Download or read book Uncertainty Analysis of Capacity Estimates and Leakage Potential for Geologic Storage of Carbon Dioxide in Saline Aquifers written by Yamama Raza and published by . This book was released on 2009 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: (cont.) Any development of regulation of geologic storage and relevant policies should take uncertainty into consideration. Better understanding of the uncertainty in the science of geologic storage can influence the areas of further research, and improve the accuracy of models that are being used. Incorporating uncertainty analysis into regulatory requirements for site characterization will provide better oversight and management of injection activities. With the proper management and monitoring of sites, the establishment of proper liability regimes, accounting rules and compensation mechanisms for leakage, geologic storage can be a safe and effective carbon mitigation tool to combat climate change.

Download or read book Uncertainty Analysis of Carbon Sequestration in an Inclined Deep Saline Aquifer written by Guang Yang and published by . This book was released on 2012 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geologic Carbon Sequestration (GCS) is a proposed means to reduce atmospheric carbon dioxide (CO2 ). In Wyoming, GCS is proposed for the Nugget Sandstone, an eolian sandstone exhibiting permeability heterogeneity. Using subsets of static site characterization data, this study builds a suite of increasingly complex geologic model families for the Nugget Sandstone in the Wyoming Overthrust Belt, which is an inclined deep saline aquifer. These models include: a homogeneous model (FAM1), a stationary geostatistical facies model with constant petrophyscial properties in each facies (FAM2a), a stationary geostatistical petrophysical model (FAM2b), a stationary facies model with sub-facies petrophysical variability (FAM3), and a non-stationary facies model (with sub-facies variability) conditioned to soft data (FAM4). These families, representing increasingly sophisticated conceptual models built with increasing amounts of site data, were simulated with the same CO2 injection test (50-year duration at ~1/3 Mt per year), followed by a 2000-year monitoring phase. Based on the Design of Experiment (DOE), an efficient sensitivity analysis (SA) is conducted for all model families, systematically varying uncertain input parameters, while assuming identical production scenario (i.e., well configuration, rate, BHP constraint) and boundary condition (i.e., model is part of a larger semi-infinite system where the injected gas can flow out). Results are compared among the families at different time scales to identify parameters that have first order impact on select simulation outcomes. For predicting CO2 storage ratio (SR) and brine leakage, at both time scales (i.e., end of injection and end of monitoring), more geologic factors are revealed to be important as model complexity is increased, while the importance of engineering factors is simultaneously diminished. In predicting each of the trapped and dissolved gases, when model is of greater complexity, more geologic factors are identified as important with increasing time. This effect, however, cannot be revealed by simpler models. Based on results of the SA, a response surface (RS) analysis is conducted next to generate prediction envelopes of the outcomes which are further compared among the model families. Results suggest a large uncertainty range in the SR given the uncertainties of the parameter and modeling choices. At the end of injection, SR ranges from 0.18 to 0.38; at the end of monitoring, SR ranges from 0.71 to 0.98. In predicting the SR, during the entire simulation time, uncertainty ranges of FAM2b, FAM3, and FAM4 are larger than those of FAM1 and FAM2a, since the former models incorporate more geological complexities. The uncertainty range also changes with time and with the model families. By the end of injection, prediction envelops of all families are more or less similar. Over this shorter time scale, where heterogeneities near the injection site are not significantly different among the different model representations, simpler models can capture the uncertainty in the predicted SR. During the monitoring phase, prediction envelope of each family deviates gradually from one another, reflecting the different (evolving) large scale heterogeneity experienced by each family as plume migrates and grows continuously. Compared to FAM4 (i.e., the most sophisticated model), all other families estimate higher mean SRs. The lesser the amount of site data are incorporated (i.e., lesser geological complexities), the greater the estimated mean SR. In terms of magnitude and range of the uncertainty, prediction envelop of FAM3 is the closest to that of FAM4, while FAM2b's uncertainty range is the largest and FAM1 and FAM2a's ranges are small. Finally, end-member gas plume footprint for each family is established from results of the RS designs (i.e., corresponding to SR minimum, median, and maximum). For FAM1 and FAM2a, at each time scale inspected, the end-member gas plume footprints are not as drastically different as in FAM2b, 3, and 4, since their SR uncertainty range is comparatively small. However, for families of greater geological complexity (i.e., FAM2b, FAM3, and FAM4), the differences are much more significant: gas plume of minimum SR sits around the wellbore and doesn't migrate far, while gas plume of maximum SR migrates a great distance from the wellbore. To summarize, geologic factors and associated conceptual model uncertainty can dominate the uncertainty in predicting SR, brine leakage, and plume footprint. At the study site, better characterization of geologic data such as porosity-permeability transform and facies correlation structure, can lead to significantly reduced uncertainty in predictions. Given the current uncertainty in parameters and modeling choices, CO2 plume predicted by the majority of the simulation runs is either trapped near the injection site (e.g., due to low formation permeability and its heterogeneity) or is gravity-stable under conditions of higher permeability and lower temperature gradient, suggesting a low leakage risk. The inclined Nugget Sandstone at the study site appears to be a viable candidate for safe GCS in this region.

