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Very limited investigations have been done on the numerical simulation of carbon dioxide (CO2) migration in sandstone aquifers taking consideration of the interactions between fluid flow and rock stress. Based on the poroelasticity theory and multiphase flow theory, this study establishes a mathematical model to describe CO2 migration, coupling the flow and stress fields. Both finite difference method (FDM) and finite element method (FEM) were used to discretize the mathematical model and generate a numerical model. A case study was carried out using the numerical model on the Jiangling sandstone aquifer in the Jianghan basin, China. The rock mechanics parameters of reservoir and overlying strata of Jiangling depression were obtained by triaxial tests. A two-dimensional model was then built to simulate carbon dioxide migration in the sandstone aquifer. The numerical simulation analyzes the carbon dioxide migration distribution rule with and without considering capillary pressure. Time-dependent migration of CO2 in the sandstone aquifer was analyzed, and the result from the coupled model was compared with that from a traditional non-coupled model. The calculation result indicates a good consistency between the coupled model and the non-coupled model. At the injection point, the CO2 saturation given by the coupled model is 15.39 % higher than that given by the non-coupled model; while the pore pressure given by the coupled model is 4.8 % lower than that given by the non-coupled model. Therefore, it is necessary to consider the coupling of flow and stress fields while simulating CO2 migration for CO2 disposal in sandstone aquifers. The result from the coupled model was also sensitized to several parameters including reservoir permeability, porosity, and CO2 injection rate. Sensitivity analyses show that CO2 saturation is increased non-linearly with CO2 injection rate and decreased non-linearly with reservoir porosity. Pore pressure is decreased non-linearly with reservoir porosity and permeability, and increased non-linearly with CO2 injection rate. When the capillary pressure was considered, the computed gas saturation of carbon dioxide was increased by 10.75 % and the pore pressure was reduced by 0.615 %. 相似文献
3.
Holger Class Anozie Ebigbo Rainer Helmig Helge K. Dahle Jan M. Nordbotten Michael A. Celia Pascal Audigane Melanie Darcis Jonathan Ennis-King Yaqing Fan Bernd Flemisch Sarah E. Gasda Min Jin Stefanie Krug Diane Labregere Ali Naderi Beni Rajesh J. Pawar Adil Sbai Sunil G. Thomas Laurent Trenty Lingli Wei 《Computational Geosciences》2009,13(4):409-434
4.
In this paper, we analyze the time scales associated with instable fingering induced by density contrasts in miscible displacement porous media flow. We perform numerical simulations of a two-dimensional domain with boundaries that are closed to flow and identify the three regimes of the dynamics, namely the development of a stable diffusive boundary layer, the onset and growth of instabilities, and the fully nonlinear dynamics. Special focus is given to the onset of the fully nonlinear regime. The results are generic in the sense that there are no parameters in the non-dimensional model problem. Large ensembles are studied and an error estimate is given based on the combined effect of numerical errors and sampling errors. The nonlinear time scales show a dependence on the size of initial perturbations. We estimate this size for three formations used for CO2 storage and find that the onset of enhanced convective mixing is considerably delayed compared with the linear onset time. 相似文献
5.
Convective mixing of dissolved carbon dioxide (CO2) with formation brine has been shown to be a significant factor for the rate of dissolution of CO2 and thus for determining the viability of geological CO2 storage sites. In most previous convection investigations, a no-flow boundary condition was used to represent the interface between an upper region with CO2 and brine and the single-phase brine region beneath. However, due to interfacial tension between the phases, the water phase is partly mobile in the upper region and advection may occur. Based on linear stability analysis and numerical simulations, we show that advection across the interface leads to considerable destabilization of the system. In particular, the time of onset of instability is reduced by a factor of two and the rate of dissolution is enhanced by a factor of two for three of four formations we consider, and by 40 % for the fourth formation. It is found that exponential decay of the relative permeability away from the interface provides a useful approximation to the real system. In addition, the exponential decay also simplifies the linear stability analysis. Interestingly, formations with large absolute permeability and small porosity have the largest impact from the transition zone, despite the fact that the relative permeability decays quickly above the interface in these formations. This is because the length-scale of instability is smallest in these formations. 相似文献
6.
