Download or read book Geomechanics in CO2 Storage Facilities written by Gilles Pijaudier-Cabot and published by John Wiley & Sons. This book was released on 2013-01-29 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: CO2 capture and geological storage is seen as the most effective technology to rapidly reduce the emission of greenhouse gases into the atmosphere. Up until now and before proceeding to an industrial development of this technology, laboratory research has been conducted for several years and pilot projects have been launched. So far, these studies have mainly focused on transport and geochemical issues and few studies have been dedicated to the geomechanical issues in CO2 storage facilities. The purpose of this book is to give an overview of the multiphysics processes occurring in CO2 storage facilities, with particular attention given to coupled geomechanical problems. The book is divided into three parts. The first part is dedicated to transport processes and focuses on the efficiency of the storage complex and the evaluation of possible leakage paths. The second part deals with issues related to reservoir injectivity and the presence of fractures and occurrence of damage. The final part of the book concerns the serviceability and ageing of the geomaterials whose poromechanical properties may be altered by contact with the injected reactive fluid.

Download or read book The Geomechanics of CO2 Storage in Deep Sedimentary Formations written by and published by . This book was released on 2012 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stress-strain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deployments, mainly at the In Salah CO2 storage project in Algeria, are also integrated into the review. The In Salah project, with its injection into a relatively thin, low-permeability sandstone is an excellent analogue to the saline aquifers that might be used for large scale GCS in parts of Northwest Europe, the U.S. Midwest, and China. Some of the lessons learned at In Salah related to geomechanics are discussed, including how monitoring of geomechanical responses is used for detecting subsurface geomechanical changes and tracking fluid movements, and how such monitoring and geomechanical analyses have led to preventative changes in the injection parameters. Recently, the importance of geomechanics has become more widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO2 repository (as well as how it could impact the public perception of GCS). As described in the paper, to date, no notable seismic event has been reported from any of the current CO2 storage projects, although some unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large power plants will require injection at a much larger scale. In conclusion, for such large-scale injections, a staged, learn-as-you-go approach is recommended, involving a gradual increase of injection rates combined with continuous monitoring of geomechanical changes, as well as siting beneath a multiple layered overburden for multiple flow barrier protection, should an unexpected deep fault reactivation occur.

Download or read book Microseismic Monitoring and Geomechanical Modelling of CO2 Storage in Subsurface Reservoirs written by James P. Verdon and published by Springer Science & Business Media. This book was released on 2012-01-11 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an impressive summary of the potential to use passive seismic methods to monitor the sequestration of anthropogenic CO2 in geologic reservoirs. It brings together innovative research in two distinct areas – seismology and geomechanics – and involves both data analysis and numerical modelling. The data come from the Weyburn-Midale project, which is currently the largest Carbon Capture and Storage (CCS) project in the world. James Verdon’s results show how passive seismic monitoring can be used as an early warning system for fault reactivation and top seal failure, which may lead to the escape of CO2 at the surface.

Download or read book Geomechanical Simulations of CO2 Storage Integrity Using the Livermore Distinct Element Method written by and published by . This book was released on 2008 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-scale carbon capture and sequestration (CCS) projects involving annual injections of millions of tons of CO2 are a key infrastructural element needed to substantially reduce greenhouse gas emissions. The large rate and volume of injection will induce pressure and stress gradients within the formation that could activate existing fractures and faults, or drive new fractures through the caprock. We will present results of an ongoing investigation to identify conditions that will activate existing fractures/faults or make new fractures within the caprock using the Livermore Distinct Element Code (LDEC). LDEC is a multiphysics code, developed at LLNL, capable of simulating dynamic fracture of rock masses under a range of conditions. As part of a recent project, LDEC has been extended to consider fault activation and dynamic fracture of rock masses due to pressurization of the pore-space. We will present several demonstrations of LDEC functionality and applications of LDEC to CO2 injection scenarios including injection into an extensively fractured rockmass. These examples highlight the advantages of explicitly including the geomechanical response of each interface within the rockmass. We present results from our investigations of Teapot Dome using LDEC to study the potential for fault activation during injection. Using this approach, we built finite element models of the rock masses surrounding bounding faults and explicitly simulated the compression and shear on the fault interface. A CO2 injection source was introduced and the area of fault activation was predicted as a function of injection rate. This work presents an approach where the interactions of all locations on the fault are considered in response to specific injection scenarios. For example, with LDEC, as regions of the fault fail, the shear load is taken up elsewhere on the fault. The results of this study are consistent with previous studies of Teapot Dome and indicate significantly elevated pore pressures are required to activate the bounding faults, given the assumed in situ stress state on the faults.

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 Geomechanical Characterization of CO2 Storage Reservoirs on the Rock Springs Uplift WY written by Hua Yu and published by . This book was released on 2018 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon sequestration in deep geological formations has been considered as an important and practical solution to significantly reduce the CO2 emission. CO2 injection into reservoirs may lead to mechanical, chemical, and hydrological effects on the geological formations. This Ph.D. research primarily focuses on quantifying and analyzing geomechanical properties and the effect of CO2 on geomechanical properties of reservoir rocks. The research includes: 1) select and prepare rock samples (Weber Sandstone) from Rock Springs Uplift, Wyoming; 2) design and conduct geomechanical experiments; 3) improve the estimations of geomechanical properties of rocks; 4) develop the analytical model describing the nonlinear rock failure behavior; 5) investigate the effect of compliant pores on reservoir rocks under different stress states; 6) quantify and analyze the changes in geomechanical properties of reservoir rocks due to CO2. Major conclusions drawn from this research were summarized. First, a new method proposed for estimating elastic constants and crack propagation stress thresholds significantly eliminates bias due to both user-defined data interval and poor data resolution on the stress-strain data analysis procedures. Second, a generalized power-law failure criterion was derived in terms of the rock strength properties and validated through published test data for different rock types. Third, the nonlinear pore pressure-volumetric strain relationship at low confining pressure changes to a linear behavior at high confining pressure. Fourth, the unstable crack growth region governed by the initial compliant porosity is independent of the differential pressure. Fifth, the effect of CO2 on geomechanical properties of Weber Sandstone in the linear elastic, nonlinear plastic, and post-failure regime is limited. However, a consistent change in Mohr failure coefficients due to CO2 was observed.

Download or read book Numerical study of underground CO2 storage and the utilization in depleted gas reservoirs written by Cheng Cao and published by Cuvillier Verlag. This book was released on 2021-03-01 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon capture and storage (CCS) is considered as the most promising technology for slowing down the atmospheric CO2 emissions. However, CCS has not been implemented on large scale because of the related risks and the lack of financial incentives. Regarding the risks associated with CCS, a parametric uncertainty analysis for CO2 storage was conducted and the general roles of different key geomechanical and hydrogeological parameters in response to CO2 injection were determined, which is beneficial for guiding time and effort spent mitigating the uncertainty to acquire trustworthy model forecasts and risk assessments. Regarding the financial incentives of CCS, co-injection of CO2 with impurities associated with enhanced gas recovery was analyzed, which is advantageous for decreasing the cost on gas separation and generating additional economic profit. In addition, the utilization of CO2 as cushion gas in the underground gas storage reservoir was proposed and analyzed, which can also be beneficial for improving the cost-effectiveness of CCS. Overall, this thesis is advantageous for promoting the application of CCS on large scale and mitigating the atmospheric CO2 emissions. Die Kohlenstoffabscheidung und –speicherung (CCS) gilt als die vielversprechendste Technologie zur Verlangsamung der atmosphärischen CO2–Emissionen. CCS wurde jedoch aufgrund der damit verbundenen Risiken und des Mangels an finanziellen Anreizen nicht in großem Umfang implementiert. In Bezug auf die mit CCS verbundenen Risiken wurde eine parametrische Unsicherheitsanalyse für die CO2-Speicherung durchgeführt und die allgemeinen Rollen verschiedener geomechanischer und hydrogeologischer Schlüsselparameter als Reaktion auf die CO2-Injektion ermittelt. Dies ist hilfreich, um den Zeit- und Arbeitsaufwand für die Minderung der Unsicherheit zu verringern, um vertrauenswürdig zu werden Modellprognosen und Risikobewertungen. In Bezug auf die finanziellen Anreize von CCS wurde die gleichzeitige Injektion von CO2 mit Verunreinigungen im Zusammenhang mit einer verbesserten Gasrückgewinnung analysiert. Dies ist vorteilhaft, um die Kosten für die Gastrennung zu senken und zusätzlichen wirtschaftlichen Gewinn zu erzielen. Darüber hinaus wurde die Verwendung von CO2 als Polstergas im unterirdischen Gasspeicher vorgeschlagen und analysiert, was auch zur Verbesserung der Wirtschaftlichkeit von CCS beitragen kann. Insgesamt ist diese These vorteilhaft, um die Anwendung von CCS in großem Maßstab zu fördern und die atmosphärischen CO2-Emissionen zu verringern.

Download or read book How to Store CO2 Underground Insights from early mover CCS Projects written by Philip Ringrose and published by Springer Nature. This book was released on 2020-01-01 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the scientific basis and engineering practice for CO2 storage, covering topics such as storage capacity, trapping mechanisms, CO2 phase behaviour and flow dynamics, engineering and geomechanics of geological storage, injection well design, and geophysical and geochemical monitoring. It also provides numerous examples from the early mover CCS projects, notably Sleipner and Snøhvit offshore Norway, as well as other pioneering CO2 storage projects.

Download or read book The Geomechanics of CO sub 2 Storage in Deep Sedimentary Formations written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper provides a review of the geomechanics and modeling of geomechanics associated with geologic carbon storage (GCS), focusing on storage in deep sedimentary formations, in particular saline aquifers. The paper first introduces the concept of storage in deep sedimentary formations, the geomechanical processes and issues related with such an operation, and the relevant geomechanical modeling tools. This is followed by a more detailed review of geomechanical aspects, including reservoir stress-strain and microseismicity, well integrity, caprock sealing performance, and the potential for fault reactivation and notable (felt) seismic events. Geomechanical observations at current GCS field deployments, mainly at the In Salah CO2 storage project in Algeria, are also integrated into the review. The In Salah project, with its injection into a relatively thin, low-permeability sandstone is an excellent analogue to the saline aquifers that might be used for large scale GCS in parts of Northwest Europe, the U.S. Midwest, and China. Some of the lessons learned at In Salah related to geomechanics are discussed, including how monitoring of geomechanical responses is used for detecting subsurface geomechanical changes and tracking fluid movements, and how such monitoring and geomechanical analyses have led to preventative changes in the injection parameters. Recently, the importance of geomechanics has become more widely recognized among GCS stakeholders, especially with respect to the potential for triggering notable (felt) seismic events and how such events could impact the long-term integrity of a CO2 repository (as well as how it could impact the public perception of GCS). As described in the paper, to date, no notable seismic event has been reported from any of the current CO2 storage projects, although some unfelt microseismic activities have been detected by geophones. However, potential future commercial GCS operations from large power plants will require injection at a much larger scale. For such largescale injections, a staged, learn-as-you-go approach is recommended, involving a gradual increase of injection rates combined with continuous monitoring of geomechanical changes, as well as siting beneath a multiple layered overburden for multiple flow barrier protection, should an unexpected deep fault reactivation occur.

Download or read book Science of Carbon Storage in Deep Saline Formations written by Pania Newell and published by Elsevier. This book was released on 2018-09-10 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Science of Carbon Storage in Deep Saline Formations: Process Coupling across Time and Spatial Scales summarizes state-of-the-art research, emphasizing how the coupling of physical and chemical processes as subsurface systems re-equilibrate during and after the injection of CO2. In addition, it addresses, in an easy-to-follow way, the lack of knowledge in understanding the coupled processes related to fluid flow, geomechanics and geochemistry over time and spatial scales. The book uniquely highlights process coupling and process interplay across time and spatial scales that are relevant to geological carbon storage.

Download or read book Geological Storage of CO2 Long Term Security Aspects written by Axel Liebscher and published by Springer. This book was released on 2015-02-21 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the industrial use of secure, permanent storage technologies for carbon dioxide (CO2), especially geological CO2 storage. Readers are invited to discover how this greenhouse gas could be spared from permanent release into the atmosphere through storage in deep rock formations. Themes explored here include CO2 reservoir management, caprock formation, bio-chemical processes and fluid migration. Particular attention is given to groundwater protection, the improvement of sensor technology, borehole seals and cement quality. A collaborative work by scientists and industrial partners, this volume presents original research, it investigates several aspects of innovative technologies for medium-term use and it includes a detailed risk analysis. Coal-based power generation, energy consuming industrial processes (such as steel and cement) and the burning of biomass all result in carbon dioxide. Those involved in such industries who are considering geological storage of CO2, as well as earth scientists and engineers will value this book and the innovative monitoring methods described. Researchers in the field of computer imaging and pattern recognition will also find something of interest in these chapters.

Download or read book Thermo Hydro Mechanical Coupling in Fractured Rock written by Hans-Joachim Kümpel and published by Springer Science & Business Media. This book was released on 2003-03-21 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: The supply and protection of groundwater, the production of hydrocarbon reservoirs, land subsidence in coastal areas, exploitation of geothermal energy, the long-term disposal of critical wastes ... What do these issues have in common besides their high socio-economic impact? They are all closely related to fluid flow in porous and/or fractured rock. As the conditions of fluid flow in many cases depend on the mechanical behavior of rocks, coupling between the liquid phase and the rock matrix can generally not be neglected. For the past five years or so, studies of rock physics and rock mechanics linked to coupling phenomena have received increased attention. In recognition of this, a Euroconference on thermo-hydro-mechanical coupling in fractured rock was held at Bad Honnef, Germany, in November 2000. Most of the twenty papers collected in this volume were presented at this meeting. The contributions lead to deeper insight in processes where such coupling is relevant.

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 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. Book Review: William R. Green, Patrick Taylor, Sven Treitel, and Moritz Fliedner, (2020), "Reviews," The Leading Edge 39: 214–216 Geological Carbon Storage: Subsurface Seals and Caprock Integrity, edited by Stéphanie Vialle, Jonathan Ajo-Franklin, and J. William Carey, ISBN 978-1-119-11864-0, 2018, American Geophysical Union and Wiley, 364 p., US$199.95 (print), US$159.99 (eBook). This volume is a part of the AGU/Wiley Geophysical Monograph Series. The editors assembled an international team of earth scientists who present a comprehensive approach to the major problem of placing unwanted and/or hazardous fluids beneath a cap rock seal to be impounded. The compact and informative preface depicts the nature of cap rocks and the problems that may occur over time or with a change in the formation of the cap rock. I have excerpted a quote from the preface that describes the scope of the volume in a concise and thorough matter. “Caprocks can be defined as a rock that prevents the flow of a given fluid at certain temperature, pressure, and chemical conditions. ... A fundamental understanding of these units and of their evolution over time in the context of subsurface carbon storage is still lacking.” This volume describes the scope of current research being conducted on a global scale, with 31 of the 83 authors working outside of the United States. The studies vary but can be generalized as monitoring techniques for cap rock integrity and the consequence of the loss of that integrity. The preface ends by calling out important problems that remain to be answered. These include imaging cap rocks in situ, detecting subsurface leaks before they reach the surface, and remotely examining the state of the cap rock to avert any problems. Chapter 3 describes how newer methods are used to classify shale. These advanced techniques reveal previously unknown microscopic properties that complicate classification. This is an example of the more we know, the more we don't know. A sedimentologic study of the formation of shale (by far the major sedimentary rock and an important rock type) is described in Chapter 4. The authors use diagrammatic examples to illustrate how cap rocks may fail through imperfect seal between the drill and wall rock, capillary action, or a structural defect (fault). Also, the shale pore structures vary in size, and this affects the reservoir. There are descriptions of the pore structure in the Eagle Ford and Marcellus shales and several others. Pore structures are analyzed using state-of-the-art ultra-small-angle X-ray or neutron scattering. They determine that the overall porosity decreases nonlinearly with time. There are examples of cap rock performance under an array of diagnostic laboratory analyses and geologic field examples (e.g., Marcellus Formation). The importance of the sequestration of CO2 and other contaminants highlights the significance of this volume. The previous and following chapters illuminate the life history of the lithologic reservoir seal. I would like to call out Chapter 14 in which the authors illustrate the various mechanisms by which a seal can fail and Chapter 15 in which the authors address the general problems of the effect of CO2 sequestration on the environment. They establish a field test, consisting of a trailer and large tank of fluids with numerous monitoring instruments to replicate the effect of a controlled release of CO2-saturated water into a shallow aquifer. This chapter's extensive list of references will be of interest to petroleum engineers, rock mechanics, and environmentalists. The authors of this volume present a broad view of the underground storage of CO2. Nuclear waste and hydrocarbons are also considered for underground storage. There are laboratory, field, and in situ studies covering nearly all aspects of this problem. I cannot remember a study in which so many different earth science resources were applied to a single problem. The span of subjects varies from traditional geochemical analysis with the standard and latest methods in infrared and X-ray techniques, chemical and petroleum engineering, sedimentary mineralogy, hydrology, and geomechanical studies. This volume is essential to anyone working in this field as it brings several disciplines together to produce a comprehensive study of carbon sequestration. While the volume is well illustrated, there is a lack of color figures. Each chapter should have at least two color figures, or there should be several pages of color figures bound in the center of the volume. Many of the figures would be more meaningful if they had been rendered in color. Also, the acronyms are defined in the individual chapters, but it would be helpful to have a list of acronyms after the extensive index. I recommend this monograph to all earth scientists but especially petroleum engineers, structural geologists, mineralogists, and environmental scientists. Since these chapters cover a broad range of studies, it would be best if the reader has a broad background. — Patrick Taylor Davidsonville, Maryland

Download or read book Carbon Dioxide Sequestration in Geological Media written by Matthias Grobe and published by AAPG. This book was released on 2010-03-01 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 20 years, the concept of storing or permanently storing carbon dioxide in geological media has gained increasing attention as part of the important technology option of carbon capture and storage within a portfolio of options aimed at reducing anthropogenic emissions of greenhouse gases to the earths atmosphere. This book is structured into eight parts, and, among other topics, provides an overview of the current status and challenges of the science, regional assessment studies of carbon dioxide geological sequestration potential, and a discussion of the economics and regulatory aspects of carbon dioxide sequestration.

Download or read book The Industrial Base for Carbon Dioxide Storage written by David S. Ortiz and published by Rand Corporation. This book was released on 2013-03-15 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: If policies aimed at large reductions of carbon dioxide (CO2) emissions are enacted, more carbon capture and storage will be needed. RAND researchers explored the ability of the industrial base supporting the transportation and sequestration of CO2 to expand, assessing the industrial base for transportation and injection of CO2 for both geologic storage and enhanced oil recovery.

Download or read book Negative Emissions Technologies and Reliable Sequestration written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-04-08 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: To achieve goals for climate and economic growth, "negative emissions technologies" (NETs) that remove and sequester carbon dioxide from the air will need to play a significant role in mitigating climate change. Unlike carbon capture and storage technologies that remove carbon dioxide emissions directly from large point sources such as coal power plants, NETs remove carbon dioxide directly from the atmosphere or enhance natural carbon sinks. Storing the carbon dioxide from NETs has the same impact on the atmosphere and climate as simultaneously preventing an equal amount of carbon dioxide from being emitted. Recent analyses found that deploying NETs may be less expensive and less disruptive than reducing some emissions, such as a substantial portion of agricultural and land-use emissions and some transportation emissions. In 2015, the National Academies published Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration, which described and initially assessed NETs and sequestration technologies. This report acknowledged the relative paucity of research on NETs and recommended development of a research agenda that covers all aspects of NETs from fundamental science to full-scale deployment. To address this need, Negative Emissions Technologies and Reliable Sequestration: A Research Agenda assesses the benefits, risks, and "sustainable scale potential" for NETs and sequestration. This report also defines the essential components of a research and development program, including its estimated costs and potential impact.