The merits of CO2 capture and storage to the environmental stability of our world should not be underestimated as emissions of greenhouse gases cause serious problems.It represents the only technology that might rid o...The merits of CO2 capture and storage to the environmental stability of our world should not be underestimated as emissions of greenhouse gases cause serious problems.It represents the only technology that might rid our atmosphere of the main anthropogenic gas while allowing for the continuous use of the fossil fuels which still power today’s world.Underground storage of CO2 involves the injection of CO2 into suitable geological formations and the monitoring of the injected plume over time,to ensure containment.Over the last two or three decades,attention has been paid to technology developments of carbon capture and sequestration.Therefore,it is high time to look at the research done so far.In this regard,a high-level review article is required to provide an overview of the status of carbon capture and sequestration research.This article presents a review of CO2 storage technologies which includes a background of essential concepts in storage,the physical processes involved,modeling procedures and simulators used,capacity estimation,measuring monitoring and verification techniques,risks and challenges involved and field-/pilot-scale projects.It is expected that the present review paper will help the researchers to gain a quick knowledge of CO2 sequestration for future research in this field.展开更多
This work established an evaluation index system based on a comprehensive analysis of those factors affecting the suitability of CO2 geological storage.This evaluation index system includes three evaluation index laye...This work established an evaluation index system based on a comprehensive analysis of those factors affecting the suitability of CO2 geological storage.This evaluation index system includes three evaluation index layers of geological safety,storage scale and social economy,nine evaluation index sub-layers,and 28 evaluation index factors,and adopts the analytic hierarchy process（AHP）and index overlay methods.Taking the Xining Basin in northwest China as an example,we conducted comprehensive analysis of geological conditions and performed quantitative evaluation based on this evaluation index system,which indicates that the Shuangshu depression of the Xining Basin is comparatively suitable for CO2 geological storage.It is suggested that this evaluation index system and the evaluation method proposed in this study are suitable for most continental sedimentary basins in China and should be widely applied.展开更多
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
This paper focuses on the progress in geomechanical modeling associated with carbon dioxide(CO2)geological storage.The detailed review of some geomechanical aspects,including numerical methods,stress analysis,ground d...This paper focuses on the progress in geomechanical modeling associated with carbon dioxide(CO2)geological storage.The detailed review of some geomechanical aspects,including numerical methods,stress analysis,ground deformation,fault reactivation,induced seismicity and crack propagation,is presented.It is indicated that although all the processes involved are not fully understood,integration of all available data,such as ground survey,geological conditions,microseismicity and ground level deformation,has led to many new insights into the rock mechanical response to CO2injection.The review also shows that in geomechanical modeling,continuum modeling methods are predominant compared with discontinuum methods.It is recommended to develop continuum-discontinuum numerical methods since they are more convenient for geomechanical modeling of CO2geological storage,especially for fracture propagation simulation.The Mohr-Coulomb criterion is widely used in prediction of rock mass mechanical behavior.It would be better to use a criterion considering the effect of the intermediate principal stress on rock mechanical behavior,especially for the stability analysis of deeply seated rock engineering.Some challenges related to geomechanical modeling of CO2geological storage are also discussed.展开更多
Offshore carbon dioxide(CO_(2))geological storage is a promising strategy for reducing carbon emissions and supporting sustainable development in coastal regions within a carbon neutrality framework.However,only a few...Offshore carbon dioxide(CO_(2))geological storage is a promising strategy for reducing carbon emissions and supporting sustainable development in coastal regions within a carbon neutrality framework.However,only a few works have focused on offshore basins in China.To address this gap,this study established a dual indicator system that comprises necessary and critical indices and is integrated with the analytic hierarchy process.A coupled analysis was then performed to evaluate the suitability of 10 offshore sedimentary basins in China for CO_(2)geological storage.The necessary indicator system focuses on storage potential,geological conditions,and engineering feasibility.Meanwhile,the critical indicator system emphasizes the safety of storage projects and the viability of drilling operations.Evaluation results revealed that China's offshore basins have undergone two geological evolution stages,namely,the rifting and post-rifting phases,leading to the formation of a dual-layer structure characterized by faulted lower layers and sagged upper layers.These basins have thick and widespread Cenozoic strata,generally low seismic activity,and medium-to-low geothermal gradients.They form five reservoir-caprock systems with favorable geological conditions for CO_(2)storage.The Pearl River Mouth,East China Sea Shelf,and Bohai Basins emerged as primary candidates that offer substantial storage potential to support carbon neutrality goals in the Bohai Rim Economic Zone,Yangtze River Delta Economic Zone,and Guangdong-Hong Kong-Macao Greater Bay Area.The Beibu Gulf and South Yellow Sea Basins were identified as secondary candidates,and the Qiongdongnan and Yinggehai Basins were considered potential alternatives.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