Careful site characterization is critical for successful geologic storage of carbon dioxide (CO2) because of the many physical and chemical processes impacting CO2 movement and containment under field conditions. Traditional site characterization techniques such as geological mapping,
geophysical imaging, well logging, core analyses, and hydraulic well testing provide the basis for judging whether or not
a site is suitable for CO2 storage. However, only through the injection and monitoring of CO2 itself can the coupling between buoyancy flow, geologic heterogeneity, and history-dependent multi-phase flow effects be
observed and quantified. CO2 injection and monitoring can therefore provide a valuable addition to the site-characterization process. Additionally, careful
monitoring and verification of CO2 plume development during the early stages of commercial operation should be performed to assess storage potential and demonstrate
permanence. The Frio brine pilot, a research project located in Dayton, Texas (USA) is used as a case study to illustrate
the concept of an iterative sequence in which traditional site characterization is used to prepare for CO2 injection and then CO2 injection itself is used to further site-characterization efforts, constrain geologic storage potential, and validate understanding
of geochemical and hydrological processes. At the Frio brine pilot, in addition to traditional site-characterization techniques,
CO2 movement in the subsurface is monitored by sampling fluid at an observation well, running CO2-saturation-sensitive well logs periodically in both injection and observation wells, imaging with crosswell seismic in the
plane between the injection and observation wells, and obtaining vertical seismic profiles to monitor the CO2 plume as it migrates beyond the immediate vicinity of the wells. Numerical modeling plays a central role in integrating geological,
geophysical, and hydrological field observations. 相似文献
7.
The role of near-surface cavities in the carbon dioxide cycle of karst areas: evidence from the Carburangeli Cave Natural Reserve (Italy) 总被引：2，自引：1，他引：1
Paolo Madonia Adriana Bellanca Rosario Di Pietro Laura Mirabello 《Environmental Earth Sciences》2012,67(8):2423-2439
Hydrological, chemical and meteorological data collected during the years 2006–2007 at Carburangeli Cave (Italy) have provided new insights on the near-surface cycle of carbon dioxide, particularly concerning the role played by fractures and karst conduits. Carbon dioxide is trapped in the underground atmosphere essentially when its temperature is lower than the outer one. By contrast, convective air circulation disperses all the excess CO2 in the external environment when the thermal differential is inverted. The network of fractures and karst conduits then works, in the vadose zone, as a re-circulator of CO2 from the soil to the atmosphere. The total amount of CO2 fixed in the underground is controlled, during the wet season, by the amount of infiltrating waters, which act as the main carrier of CO2 in the subsoil. By contrast, during the dry season, gravitational drainage is responsible for the accumulation of carbon dioxide in the underground voids. The quantitative balance demonstrated that the degassed CO2 amounts are one order of magnitude higher than the dissolved CO2. In light of this, if the near-surface outgassing processes are not taken into account, CO2 budgets may be affected by significant errors. 相似文献
8.
Binyam L. Alemu Per Aagaard Ingrid Anne Munz Elin Skurtveit 《Applied Geochemistry》2011,26(12):1975-1989
Crushed rock from two caprock samples, a carbonate-rich shale and a clay-rich shale, were reacted with a mixture of brine and supercritical CO2 (CO2–brine) in a laboratory batch reactor, at different temperature and pressure conditions. The samples were cored from a proposed underground CO2 storage site near the town of Longyearbyen in Svalbard. The reacting fluid was a mixture of 1 M NaCl solution and CO2 (110 bar) and the water/rock ratio was 20:1. Carbon dioxide was injected into the reactors after the solution had been bubbled with N2, in order to mimic O2-depleted natural storage conditions. A control reaction was also run on the clay-rich shale sample, where the crushed rock was reacted with brine (CO2-free brine) at the same experimental conditions. A total of 8 batch reaction experiments were run at temperatures ranging from 80 to 250 °C and total pressures of 110 bar (∼40 bar for the control experiment). The experiments lasted 1–5 weeks.Fluid analysis showed that the aqueous concentration of major elements (i.e. Ca, Mg, Fe, K, Al) and SiO2 increased in all experiments. Release rates of Fe and SiO2 were more pronounced in solutions reacted with CO2–brine as compared to those reacted with CO2-free brine. For samples reacted with the CO2–brine, lower temperature reactions (80 °C) released much more Fe and SiO2 than higher temperature reactions (150–250 °C). Analysis by SEM and XRD of reacted solids also revealed changes in mineralogical compositions. The carbonate-rich shale was more reactive at 250 °C, as revealed by the dissolution of plagioclase and clay minerals (illite and chlorite), dissolution and re-precipitation of carbonates, and the formation of smectite. Carbon dioxide was also permanently sequestered as calcite in the same sample. The clay-rich shale reacted with CO2–brine did not show major mineralogical alteration. However, a significant amount of analcime was formed in the clay-rich shale reacted with CO2-free brine; while no trace of analcime was observed in either of the samples reacted with CO2–brine. 相似文献
9.
