulations and solver strategies,this work clarifies the strengths and gaps of current approaches and contributes to the development of robust,scalable,and mechanism-oriented numerical models for long-term prediction of CO_(2)behavior in geological formations.
文摘Geological CO_(2) storage is a promising strategy for reducing greenhouse gas emissions;however,its underlying multiphase reactive flow mechanisms remain poorly understood.We conducted steady-state imbibition relative permeability experiments on sandstone from a proposed storage site,comple-mented by in situ X-ray imaging and ex situ analyses using scanning electron microscopy(SEM)and energy-dispersive X-ray spectroscopy(EDS).Despite our use of a brine that was pre-equilibrated with CO_(2),there was a significant reduction in both CO_(2) relative permeability and absolute permeability during multiphase flow due to chemical reactions.This reduction was driven by decreased pore and throat sizes,diminished connectivity,and increased irregularity of pore and throat shapes,as revealed by in situ pore-scale imaging.Mineral dissolution,primarily of feldspar,albite,and calcite,along with precipitation resulting from feldspar-to-kaolinite transformation and fines migration,were identified as contributing factors through SEM-EDS analysis.This work provides a benchmark for storage in mineralogically complex sandstones,for which the impact of chemical reactions on multiphase flow properties has been measured.
基金Supported by the National Natural Science Foundation of China(52274053)Natural Science Foundation of Beijing(3232028).
文摘Using the ultra-low permeability reservoirs in the L block of the Jiangsu oilfield as an example,a series of experiments,including slim tube displacement experiments of CO_(2)-oil system,injection capacity experiments,and high-temperature,high-pressure online nuclear magnetic resonance(NMR)displacement experiments,are conducted to reveal the oil/gas mass transfer pattern and oil production mechanisms during CO_(2) flooding in ultra-low permeability reservoirs.The impacts of CO_(2) storage pore range and miscibility on oil production and CO_(2) storage characteristics during CO_(2) flooding are clarified.The CO_(2) flooding process is divided into three stages:oil displacement stage by CO_(2),CO_(2) breakthrough stage,CO_(2) extraction stage.Crude oil expansion and viscosity reduction are the main mechanisms for improving recovery in the CO_(2) displacement stage.After CO_(2) breakthrough,the extraction of light components from the crude oil further enhances oil recovery.During CO_(2) flooding,the contribution of crude oil in large pores to the enhanced recovery exceeds 46%,while crude oil in medium pores serves as a reserve for incremental recovery.After CO_(2) breakthrough,a small portion of the crude oil is extracted and carried into nano-scale pores by CO_(2),becoming residual oil that is hard to recover.As the miscibility increases,the CO_(2) front moves more stably and sweeps a larger area,leading to increased CO_(2) storage range and volume.The CO_(2) full-storage stage contributes the most to the overall CO_(2) storage volume.In the CO_(2) escape stage,the storage mechanism involves partial in-situ storage of crude oil within the initial pore range and the CO_(2) carrying crude oil into smaller pores to increase the volume of stored CO_(2).In the CO_(2) leakage stage,as crude oil is produced,a significant amount of CO_(2) leaks out,causing a sharp decline in the storage efficiency.
文摘We study CO_(2) injection into a saline aquifer intersected by a tectonic fault using a coupled modeling approach to evaluate potential geomechanical risks.The simulation approach integrates the reservoir and mechanical simulators through a data transfer algorithm.MUFITS simulates non-isothermal multiphase flow in the reservoir,while FLAC3D calculates its mechanical equilibrium state.We accurately describe the tectonic fault,which consists of damage and core zones,and derive novel analytical closure relations governing the permeability alteration in the fault zone.We estimate the permeability of the activated fracture network in the damage zone and calculate the permeability of the main crack in the fault core,which opens on asperities due to slip.The coupled model is applied to simulate CO_(2) injection into synthetic and realistic reservoirs.In the synthetic reservoir model,we examine the impact of formation depth and initial tectonic stresses on geomechanical risks.Pronounced tectonic stresses lead to inelastic deformations in the fault zone.Regardless of the magnitude of tectonic stress,slip along the fault plane occurs,and the main crack in the fault core opens on asperities,causing CO_(2) leakage out of the storage aquifer.In the realistic reservoir model,we demonstrate that sufficiently high bottomhole pressure induces plastic deformations in the near-wellbore zone,interpreted as rock fracturing,without slippage along the fault plane.We perform a sensitivity analysis of the coupled model,varying the mechanical and flow properties of the storage layers and fault zone to assess fault stability and associated geomechanical risks.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202401501,KJZD-M202401501).
文摘The construction and operation of sulfur-containing gas storage are often more difficult than a non-sulfur storage facility due to the need to prevent environmental contamination from H_(2)S leaks,as well as the corrosive effects of H_(2)S on production facilities.Rapid elutriation of H_(2)S from the reservoir during the construction of the gas storage is an effective way to avoid these problems.However,the existing H_(2)S elutriation method has low efficiency and high economic cost,which limits the development of reconstructed gas storage of sulfur-containing gas reservoirs.To improve the efficiency of H_(2)S elutriation in sulfur-containing gas reservoirs and enhance the economic benefits,a numerical simulation model of multiphase flow components was established to study the migration law of H_(2)S in the multi-cycle operation of gas storage.Based on the H_(2)S migrate law,the displacement H_(2)S elutriation method was developed,and the elutriation mechanism and elutriation efficiency of the two methods were compared and analyzed.In addition,the main controlling factors affecting the H_(2)S elutriation efficiency were investigated,and the H_(2)S elutriation scheme of H gas storage was optimized.The results indicate that H_(2)S migrates between near-well and far-well regions under pressure differentials.The traditional H_(2)S elutriation method relies on concentration gradient diffusion,whereas the displacement elutriation approach leverages pressure differentials with higher H_(2)S elutriation efficiency.For the displacement elutriation method,higher reservoir permeability enhances the peak-shaving capacity of the gas storage but has a minor impact on H_(2)S elutriation when the formation permeability is between 30 and 100 mD.The elutriation efficiency is significantly higher when wells are drilled in the high structural parts of the reservoir compared to the low structural parts.Longer displacement elutriation time within a cycle improves H_(2)S elutriation efficiency but reduces the working gas volume of the storage.Therefore,the optimal displacement time for H gas storage is 60 days.An optimized H_(2)S elutriation scheme enabled the working gas to meet the national first-class natural gas standard within 10 cycles.This study elucidates H_(2)S migration patterns,H_(2)S elutriation mechanisms,and key influence factors on H_(2)S elutriation efficiency,offering valuable technical insights for sour gas storage operations.
