Download or read book Storage Capacity and Injection Rate Estimates for CO2 Sequestration in Deep Saline Aquifers in the Conterminous United States written by Michael Lawrence Szulczewski and published by . This book was released on 2009 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: A promising method to mitigate global warming is injecting CO2 into deep saline aquifers. In order to ensure the safety of this method, it is necessary to understand how much CO2 can be injected into an aquifer and at what rate. Since offsetting nationwide emissions requires storing very large quantities of CO2, these properties must be understood at the large scale of geologic basins. In this work, we develop simple models of storage capacity and injection rate at the basin scale. We develop a storage capacity model that calculates how much CO2 an aquifer can store based on how the plume of injected CO2 migrates. We also develop an injection rate model that calculates the maximum rate at which CO2 can be injected into an aquifer based on the pressure rise in the aquifer. We use these models to estimate storage capacities and maximum injection rates for a variety of reservoirs throughout the United States, and compare the results to predicted emissions from coal-burning power plants over the next twenty-five years and fifty years. Our results suggest that the United States has enough storage capacity to sequester all of the CO2 emitted from coal-burning plants over the next 25 years. Furthermore, our results indicate that CO2 can be sequestered at the same rate it is emitted for this time period without fracturing the aquifers. For emissions over the next 50 years, however, the results are less clear: while the United States will likely have enough capacity, maintaining sufficiently high injection rates could be problematic.

Download or read book Numerical study of physico chemical interactions for CO2 sequestration and geothermal energy utilization in the Ordos Basin China written by Hejuan Liu and published by Cuvillier Verlag. This book was released on 2014-11-10 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, three simulators (i.e. TOUGH2MP, TOUGHREACT and FLAC3D) were used to simulate the complex physical and chemical interactions induced by CO2 sequestration. The simulations were done instages, ranging from the two phase (water and CO2) fluid flow (H2), through coupled hydro-mechanical effects (H2M) and geochemical responses (i.e. CO2-water-rock interactions (H2C)), to the extension of CCS to CCUS by the application of combined geothermal production and CO2 sequestration technologies. The findings of this study are essential for a thorough understanding of the complex interactions in the multiphase, multicomponent porous media controlled by different physical and chemical mechanisms. Furthermore, the simulation results will provide an invaluable reference for field operations in CCS projects, especially for the full-integration pilot scale CCS project launched in the Ordos Basin. Subsequently, a preliminary site selection scheme for the combined geothermal production and CO2 sequestration was set up, which considered various factorsinvolved in site selection, ranging from safety, economical, environmental and technical issues. This work provides an important framework for the combined geothermal production and CO2 sequestration project. However, further numerical and field studies are still needed to improve on a series of criteria and related parameters necessary for a better understanding of the technology.

Download or read book Geochemistry of Geologic CO2 Sequestration written by Donald J. DePaolo and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 77 of Reviews in Mineralogy and Geochemistry focuses on important aspects of the geochemistry of geological CO2 sequestration. It is in large part an outgrowth of research conducted by members of the U.S. Department of Energy funded Energy Frontier Research Center (EFRC) known as the Center for Nanoscale Control of Geologic CO2 (NCGC). Eight out of the 15 chapters have been led by team members from the NCGC representing six of the eight partner institutions making up this center - Lawrence Berkeley National Laboratory (lead institution, D. DePaolo - PI), Oak Ridge National Laboratory, The Ohio State University, the University of California Davis, Pacific Northwest National Laboratory, and Washington University, St. Louis.

