Publications Database - List of storage publications

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    June, 2005

Vol 2 Chapter 19: Monitoring Options for CO₂ Storage

Rob Arts and Pascal Winthaegen

Abstract: In this paper an overview of various monitoring techniques for CO₂ storage has been given, structured into three categories: instrumentation in a well (monitoring well); instrumentation at the (near) surface (surface geophysical methods); and sampling at the (near) surface measuring CO₂ concentrations (geochemical sampling techniques). An overview of what these techniques can monitor has been provided in terms of features, events and processes (FEPs). The main categories of FEPs identified in this report are: cap rock integrity (leakage); ground movements (uplift, earthquakes); lateral spreading of the CO₂ plume; and verification of mass balance. For the geophysical methods the physically measurable parameters have been provided and the effects of CO₂ on these parameters are discussed and partially quantified.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(219 Kb)      View   Download

    June, 2005

Vol 2 Chapter 20: Atmospheric CO₂ Monitoring Systems

Patrick Shuler and Yongchun Tang

Abstract: Monitoring for atmospheric CO₂ concentrations may be an integral part of any subsurface storage project. Several CO₂ measurement methods may be used to meet the monitoring objectives of:

1. assuring there are no large leaks at the surface that might pose a health risk and
2. verifying that the injected CO₂ remains trapped below the Earth’s surface.

Options include:

1. remote sensing from satellites or aircraft,
2. open path instruments that can sample over significant distances and
3. a network of conventional fixed-point detectors.

NASA indicates satellite surveys might be useful for a “global” view of CO₂. Aircraft surveys may be a fast means to collect data near ground level, but this is only practical in an infrequent basis. Instruments located near ground level that are based on open path sampling may offer the most efficient means to monitor long term over a large surface area. They could have the capability to detect increases of just a few percent of CO₂ above normal background, over a sample path of tens of meters, and continuously with unattended operation. Many different commercial fixed-point units based on infrared (IR) spectroscopy are available. These detectors may be better suited to monitor sensitive, high-risk points of leakage rather than be deployed in a network to monitor large surface areas. Besides reviewing atmospheric monitoring options, this chapter also quantifies the capability of groundlevel instruments to identify leakages of carbon dioxide from the subsurface. In particular, the objective is to successfully detect the uniform leakage of as little as 1% of the total carbon dioxide injected into the subsurface over 100 years. This analysis suggests the local increased concentration of carbon dioxide into the atmosphere due to such a leak depends greatly on the leakage area, time duration, atmospheric conditions and proximity of the detector to the leak. In some scenarios such a leak would cause an increase of at least tens of ppmv of carbon dioxide in the near-surface atmosphere and likely would be detected by commercially available instruments as being above the natural background variations of carbon dioxide.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(609 Kb)      View   Download

    June, 2005

Vol 2 Chapter 21: Detecting Leaks from Belowground CO₂ Reservoirs Using Eddy Covariance

Natasha L. Miles, Kenneth J. Davis and John C. Wyngaard

Abstract: We describe the eddy covariance method of measuring earth–atmosphere CO₂ exchange, including past applications to measurements of volcanic venting of CO₂. The technique involves continuous atmospheric measurements of both CO₂ mixing ratio and atmospheric winds from a tower platform. Equipment is robust and commercially available, and the methodology is well established. The surface area covered by the measurement is described. The upwind coverage is typically ð10–100Þzm; where zm is the measurement height, and the cross-wind extent of this area is of the order of the upwind distance. Thus, a 10-m high tower detects fluxes from an upwind distance of 100–1000 m, and an area of order 104–106 m2. The eddy covariance method yields continuous measurements of earth–atmosphere exchange over such areas, typically expressed as averages over hourly or half-hourly time periods. The area measured depends on wind speed, wind direction, surface roughness, and stability of the atmospheric surface layer. The measurement works best under well-mixed atmospheric conditions which frequently occur on a daily basis, often for a majority of the day. We assess the ability to detect leaks from geologic CO₂ reservoirs by comparing expected leakage rates to typical ecological flux rates. While the character and magnitude of ecological fluxes are well established, reservoir leakage rates and areas are uncertain. Fairly conservative estimates based on ensuring the economic viability of CO₂ storage are constructed. Our estimates of leakage rate and area yield leakage fluxes that range from 1 to 104 times the magnitude of typical ecological fluxes. The flux measurement areas readily encompass the assumed leakage areas (10–105 m2). We conclude that this approach shows promise for the monitoring of belowground CO₂ storage. Leak detection is shown to be a simpler problem than leak quantification, but both can in principle be accomplished using eddy covariance under conditions favorable for the measurement.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(351 Kb)      View   Download

