Download or read book Probability Estimation of CO2 Leakage Through Faults at Geologic Carbon Sequestration Sites written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Leakage of CO2 and brine along faults at geologic carbon sequestration (GCS) sites is a primary concern for storage integrity. The focus of this study is on the estimation of the probability of leakage along faults or fractures. This leakage probability is controlled by the probability of a connected network of conduits existing at a given site, the probability of this network encountering the CO2 plume, and the probability of this network intersecting environmental resources that may be impacted by leakage. This work is designed to fit into a risk assessment and certification framework that uses compartments to represent vulnerable resources such as potable groundwater, health and safety, and the near-surface environment. The method we propose includes using percolation theory to estimate the connectivity of the faults, and generating fuzzy rules from discrete fracture network simulations to estimate leakage probability. By this approach, the probability of CO2 escaping into a compartment for a given system can be inferred from the fuzzy rules. The proposed method provides a quick way of estimating the probability of CO2 or brine leaking into a compartment. In addition, it provides the uncertainty range of the estimated probability.
Download or read book Percolation theory and Fuzzy Rule based Probability Estimation of Fault Leakage at Geologic Carbon Sequestration Sites written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Leakage of CO2 and displaced brine from geologic carbon sequestration (GCS) sites into potable groundwater or to the near-surface environment is a primary concern for safety and effectiveness of GCS. The focus of this study is on the estimation of the probability of CO2 leakage along conduits such as faults and fractures. This probability is controlled by (1) the probability that the CO2 plume encounters a conductive fault that could serve as a conduit for CO2 to leak through the sealing formation, and (2) the probability that the conductive fault(s) intersected by the CO2 plume are connected to other conductive faults in such a way that a connected flow path is formed to allow CO2 to leak to environmental resources that may be impacted by leakage. This work is designed to fit into the certification framework for geological CO2 storage, which represents vulnerable resources such as potable groundwater, health and safety, and the near-surface environment as discrete 'compartments'. The method we propose for calculating the probability of the network of conduits intersecting the CO2 plume and one or more compartments includes four steps: (1) assuming that a random network of conduits follows a power-law distribution, a critical conduit density is calculated based on percolation theory; for densities sufficiently smaller than this critical density, the leakage probability is zero; (2) for systems with a conduit density around or above the critical density, we perform a Monte Carlo simulation, generating realizations of conduit networks to determine the leakage probability of the CO2 plume (P{sub leak}) for different conduit length distributions, densities and CO2 plume sizes; (3) from the results of Step 2, we construct fuzzy rules to relate P{sub leak} to system characteristics such as system size, CO2 plume size, and parameters describing conduit length distribution and uncertainty; (4) finally, we determine the CO2 leakage probability for a given system using fuzzy rules. The method can be extended to apply to brine leakage risk by using the size of the pressure perturbation above some cut-off value as the effective plume size. The proposed method provides a quick way of estimating the probability of CO2 or brine leaking into a compartment for evaluation of GCS leakage risk. In addition, the proposed method incorporates the uncertainty in the system parameters and provides the uncertainty range of the estimated probability.
Download or read book Characterizing Fault plume Intersection Probability for Geologic Carbon Sequestration Risk Assessment written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Leakage of CO2 out of the designated storage region via faults is a widely recognized concern for geologic carbon sequestration. The probability of such leakage can be separated into the probability of a plume encountering a fault and the probability of flow along such a fault. In the absence of deterministic fault location information, the first probability can be calculated from regional fault population statistics and modeling of the plume shape and size. In this study, fault statistical parameters were measured or estimated for WESTCARB's Phase III pilot test injection in the San Joaquin Valley, California. Combining CO2 plume model predictions with estimated fault characteristics resulted in a 3% probability that the CO2 plume will encounter a fault fully offsetting the 180 m (590 ft) thick seal. The probability of leakage is lower, likely much lower, as faults with this offset are probably low-permeability features in this area.