Assessing potential repositories for geologic sequestration of carbon dioxide using numerical models can be complicated, costly,
and time-consuming, especially when faced with the challenge of selecting a repository from a multitude of potential repositories.
This paper presents a set of simple analytical equations (model), based on the work of previous researchers, that could be
used to evaluate the suitability of candidate repositories for subsurface sequestration of carbon dioxide. We considered the
injection of carbon dioxide at a constant rate into a confined saline aquifer via a fully perforated vertical injection well.
The validity of the analytical model was assessed via comparison with the TOUGH2 numerical model. The metrics used in comparing
the two models include (1) spatial variations in formation pressure and (2) vertically integrated brine saturation profile.
The analytical model and TOUGH2 show excellent agreement in their results when similar input conditions and assumptions are
applied in both. The analytical model neglects capillary pressure and the pressure dependence of fluid properties. However,
simulations in TOUGH2 indicate that little error is introduced by these simplifications. Sensitivity studies indicate that
the agreement between the analytical model and TOUGH2 depends strongly on (1) the residual brine saturation, (2) the difference
in density between carbon dioxide and resident brine (buoyancy), and (3) the relationship between relative permeability and
brine saturation. The results achieved suggest that the analytical model is valid when the relationship between relative permeability
and brine saturation is linear or quasi-linear and when the irreducible saturation of brine is zero or very small. 相似文献
10.
G. M. Marion A. E. Murray B. Wagner C. H. Fritsen F. Kenig P. T. Doran 《Aquatic Geochemistry》2013,19(2):135-145
Perennial ice covers on many Antarctic lakes have resulted in high lake inorganic carbon contents. The objective of this paper was to evaluate and compare the brine and CO2 chemistries of Lake Vida (Victoria Valley) and West Lake Bonney (Taylor Valley), two lakes of the McMurdo Dry Valleys (East Antarctica), and their potential consequences during global warming. An existing geochemical model (FREZCHEM-15) was used to convert measured molarity into molality needed for the FREZCHEM model, and this model added a new algorithm that converts measured DIC into carbonate alkalinity needed for the FREZCHEM model. While quite extensive geochemical information exists for ice-covered Taylor Valley lakes, such as West Lake Bonney, only limited information exists for the recently sampled brine of >25 m ice-thick Lake Vida. Lake Vida brine had a model-calculated pCO2 = 0.60 bars at the field pH (6.20); West Lake Bonney had a model-calculated pCO2 = 5.23 bars at the field pH (5.46). Despite the high degree of atmospheric CO2 supersaturation in West Lake Bonney, it remains significantly undersaturated with the gas hydrate, CO2·6H2O, unless these gas hydrates are deep in the sediment layer or are metastable having formed under colder temperatures or greater pressures. Because of lower temperatures, Lake Vida could start forming CO2·6H2O at lower pCO2 values than West Lake Bonney; but both lakes are significantly undersaturated with the gas hydrate, CO2·6H2O. For both lakes, simulation of global warming from current subzero temperatures (?13.4 °C in Lake Vida and ?4.7 °C in West Lake Bonney) to 10 °C has shown that a major loss of solution-phase carbon as CO2 gases and carbonate minerals occurred when the temperatures rose above 0 °C and perennial ice covers would disappear. How important these Antarctic CO2 sources will be for future global warming remains to be seen. But a recent paper has shown that methane increased in atmospheric concentration due to deglaciation about 10,000 years ago. So, CO2 release from ice lakes might contribute to atmospheric gases in the future. 相似文献
11.