Download or read book Understanding the Plume Dynamics and Risk Associated with CO2 Injection in Deep Saline Aquifers written by Abhishek Kumar Gupta and published by . This book was released on 2011 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological sequestration of CO2 in deep saline reservoirs is one of the ways to reduce its continuous emission into the atmosphere to mitigate the greenhouse effect. The effectiveness of any CO2 sequestration operation depends on pore volume and the sequestration efficiency of the reservoir. Sequestration efficiency is defined here as the maximum storage with minimum risk of leakage to the overlying formations or to the surface. This can be characterized using three risk parameters i) the time the plume takes to reach the top seal; ii) maximum lateral extent of the plume and iii) the percentage of mobile CO2 present at any time. The selection among prospective saline reservoirs can be expedited by developing some semi-analytical correlations for these risk parameters which can be used in place of reservoir simulation study for each and every saline reservoir. Such correlations can reduce the cost and time for commissioning a geological site for CO2 sequestration. To develop such correlations, a database has been created from a large number of compositional reservoir simulations for different elementary reservoir parameters including porosity, permeability, permeability anisotropy, reservoir depth, thickness, dip, perforation interval and constant pressure far boundary condition. This database is used to formulate different correlations that relate the sequestration efficiency to reservoir properties and operating conditions. The various elementary reservoir parameters are grouped together to generate different variants of gravity number used in the correlations. We update a previously reported correlation for time to hit the top seal and develop new correlations for other two parameters using the newly created database. A correlation for percentage of trapped CO2 is also developed using a previously created similar database. We find that normalizing all risk parameters with their respective characteristic values yields reasonable correlations with different variants of gravity number. All correlations confirm the physics behind plume movement in a reservoir. The correlations reproduce almost all simulation results within a factor of two, and this is adequate for rapid ranking or screening of prospective storage reservoirs. CO2 injection in saline reservoirs on the scale of tens of millions of tonnes may result in fracturing, fault activation and leakage of brine along conductive pathways. Critical contour of overpressure (CoP) is a convenient proxy to determine the risk associated with pressure buildup at different location and time in the reservoir. The location of this contour varies depending on the target aquifer properties (porosity, permeability etc.) and the geology (presence and conductivity of faults). The CoP location also depends on relative permeability, and we extend the three-region injection model to derive analytical expressions for a specific CoP as a function of time. We consider two boundary conditions at the aquifer drainage radius, constant pressure or an infinite aquifer. The model provides a quick tool for estimating pressure profiles. Such tools are valuable for screening and ranking sequestration targets. Relative permeability curves measured on samples from seven potential storage formations are used to illustrate the effect on the CoPs. In the case of a constant pressure boundary and constant rate injection scenario, the CoP for small overpressures is time-invariant and independent of relative permeability. Depending on the relative values of overall mobilities of two-phase region and of brine region, the risk due to a critical CoP which lies in the two-phase region can either increase or decrease with time. In contrast, the risk due to a CoP in the drying region always decreases with time. The assumption of constant pressure boundaries is optimistic in the sense that CoPs extend the least distance from the injection well. We extend the analytical model to infinite-acting aquifers to get a more widely applicable estimate of risk. An analytical expression for pressure profile is developed by adapting water influx models from traditional reservoir engineering to the "three-region" saturation distribution. For infinite-acting boundary condition, the CoP trends depend on same factors as in the constant pressure case, and also depend upon the rate of change of aquifer boundary pressure with time. Commercial reservoir simulators are used to verify the analytical model for the constant pressure boundary condition. The CoP trends from the analytical solution and simulation results show a good match. To achieve safe and secure CO2 storage in underground reservoirs several state and national government agencies are working to develop regulatory frameworks to estimate various risks associated with CO2 injection in saline aquifers. Certification Framework (CF), developed by Oldenburg et al (2007) is a similar kind of regulatory approach to certify the safety and effectiveness of geologic carbon sequestration sites. CF is a simple risk assessment approach for evaluating CO2 and brine leakage risk associated only with subsurface processes and excludes compression, transportation, and injection-well leakage risk. Certification framework is applied to several reservoirs in different geologic settings. These include In Salah CO2 storage project Krechba, Algeria, Aquistore CO2 storage project Saskatchewan, Canada and WESTCARB CO2 storage project, Solano County, California. Compositional reservoir simulations in CMG-GEM are performed for CO2 injection in each storage reservoir to predict pressure build up risk and CO2 leakage risk. CO2 leakage risk is also estimated using the catalog of pre-computed reservoir simulation results. Post combustion CO2 capture is required to restrict the continuous increase of carbon content in the atmosphere. Coal fired electricity generating stations are the dominant players contributing to the continuous emissions of CO2 into the atmosphere. U.S. government has planned to install post combustion CO2 capture facility in many coal fired power plants including W.A. Parish electricity generating station in south Texas. Installing a CO2 capture facility in a coal fired power plant increases the capital cost of installation and operating cost to regenerate the turbine solvent (steam or natural gas) to maintain the stripper power requirement. If a coal-fired power plant with CO2 capture is situated over a viable source for geothermal heat, it may be desirable to use this heat source in the stripper. Geothermal brine can be used to replace steam or natural gas which in turn reduces the operating cost of the CO2 capture facility. High temperature brine can be produced from the underground geothermal brine reservoir and can be injected back to the reservoir after the heat from the hot brine is extracted. This will maintain the reservoir pressure and provide a long-term supply of hot brine to the stripper. Simulations were performed to supply CO2 capture facility equivalent to 60 MWe electric unit to capture 90% of the incoming CO2 in WA Parish electricity generating station. A reservoir simulation study in CMG-GEM is performed to evaluate the feasibility to recycle the required geothermal brine for 30 years time. This pilot study is scaled up to 15 times of the original capacity to generate 900 MWe stripping system to capture CO2 at surface.