Download or read book Risk Assessment Framework for Geologic Carbon Sequestration Sites written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have developed a simple and transparent approach for assessing CO2 and brine leakage risk associated with CO2 injection at geologic carbon sequestration (GCS) sites. The approach, called the Certification Framework (CF), is based on the concept of effective trapping, which takes into account both the probability of leakage from the storage formation and impacts of leakage. The effective trapping concept acknowledges that GCS can be safe and effective even if some CO2 and brine were to escape from the storage formation provided the impact of such leakage is below agreed-upon limits. The CF uses deterministic process models to calculate expected well- and fault-related leakage fluxes and concentrations. These in turn quantify the impacts under a given leakage scenario to so-called 'compartments, ' which comprise collections of vulnerable entities. The probabilistic part of the calculated risk comes from the likelihood of (1) the intersections of injected CO2 and related pressure perturbations with well or fault leakage pathways, and (2) intersections of leakage pathways with compartments. Two innovative approaches for predicting leakage likelihood, namely (1) fault statistics, and (2) fuzzy rules for fault and fracture intersection probability, are highlighted here.
Download or read book Measuring and Modeling Fault Density for Plume Fault Encounter Probability Estimation written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Emission of carbon dioxide from fossil-fueled power generation stations contributes to global climate change. Storage of this carbon dioxide within the pores of geologic strata (geologic carbon storage) is one approach to mitigating the climate change that would otherwise occur. The large storage volume needed for this mitigation requires injection into brine-filled pore space in reservoir strata overlain by cap rocks. One of the main concerns of storage in such rocks is leakage via faults. In the early stages of site selection, site-specific fault coverages are often not available. This necessitates a method for using available fault data to develop an estimate of the likelihood of injected carbon dioxide encountering and migrating up a fault, primarily due to buoyancy. Fault population statistics provide one of the main inputs to calculate the encounter probability. Previous fault population statistics work is shown to be applicable to areal fault density statistics. This result is applied to a case study in the southern portion of the San Joaquin Basin with the result that the probability of a carbon dioxide plume from a previously planned injection had a 3% chance of encountering a fully seal offsetting fault.
Download or read book Case Studies of the Application of the Certification Framework to Two Geologic Carbon Sequestration Sites written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have developed a certification framework (CF) for certifying that the risks of geologic carbon sequestration (GCS) sites are below agreed-upon thresholds. The CF is based on effective trapping of CO2, the proposed concept that takes into account both the probability and impact of CO2 leakage. The CF uses probability estimates of the intersection of conductive faults and wells with the CO2 plume along with modeled fluxes or concentrations of CO2 as proxies for impacts to compartments (such as potable groundwater) to calculate CO2 leakage risk. In order to test and refine the approach, we applied the CF to (1) a hypothetical large-scale GCS project in the Texas Gulf Coast, and (2) WESTCARB's Phase III GCS pilot in the southern San Joaquin Valley, California.
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 Issues in Environmental Research and Application 2011 Edition written by and published by ScholarlyEditions. This book was released on 2012-01-09 with total page 3062 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues in Environmental Research and Application: 2011 Edition is a ScholarlyEditions™ eBook that delivers timely, authoritative, and comprehensive information about Environmental Research and Application. The editors have built Issues in Environmental Research and Application: 2011 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about Environmental Research and Application in this eBook to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Issues in Environmental Research and Application: 2011 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.
Download or read book 420 000 Year Assessment of Fault Leakage Rates Shows Geological Carbon Storage is Secure written by Johannes M. Miocic and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Carbon capture and storage (CCS) technology is routinely cited as a cost effective tool for climate change mitigation. CCS can directly reduce industrial CO2 emissions and is essential for the retention of CO2 extracted from the atmosphere. To be effective as a climate change mitigation tool, CO2 must be securely retained for 10,000 years (10 ka) with a leakage rate of below 0.01% per year of the total amount of CO2 injected. Migration of CO2 back to the atmosphere via leakage through geological faults is a potential high impact risk to CO2 storage integrity. Here, we calculate for the first time natural leakage rates from a 420 ka paleo-record of CO2 leakage above a naturally occurring, faulted, CO2 reservoir in Arizona, USA. Surface travertine (CaCO3) deposits provide evidence of vertical CO2 leakage linked to known faults. U-Th dating of travertine deposits shows leakage varies along a single fault and that individual seeps have lifespans of up to 200 ka. Whilst the total volumes of CO2 required to form the travertine deposits are high, time-averaged leakage equates to a linear rate of less than 0.01%/yr. Hence, even this natural geological storage site, which would be deemed to be of too high risk to be selected for engineered geologic storage, is adequate to store CO2 for climate mitigation purposes
Download or read book Modeling CO2 Leakage Through Faults and Fractures from Subsurface Storage Sites written by Hariharan Ramachandran and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the concerns about the effect of greenhouse gases on the climate, geologic CO2 storage is a very active area of research. Storage will take place in specifically selected target formations to achieve permanent containment. The biggest risk associated with geological storage is the possibility of leakage. The motivation for this research was the need to have a better understanding of potential leakage scenarios, leakage behavior, factors controlling leakage and other essential information about potential leakage. Possible leakage pathways include faults/fractures and leaky wells. Multiphase flow is likely because spatial gradients in pressure and temperature will occur as the CO2 flows toward the surface. Below the CO2 saturation pressure, liquid condensation of the CO2 may occur. At even lower temperatures and pressures and in the presence of water, hydrate formation may occur. As a consequence, the fluid properties will change and affect leakage mass flux. The main purpose of this dissertation research was to develop and test models needed to estimate the leakage mass flux for different scenarios taking thermodynamic phase changes into account. A numerical model with coupled mass and energy balances was developed to estimate the flux as a function of time. Due to wide temperature and pressure changes over the course of the simulation, an accurate fluid properties model was required. The multi-parameter Span-Wagner technical equation of state for CO2 was used to achieve this. The numerical model allows for CO2 to exist in gas, liquid and hydrate phases. Heat flux from the surroundings plays an important role because of its effect on the phase behavior. Example calculations indicate a cyclical nature of the leakage mass flux under certain conditions. Hydrate formation results in partial to complete blockage of the fault until melted. The effect of factors such as constant and varying reservoir pressure at the bottom of the fault, permeability and fault effective width were quantified with numerical simulations. A steady-state flow model was also developed for quick estimation of leakage mass fluxes through faults and fractures. The model was highly simplified and was intended for inclusion in risk assessment studies at the site-selection phase for geologic storage. The model was motivated by geological, non-isothermal properties and multiphase flow considerations. The model will estimate leakage mass fluxes for two different temperature conditions, namely, 1) non-isothermal conditions and 2) adiabatic temperature conditions. The resulting estimates act as the lower (multiphase coexistence and hydrates) and upper (non-isothermal nature) bounds for possible leakage mass flux for a particular set of physical properties of the pathway and surrounding geology. The effects of multiphase coexistence and hydrates on leakage mass flux were quantified. The effects of factors such as reservoir pressure and temperature, depth and permeability that affect multiphase coexistence and leakage mass flux were quantified with a sensitivity analysis.
Download or read book Geological Storage of Carbon Dioxide CO2 written by J Gluyas and published by Elsevier. This book was released on 2013-11-23 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological storage and sequestration of carbon dioxide, in saline aquifers, depleted oil and gas fields or unminable coal seams, represents one of the most important processes for reducing humankind's emissions of greenhouse gases. Geological storage of carbon dioxide (CO2) reviews the techniques and wider implications of carbon dioxide capture and storage (CCS).Part one provides an overview of the fundamentals of the geological storage of CO2. Chapters discuss anthropogenic climate change and the role of CCS, the modelling of storage capacity, injectivity, migration and trapping of CO2, the monitoring of geological storage of CO2, and the role of pressure in CCS. Chapters in part two move on to explore the environmental, social and regulatory aspects of CCS including CO2 leakage from geological storage facilities, risk assessment of CO2 storage complexes and public engagement in projects, and the legal framework for CCS. Finally, part three focuses on a variety of different projects and includes case studies of offshore CO2 storage at Sleipner natural gas field beneath the North Sea, the CO2CRC Otway Project in Australia, on-shore CO2 storage at the Ketzin pilot site in Germany, and the K12-B CO2 injection project in the Netherlands.Geological storage of carbon dioxide (CO2) is a comprehensive resource for geoscientists and geotechnical engineers and academics and researches interested in the field. - Reviews the techniques and wider implications of carbon dioxide capture and storage (CCS) - An overview of the fundamentals of the geological storage of CO2 discussing the modelling of storage capacity, injectivity, migration and trapping of CO2 among other subjects - Explores the environmental, social and regulatory aspects of CCS including CO2 leakage from geological storage facilities, risk assessment of CO2 storage complexes and the legal framework for CCS
Download or read book On Leakage and Seepage from Geological Carbon Sequestration Sites written by and published by . This book was released on 2002 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO2) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO2 deep into subsurface target formations. These target formations will typically be either depleted oil and gas reservoirs, or brine-filled permeable formations referred to here as brine formations. Injected CO2 will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO2 rises until trapped by a confining caprock; (2) solubility trapping, for example when CO2 dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO2 reacts to produce stable carbonate minerals. When CO2 is trapped in the subsurface by any of these mechanisms, it is effectively sequestered away from the atmosphere where it would otherwise act as a greenhouse gas. The purpose of this report is to summarize our work aimed at quantifying potential CO2 seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant properties of CO2 over the range of conditions from the deep subsurface to the vadose zone (Section 2), and then discuss conceptual models for how leakage might occur (Section 3). The discussion includes consideration of gas reservoir and natural gas storage analogs, along with some simple estimates of seepage based on assumed leakage rates. The conceptual model discussion provides the background for the modeling approach wherein we focus on simulating transport in the vadose zone, the last potential barrier to CO2 seepage (Section 4). Because of the potentially wide range of possible properties of actual future geologic sequestration sites, we carry out sensitivity analyses by means of numerical simulation and derive the trends in seepage flux and near-surface CO2 concentrations that will arise from variations in fundamental hydrogeological properties.
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 Fault Geomechanics and Carbon Dioxide Leakage Applied to Geological Storage written by and published by . This book was released on 2007 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safe and permanent storage of carbon dioxide in geologic reservoirs is critical to geologic sequestration. The objective of this study is to quantify the conditions under which a general (simulated) fault network and a specific (field case) fault network will fail and leak carbon dioxide out of a reservoir. Faults present a potential fast-path for CO2 leakage from reservoirs to the surface. They also represent potential induced seismicity hazards. It is important to have improved quantitative understandings of the processes that trigger activity on faults and the risks they present. Fortunately, the conditions under which leakage along faults is induced can be predicted and quantified given the fault geometry, reservoir pressure, an in-situ stress tensor. We proposed to expand the current capabilities of fault threshold characterization and apply that capability to a site where is CO2 injection is active or planned. Specifically, we proposed to use a combination of discrete/explicit and continuum/implicit codes to provide constrain the conditions of fault failure. After minor enhancements of LLNL's existing codes (e.g., LDEC), we would create a 3D synthetic model of a common configuration (e.g., a faulted dome). During these steps, we will identify a field site where the necessary information is available and where the operators are willing to share the necessary information. We would then execute an analysis specific to the field case. The primary products by quarter are: 1Q--Identification of likely field case; 2Q--Functioning prototype fault model; 3Q--Execution of fault-slip/migration calculation for synthetic case; and 4Q--Begin simulation of fault-slip/migration calculation for field system. It is worth noting that due to the continuing resolution, we did not receive any funds until 3Q, and did not receive>65% of the support until 4Q. That said, we were still able to meet all of our milestones for FY07 on time and on budget.
Download or read book Certification Framework Based on Effective Trapping for Geologic Carbon Sequestration written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have developed a certification framework (CF) for certifying the safety and effectiveness of geologic carbon sequestration (GCS) sites. Safety and effectiveness are achieved if CO2 and displaced brine have no significant impact on humans, other living things, resources, or the environment. In the CF, we relate effective trapping to CO2 leakage risk which takes into account both the impact and probability of leakage. We achieve simplicity in the CF by using (1) wells and faults as the potential leakage pathways, (2) compartments to represent environmental resources that may be impacted by leakage, (3) CO2 fluxes and concentrations in the compartments as proxies for impact to vulnerable entities, (4) broad ranges of storage formation properties to generate a catalog of simulated plume movements, and (5) probabilities of intersection of the CO2 plume with the conduits and compartments. We demonstrate the approach on a hypothetical GCS site in a Texas Gulf Coast saline formation. Through its generality and flexibility, the CF can contribute to the assessment of risk of CO2 and brine leakage as part of the certification process for licensing and permitting of GCS sites around the world regardless of the specific regulations in place in any given country.
Download or read book The Consequences of Failure Should be Considered in Siting Geologic Carbon Sequestration Projects written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Geologic carbon sequestration is the injection of anthropogenic CO2 into deep geologic formations where the CO2 is intended to remain indefinitely. If successfully implemented, geologic carbon sequestration will have little or no impact on terrestrial ecosystems aside from the mitigation of climate change. However, failure of a geologic carbon sequestration site, such as large-scale leakage of CO2 into a potable groundwater aquifer, could cause impacts that would require costly remediation measures. Governments are attempting to develop regulations for permitting geologic carbon sequestration sites to ensure their safety and effectiveness. At present, these regulations focus largely on decreasing the probability of failure. In this paper we propose that regulations for the siting of early geologic carbon sequestration projects should emphasize limiting the consequences of failure because consequences are easier to quantify than failure probability.
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.