In this paper, Shell’s in-house reservoir simulator MoReS is applied to a recently introduced CO2 sequestration benchmark problem entitled “Estimation of the CO2 Storage Capacity of a Geological Formation” (Class et al. 2008). The principal objective of this benchmark is the simulation of CO2 distribution within a modeling region, and leakage of CO2 outside of it, for a period of 50 years. This study goes beyond the benchmarking exercise to investigate additional factors
with direct relevance to CO2 storage capacity estimations: water and gas relative permeabilities, permeability anisotropy, presence of sub-seismic features
(conductive fractures, thin shale layers), regional hydrodynamic gradient, CO2-enriched brine convection (due to brine density differences), and injection rates. The effects of hydrodynamic gradients
and gravitationally induced convection only become significant over 100 s of years. This study has thus extended simulation
time to 1,000 years. It is shown that grid resolution significantly impacts results. Vertical-grid refinement results in larger
and thinner CO2 plumes. Lateral-grid refinement delays leakage out of the model domain and reduces injection pressure for a given injection
rate. Sub-seismic geological features such as fractures/faults and shale layers are demonstrated to have impact on CO2 sequestration. Fractures located up-dip from the injector may lead to more leakage while the opposite may happen in the presence
of fractures perpendicular to the dip. Thin shale layers produce stacked CO2 blankets. They should be explicitly represented instead of being upscaled using a reduced vertical to horizontal permeability
ratio. Results are seen to be far more sensitive to gas relative permeability and hysteresis than to variations in the water
relative permeability models used. For a multi-injectors project, there is scope to optimize the phasing of injections to
avoid potential fracturing near injectors. 相似文献
12.
Geologic carbon sequestration is the capture of anthropogenic carbon dioxide (CO2) and its storage in deep geologic formations. The processes of CO2 seepage into surface water after migration through water-saturated sediments are reviewed. Natural CO2 and CH4 fluxes are pervasive in surface-water environments and are good analogues to potential leakage and seepage of CO2. Buoyancy-driven bubble rise in surface water reaches a maximum velocity of approximately 30 cm s−1. CO2 rise in saturated porous media tends to occur as channel flow rather than bubble flow. A comparison of ebullition versus dispersive gas transport for CO2 and CH4 shows that bubble flow will dominate over dispersion in surface water. Gaseous CO2 solubility in variable-salinity waters decreases as pressure decreases leading to greater likelihood of ebullition and bubble flow in surface water as CO2 migrates upward. 相似文献
13.
Ø. Hammer D.K. Dysthe H. Lund P. Meakin B. Jamtveit 《Geochimica et cosmochimica acta》2008,72(20):5009-5021
We present a 2D numerical model for the growth of calcite from supersaturated aqueous solutions under laminar, open-channel flow conditions. The model couples solution chemistry, precipitation at solution/calcite interfaces, hydrodynamics, diffusion and degassing. The model output is compared with experimental results obtained using an oversaturated calcite solution produced by mixing CaCl2 and Na2CO3. The precipitation rate is observed to increase when the supersaturated solution flows over an obstruction, leading to a growth instability that causes the formation of terraces. At relatively high flow rates, the most important mechanism for this behaviour seems to be hydrodynamic advection of dissolved species either towards or away from the calcite surface, depending on location relative to the obstruction, which deforms the concentration gradients. At lower flow rates, steepening of diffusion gradients around protrusions becomes important. Enhanced degassing over the obstruction due to shallowing and pressure drop is not important on small scales. Diffusion controlled transport close to the calcite surface can lead to a fingering-type growth instability, which generates porous textures. Our results are consistent with existing diffusive boundary layer theory, but for flow over non-smooth surfaces, simple calcite precipitation models that include empirical correlations between fluid flow rate and calcite precipitation rate are inaccurate. 相似文献
14.