    June, 2005

Vol 2 Chapter 22: Hyperspectral Geobotanical Remote Sensing for CO₂ Storage Monitoring

William L. Pickles and Wendy A. Cover

Abstract: This project has developed an airborne remote sensing method for detection and mapping of CO₂ that might be leaking up from an underground storage formation. The method uses high-resolution hyperspectral imagery to detect and map the effects of elevated CO₂ soil concentrations on the roots of the local plants. The method also detects subtle or hidden faulting systems which localize the CO₂ pathways to the surface. Elevated CO₂ soil concentrations deprive the plant root systems of oxygen which is essential for a healthy plant. Excessive soil CO₂ concentrations are observed to significantly affect local plant health, and hence plant species distributions. These effects were studied in a previous remote sensing research program at Mammoth Mountain, CA, USA. This earlier research showed that subtle hidden faults can be mapped using the spectral signatures of altered minerals and of plant species and health distributions. Mapping hidden faults is important because these highly localized pathways are the conduits for potentially significant CO₂ leaks from deep underground formations. The detection and discrimination methods we are developing use advanced airborne reflected light hyperspectral imagery. The spatial resolutions are 1–3 m and 128 band to 225 wavelength resolution in the visible and near infrared. We are also using the newly available “Quickbird” satellite imagery that has spatial resolutions of 0.6 m for panchromatic images and 2.4 m for multispectral. These are two commercial providers of the hyperspectral imagery acquisitions, so that eventually the ongoing surveillance of CO₂ storage fields can be contracted for commercially. In this project we had a commercial provider acquire airborne hyperspectral visible and near infrared reflected light imagery of the Rangely, CO enhanced oil recovery field and the surrounding areas in August 2002. The images were analyzed using several of the methods available in the suite of tools in the “ENVI” commercial hyperspectral image processing software to create highly detailed maps of soil types, plant coverages, plant health, local ecologies or habitats, water conditions, and man-made objects throughout the entire Rangely oil field and surrounding areas. The results were verified during a field trip to Rangely, CO in August 2003. These maps establish an environmental and ecological baseline against which any future CO₂ leakage effects on the plants, plant habitats, soils and water conditions can be detected and verified. We have also seen signatures that may be subtle hidden faults. If confirmed these faults might provide pathways for upward CO₂ migration if that occurred at any time during the future.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(2195 Kb)      View   Download