Download or read book Using Pressure and Volumetric Approaches to Estimate CO2 Storage Capacity in Deep Saline Aquifers written by and published by . This book was released on 2014 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various approaches are used to evaluate the capacity of saline aquifers to store CO2, resulting in a wide range of capacity estimates for a given aquifer. The two approaches most used are the volumetric "open aquifer" and "closed aquifer" approaches. We present four full-scale aquifer cases, where CO2 storage capacity is evaluated both volumetrically (with "open" and/or "closed" approaches) and through flow modeling. These examples show that the "open aquifer" CO2 storage capacity estimation can strongly exceed the cumulative CO2 injection from the flow model, whereas the "closed aquifer" estimates are a closer approximation to the flow-model derived capacity. An analogy to oil recovery mechanisms is presented, where the primary oil recovery mechanism is compared to CO2 aquifer storage without producing formation water; and the secondary oil recovery mechanism (water flooding) is compared to CO2 aquifer storage performed simultaneously with extraction of water for pressure maintenance. This analogy supports the finding that the "closed aquifer" approach produces a better estimate of CO2 storage without water extraction, and highlights the need for any CO2 storage estimate to specify whether it is intended to represent CO2 storage capacity with or without water extraction.

Download or read book Geological Carbon Storage written by Stéphanie Vialle and published by John Wiley & Sons. This book was released on 2018-11-15 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological Carbon Storage Subsurface Seals and Caprock Integrity Seals and caprocks are an essential component of subsurface hydrogeological systems, guiding the movement and entrapment of hydrocarbon and other fluids. Geological Carbon Storage: Subsurface Seals and Caprock Integrity offers a survey of the wealth of recent scientific work on caprock integrity with a focus on the geological controls of permanent and safe carbon dioxide storage, and the commercial deployment of geological carbon storage. Volume highlights include: Low-permeability rock characterization from the pore scale to the core scale Flow and transport properties of low-permeability rocks Fundamentals of fracture generation, self-healing, and permeability Coupled geochemical, transport and geomechanical processes in caprock Analysis of caprock behavior from natural analogues Geochemical and geophysical monitoring techniques of caprock failure and integrity Potential environmental impacts of carbon dioxide migration on groundwater resources Carbon dioxide leakage mitigation and remediation techniques Geological Carbon Storage: Subsurface Seals and Caprock Integrity is an invaluable resource for geoscientists from academic and research institutions with interests in energy and environment-related problems, as well as professionals in the field.