CO_(2)injection into geological formations has been proven to be an effective approach for carbon storage.When dissolved in formation water,CO_(2)forms carbonic acid that induces mineral dissolution at pore surfaces u...CO_(2)injection into geological formations has been proven to be an effective approach for carbon storage.When dissolved in formation water,CO_(2)forms carbonic acid that induces mineral dissolution at pore surfaces under acidic conditions.Comprehensive understanding of geochemical interaction between carbonic acid and reservoir rocks is crucial for assessing environmental impact on geological formations.This study focuses on a tight oil sandstone reservoir.After characterizing basic petrophysical properties and mineral composition of rock samples,a series of carbonic acid corrosion experiments with both core and corresponding pure mineral samples were carried out,respectively.Dissolution solutions collected during the experiments were analyzed to examine the variations of ion concentrations in both core and pure mineral solutions.The carbonic acid-pure mineral corrosion kinetics were investigated.The correlations between carbonic acid with core and pure mineral corrosion scenarios were established from the sample mass,reaction rate,and ion concentration.The results show that after corrosion,the mass of calcite and dolomite in the rock sample decreased by 66.7%and 27.3%,respectively.When the corrosion was stabilized,the concentrations of Ca^(2+)and Mg^(2+)in the core solution were 72.9 and 74.4 mg/L.respectively,which was 40.5-41.3 times higher than that of Na+.The reaction kinetics analysis of carbonic acid-rock revealed a two-stage reaction in the pure mineral corrosion process,rapid reaction stage,and slow reaction stage,with different reaction rate constants and reaction orders for each ion.With the correlation between carbonic acid reaction with core and pure minerals,an effective and rapid evaluation method with pure minerals for the carbonic water-rock reaction is established,which costs a shorter time and is easier to investigate.This study provides a simple and faster method to evaluate the carbonic acid corrosion reaction during geological carbon storage.展开更多
During the CO_(2)injection and geological storage process,the integrity of the cap rock significantly influences the long-term safety of CO_(2)storage.Natural fractures within the cap rock serve as potential pathways ...During the CO_(2)injection and geological storage process,the integrity of the cap rock significantly influences the long-term safety of CO_(2)storage.Natural fractures within the cap rock serve as potential pathways for CO_(2)migration,thereby increasing the risk of CO_(2)leakage.In this study,we determined the types,developmental characteristics,permeability changes,and CO_(2)-H_(2)O-Rock reactions of natural fractures in the mudstone cap rocks of the Sanduo Formation(E_(3)s)and Dainan Formation(E_(2)d)in the Gaoyou Sag of the Subei Basin using core observations,thin-section analysis,rock mechanics experiments,and paleomagnetic directional analysis.We identified four tectonic fracture sets(NNW,NWW,EW,and NE);high-angle shear fractures,ranging from 60°to 90°(average 82°)and typically measuring4-12 cm(average 7.5 cm),dominate the assemblage,while slip fractures,ranging from 32°to 50°(average 36°)and measuring 3-6 cm(average 3.9 cm),are also present.At the microscale,shear fractures average 160μm,and bedding fractures average 82μm.Notably,85.78%of shear fractures are unfilled,with calcite filling observed in 14.22%,while other fracture types show no filling.Permeability tests on samples without fractures reveal that permeability declines rapidly below 9 MPa,especially in shallower samples,followed by a slower reduction between 9 and 13 MPa,and ultimately stabilizes at approximately 0.00003 mD.In contrast,samples with fractures exhibit permeability that is 3-4 orders of magnitude higher;their fracture permeability decays according to a power law with pressure yet remains above 10 mD even at 46 MPa.Fractures with larger dip angles and those aligned with the maximum principal stress demonstrate the highest permeability.While silicate-filled fractures exhibit negligible changes in permeability,carbonate-filled fractu res experience a temporary enhancement due to dissolution;however,subsequent permeability remains controlled by factors such as effective stress and fracture orientation.展开更多
China has pledged to peak carbon dioxide(CO_(2))emissions by 2030 and achieve carbon neutrality by 2060.Carbon capture and storage(CCS)will play a key role in these efforts.Over the past several years,the China Geolog...China has pledged to peak carbon dioxide(CO_(2))emissions by 2030 and achieve carbon neutrality by 2060.Carbon capture and storage(CCS)will play a key role in these efforts.Over the past several years,the China Geological Survey(CGS)has completed the Suitability Evaluation Map of CO_(2)Geological Storage in Main Sedimentary Basins in China and Adjacent Sea Regions in 2017.This map reflects the suitability of the first-and secondary-order tectonic units within sedimentary basins for cO_(2)geological storage for CCS planning.The Junggar Basin is recognized as an important region for future CCS projects.Results from a mesoscale evaluation using the volume method indicate that deep saline aquifers represent the most significant resources for CO_(2)storage,with potential ranging from 48×10^(9)to 164×10^(9)t(with a P50 value of 96×10^(9)t).The highest storage potential is identified in the central and northern parts of the basin,reaching up to 9.5×10^(6)t/km^(2)at the P50 probability level.In contrast,the hinterland,eastern,and western parts of the basin generally exhibit storage potential of below 1.0×10^(6)t/km^(2)at the same probability level.The CGs has also characterized historical CO_(2)plume migration in reservoirs at the storage site of the Shenhua CCS demonstration project and conducted numerical simulations of CO_(2)plume migration for periods of 10 and 20 years following the shutdown of the injection well.The CGS implemented a kiloton-scale pilot test on CO_(2)-enhanced water recovery(CO_(2)-EWR)in eastern Junggar,revealing that CO_(2)flooding can improve the pressure for fluid production,with the highest ratio of CO_(2)to produced fluids estimated at approximately 1.2.Besides,an observation field for natural CO_(2)leakage,covering about 930 m^(2),was built in Qinghai Province.In natural CO_(2)fields or at artificial CO_(2)injection research sites,cO_(2)leakage points are primarily related to the distribution of faults(especially fault crossing),which can serve as pathways for CO_(2)leakage.The observation field provides a natural analog to wellbore failure and offers an opportunity to further monitor CO_(2)geological storage sites.However,it has been inferred that borehole ZK10 at the observation field has become a leakage pathway due to the drilling activities,inadequate well-plugging,and abandonment procedures without considering CO_(2)corrosion.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
Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transform...Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transformation underground over time at the reservoir scale.To address this issue,we conducted a rig-orous numerical simulation integrating microseismic events,multi-geomechanics,and multi-geochemistry to represent the complex fracture geometry,rock stress sensitivity,and CO_(2)-oil-brine-rock interactions.The fluid model,reservoir model,and geochemical reaction kinetics were carefully validated and calibrated using experimental data.The performance of CO_(2) utilization and geological storage was comprehensively investigated in terms of changes in oil production,CO_(2) storage,carbon distribution,and petrophysical properties.The results indicate that 48.3%of the injected CO_(2) was stored stably under-ground after ten cycles(ten years),with a 3.4%increase in oil recovery.The presence of multiple CO_(2) stor-age forms,such as dissolved in water and mineralized carbonate,impeded CO_(2)-oil interaction,leading to a 25.9%reduction in the volume of the CO_(2)-oil mixing zone and a 2.2%decrease in cumulative oil pro-duction,albeit with a 7.7%increase in the storage rate.The cyclic injection mode had a significant impact on the migration and transformation of CO_(2) in the reservoir.While dissolved CO_(2) in oil accounted for over half of the total storage,it had the possibility of being released during production.After ten cycles,20%of the injected CO_(2)(approximately 12000 t)reached long-term storage in four forms:mineralized carbon-ate(6%),water-dissolved CO_(2)(6%),aqueous ions(4%),and trapped gas(4%).Notably,the non-fracture zone within the stimulated reservoir volume(SRV)served as the primary trapping area for residual gas.This work provides valuable insights into dynamic CO_(2) transport and transformation processes under cyclic injection and presents a more comprehensive and precise framework for assessing CO_(2) capture,utilization,and storage with enhanced oil recovery(CCUS-EOR)performance in unconventional reser-voirs after fracturing.展开更多
The well-developed coal electricity generation and coal chemical industries have led to huge carbon dioxide(CO_(2))emissions in the northeastern Ordos Basin.The geological storage of CO_(2) in saline aquifers is an ef...The well-developed coal electricity generation and coal chemical industries have led to huge carbon dioxide(CO_(2))emissions in the northeastern Ordos Basin.The geological storage of CO_(2) in saline aquifers is an effective backup way to achieve carbon neutrality.In this case,the potential of saline aquifers for CO_(2) storage serves as a critical basis for subsequent geological storage project.This study calculated the technical control capacities of CO_(2) of the saline aquifers in the fifth member of the Shiqianfeng Formation(the Qian-5 member)based on the statistical analysis of the logging and the drilling and core data from more than 200 wells in the northeastern Ordos Basin,as well as the sedimentary facies,formation lithology,and saline aquifer development patterns of the Qian-5 member.The results show that(1)the reservoirs of saline aquifers in the Qian-5 member,which comprise distributary channel sand bodies of deltaic plains,feature low porosities and permeabilities;(2)The study area hosts three NNE-directed saline aquifer zones,where saline aquifers generally have a single-layer thickness of 3‒8 m and a cumulative thickness of 8‒24 m;(3)The saline aquifers of the Qian-5 member have a total technical control capacity of CO_(2) of 119.25×10^(6) t.With the largest scale and the highest technical control capacity(accounting for 61%of the total technical control capacity),the Jinjie-Yulin saline aquifer zone is an important prospect area for the geological storage of CO_(2) in the saline aquifers of the Qian-5 member in the study area.展开更多
Carbon Capture and Storage(CCS)is one of the effective means to deal with global warming,and saline aquifer storage is considered to be the most promising storage method.Junggar Basin,located in the northern part of X...Carbon Capture and Storage(CCS)is one of the effective means to deal with global warming,and saline aquifer storage is considered to be the most promising storage method.Junggar Basin,located in the northern part of Xinjiang and with a large distribution area of saline aquifer,is an effective carbon storage site.Based on well logging data and 2D seismic data,a 3D heterogeneous geological model of the Cretaceous Donggou Formation reservoir near D7 well was constructed,and dynamic simulations under two scenarios of single-well injection and multi-well injection were carried out to explore the storage potential and CO2 storage mechanism of deep saline aquifer with real geological conditions in this study.The results show that within 100 km^(2)of the saline aquifer of Donggou Formation in the vicinity of D7 well,the theoretical static CO_(2)storage is 71.967×106 tons(P50)①,and the maximum dynamic CO_(2)storage is 145.295×106 tons(Case2).The heterogeneity of saline aquifer has a great influence on the spatial distribution of CO_(2)in the reservoir.The multi-well injection scenario is conducive to the efficient utilization of reservoir space and safer for storage.Based on the results from theoretical static calculation and the dynamic simulation,the effective coefficient of CO_(2)storage in deep saline aquifer in the eastern part of Xinjiang is recommended to be 4.9%.This study can be applied to the engineering practice of CO_(2)sequestration in the deep saline aquifer in Xinjiang.展开更多
Offshore carbon dioxide(CO_(2)) geological storage(OCGS) represents a significant strategy for addressing climate change by curtailing greenhouse gas emissions. Nonetheless, the risk of CO_(2) leakage poses a substant...Offshore carbon dioxide(CO_(2)) geological storage(OCGS) represents a significant strategy for addressing climate change by curtailing greenhouse gas emissions. Nonetheless, the risk of CO_(2) leakage poses a substantial concern associated with this technology. This study introduces an innovative approach for establishing OCGS leakage scenarios, involving four pivotal stages, namely, interactive matrix establishment, risk matrix evaluation, cause–effect analysis, and scenario development, which has been implemented in the Pearl River Estuary Basin in China. The initial phase encompassed the establishment of an interaction matrix for OCGS systems based on features, events, and processes. Subsequent risk matrix evaluation and cause–effect analysis identified key system components, specifically CO_(2) injection and faults/features. Building upon this analysis, two leakage risk scenarios were successfully developed, accompanied by the corresponding mitigation measures. In addition, this study introduces the application of scenario development to risk assessment, including scenario numerical simulation and quantitative assessment. Overall, this research positively contributes to the sustainable development and safe operation of OCGS projects and holds potential for further refinement and broader application to diverse geographical environments and project requirements. This comprehensive study provides valuable insights into the establishment of OCGS leakage scenarios and demonstrates their practical application to risk assessment, laying the foundation for promoting the sustainable development and safe operation of ocean CO_(2) geological storage projects while proposing possibilities for future improvements and broader applications to different contexts.展开更多
Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological storage.Based on the Navier-Stokes equation,component mass conservation equation,and fluid proper...Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological storage.Based on the Navier-Stokes equation,component mass conservation equation,and fluid property-composition relationship,a mathematical model for pore-scale CO_(2) injection in oilsaturated porous media was developed in this study.The model can reflect the effects of gravity assistance,component diffusion,fluid density variation,and velocity change on EOR and CO_(2) storage.For nonhomogeneous porous media,the gravity influence and large density difference help to minimize the velocity difference between the main flow path and the surrounding area,thus improving the oil recovery and CO_(2) storage.Large CO_(2) injection angles and oil-CO_(2) density differences can increase the oil recovery by 22.6% and 4.2%,respectively,and increase CO_(2) storage by 37.9% and 4.7%,respectively.Component diffusion facilitates the transportation of the oil components from the low-velocity region to the main flow path,thereby reducing the oil/CO_(2) concentration difference within the porous media.Component diffusion can increase oil recovery and CO_(2) storage by 5.7% and 6.9%,respectively.In addition,combined with the component diffusion,a low CO_(2) injection rate creates a more uniform spatial distribution of the oil/CO_(2) component,resulting in increases of 9.5% oil recovery and 15.7% CO_(2) storage,respectively.This study provides theoretical support for improving the geological CO_(2) storage and EOR processes.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 partial underground CO_(2) storage as a working agent to harvest geothermal energy is a promising carbon capture,utilization,and storage(CCUS)method.It is particularly economically feasible to use or retrofit th...Using partial underground CO_(2) storage as a working agent to harvest geothermal energy is a promising carbon capture,utilization,and storage(CCUS)method.It is particularly economically feasible to use or retrofit the existing infrastructure of a hydrocarbon field.Although technical advantages of integrated CO_(2) sequestration and CO_(2)-circulated geothermal harvest using depleted hydrocarbon reservoirs have been reported,quantitative evaluations of economic benefits using existing wells of realistic reservoirs are rare.In this study,a 3-D hydrothermal flow model is built for the Triassic Argilo-Gre seux Supe rieur(TAGS)Formation of the Toual gas field,Algeria using Schlumberger Petrel and CMG-STARS software.A three-phase operational scheme is proposed for sequential CO_(2) sequestration and CO_(2)-circulated geothermal extraction over 100 years.The first phase is injecting CO_(2) for 30 years,followed by concurrent cold CO_(2) injection and hot CO_(2) extraction in the developed CO_(2) plume(circulation)for 40 years as the second phase.In the third phase,producing wells in the second phase are converted to injection wells while outer wells start to extract hot CO_(2) for another 30 years.Scenario 1 is simulated using the selected nine existing wells of the field,while an optimized Scenario 2 is designed and simulated by adding seven newly drilled wells in addition to the existing wells.Scenario 3 shares the same numerical simulation of Scenario 1,but assumes the selected nine existing wells are newly drilled for the economic evaluation.Levelized Cost of Energy(LCOE),Net Present Value(NPV),and Return on Investment(ROI)are used as economic indicators.The results demonstrate that Scenario 2,which combines the use of existing and newly drilled wells,yields improved economic metrics compared to Scenario 1:0.97 USD/MWh vs.1.54 USD/MWh for LCOE and$2.9M vs.$1.1M for NPV.Both scenarios represent profitable endeavors,with ROI values of 1.3%and 1.5%,respectively.In contrast,Scenario 3 represents the worst-case scenario,with the highest LCOE at 2.90 USD/MWh and the lowest NPV and ROI at-$0.4M and-0.2%,respectively.The negative NPV and ROI in Scenario 3 indicates that CO_(2)-circulated geothermal harvesting in aquifers or giant depleted hydrocarbon fields,without leveraging existing infrastructure,is economically infeasible.展开更多
为探究地层倾角对咸水层CO_(2)地质封存中羽流迁移、压力响应及封存分布的影响。基于准噶尔盆地东沟组砂岩储层相关资料,构建三维地质模型,对超临界CO_(2)在倾斜地层中运移规律进行模拟研究。结果表明:地层倾角增大显著增大了CO_(2)羽...为探究地层倾角对咸水层CO_(2)地质封存中羽流迁移、压力响应及封存分布的影响。基于准噶尔盆地东沟组砂岩储层相关资料,构建三维地质模型,对超临界CO_(2)在倾斜地层中运移规律进行模拟研究。结果表明:地层倾角增大显著增大了CO_(2)羽流的侧向迁移距离,促使其沿盖层下缘汇聚,增加了突破盖层的潜在风险。封存过程中随着部分CO_(2)相态改变,扩散范围持续扩大但迁移速率减缓。压力场演化中,注入期近井区域压力显著抬升并向两侧传播;相较于水平地层,倾斜地层压力影响半径更大,压力等值线呈不对称分布。封存量分配受倾角影响,储层上半区域有利于构造封存;停注后残余与溶解封存持续增强,形成封存机制的动态转换,储层上半区域累计封存量占比较高。研究结果为倾斜地层CO_(2)地质封存的封存效率与安全性评价提供相关的理论依据,为碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)工程选址及注入策略提供优化。展开更多
基金support provided by the Department of Petroleum Engineering,Khalifa University of Science and Technology,Sas Al Nakhl Campus,Abu Dhabi,UAE
文摘The merits of CO2 capture and storage to the environmental stability of our world should not be underestimated as emissions of greenhouse gases cause serious problems.It represents the only technology that might rid our atmosphere of the main anthropogenic gas while allowing for the continuous use of the fossil fuels which still power today’s world.Underground storage of CO2 involves the injection of CO2 into suitable geological formations and the monitoring of the injected plume over time,to ensure containment.Over the last two or three decades,attention has been paid to technology developments of carbon capture and sequestration.Therefore,it is high time to look at the research done so far.In this regard,a high-level review article is required to provide an overview of the status of carbon capture and sequestration research.This article presents a review of CO2 storage technologies which includes a background of essential concepts in storage,the physical processes involved,modeling procedures and simulators used,capacity estimation,measuring monitoring and verification techniques,risks and challenges involved and field-/pilot-scale projects.It is expected that the present review paper will help the researchers to gain a quick knowledge of CO2 sequestration for future research in this field.