    June, 2005

Vol 2 Chapter 23: Non-seismic Geophysical Approaches to Monitoring

G.M. Hoversten and Erika Gasperikova

Abstract: This chapter considers the application of a number of different geophysical techniques for monitoring geologic storage of CO₂. The relative merits of the seismic, gravity, electromagnetic (EM) and streaming potential (SP) geophysical techniques as monitoring tools are examined. An example of tilt measurements illustrates another potential monitoring technique, although it has not been studied to the extent of other techniques in this chapter. This work does not represent an exhaustive study, but rather demonstrates the capabilities of a number of geophysical techniques on two synthetic modeling scenarios. The first scenario represents combined CO₂ enhance oil recovery (EOR) and storage in a producing oil field, the Schrader Bluff field on the north slope of Alaska, USA. The second scenario is of a pilot DOE CO₂ storage experiment scheduled for summer 2004 in the Frio Brine Formation in South Texas, USA. Numerical flow simulations of the CO₂ injection process for each case were converted to geophysical models using petrophysical models developed from well log data. These coupled flow simulation–geophysical models allow comparison of the performance of monitoring techniques over time on realistic 3D models by generating simulated responses at different times during the CO₂ injection process. These time-lapse measurements are used to produce time-lapse changes in geophysical measurements that can be related to the movement of CO₂ within the injection interval. The time-lapse performance of seismic, gravity, and EM techniques are considered for the Schrader Bluff model. Surface gravity, surface tilt and SP measurements are considered for the Frio brine formation model. These two models represent end members of a complex spectrum of possible storage scenarios. EOR/storage projects in general and Schrader Bluff in particular represent relatively thin injection intervals with multiple fluid components (oil, hydrocarbon gas, brine, and CO₂) while brine formations such as the Frio will usually have much thicker injection intervals and only two component (brine and CO₂) systems.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(2770 Kb)      View   Download

    June, 2005

Vol 2 Chapter 24: The Use of Noble Gas Isotopes for Monitoring Leakage of Geologically Stored CO₂

Gregory J. Nimz and G. Bryant Hudson

Abstract: One of the primary concerns in CO₂ storage is monitoring the storage site on a long-term basis for possible leakage of CO₂. Concentrations of CO₂ vary widely in the Earth’s crust, making detection of very small releases difficult. Small amounts of noble gas isotopes can be dissolved into the CO₂ being injected for storage and used as tracers to monitor CO₂ movement. Noble gases are chemically inert, environmentally safe, and are persistent and stable in the environment. The unique isotopic compositions that can be imparted to the CO₂ can be unambiguously identified during monitoring. Among the noble gases, xenon isotopes have commercial costs and availability suitable for use in large CO₂ storage operations. Required xenon volumes are low, simplifying handling and injection. Multiple batches of injected CO₂ at the same site could be imparted with different xenon isotopic compositions, making each of them identifiable with only a single xenon analysis. These characteristics are believed to make xenon a superior tracer to other option, SF6 and 14 CO₂ . A case study in noble gas tracing at the Mabee Enhanced Oil Recovery field in West Texas indicates that unique noble gas isotopic compositions within a CO₂ injection stream can be detected and readily identified in outlying wells, and that noble gas behavior in a CO₂ storage setting will be systematic and predictable.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(393 Kb)      View   Download

    June, 2005

Vol 2 Chapter 25: Lessons Learned from Industrial and Natural Analogs for Health, Safety and Environmental Risk Assessment for Geologic Storage of Carbon Dioxide

Sally M. Benson

Abstract: This literature survey was conducted to gather and interpret information regarding potential approaches for assessing, managing and mitigating risks associated with the deep geologic storage of CO₂. Information was gathered from three principle sources:

1. industrial analogs such as natural gas storage, deep injection of hazardous wastes and nuclear waste storage and
2. natural analogs, especially those with CO₂ leaks at the surface and
3. industrial uses of CO₂ for a variety of applications.

A set of lessons learned from these analogs was compiled and forms the basis for recommendations in the areas of risk assessment framework and methodology, risk management approaches and risk mitigation and remediation methods.