Download or read book Future Energy written by Trevor Letcher and published by Elsevier. This book was released on 2020-01-18 with total page 822 pages. Available in PDF, EPUB and Kindle. Book excerpt: Future Energy: Improved, Sustainable and Clean Options for Our Planet, Third Edition provides scientists and decision-makers with the knowledge they need to understand the relative importance and magnitude of various energy production methods in order to make the energy decisions necessary for sustaining development and dealing with climate change. The third edition of Future Energy looks at the present energy situation and extrapolates to future scenarios related to global warming and the increase of carbon dioxide and other greenhouse gases in the atmosphere. This thoroughly revised and updated edition contains over 40 chapters on all aspects of future energy, with each chapter updated and expanded by expert scientists and engineers in their respective fields. - Provides readers with an up-to-date overview of available energy options, both traditional and renewable, as well as the necessary tools needed to make informed decisions - Covers a wide spectrum of future energy resources presented in a single book with chapters written by experts from each particular field - Includes many new chapters that cover topics on conventional oil and fossil fuels, a new section on energy storage, and a look at new energy

Download or read book Sensitivity Study of CO2 Storage Capacity in Brine Aquifers Withclosed Boundaries written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In large-scale geologic storage projects, the injected volumes of CO2 will displace huge volumes of native brine. If the designated storage formation is a closed system, e.g., a geologic unit that is compartmentalized by (almost) impermeable sealing units and/or sealing faults, the native brine cannot (easily) escape from the target reservoir. Thus the amount of supercritical CO2 that can be stored in such a system depends ultimately on how much pore space can be made available for the added fluid owing to the compressibility of the pore structure and the fluids. To evaluate storage capacity in such closed systems, we have conducted a modeling study simulating CO2 injection into idealized deep saline aquifers that have no (or limited) interaction with overlying, underlying, and/or adjacent units. Our focus is to evaluate the storage capacity of closed systems as a function of various reservoir parameters, hydraulic properties, compressibilities, depth, boundaries, etc. Accounting for multi-phase flow effects including dissolution of CO2 in numerical simulations, the goal is to develop simple analytical expressions that provide estimates for storage capacity and pressure buildup in such closed systems.

Download or read book Simulation of CO2 Sequestration at Rock Spring Uplift Wyoming written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many geological, geochemical, geomechanical and hydrogeological factors control CO2 storage in subsurface. Among them heterogeneity in saline aquifer can seriously influence design of injection wells, CO2 injection rate, CO2 plume migration, storage capacity, and potential leakage and risk assessment. This study applies indicator geostatistics, transition probability and Markov chain model at the Rock Springs Uplift, Wyoming generating facies-based heterogeneous fields for porosity and permeability in target saline aquifer (Pennsylvanian Weber sandstone) and surrounding rocks (Phosphoria, Madison and cap-rock Chugwater). A multiphase flow simulator FEHM is then used to model injection of CO2 into the target saline aquifer involving field-scale heterogeneity. The results reveal that (1) CO2 injection rates in different injection wells significantly change with local permeability distributions; (2) brine production rates in different pumping wells are also significantly impacted by the spatial heterogeneity in permeability; (3) liquid pressure evolution during and after CO2 injection in saline aquifer varies greatly for different realizations of random permeability fields, and this has potential important effects on hydraulic fracturing of the reservoir rock, reactivation of pre-existing faults and the integrity of the cap-rock; (4) CO2 storage capacity estimate for Rock Springs Uplift is 6614 ± 256 Mt at 95% confidence interval, which is about 36% of previous estimate based on homogeneous and isotropic storage formation; (5) density profiles show that the density of injected CO2 below 3 km is close to that of the ambient brine with given geothermal gradient and brine concentration, which indicates CO2 plume can sink to the deep before reaching thermal equilibrium with brine. Finally, we present uncertainty analysis of CO2 leakage into overlying formations due to heterogeneity in both the target saline aquifer and surrounding formations. This uncertainty in leakage will be used to feed into risk assessment modeling.

