Optimization of Remediation of Possible Leakage from Geologic CO2 Storage Reservoirs into Groundwater Aquifers (original) (raw)
Related papers
Underground storage of CO2 in aquifers and oil reservoirs
Energy Conversion and Management, 1995
Reservoir simulations of CO* injection into a water flooded oil reservoir show that significant amounts of oil may be recovered, and a high storage capacity of CO, is obtained also through displacement of water. Simulated storage capacities for CO, injection into an aquifer vary in the range 13-68% pore volume, depending on the prevailing displacement mechanisms.
International Journal of Greenhouse Gas Control, 2014
Geologic carbon sequestration has the potential to reduce greenhouse gas concentrations in the atmosphere. However, one barrier to large scale implementation is concern for water quality degradation from leakage of high CO 2 fluids into drinking water aquifers. The hydrogeochemical response to simulated CO 2 leakage was studied to estimate major and trace element release and to develop criteria for water quality monitoring and risk assessment. In this study, approximately 3100 L aquifer water enhanced with 1 atmosphere pressure CO 2 gas was injected into a fracture zone located at 362-366 m below the ground surface in a sandstone/siltstone/mudstone interbedded aquifer in the Newark Basin. This was followed by a 3-6 week long incubation and then continuous monitoring of the hydrogeochemistry in the pumped-back water samples. Relative to background conditions, the recovered aquifer water displayed a decrease of pH, increase of alkalinity, Ca, Mg and Si concentrations, decrease of sulfate and Mo concentrations, and increased concentrations of trace elements including Fe, Mn, Cr, Co, Ni, Cu, Zn, Rb, Sr, Ba and U. These changes in aquifer water geochemistry can be explained by (a) dissolution of silicate and carbonate minerals and (b) trace element release that appear to be dependent on pH and pCO 2 and affected by the altered redox conditions in the aquifer. Rapid and simultaneous changes of pH, specific conductance, major and trace metal release in aquifer water could be used as indicators of CO 2 leakage from geologic sequestration sites. Hydrogeochemical parameters including pH, total dissolved solids and trace elements, particularly Fe, Mn, and Zn, need to be monitored in compliance with the U.S. Environmental Protection Agency (EPA) drinking water regulations. (Q. Yang). upward migration of stored CO 2 through faults, fractures, poorly sealed or abandoned wells into shallow drinking water aquifers have led to the slow process of public acceptance and the delay of wide applications of carbon capture and storage (CCS) . The increased acidity from CO 2 intrusion into freshwater and altered aquifer redox conditions could enhance the dissolution of carbonate and silicate minerals, and increase the dissolved concentrations of trace elements (Kharaka et al.
Transport in Porous Media, 2011
This article presents a numerical modeling application using the code TOUGH-REACT of a leakage scenario occurring during a CO 2 geological storage performed in the Jurassic Dogger formation in the Paris Basin. This geological formation has been intensively used for geothermal purposes and is now under consideration as a site for the French national program of reducing greenhouse gas emissions and CO 2 geological storage. Albian sandstone, situated above the Dogger limestone is a major strategic potable water aquifer; the impacts of leaking CO 2 due to potential integrity failure have, therefore, to be investigated. The present case-study illustrates both the capacity and the limitations of numerical tools to address such a critical issue. The physical and chemical processes simulated in this study have been restricted to: (i) supercritical CO 2 injection and storage within the Dogger reservoir aquifer, (ii) CO 2 upwards migration through the leakage zone represented as a 1D vertical porous medium to simulate the cement-rock formation interface in the abandoned well, and (iii) impacts on the Albian aquifer water quality in terms of chemical composition and the mineral phases representative of the porous rock by estimating fluid-rock interactions in both aquifers. Because of CPU time and memory constraints, approximation and simplification regarding the geometry of the geological structure, the mineralogical assemblages and the injection period (up to 5 years) have been applied to the system, resulting in limited analysis of the estimated impacts. The CO 2 migration rate and the quantity of CO 2 arriving as free gas and dissolving, firstly in the storage water and secondly in the water of the overlying aquifer, are calculated. CO 2 dissolution into the Dogger aquifer induces a pH drop from about 7.3 to 4.9 limited by calcite dissolution buffering. Glauconite present in the Albian aquifer also dissolves, causing an increase of the silicon and aluminum in solution and triggering the precipitation of kaolinite and quartz around the intrusion point. A sensitivity analysis of the leakage rate according to the location of the leaky well and the variability of the petro-physical properties of the reservoir, the leaky well zone and the Albian aquifers is also provided.
Energy Procedia, 2011
A prerequisite to the wide deployment of CO 2 geological storage at an industrial scale is demonstrating that potential risks can be efficiently managed, which includes deploying an adequate monitoring during the injection phase and having intervention plans ready in case of major irregularity. This paper considers the injection of CO 2 into a saline formation linked to a shallower aquifer through a leaky pathway. Brine, possibly followed by CO 2 , may start migrating up through the leak if sufficient pressure buildsup in the storage reservoir. For some man-made leakages (e.g. abandoned well), and more importantly for most of the natural ones (e.g. faults, fractured zone), acting on the transfer itself (i.e. on the leaky pathway) is hardly feasible. Consequently, the corrective measure hereby investigated aims at countering the main driving force of the CO 2 upwards migration which is the pressure build-up under the leak by injecting brine into the shallower aquifer, thus creating a hydraulic barrier. Results show that this can be an efficient way to stop a leakage in less than a year instead of letting it continue for hundreds of years, even with a low and decreasing flow rate. It may also be implemented as a preventive measure, while continuing storing CO 2 .
Transport in Porous Media, 2010
Concern has been expressed that carbon dioxide (CO 2) leaking from deep geological storage could adversely impact water quality in overlying potable aquifers by mobilizing hazardous trace elements. In this article, we present a systematic evaluation of the possible water quality changes in response to CO 2 intrusion into aquifers currently used as sources of potable water in the United States. The evaluation was done in three parts. First, we developed a comprehensive geochemical model of aquifers throughout the United States, evaluating the initial aqueous abundances, distributions, and modes of occurrence of selected hazardous trace elements in a large number of potable groundwater quality analyses from the National Water Information System (NWIS) database. For each analysis, we calculated the saturation indices (SIs) of several minerals containing these trace elements. The minerals were initially selected through literature surveys to establish whether field evidence supported their postulated presence in potable water aquifers. Mineral assemblages meeting the criterion of thermodynamic saturation were assumed to control the aqueous concentrations of the hazardous elements at initial system state as well as at elevated CO 2 concentrations caused by the ingress of leaking CO 2. In the second step, to determine those hazardous trace elements of greatest concern in the case of CO 2 leakage, we conducted thermodynamic calculations to predict the impact of increasing CO 2 partial pressures on the solubilities of the identified trace element mineral hosts. Under reducing conditions characteristic of many groundwaters, the trace elements of greatest concern are arsenic (As) and lead (Pb). In the final step, a series of reactive-transport simulations was performed to investigate the chemical evolution of aqueous As and Pb after the intrusion of CO 2 from a storage reservoir into a shallow confined groundwater resource. Results from the reactive-transport model suggest that a significant increase of aqueous As and Pb concentrations may occur in response to CO 2 intrusion, but that the maximum concentration values remain below or close to specified maximum contaminant levels (MCLs). Adsorption/desorption from mineral surfaces may strongly impact the mobilization of As and Pb.
Chemosphere, 2018
Despite the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO 2-acidified 0.01M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.