Lessons learned include:

1. There is an abundant base of experience to draw on that is relevant and suggests that CO₂ can be stored safely if geologic storage sites are carefully selected and monitored.
2. The human health effects of exposure to elevated concentrations of CO₂ have been extensively studied and occupational safety regulations are in place for safe use. Ecosystem impacts from elevated soil gas concentrations are less well characterized and may require additional research.
3. The hazard created by CO₂ releases depends more on the nature of the release rather than the size of the release. In particular, since CO₂ is denser than air, hazardous situations arise when large amounts of CO₂ accumulate in low-lying, confined or poorly ventilated spaces. Releases, even large ones, do not pose a hazard if they are quickly dissipated in the atmosphere, such as from tall industrial stacks or explosive volcanic events.
4. Many of the risks of CO₂ storage are well understood based on experience from natural gas storage and deep injection of hazardous waste. Experience from these analogs suggest that the biggest risks from CO₂ storage will be due to:
   • leakage through poor quality or aging injection well completions;
   • leakage up abandoned wells;
   • leakage due to inadequate cap rock characterization;
   • and inconsistent or inadequate monitoring of injection wells, groundwater in overlying formations and leakage from abandoned wells.
5. Regulatory paradigms and approaches for the industrial analogs vary and none address all the issues that are important for CO₂ storage.

This chapter reviews the lessons learned and also provides recommendations for additional research to address gaps in knowledge and risk management approaches.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(121 Kb)      View   Download

    June, 2005

Vol 2 Chapter 26: Human Health and Ecological Effects of Carbon Dioxide Exposure

Robert P. Hepple

Abstract: Understanding of human health and ecosystem impacts from exposure to elevated concentrations of CO₂ in air, soils and water is needed to assess the consequences of leakage from geologic storage projects. This chapter places CO₂ storage in the context of the global carbon cycle, reviews information on human health effects and ecosystem impacts from exposure to high concentrations of CO₂, and reviews industrial uses of CO₂ and describes the regulations put in place to protect workers and the public. This information provides the foundation for understanding and assessing risks of leakage from geological storage projects.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(840 Kb)      View   Download

    June, 2005

Vol 2 Chapter 27: The Regulatory Climate Governing the Disposal of Liquid Wastes in Deep Geological Formations: A Paradigm for Regulations for the Subsurface Storage of CO₂

John A. Apps

Abstract: Federal and state regulations covering the deep injection disposal of liquid waste have evolved over the last 30 years in response to legislation designed to protect underground sources of drinking water (USDW). These regulations apply to so-called Class I wells, and address issues relating to the confinement of hazardous and nonhazardous wastes below the lowermost USDW. They have been made progressively more stringent with time, and are now quite effective in protecting USDWs. The deep injection disposal of compressed carbon dioxide (CO₂) into similar environments will undoubtedly require similar regulation. Accordingly, the history relating to the development of legislation to protect groundwater supplies, and resulting regulations is reviewed and conclusions drawn regarding the extent to which these regulations might eventually be applied to CO₂ injection.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(586 Kb)      View   Download

    June, 2005

Vol 2 Chapter 28: Prospects for Early Detection and Options for Remediation of Leakage from CO₂ Storage Projects

Sally Benson and Robert Hepple

Abstract: Geologic storage projects of CO₂ should be designed to maintain secure storage thousands of years or longer. However, in some cases, leakage may occur and remediation measures, either to stop the leak or to prevent human or ecosystem impacts will be needed. Moreover, the availability of remediation options will reassure the public that geologic storage can be safe and effective and help build confidence in carbon capture and storage. This study reviews the remediation options available for many of the types of leakage that may occur based on analogous situations in natural gas storage, oil and gas production, groundwater remediation, and soil gas and vadose zone cleanup. Remediation options are discussed for damaged injection wells, leaking abandoned wells, over pressured reservoirs, carbon dioxide accumulations in shallow groundwater, secondary contamination of groundwater by acidification, vadose zone and soil gas accumulations, and surface releases. Examples of remediation options for buildings and surface water are also discussed. This study demonstrates that remediation options are available for many of the leakage scenarios that can be envisioned.

Carbon Dioxide Capture for Storage in Deep Geologic Formations – Results from the CO₂ Capture Project Geologic Storage of Carbon Dioxide with Monitoring and Verification - Volume 2
Edited by: Sally M. Benson, Lawrence Berkeley Laboratory, Berkeley, CA, USA

(429 Kb)      View   Download

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