基金supported by the Land and Resources Survey Program from China Geological Survey(grant No. DD2016024012120113006600)+1 种基金Land and Resources Public Welfare Scientific Research Project(grant No. 201211063)National Natural Science Foundation of China(grant No.41502259)
文摘This work established an evaluation index system based on a comprehensive analysis of those factors affecting the suitability of CO2 geological storage.This evaluation index system includes three evaluation index layers of geological safety,storage scale and social economy,nine evaluation index sub-layers,and 28 evaluation index factors,and adopts the analytic hierarchy process（AHP）and index overlay methods.Taking the Xining Basin in northwest China as an example,we conducted comprehensive analysis of geological conditions and performed quantitative evaluation based on this evaluation index system,which indicates that the Shuangshu depression of the Xining Basin is comparatively suitable for CO2 geological storage.It is suggested that this evaluation index system and the evaluation method proposed in this study are suitable for most continental sedimentary basins in China and should be widely applied.
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finically supported by the National Natural Science Foundation of China(Grant Nos.41272349 and 51322906)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDB-SSW-DQC029)
文摘This paper focuses on the progress in geomechanical modeling associated with carbon dioxide(CO2)geological storage.The detailed review of some geomechanical aspects,including numerical methods,stress analysis,ground deformation,fault reactivation,induced seismicity and crack propagation,is presented.It is indicated that although all the processes involved are not fully understood,integration of all available data,such as ground survey,geological conditions,microseismicity and ground level deformation,has led to many new insights into the rock mechanical response to CO2injection.The review also shows that in geomechanical modeling,continuum modeling methods are predominant compared with discontinuum methods.It is recommended to develop continuum-discontinuum numerical methods since they are more convenient for geomechanical modeling of CO2geological storage,especially for fracture propagation simulation.The Mohr-Coulomb criterion is widely used in prediction of rock mass mechanical behavior.It would be better to use a criterion considering the effect of the intermediate principal stress on rock mechanical behavior,especially for the stability analysis of deeply seated rock engineering.Some challenges related to geomechanical modeling of CO2geological storage are also discussed.
基金the National Natural Science Foundation of China(Nos.42206234,42476228,42076220)the Key R&D Project of Shandong Province(No.2024SFGC0302)+2 种基金the Project of Laoshan Laboratory(No.LSKJ202203404)the Project of China Geology Survey(Nos.DD202503023,DD20230401)support from the Ocean Negative Carbon Emissions(ONCE)Program。
文摘Offshore carbon dioxide(CO_(2))geological storage is a promising strategy for reducing carbon emissions and supporting sustainable development in coastal regions within a carbon neutrality framework.However,only a few works have focused on offshore basins in China.To address this gap,this study established a dual indicator system that comprises necessary and critical indices and is integrated with the analytic hierarchy process.A coupled analysis was then performed to evaluate the suitability of 10 offshore sedimentary basins in China for CO_(2)geological storage.The necessary indicator system focuses on storage potential,geological conditions,and engineering feasibility.Meanwhile,the critical indicator system emphasizes the safety of storage projects and the viability of drilling operations.Evaluation results revealed that China's offshore basins have undergone two geological evolution stages,namely,the rifting and post-rifting phases,leading to the formation of a dual-layer structure characterized by faulted lower layers and sagged upper layers.These basins have thick and widespread Cenozoic strata,generally low seismic activity,and medium-to-low geothermal gradients.They form five reservoir-caprock systems with favorable geological conditions for CO_(2)storage.The Pearl River Mouth,East China Sea Shelf,and Bohai Basins emerged as primary candidates that offer substantial storage potential to support carbon neutrality goals in the Bohai Rim Economic Zone,Yangtze River Delta Economic Zone,and Guangdong-Hong Kong-Macao Greater Bay Area.The Beibu Gulf and South Yellow Sea Basins were identified as secondary candidates,and the Qiongdongnan and Yinggehai Basins were considered potential alternatives.
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the National Natural Science Foundation of China(52474073,52288101,52120105007,51804327)Shandong Provincial Natural Science Foundation(ZR2023ME016)Climb Taishan Scholar Program in Shandong Province(tspd20230605).
文摘CO_(2)injection into geological formations has been proven to be an effective approach for carbon storage.When dissolved in formation water,CO_(2)forms carbonic acid that induces mineral dissolution at pore surfaces under acidic conditions.Comprehensive understanding of geochemical interaction between carbonic acid and reservoir rocks is crucial for assessing environmental impact on geological formations.This study focuses on a tight oil sandstone reservoir.After characterizing basic petrophysical properties and mineral composition of rock samples,a series of carbonic acid corrosion experiments with both core and corresponding pure mineral samples were carried out,respectively.Dissolution solutions collected during the experiments were analyzed to examine the variations of ion concentrations in both core and pure mineral solutions.The carbonic acid-pure mineral corrosion kinetics were investigated.The correlations between carbonic acid with core and pure mineral corrosion scenarios were established from the sample mass,reaction rate,and ion concentration.The results show that after corrosion,the mass of calcite and dolomite in the rock sample decreased by 66.7%and 27.3%,respectively.When the corrosion was stabilized,the concentrations of Ca^(2+)and Mg^(2+)in the core solution were 72.9 and 74.4 mg/L.respectively,which was 40.5-41.3 times higher than that of Na+.The reaction kinetics analysis of carbonic acid-rock revealed a two-stage reaction in the pure mineral corrosion process,rapid reaction stage,and slow reaction stage,with different reaction rate constants and reaction orders for each ion.With the correlation between carbonic acid reaction with core and pure minerals,an effective and rapid evaluation method with pure minerals for the carbonic water-rock reaction is established,which costs a shorter time and is easier to investigate.This study provides a simple and faster method to evaluate the carbonic acid corrosion reaction during geological carbon storage.
基金supported by the National Natural Science Foundation of China(Grant No.42402171)the China Postdoctoral Science Foundation(Grant No.2023MD744255)+6 种基金the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-YBQN-0353)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.23JK0600)the Shaanxi Postdoctoral Science Foundation(Grant No.2023B SHEDZZ324)the project of Theory of Hydrocarbon Enrichment under Multi-Spheric Interactions of the Earth(Grant No.THEMSIE04010107)the Key Research and Development Program of Shaanxi(Grant No.2021KW-10)the Innovation Capability Support Program of Shaanxi(Grant No.2022PT-08)the SINOPEC CCUS Fund Project(Grant No.33550000-22-ZC0613-0326)。
文摘During the CO_(2)injection and geological storage process,the integrity of the cap rock significantly influences the long-term safety of CO_(2)storage.Natural fractures within the cap rock serve as potential pathways for CO_(2)migration,thereby increasing the risk of CO_(2)leakage.In this study,we determined the types,developmental characteristics,permeability changes,and CO_(2)-H_(2)O-Rock reactions of natural fractures in the mudstone cap rocks of the Sanduo Formation(E_(3)s)and Dainan Formation(E_(2)d)in the Gaoyou Sag of the Subei Basin using core observations,thin-section analysis,rock mechanics experiments,and paleomagnetic directional analysis.We identified four tectonic fracture sets(NNW,NWW,EW,and NE);high-angle shear fractures,ranging from 60°to 90°(average 82°)and typically measuring4-12 cm(average 7.5 cm),dominate the assemblage,while slip fractures,ranging from 32°to 50°(average 36°)and measuring 3-6 cm(average 3.9 cm),are also present.At the microscale,shear fractures average 160μm,and bedding fractures average 82μm.Notably,85.78%of shear fractures are unfilled,with calcite filling observed in 14.22%,while other fracture types show no filling.Permeability tests on samples without fractures reveal that permeability declines rapidly below 9 MPa,especially in shallower samples,followed by a slower reduction between 9 and 13 MPa,and ultimately stabilizes at approximately 0.00003 mD.In contrast,samples with fractures exhibit permeability that is 3-4 orders of magnitude higher;their fracture permeability decays according to a power law with pressure yet remains above 10 mD even at 46 MPa.Fractures with larger dip angles and those aligned with the maximum principal stress demonstrate the highest permeability.While silicate-filled fractures exhibit negligible changes in permeability,carbonate-filled fractu res experience a temporary enhancement due to dissolution;however,subsequent permeability remains controlled by factors such as effective stress and fracture orientation.
基金funded by the National Natural Science Foundation of China(No.42141013)China Geological Survey(DD20221818,DD20242513).
文摘China has pledged to peak carbon dioxide(CO_(2))emissions by 2030 and achieve carbon neutrality by 2060.Carbon capture and storage(CCS)will play a key role in these efforts.Over the past several years,the China Geological Survey(CGS)has completed the Suitability Evaluation Map of CO_(2)Geological Storage in Main Sedimentary Basins in China and Adjacent Sea Regions in 2017.This map reflects the suitability of the first-and secondary-order tectonic units within sedimentary basins for cO_(2)geological storage for CCS planning.The Junggar Basin is recognized as an important region for future CCS projects.Results from a mesoscale evaluation using the volume method indicate that deep saline aquifers represent the most significant resources for CO_(2)storage,with potential ranging from 48×10^(9)to 164×10^(9)t(with a P50 value of 96×10^(9)t).The highest storage potential is identified in the central and northern parts of the basin,reaching up to 9.5×10^(6)t/km^(2)at the P50 probability level.In contrast,the hinterland,eastern,and western parts of the basin generally exhibit storage potential of below 1.0×10^(6)t/km^(2)at the same probability level.The CGs has also characterized historical CO_(2)plume migration in reservoirs at the storage site of the Shenhua CCS demonstration project and conducted numerical simulations of CO_(2)plume migration for periods of 10 and 20 years following the shutdown of the injection well.The CGS implemented a kiloton-scale pilot test on CO_(2)-enhanced water recovery(CO_(2)-EWR)in eastern Junggar,revealing that CO_(2)flooding can improve the pressure for fluid production,with the highest ratio of CO_(2)to produced fluids estimated at approximately 1.2.Besides,an observation field for natural CO_(2)leakage,covering about 930 m^(2),was built in Qinghai Province.In natural CO_(2)fields or at artificial CO_(2)injection research sites,cO_(2)leakage points are primarily related to the distribution of faults(especially fault crossing),which can serve as pathways for CO_(2)leakage.The observation field provides a natural analog to wellbore failure and offers an opportunity to further monitor CO_(2)geological storage sites.However,it has been inferred that borehole ZK10 at the observation field has become a leakage pathway due to the drilling activities,inadequate well-plugging,and abandonment procedures without considering CO_(2)corrosion.
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support from the National Key Research and Development Program of China(2023YFE0120700)National Natural Science Foundation of China(52274041)Distinguished Young Sichuan Science Scholars(2023NSFSC1954).