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 Essentials of Risk Theory written by Sabine Roeser and published by Springer Science & Business Media. This book was released on 2012-11-02 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Risk has become one of the main topics in fields as diverse as engineering, medicine and economics, and it is also studied by social scientists, psychologists and legal scholars. This Springer Essentials version offers an overview of the in-depth handbook and highlights some of the main points covered in the Handbook of Risk Theory. The topic of risk also leads to more fundamental questions such as: What is risk? What can decision theory contribute to the analysis of risk? What does the human perception of risk mean for society? How should we judge whether a risk is morally acceptable or not? Over the last couple of decades questions like these have attracted interest from philosophers and other scholars into risk theory. This brief offers the essentials of the handbook provides for an overview into key topics in a major new field of research and addresses a wide range of topics, ranging from decision theory, risk perception to ethics and social implications of risk. It aims to promote communication and information among all those who are interested in theoretical issues concerning risk and uncertainty. The Essentials of Risk Theory brings together internationally leading philosophers and scholars from other disciplines who work on risk theory. The contributions are accessibly written and highly relevant to issues that are studied by risk scholars. The Essentials of Risk Theory will be a helpful starting point for all risk scholars who are interested in broadening and deepening their current perspectives. ​

Download or read book Handbook of Risk Theory written by Rafaela Hillerbrand and published by Springer Science & Business Media. This book was released on 2012-01-12 with total page 1209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Risk has become one of the main topics in fields as diverse as engineering, medicine and economics, and it is also studied by social scientists, psychologists and legal scholars. But the topic of risk also leads to more fundamental questions such as: What is risk? What can decision theory contribute to the analysis of risk? What does the human perception of risk mean for society? How should we judge whether a risk is morally acceptable or not? Over the last couple of decades questions like these have attracted interest from philosophers and other scholars into risk theory. This handbook provides for an overview into key topics in a major new field of research. It addresses a wide range of topics, ranging from decision theory, risk perception to ethics and social implications of risk, and it also addresses specific case studies. It aims to promote communication and information among all those who are interested in theoetical issues concerning risk and uncertainty. This handbook brings together internationally leading philosophers and scholars from other disciplines who work on risk theory. The contributions are accessibly written and highly relevant to issues that are studied by risk scholars. We hope that the Handbook of Risk Theory will be a helpful starting point for all risk scholars who are interested in broadening and deepening their current perspectives.

Download or read book Handbook of Risk Theory written by Sabine Roeser and published by Springer Science & Business Media. This book was released on 2012 with total page 1209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Risk has become one of the main topics in fields as diverse as engineering, medicine and economics, and it is also studied by social scientists, psychologists and legal scholars. But the topic of risk also leads to more fundamental questions such as: What is risk? What can decision theory contribute to the analysis of risk? What does the human perception of risk mean for society? How should we judge whether a risk is morally acceptable or not? Over the last couple of decades questions like these have attracted interest from philosophers and other scholars into risk theory. This handbook provides for an overview into key topics in a major new field of research. It addresses a wide range of topics, ranging from decision theory, risk perception to ethics and social implications of risk, and it also addresses specific case studies. It aims to promote communication and information among all those who are interested in theoetical issues concerning risk and uncertainty. This handbook brings together internationally leading philosophers and scholars from other disciplines who work on risk theory. The contributions are accessibly written and highly relevant to issues that are studied by risk scholars. We hope that the Handbook of Risk Theory will be a helpful starting point for all risk scholars who are interested in broadening and deepening their current perspectives.