Download or read book Geologic CO2 Storage written by YagnaDeepika Oruganti and published by . This book was released on 2010 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt: When CO2 is injected in deep saline aquifers on the scale of gigatonnes, pressure buildup in the aquifer during injection will be a critical issue. Because fracturing, fault activation and leakage of brine along pathways such as abandoned wells all require a threshold pressure (Nicot et al., 2009); operators and regulators will be concerned with the spatial extent of the pressure buildup. Thus a critical contour of overpressure is a convenient proxy for risk. The location of this contour varies depending on the target aquifer properties (porosity, permeability etc.), the geology (presence of faults, abandoned wells etc.), and boundary conditions. Importantly, the extent also depends on relative permeability (Burton et al., 2008). First we describe ways of quantifying the risk due to pressure buildup in an aquifer with a constant pressure boundary, using the three-region injection model to derive analytical expressions for a specific contour of overpressure at any given time. All else being the same, the two-phase-region mobilities (and hence relative permeability characteristics) provide a basis for the ranking of storage formations based on risk associated with pressure elevation during injection. The pressure buildup during CO2 injection will depend strongly upon the boundary conditions at the boundary of the storage formation. An analytical model for pressure profile in the infinite-acting aquifer is developed by combining existing water influx models in traditional reservoir engineering (Van-Everdingen and Hurst model, Carter-Tracy model) to the current problem for describing brine efflux from the storage aquifer when CO2 injection creates a "three-region" saturation distribution. We determine evolution of overpressure with time for constant pressure, no-flow and infinite-acting boundary conditions, and conclude that constant pressure and no-flow boundary conditions give the most optimistic and pessimistic estimates of risk respectively. Compositional reservoir simulation results, using CMG-GEM simulator are presented, to show the effect of an isolated no-flow boundary on pressure buildup and injectivity in saline aquifers. We investigate the effect of multiple injection wells on single-phase fluid flow on aquifer pressure buildup, and demonstrate the use of an equivalent injection well concept to approximate the aquifer pressure profile. We show a relatively inexpensive method of predicting the presence of unanticipated heterogeneities in the formation, by employing routine measurements such as injection rate and injection pressure to track deviation in the plume path. This idea is implemented by combining Pro-HMS (probabilistic history matching software, that carries out geologically consistent parameter estimation), and a CMG-GEM model which has been tuned to the physics of the CO2-brine system.

Download or read book Influence of Relative Permeability Curves on Extent of CO2 Plume During Injection Into Deep Saline Aquifers written by Sang-yeop Park and published by . This book was released on 2007 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Offsetting Water Requirements and Stress with Enhanced Water Recovery from CO2 Storage written by and published by . This book was released on 2016 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon dioxide (CO2) capture, utilization, and storage (CCUS) operations ultimately require injecting and storing CO2 into deep saline aquifers. Reservoir pressure typically rises as CO2 is injected increasing the cost and risk of CCUS and decreasing viable storage within the formation. Active management of the reservoir pressure through the extraction of brine can reduce the pressurization while providing a number of benefits including increased storage capacity for CO2, reduced risks linked to reservoir overpressure, and CO2 plume management. Through enhanced water recovery (EWR), brine within the saline aquifer can be extracted and treated through desalination technologies which could be used to offset the water requirements for thermoelectric power plants or local water needs such as agriculture, or produce a marketable such as lithium through mineral extraction. This paper discusses modeled scenarios of CO2 injection into the Rock Springs Uplift (RSU) formation in Wyoming with EWR. The Finite Element Heat and Mass Transfer Code (FEHM), developed by Los Alamos National Laboratory (LANL), was used to model CO2 injection with brine extraction and the corresponding pressure tradeoffs. Scenarios were compared in order to analyze how pressure management through the quantity and location of brine extraction wells can increase CO2 storage capacity and brine extraction while reducing risks associated with over pressurization. Future research will couple a cost-benefit analysis to these simulations in order to determine if the benefit of subsurface pressure management and increase CO2 storage capacity can outweigh multiple extraction wells with increased cost of installation and maintenance as well as treatment and/or disposal of the extracted brine.

Download or read book Geologic Carbon Sequestration written by V. Vishal and published by Springer. This book was released on 2016-05-11 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: This exclusive compilation written by eminent experts from more than ten countries, outlines the processes and methods for geologic sequestration in different sinks. It discusses and highlights the details of individual storage types, including recent advances in the science and technology of carbon storage. The topic is of immense interest to geoscientists, reservoir engineers, environmentalists and researchers from the scientific and industrial communities working on the methodologies for carbon dioxide storage. Increasing concentrations of anthropogenic carbon dioxide in the atmosphere are often held responsible for the rising temperature of the globe. Geologic sequestration prevents atmospheric release of the waste greenhouse gases by storing them underground for geologically significant periods of time. The book addresses the need for an understanding of carbon reservoir characteristics and behavior. Other book volumes on carbon capture, utilization and storage (CCUS) attempt to cover the entire process of CCUS, but the topic of geologic sequestration is not discussed in detail. This book focuses on the recent trends and up-to-date information on different storage rock types, ranging from deep saline aquifers to coal to basaltic formations.

Download or read book System Design and Optimization of CO2 Storage in Deep Saline Aquifers written by Hossein Shamshiri and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Optimization of waterflooding sweep efficiency has been widely applied in reservoir engineering to improve hydrocarbon recovery while delaying water breakthrough and minimizing the bypassed oil in reservoirs. We develop a new framework to optimize flooding sweep efficiency in geologic formations with heterogeneous properties and demonstrate its application to waterflooding and geological CO2 sequestration problems. The new method focuses on equalizing and delaying (under constant total injected volume) the breakthrough time of the injected fluid at production wells. For application to CO2 sequestration where producers may not be present, we introduce the concept of pseudo production wells that have insignificant production rates (with negligible effect on the overall flow regime) for quantification of hypothetical breakthrough curves that can be used for optimization purpose. We apply the new method to waterflooding and CO2 sequestration optimization using two heterogeneous reservoir models. We show that in water flooding experiments, the proposed method improves the sweep efficiency by delaying the field breakthrough and equalizing breakthrough times in all production wells. In this case, the optimization results in increased oil recovery and decreased water production. We apply a modified version of the proposed algorithm to geologic CO2 sequestration problems to maximize the storage capacity of aquifers by enhancing the residual and dissolution trapping. The results from applying the proposed approach to optimization of geologic CO2 storage problems illustrate the effectiveness of the algorithm in improving residual and solubility trapping by increasing the contact between available fresh brine and the injected CO2 plume through a more uniform distribution of CO2 in the aquifer.

Download or read book Experimental and Numarical Investigation of Carbon Dioxide Sequestration in Deep Saline Aquifers written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Started as an EOR technique to produce oil, injection of carbon dioxide which is essentially a greenhouse gas is becoming more and more important. Although there are a number of mathematical modeling studies, experimental studies are limited and most studies focus on injection into sandstone reservoirs as opposed to carbonate ones. This study presents the results of computerized tomography (CT) monitored laboratory experiments to characterize relevant chemical reactions associated with injection and storage of CO2 in carbonate formations. Porosity changes along the core plugs and the corresponding permeability changes are reported for varying CO2 injection rates, temperature and salt concentrations. CT monitored experiments are designed to model fast near well bore flow and slow reservoir flows. It was observed that either a permeability improvement or a permeability reduction can be obtained. The trend of change in rock properties is very case dependent because it is related to distribution of pores, brine composition and as well the thermodynamic conditions. As the salt concentration decreased the porosity and thus the permeability decrease was less pronounced. Calcite scaling is mainly influenced by orientation and horizontal flow resulted in larger calcite deposition compared to vertical flow. The duration of CO2 – rock contact and the amount of area contacted by CO2 seems to have a more pronounced effect compared to rate effect. The experiments were modeled using a multi-phase, non-isothermal commercial simulator where solution and deposition of calcite were considered by the means of chemical reactions. The calibrated model was then used to analyze field scale injections and to model the potential CO2 sequestration capacity of a hypothetical carbonate aquifer formation. It was observed that solubility and hydrodynamic storage of CO2 is larger compared to mineral trapping.