文摘Cyclic injection holds great potential for CO_(2) emission reduction coupled with enhanced unconventional oil recovery.There is,however,a lack of a thorough understanding of carbon distribution,migration,and transformation underground over time at the reservoir scale.To address this issue,we conducted a rig-orous numerical simulation integrating microseismic events,multi-geomechanics,and multi-geochemistry to represent the complex fracture geometry,rock stress sensitivity,and CO_(2)-oil-brine-rock interactions.The fluid model,reservoir model,and geochemical reaction kinetics were carefully validated and calibrated using experimental data.The performance of CO_(2) utilization and geological storage was comprehensively investigated in terms of changes in oil production,CO_(2) storage,carbon distribution,and petrophysical properties.The results indicate that 48.3%of the injected CO_(2) was stored stably under-ground after ten cycles(ten years),with a 3.4%increase in oil recovery.The presence of multiple CO_(2) stor-age forms,such as dissolved in water and mineralized carbonate,impeded CO_(2)-oil interaction,leading to a 25.9%reduction in the volume of the CO_(2)-oil mixing zone and a 2.2%decrease in cumulative oil pro-duction,albeit with a 7.7%increase in the storage rate.The cyclic injection mode had a significant impact on the migration and transformation of CO_(2) in the reservoir.While dissolved CO_(2) in oil accounted for over half of the total storage,it had the possibility of being released during production.After ten cycles,20%of the injected CO_(2)(approximately 12000 t)reached long-term storage in four forms:mineralized carbon-ate(6%),water-dissolved CO_(2)(6%),aqueous ions(4%),and trapped gas(4%).Notably,the non-fracture zone within the stimulated reservoir volume(SRV)served as the primary trapping area for residual gas.This work provides valuable insights into dynamic CO_(2) transport and transformation processes under cyclic injection and presents a more comprehensive and precise framework for assessing CO_(2) capture,utilization,and storage with enhanced oil recovery(CCUS-EOR)performance in unconventional reser-voirs after fracturing.
基金funded by the Top 10 key scientific and technological projects of CHN Energy in 2021 entitled Research and Demonstration of Technology for Carbon Dioxide Capture and Energy Recycling Utilization(GJNYKJ[2021]No.128,No.:GJNY-21-51)the Carbon Neutrality College(Yulin)Northwest University project entitled Design and research of large-scale CCUS cluster construction in Yulin area,Shaanxi Province(YL2022-38-01).
文摘The well-developed coal electricity generation and coal chemical industries have led to huge carbon dioxide(CO_(2))emissions in the northeastern Ordos Basin.The geological storage of CO_(2) in saline aquifers is an effective backup way to achieve carbon neutrality.In this case,the potential of saline aquifers for CO_(2) storage serves as a critical basis for subsequent geological storage project.This study calculated the technical control capacities of CO_(2) of the saline aquifers in the fifth member of the Shiqianfeng Formation(the Qian-5 member)based on the statistical analysis of the logging and the drilling and core data from more than 200 wells in the northeastern Ordos Basin,as well as the sedimentary facies,formation lithology,and saline aquifer development patterns of the Qian-5 member.The results show that(1)the reservoirs of saline aquifers in the Qian-5 member,which comprise distributary channel sand bodies of deltaic plains,feature low porosities and permeabilities;(2)The study area hosts three NNE-directed saline aquifer zones,where saline aquifers generally have a single-layer thickness of 3‒8 m and a cumulative thickness of 8‒24 m;(3)The saline aquifers of the Qian-5 member have a total technical control capacity of CO_(2) of 119.25×10^(6) t.With the largest scale and the highest technical control capacity(accounting for 61%of the total technical control capacity),the Jinjie-Yulin saline aquifer zone is an important prospect area for the geological storage of CO_(2) in the saline aquifers of the Qian-5 member in the study area.
基金This work was supported by the National Natural Science Foundation of China(NSFC,Grant No.41702284,41602272)National key R&D program of China(Grant No.2019YFE0100100)+2 种基金the Na-tural Science Foundation of Hubei Province,China(Grant No.2019CFB451)and the Open Fund of Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources(Grant No.2020zy003)This work was also par-tially supported by the China Australia Geological Storage of CO_(2)project(CAGS),and the China Geo-logical Survey project(Grant No.DD20160307).
文摘Carbon Capture and Storage(CCS)is one of the effective means to deal with global warming,and saline aquifer storage is considered to be the most promising storage method.Junggar Basin,located in the northern part of Xinjiang and with a large distribution area of saline aquifer,is an effective carbon storage site.Based on well logging data and 2D seismic data,a 3D heterogeneous geological model of the Cretaceous Donggou Formation reservoir near D7 well was constructed,and dynamic simulations under two scenarios of single-well injection and multi-well injection were carried out to explore the storage potential and CO2 storage mechanism of deep saline aquifer with real geological conditions in this study.The results show that within 100 km^(2)of the saline aquifer of Donggou Formation in the vicinity of D7 well,the theoretical static CO_(2)storage is 71.967×106 tons(P50)①,and the maximum dynamic CO_(2)storage is 145.295×106 tons(Case2).The heterogeneity of saline aquifer has a great influence on the spatial distribution of CO_(2)in the reservoir.The multi-well injection scenario is conducive to the efficient utilization of reservoir space and safer for storage.Based on the results from theoretical static calculation and the dynamic simulation,the effective coefficient of CO_(2)storage in deep saline aquifer in the eastern part of Xinjiang is recommended to be 4.9%.This study can be applied to the engineering practice of CO_(2)sequestration in the deep saline aquifer in Xinjiang.