:Reactivation of metasomatized mantle lithosphere may occur during continental extension,which is an important component of plate tectonics.The lower most part of the metasomatized domains in the subcontinental mantle lithosphere can be locally enriched in CO2.Therefore,partial melting of these metasomatized domains may play a crucial role in the global carbon cycle.However,little is known about this process and up until now few numerical constraints are available.Here we address this knowledge gap and use a 2-D high resolution petrological-thermomechanical model to assess lithospheric rifting.CO2 degassing and melting.We test 4 lithospheric thicknesses:90,110,130 and 200 km with a 10 km thick metasomatized layer at the base using CO2 of 2 wt.%in the bulk composition.The carbonate enriched layer is stable below^3 GPa(>110 km)for a temperature of 1300℃;therefore,we only observe degassing patterns for lithospheric models that are 130 km and 200 km thick.The metasomatized layer for the 130 km thick lithosphere mostly comprises carbonatite melting,whereas in the 200 km thick scenario propagation of melt development from kimberlites to carbonatites occurs as the metasomatic mantle is exhumed during extension.The numerical models fit well into natural rifting zones of the European Cenozoic Rift System for young(shallow)and of the North Atlantic Rift for old(thick)lithosphere. 相似文献
15.
With heightened concerns on CO2 emissions from pulverized-coal (PC) power plants, there has been major emphasis in recent years on the development of safe and economical geological carbon sequestration (GCS) technology. Saline aquifers are considered very attractive for GCS because of their large storage capacity in U.S. and other parts of the world for long-term sequestration. However, uncertainties about storage efficiency as well as leakage risks remain major areas of concern that need to be addressed before the saline aquifers can be fully exploited for carbon sequestration. A genetic algorithm-based optimizer has been developed and coupled with the well-known multiphase numerical solver TOUGH2 to optimally examine various injection strategies for increasing the CO2 storage efficiency as well as for reducing its plume migration. The optimal injection strategies for CO2 injection employing a vertical injection well and a horizontal injection well are considered. To ensure the accuracy of the results, the combined hybrid numerical solver/optimizer code was validated by conducting simulations of three widely used benchmark problems employed by carbon sequestration researchers worldwide. The validated code is then employed to optimize the proposed water-alternating-gas injection scheme for CO2 sequestration using both the vertical and the horizontal injection wells. The results suggest the potential benefits of CO2 migration control and dissolution. The optimization capability of the hybrid code holds a great promise in studying a host of other problems in GCS, namely how to optimally enhance capillary trapping, accelerate the dissolution of CO2 in water or brine, and immobilize the CO2 plume. 相似文献
16.
Christopher W. Hunt Joseph E. Salisbury Douglas Vandemark Wade McGillis 《Estuaries and Coasts》2011,34(1):68-77
Four surveys of the adjacent Cocheco, Bellamy, and Oyster estuaries reveal spatial heterogeneity with respect both to river-born
carbon dioxide (CO2) fluxes and CO2 exchange with the atmosphere (−17 to 51 mmol m−2 day−1), a finding partially explained by CO2 inputs from contributing watersheds. Nonuniform nutrient and organic carbon loading from upstream rivers and within the estuaries
is considered as a mechanism resulting in the variability between estuaries. Conditions during the surveys included spring
river runoff and phytoplankton blooms, drought with baseline river flow, and a historic flood which led to a large CO2 release to the atmosphere. This study highlights the variability of CO2 transport and release found between proximate estuaries over a wide range of flow conditions. 相似文献
17.
Paolo Papale 《Contributions to Mineralogy and Petrology》1997,126(3):237-251
The modeling of the solubility of water and carbon dioxide in silicate liquids (flash problem) is performed by assuming mechanical,
thermal, and chemical equilibrium between the liquid magma and the gas phase. The liquid phase is treated as a mixture of
ten silicate components + H2O or CO2, and the gas phase as a pure H2O or CO2. A general model for the solubility of a volatile component in a liquid is adopted. This requires the definition of a mixing
equation for the excess Gibbs free energy of the liquid phase and an appropriate reference state for the dissolved volatile.
To constrain the model parameters and identify the most appropriate form of the solubility equations for each dissolved volatile,
a large number of experimental solubility determinations (640 for H2O and 263 for CO2) have been used. These determinations cover a large region of the P-T-composition space of interest. The resultant water and carbon dioxide solubility models differ in that the water model is
regular and isometric, and the carbon dioxide model is regular and non-isometric. This difference is consistent with the different
speciation modalities of the two volatiles in the silicate liquids, producing a composition-independent partial molar volume
of dissolved water and a composition-dependent partial molar volume of dissolved carbon dioxide. The H2O solubility model may be applied to natural magmas of virtually any composition in the P-T range 0.1 MPa–1 GPa and > 1000 K, whereas the CO2 solubility model may be applied to several GPa pressures. The general consistency of the water solubility data and their
relatively large number as compared to the calibrated model parameters (11) contrast with the large inconsistencies of the
carbon dioxide solubility determinations and their low number with respect to the CO2 model parameters (22). As a result, most of the solubility data in the database are reproduced within 10% of approximation
in the case of water, and 30% in the case of carbon dioxide. When compared with the experimental data, the H2O and CO2 solubility models correctly predict many features of the saturation surface in the P-T-composition space, including the change from retrograde to prograde H2O solubility in albitic liquids with increasing pressure, the so-called alkali effect, the increasing CO2 solubility with increasing degree of silica undersaturation, the Henrian behavior of CO2 in most silicate liquids up to about 30–50 MPa, and the proportionality between the fugacity in the gas phase, or the saturation
activity in the liquid phase, and the square of the mole fraction of the dissolved volatile found in some unrelated silicate
liquid compositions.
Received: 21 August 1995 / Accepted: 8 July 1996 相似文献
18.
Pressure buildup limits CO2 injectivity and storage capacity and pressure loss limits the brine production capacity and security, particularly for closed and semi-closed formations. In this study, we conduct a multiwell model to examine the potential advantages of combined exhaustive brine production and complete CO2 storage in deep saline formations in the Jiangling Depression, Jianghan Basin of China. Simulation results show that the simultaneous brine extraction and CO2 storage in saline formation not only effectively regulate near-wellbore and regional pressure of storage formation, but also can significantly enhance brine production capacity and CO2 injectivity as well as storage capacity, thereby achieving maximum utilization of underground space. In addition, the combination of brine production and CO2 injection can effectively mitigate the leakage risk between the geological units. With regard to the scheme of brine production and CO2 injection, constant pressure injection is much superior to constant rate injection thanks to the mutual enhancement effect. The simultaneous brine production of nine wells and CO2 injection of four wells under the constant pressure injection scheme act best in all respects of pressure regulation, brine production efficiency, CO2 injectivity and storage capacity as well as leakage risk mitigation. Several ways to further optimize the combined strategy are investigated and the results show that increasing the injection pressure and adopting fully penetrating production wells can further significantly enhance the combined efficiency; however, there is no obvious promoting effect by shortening the well spacing and changing the well placement. 相似文献
19.
Curtis M. Oldenburg 《Environmental Geology》2008,54(8):1687-1694
A screening and ranking framework (SRF) has been developed to evaluate potential geologic carbon dioxide (CO2) storage sites on the basis of health, safety, and environmental (HSE) risk arising from CO2 leakage. The approach is based on the assumption that CO2 leakage risk is dependent on three basic characteristics of a geologic CO2 storage site: (1) the potential for primary containment by the target formation; (2) the potential for secondary containment
if the primary formation leaks; and (3) the potential for attenuation and dispersion of leaking CO2 if the primary formation leaks and secondary containment fails. The framework is implemented in a spreadsheet in which users
enter numerical scores representing expert opinions or published information along with estimates of uncertainty. Applications
to three sites in California demonstrate the approach. Refinements and extensions are possible through the use of more detailed
data or model results in place of property proxies. 相似文献
20.
Zsuzsanna Szabó Nóra Edit Gál Éva Kun Teodóra Szőcs György Falus 《Environmental Earth Sciences》2018,77(12):460
CO2 geological storage is a transitional technology for the mitigation of climate change. In the vicinity of potential CO2 reservoirs in Hungary, protected freshwater aquifers used for drinking water supplies exist. Effects of disaster events of CO2 escape and brine displacement to one of these aquifers have been studied by kinetic 1D reactive transport modelling in PHREEQC. Besides verifying that ion concentrations in the freshwater may increase up to drinking water limit values in both scenarios (CO2 or brine leakage), total porosity of the rock is estimated. Pore volume is expected to increase at the entry point of CO2 and to decrease at further distances, whereas it shows minor increase along the flow path for the effect of brine inflow. Additionally, electrical conductivity of water is estimated and suggested to be the best parameter to measure for cost-effective monitoring of both worst-case leakage scenarios. 相似文献