基金supported by the National Key R&D Program of China(No.2023YFB3809500)the Fundamental Research Funds for the Central Universities(No.2024CDJXY003)+1 种基金the Venture&Innovation Support Program for Chongqing Overseas Returnees(cx2023087)The Chongqing Technology Innovation and Application Development Project(No.2024TIAD-KPX0003).
文摘Micro-sized anatase TiO_(2) displays inferior capacity as cathode material for magnesium ion batteries because of the higher diffusion energy barrier of Mg^(2+)in anatase TiO_(2) lattice.Herein,we report that nanosized anatase TiO_(2) exposed(001)facet doubles the capacity compared to the micro-sized sample ascribed to the interfacial Mg^(2+)ion storage.First-principles calculations reveal that the diffusion energy barrier of Mg^(2+)on the(001)facet is significantly lower than those in the bulk phase and on(100)facet,and the adsorption energy of Mg^(2+)on the(001)facet is also considerably lower than that on(100)facet,which guarantees superior interfacial Mg^(2+)storage of(001)facet.Moreover,anatase TiO_(2) exposed(001)facet displays a significantly higher capacity of 312.9 mAh g^(−1) in Mg-Li dual-salt electrolyte compared to 234.3 mAh g^(−1) in Li salt electrolyte.The adsorption energies of Mg^(2+)on(001)facet are much lower than the adsorption energies of Li+on(001)facet,implying that the Mg^(2+)ion interfacial storage is more favorable.These results highlight that controlling the crystal facet of the nanocrystals effectively enhances the interfacial storage of multivalent ions.This work offers valuable guidance for the rational design of high-capacity storage systems.
基金support provided by the National Natural Science Foundation of China(Grant No.42177141).
文摘The objective of this study is to investigate the potential of the microbially induced carbonate precipitation(MICP)method for leakage control in geological CO_(2) storage.It is crucial to understand the influence of supercritical environmental factors on the MICP,as this is directly related to the safety of geological storage systems.This paper analyzes the impact of four key factors on the MICP process and the resulting CaCO_(3) precipitation.These factors are temperature,CO_(2) pressure,bacterial suspension(BS),and cementation solution(CS)concentration.The influence of the above four factors on the MICP process and the resulting CaCO_(3) precipitation is investigated by solution tests,scanning electron microscopy(SEM)tests,X-ray diffraction(XRD)tests,and ultrasonic oscillation tests.The results indicate that the MICP process is inhibited in high temperature and CO_(2) pressure environments.Under supercritical CO_(2)(SC-CO_(2))conditions,the quantity of CaCO_(3) precipitation formed is reduced by approximately 35%compared to that produced under normal temperature and pressure conditions.The morphology and mineral composition of CaCO_(3) crystals are influenced by temperature and CO_(2) pressure,which in turn control their cementitious properties.The optimal concentration of CS is 0.5-0.75 mol/L,with a temperature of 45℃ and a CO_(2) pressure of 7.5 MPa.Furthermore,increasing the BS concentration can mitigate the inhibition of SC-CO_(2) in the MICP process.The findings of this study are significant for the application of the MICP method in geological CO_(2) storage.
基金supported by the National Natural Science Foundation of China(No.52102318)the Fellowship of China Postdoctoral Science Foundation(Nos.2021TQ0287 and 2022M722855)Xingdian Talent Support Foundation of Yunnan Province(2020).
文摘As a promising cathode material for aqueous zinc-ion batteries,1T-MoS_(2)has been extensively investigated because of its facile two-dimensional ion-diffusion channels and high electrical conductivity.However,the limited number of available Zn storage sites,i.e.,limited capacity,hinders its application because the inserted Zn^(2+),which form strong electrostatic interactions with 1T-MoS_(2),preventing subsequent Zn^(2+)insertion.Currently,the approach of enlarging the interlayer distance to reduce electrostatic interactions has been commonly used to enhance the capacity and reduce Zn^(2+)migration barriers.However,an enlarged interlayer spacing can weaken the van der Waals force between 1T-MoS_(2)monolayers,easily disrupting the structural stability.Herein,to address this issue,an effective strategy based on Fe doping is proposed for 1T-MoS_(2)(Fe-1T-MoS_(2)).The theoretical calculations reveal that Fe doping can simultaneously moderate the rate of decrease in the adsorption energy after gradually increasing the number of stored atoms,and enhance the electron delocalization on metal-O bonds.Therefore,the experiment results show that Fe doping can simultaneously activate more Zn storage sites,thus enhancing the capacity,and stabilize the structural stability for improved cycling performance.Consequently,Fe-1T-MoS_(2)exhibits a larger capacity(189 mAh·g^(-1)at 0.1 A·g^(-1))and superior cycling stability(78%capacity retention after 400 cycles at 2 A·g^(-1))than pure 1T-MoS_(2).This work may open up a new avenue for constructing high-performance MoS_(2)-based cathodes.