文摘Offshore carbon dioxide(CO_(2)) geological storage(OCGS) represents a significant strategy for addressing climate change by curtailing greenhouse gas emissions. Nonetheless, the risk of CO_(2) leakage poses a substantial concern associated with this technology. This study introduces an innovative approach for establishing OCGS leakage scenarios, involving four pivotal stages, namely, interactive matrix establishment, risk matrix evaluation, cause–effect analysis, and scenario development, which has been implemented in the Pearl River Estuary Basin in China. The initial phase encompassed the establishment of an interaction matrix for OCGS systems based on features, events, and processes. Subsequent risk matrix evaluation and cause–effect analysis identified key system components, specifically CO_(2) injection and faults/features. Building upon this analysis, two leakage risk scenarios were successfully developed, accompanied by the corresponding mitigation measures. In addition, this study introduces the application of scenario development to risk assessment, including scenario numerical simulation and quantitative assessment. Overall, this research positively contributes to the sustainable development and safe operation of OCGS projects and holds potential for further refinement and broader application to diverse geographical environments and project requirements. This comprehensive study provides valuable insights into the establishment of OCGS leakage scenarios and demonstrates their practical application to risk assessment, laying the foundation for promoting the sustainable development and safe operation of ocean CO_(2) geological storage projects while proposing possibilities for future improvements and broader applications to different contexts.
基金The project supported by National Natural Science Foundation of China(No.51991364,51974347)the Major Scientific and Technological Projects of CNPC under Grant ZD2019-184-002。
文摘Gravity assistance is a critical factor influencing CO_(2)-Oil mixing and miscible flow during EOR and CO_(2)geological storage.Based on the Navier-Stokes equation,component mass conservation equation,and fluid property-composition relationship,a mathematical model for pore-scale CO_(2) injection in oilsaturated porous media was developed in this study.The model can reflect the effects of gravity assistance,component diffusion,fluid density variation,and velocity change on EOR and CO_(2) storage.For nonhomogeneous porous media,the gravity influence and large density difference help to minimize the velocity difference between the main flow path and the surrounding area,thus improving the oil recovery and CO_(2) storage.Large CO_(2) injection angles and oil-CO_(2) density differences can increase the oil recovery by 22.6% and 4.2%,respectively,and increase CO_(2) storage by 37.9% and 4.7%,respectively.Component diffusion facilitates the transportation of the oil components from the low-velocity region to the main flow path,thereby reducing the oil/CO_(2) concentration difference within the porous media.Component diffusion can increase oil recovery and CO_(2) storage by 5.7% and 6.9%,respectively.In addition,combined with the component diffusion,a low CO_(2) injection rate creates a more uniform spatial distribution of the oil/CO_(2) component,resulting in increases of 9.5% oil recovery and 15.7% CO_(2) storage,respectively.This study provides theoretical support for improving the geological CO_(2) storage and EOR processes.
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funded by grants from Sultan Qaboos University(#CL/SQU-IGGCAS/WRC/23/01,#IG/DVC/WRC/24/01)the PRFU project from Larbi Ben M'hidi University-Oum El Bouaghi Algeria(#E04N01UN040120230001)。
文摘Using partial underground CO_(2) storage as a working agent to harvest geothermal energy is a promising carbon capture,utilization,and storage(CCUS)method.It is particularly economically feasible to use or retrofit the existing infrastructure of a hydrocarbon field.Although technical advantages of integrated CO_(2) sequestration and CO_(2)-circulated geothermal harvest using depleted hydrocarbon reservoirs have been reported,quantitative evaluations of economic benefits using existing wells of realistic reservoirs are rare.In this study,a 3-D hydrothermal flow model is built for the Triassic Argilo-Gre seux Supe rieur(TAGS)Formation of the Toual gas field,Algeria using Schlumberger Petrel and CMG-STARS software.A three-phase operational scheme is proposed for sequential CO_(2) sequestration and CO_(2)-circulated geothermal extraction over 100 years.The first phase is injecting CO_(2) for 30 years,followed by concurrent cold CO_(2) injection and hot CO_(2) extraction in the developed CO_(2) plume(circulation)for 40 years as the second phase.In the third phase,producing wells in the second phase are converted to injection wells while outer wells start to extract hot CO_(2) for another 30 years.Scenario 1 is simulated using the selected nine existing wells of the field,while an optimized Scenario 2 is designed and simulated by adding seven newly drilled wells in addition to the existing wells.Scenario 3 shares the same numerical simulation of Scenario 1,but assumes the selected nine existing wells are newly drilled for the economic evaluation.Levelized Cost of Energy(LCOE),Net Present Value(NPV),and Return on Investment(ROI)are used as economic indicators.The results demonstrate that Scenario 2,which combines the use of existing and newly drilled wells,yields improved economic metrics compared to Scenario 1:0.97 USD/MWh vs.1.54 USD/MWh for LCOE and$2.9M vs.$1.1M for NPV.Both scenarios represent profitable endeavors,with ROI values of 1.3%and 1.5%,respectively.In contrast,Scenario 3 represents the worst-case scenario,with the highest LCOE at 2.90 USD/MWh and the lowest NPV and ROI at-$0.4M and-0.2%,respectively.The negative NPV and ROI in Scenario 3 indicates that CO_(2)-circulated geothermal harvesting in aquifers or giant depleted hydrocarbon fields,without leveraging existing infrastructure,is economically infeasible.
文摘为探究地层倾角对咸水层CO_(2)地质封存中羽流迁移、压力响应及封存分布的影响。基于准噶尔盆地东沟组砂岩储层相关资料,构建三维地质模型,对超临界CO_(2)在倾斜地层中运移规律进行模拟研究。结果表明:地层倾角增大显著增大了CO_(2)羽流的侧向迁移距离,促使其沿盖层下缘汇聚,增加了突破盖层的潜在风险。封存过程中随着部分CO_(2)相态改变,扩散范围持续扩大但迁移速率减缓。压力场演化中,注入期近井区域压力显著抬升并向两侧传播;相较于水平地层,倾斜地层压力影响半径更大,压力等值线呈不对称分布。封存量分配受倾角影响,储层上半区域有利于构造封存;停注后残余与溶解封存持续增强,形成封存机制的动态转换,储层上半区域累计封存量占比较高。研究结果为倾斜地层CO_(2)地质封存的封存效率与安全性评价提供相关的理论依据,为碳捕集、利用与封存(Carbon Capture,Utilization and Storage,CCUS)工程选址及注入策略提供优化。