Download or read book Development of Science Based Permitting Guidance for Geological Sequestration of CO2 in Deep Saline Aquifers Based on Modeling and Risk Assessment written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Underground carbon storage may become one of the solutions to address global warming. However, to have an impact, carbon storage must be done at a much larger scale than current CO2 injection operations for enhanced oil recovery. It must also include injection into saline aquifers. An important characteristic of CO2 is its strong buoyancy--storage must be guaranteed to be sufficiently permanent to satisfy the very reason that CO2 is injected. This long-term aspect (hundreds to thousands of years) is not currently captured in legislation, even if the U.S. has a relatively well-developed regulatory framework to handle carbon storage, especially in the operational short term. This report proposes a hierarchical approach to permitting in which the State/Federal Government is responsible for developing regional assessments, ranking potential sites (''General Permit'') and lessening the applicant's burden if the general area of the chosen site has been ranked more favorably. The general permit would involve determining in the regional sense structural (closed structures), stratigraphic (heterogeneity), and petrophysical (flow parameters such as residual saturation) controls on the long-term fate of geologically sequestered CO2. The state-sponsored regional studies and the subsequent local study performed by the applicant will address the long-term risk of the particular site. It is felt that a performance-based approach rather than a prescriptive approach is the most appropriate framework in which to address public concerns. However, operational issues for each well (equivalent to the current underground injection control-UIC-program) could follow regulations currently in place. Area ranking will include an understanding of trapping modes. Capillary (due to residual saturation) and structural (due to local geological configuration) trappings are two of the four mechanisms (the other two are solubility and mineral trappings), which are the most relevant to the time scale of interest. The most likely pathways for leakage, if any, are wells and faults. We favor a defense-in-depth approach, in which storage permanence does not rely upon a primary seal only but assumes that any leak can be contained by geologic processes before impacting mineral resources, fresh ground water, or ground surface. We examined the Texas Gulf Coast as an example of an attractive target for carbon storage. Stacked sand-shale layers provide large potential storage volumes and defense-in-depth leakage protection. In the Texas Gulf Coast, the best way to achieve this goal is to establish the primary injection level below the total depth of most wells (>2,400 m-8,000 ft). In addition, most faults, particularly growth faults, present at the primary injection level do not reach the surface. A potential methodology, which includes an integrated approach comprising the whole chain of potential events from leakage from the primary site to atmospheric impacts, is also presented. It could be followed by the State/Federal Government, as well as by the operators.

Download or read book CO2 Injection Into a Deep Saline Aquifer written by Michael John Gragg and published by . This book was released on 2012 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic levels of atmospheric greenhouse gases, particularly carbon dioxide (CO2) have increased rapidly over the last several decades and coincide with rising temperatures globally. One possible solution is to capture CO2 before it is released into the atmosphere by large point sources, such as fossil fuel power plants. Once captured, the CO2 can be condensed and transported to a storage facility. Of the available options for storage of condensed CO2, geologic sequestration in deep saline aquifers is considered the most viable option. Porosity measurements were obtained for nearly 100 core samples of the Knox and Stones River groups from the middle Tennessee area as part of a larger project for the Tennessee Division of Geology, characterizing the potential for geologic CO2 sequestration in Tennessee. Certain formations within these groups were found to exhibit higher porosity (higher storage potential) than others. Measured porosity values were quite low, ranging from 0.21 - 10.67 % with a median value of 1.21 %. These data can be used to aid in the decision making process concerning possible geologic targets for geologic CO2 sequestration in Tennessee. A sensitivity analysis was also performed using a numerical model for geologic carbon sequestration (STOMP). Intrinsic permeability, porosity, pore compressibility, the van Genuchten residual liquid saturation, [alpha] and m parameters, and the Brooks and Corey residual liquid and gas saturations were varied independently and their influence on CO2 storage was determined. Changes in costs based on the parameter variations were calculated to evaluate the relative importance of the various parameters. The most influential parameters were intrinsic permeability, the van Genuchten m parameter, and the Brooks and Corey residual gas saturation. These results highlight the need for accurate measurement of intrinsic permeability and capillary pressure saturation parameters in addition to more commonly measured properties like porosity.