Download or read book Estimating Plume Volume for Geologic Storage of CO2 in Saline Aquifers written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Typically, when a new subsurface flow and transport problem is first being considered, very simple models with a minimal number of parameters are used to get a rough idea of how the system will evolve. For a hydrogeologist considering the spreading of a contaminant plume in an aquifer, the aquifer thickness, porosity, and permeability might be enough to get started. If the plume is buoyant, aquifer dip comes into play. If regional groundwater flow is significant or there are nearby wells pumping, these features need to be included. Generally, the required parameters tend to be known from pre-existing studies, are parameters that people working in the field are familiar with, and represent features that are easy to explain to potential funding agencies, regulators, stakeholders, and the public. The situation for geologic storage of carbon dioxide (CO2) in saline aquifers is quite different. It is certainly desirable to do preliminary modeling in advance of any field work since geologic storage of CO2 is a novel concept that few people have much experience with or intuition about. But the parameters that control CO2 plume behavior are a little more daunting to assemble and explain than those for a groundwater flow problem. Even the most basic question of how much volume a given mass of injected CO2 will occupy in the subsurface is non-trivial. However, with a number of simplifying assumptions, some preliminary estimates can be made, as described below. To make efficient use of the subsurface storage volume available, CO2 density should be large, which means choosing a storage formation at depths below about 800 m, where pressure and temperature conditions are above the critical point of CO2 (P = 73.8 bars, T = 31 C). Then CO2 will exist primarily as a free-phase supercritical fluid, while some CO2 will dissolve into the aqueous phase.

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 Aquifer Management for CO2 Sequestration written by Abhishek Anchliya and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Storage of carbon dioxide is being actively considered for the reduction of green house gases. To make an impact on the environment CO2 should be put away on the scale of gigatonnes per annum. The storage capacity of deep saline aquifers is estimated to be as high as 1,000 gigatonnes of CO2.(IPCC). Published reports on the potential for sequestration fail to address the necessity of storing CO2 in a closed system. This work addresses issues related to sequestration of CO2 in closed aquifers and the risk associated with aquifer pressurization. Through analytical modeling we show that the required volume for storage and the number of injection wells required are more than what has been envisioned, which renders geologic sequestration of CO2 a profoundly nonfeasible option for the management of CO2 emissions unless brine is produced to create voidage and pressure relief. The results from our analytical model match well with a numerical reservoir simulator including the multiphase physics of CO2 sequestration. Rising aquifer pressurization threatens the seal integrity and poses a risk of CO2 leakage. Hence, monitoring the long-term integrity of CO2 storage reservoirs will be a critical aspect for making geologic sequestration a safe, effective and acceptable method for greenhouse gas control. Verification of long-term CO2 residence in receptor formations and quantification of possible CO2 leaks are required for developing a risk assessment framework. Important aspects of pressure falloff tests for CO2 storage reservoirs are discussed with a focus on reservoir pressure monitoring and leakage detection. The importance of taking regular pressure falloffs for a commercial sequestration project and how this can help in diagnosing an aquifer leak will be discussed. The primary driver for leakage in bulk phase injection is the buoyancy of CO2 under typical deep reservoir conditions. Free-phase CO2 below the top seal is prone to leak if a breach happens in the top seal. Consequently, another objective of this research is to propose a way to engineer the CO2 injection system in order to accelerate CO2 dissolution and trapping. The engineered system eliminates the buoyancy-driven accumulation of free gas and avoids aquifer pressurization by producing brine out of the system. Simulations for 30 years of CO2 injection followed by 1,000 years of natural gradient show how CO2 can be securely and safely stored in a relatively smaller closed aquifer volume and with a greater storage potential. The engineered system increases CO2 dissolution and capillary trapping over what occurs under the bulk phase injection of CO2. This thesis revolves around identification, monitoring and mitigation of the risks associated with geological CO2 sequestration.

Download or read book Carbon Sequestration and Its Role in the Global Carbon Cycle written by Brian J. McPherson and published by John Wiley & Sons. This book was released on 2013-05-02 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 183. For carbon sequestration the issues of monitoring, risk assessment, and verification of carbon content and storage efficacy are perhaps the most uncertain. Yet these issues are also the most critical challenges facing the broader context of carbon sequestration as a means for addressing climate change. In response to these challenges, Carbon Sequestration and Its Role in the Global Carbon Cycle presents current perspectives and research that combine five major areas: The global carbon cycle and verification and assessment of global carbon sources and sinks Potential capacity and temporal/spatial scales of terrestrial, oceanic, and geologic carbon storage Assessing risks and benefits associated with terrestrial, oceanic, and geologic carbon storage Predicting, monitoring, and verifying effectiveness of different forms of carbon storage Suggested new CO2 sequestration research and management paradigms for the future. The volume is based on a Chapman Conference and will appeal to the rapidly growing group of scientists and engineers examining methods for deliberate carbon sequestration through storage in plants, soils, the oceans, and geological repositories.