International Journal of Greenhouse Gas Control, 2016
A series of batch and column experiments combined with solid phase characterization studies was conducted to evaluate the impacts of the potential leakage of carbon dioxide (CO 2) from deep subsurface storage reservoirs to overlying potable carbonate aquifers. The main objective was to gain an understanding on CO 2 gas-induced changes in aquifer pH and mobilization of major, minor, and trace elements from dissolving minerals in rocks representative of an unconfined, oxidizing carbonate aquifer within the continental US. Samples from the unconfined portion of the Edwards limestone aquifer in Texas were exposed to a CO 2 gas stream or were leached with a CO 2-saturated influent solution simulating different leaking scenarios [i.e., sudden, fast, and short-lived release of CO 2 (batch experiments) and gradual release (column experiments)]. The results from the batch and column experiments confirmed that exposure to excess CO 2 gas caused significant decrease in pH (about two pH units); the release of major chemical elements into the contacting aqueous phase (such as Ca, Mg, Ba, Sr, Si, Na, and K); the mobilization and possible rapid immobilization of minor elements (such as Al and Mn), which are able to form highly reactive secondary phases; and sustained but lowconcentration releases of some trace elements (such as Mo, Cs, Sn) in some samples. Spikes of low concentrations of other trace elements (such as As, Cd, Pb, Cu, Zn, Se, etc.), were observed sporadically during these experiments. The results help in developing a systematic understanding of how CO 2 leakage is likely to influence pertinent geochemical processes (such as dissolution/precipitation and sorption/desorption) in the aquifer sediments and will support site selection, risk assessment, policymaking, and public education efforts associated with geologic CO 2 sequestration.
A method and cost model for treatment of water extracted during geologic CO2 storage
International Journal of Greenhouse Gas Control, 2013
Extraction of water as a part of CO 2 storage may be desirable for risk management and process optimization. Treatment and repurposing of this water creates a useful resource and reduces the volumes that must otherwise be disposed. To better understand the tradeoff of costs versus processes and risks, we use a systems approach to evaluate treatment costs that are reasonable for the chemical and physical qualities (salinity, temperature, pH and turbidity) of water that could be extracted from target geologic formations. We evaluate primary and secondary pretreatments, membrane desalination processes (reverse osmosis and nanofiltration), thermal processes (multiple effect distillation and multi-stage flash distillation), and several concentrate (brine) disposal methods. The results indicate that for waters extracted from storage sites, salinities and temperatures may often be higher than for municipal treatment scenarios. Thus, thermal treatment methods are more cost-feasible than membrane methods in many cases, although pressure recovery methods for reverse osmosis can mitigate this. Treatment costs including concentrate disposal fall within a range of US$0.50-2.50/ton CO 2 injected, although some costs can be much higher (up to US$30/ton CO 2 under certain concentrate disposal cost ranges). A sensitivity analysis shows that temperature is the most important in determining costs followed by selection of concentrate disposal method.
2013
The sediments samples from the High Plains aquifer in Kansas were provided by the Kansas Geological Survey Drill Core Library. We are grateful to David Laflen, Manager of the Kansas Geological Survey Geological Materials Archive and Laboratory, for his help and support. The authors wish to thank Jeff Serne for his technical peer review, and Susan Ennor and Kathy Neiderhiser for editorial review and document production. vii Acronyms and Abbreviations °C degree(s) Celsius Al aluminum As arsenic AsFeS arsenopyrite Ba barium Ca calcium Cd cadmium cm centimeter(s) cm 3 cubic centimeter(s) CO carbon monoxide CO 2 carbon dioxide Cs cesium Cu copper
Energy Conversion and Management, 1992
There exist huge volumes of unused aquifers in the earth due to high salinity of the groundwater. Deep aquifers can contain large amount of CO, in the form of compressed gas, liquid or aqueous solution under high formation pressure. Natural gas dissolved in saline groundwater is exploited in some areas in Japan. A preliminary technical and economic survey on the C02 injection system suggests favorable results. More investigations are necessary for assessment of the effect of CO, injection on groundwater environment.