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 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 Carbon Capture and Sequestration written by M. Granger Morgan and published by Routledge. This book was released on 2012-05-31 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The United States produces over seventy percent of all its electricity from fossil fuels and nearly fifty percent from coal alone. Worldwide, forty-one percent of all electricity is generated from coal, making it the single most important fuel source for electricity generation, followed by natural gas. This means that an essential part of any portfolio for emissions reduction will be technology to capture carbon dioxide and permanently sequester it in suitable geologic formations. While many nations have incentivized development of CCS technology, large regulatory and legal barriers exist that have yet to be addressed. This book identifies current law and regulation that applies to geologic sequestration in the U.S., the regulatory needs to ensure that geologic sequestration is carried out safely and effectively, and barriers that current law and regulation present to timely deployment of CCS. The authors find the three most significant barriers to be: an ill-defined process to access pore space in deep saline formations; a piecemeal, procedural, and static permitting system; and the lack of a clear, responsible plan to address long-term liability associated with sequestered CO2. The book provides legislative options to remove these barriers and address the regulatory needs, and makes recommendations on the best options to encourage safe, effective deployment of CCS. The authors operationalize their recommendations in legislative language, which is of particular use to policymakers faced with the challenge of addressing climate change and energy.

Download or read book Storage of Carbon Dioxide in Saline Aquifers written by Philip Ringrose and published by . This book was released on 2023-08 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon capture and storage is part of global efforts to reduce greenhouse gas emissions. This book reviews the science and technology underpinning CO2 storage in deep saline aquifer formations using insights from several industrial-scale projects. Factors which limit storage capacity are analyzed. Then, we discuss how to optimize monitoring methods.

Download or read book Sensitivity Analysis of Carbon Dioxide Storage in Saline Aquifers in the Presence of a Gas Cap written by Silvia Veronica Solano and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Deep brine-bearing formations contain a significant CO2 storage potential as they are usually permeable sandstones at depths in which pressure and temperature conditions assure supercritical state for the injected CO2. When injecting CO2 in a hydrocarbon-rich area, presence of a gas cap significantly impacts the CO2 plume behavior. This study focuses on the assessment of the CO2 plume properties in formations typical of the Gulf Coast area, under the presence of a gas cap and its consequences for long-term storage. The study is prompted by the presence of a large depleted gas cap at Cranfield, Mississippi where CO2 is being injected for long-term storage. Presence of the gas cap, even depleted, near the injection site provides an exceptional opportunity to investigate an area made of higher compressibility fluids and its impact on reservoir and operational parameters, particularly CO2 plume behavior. Enhanced gas recovery is not planned within this area. Considerable volumes of native brine are displaced when large amounts of CO2 are injected, and when this displacement occurs in a closed system, the amount of stored CO2 will depend solely on the additional pore space available owing to compressibility of the pore structure and fluids. As a result, presence of a gas cap is expected to impact plume characteristics, as well as operational conditions, because of its larger compressibility. A multi-parameter sensitivity analysis, based on a generic reservoir model, was performed to appreciate relevant factors to CO2 migration under the influence of the nearby gas cap. It was achieved using the compositional reservoir simulator CMG-GEM and allied modules. Main parameters taken into account for the sensitivity analysis included variation in gas cap properties such as: volume, gas composition and gas residual saturation. Additionally, other parameters have been included in this study such as reservoir dip, injector-gas-cap distance, injection pressure, plume asymmetry and horizontal centroid location. The CO2 plume extends farther as the gas cap volume increases and the distance to the gas cap decreases. Gas residual saturation conditions in the gas cap region are not expected to affect the maximum lateral plume extent as much as the existent volume of gas. The effect of gas cap composition in CO2 migration is dominated by pressure changes within the formation which subsequently affects the gas cap compressibility and in consequence the plume maximum lateral extent. For example, contamination of a methane-rich gas cap by injected CO2 has a strong effect on the plume maximum lateral extent due to compressibility changes. This, in turn, affects regulatory Area of Review, project technical risks, and economics. In another part of the study, a dimensional analysis was performed to identify and assess dominant forces relevant to CO2 plume distribution in the presence of a gas cap. Dimensionless groups were used to express the relationship between centroid location and the ratio of gravity and viscous forces given by the gravity number. Appropriate assessment of gas cap impact on CO2 plume distribution and on aquifer pressure build-up is fundamental for developing an accurate economic outlook as well as for taking into account regulatory constraints (including a monitoring plan addressing leakage risk and possible aquifer contamination).

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 Federal Register written by and published by . This book was released on 2014 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: