Earth Sciences Division Berkeley Lab
Climate Change and Carbon Management Program
Research Summaries 2004-2005
SCREENING AND RANKING FRAMEWORK FOR GEOLOGIC CO2 STORAGE Curtis M. Oldenburg Contact: Curtis M. Oldenburg, 510/486-7419, cmoldenburg@lbl.gov
RESEARCH OBJECTIVES
Attribute Assessment
The injection of CO2 into deep geologic formations for geologproperties for all of the other attributes are listed in the spreadic CO2 storage involves the risk that CO2 will leak from the target sheet. The user simply assigns numerical values to these attributes, based on suggestions in the spreadsheet. In addition, the formation to the near-surface environment. Once in the near-surcause detrienvironment, CO user must assign weights and uncertainface 2 can Excellent 2.00 ties to the properties, which are carried mental health, safety, and environmental Prim. Cont. along to the final display. The results are (HSE) effects. One consideration in the 1.00 Sec. Cont. summarized and displayed graphically selection of geologic CO2 storage sites is Atten. Pd. in the summary worksheet, one graphic the minimization of potential HSE risks. Average 0.00 Poor from which is shown in Figure 1. The objective of this work is to develop a Good -1.00 screening and ranking framework (SRF) ACCOMPLISHMENTS to evaluate the relative risk that CO2 will -2.00 Poor An HSE screening and ranking leak to the near-surface environment 0.00 0.50 1.00 1.50 2.00 framework has been developed, based and cause HSE effects. The SRF is Uncertain Certainty Well known on the three fundamental characterisdesigned so that it can be applied to sites Figure 1. Summary graphic showing the attribute tics of a CO2 sequestration site. The with limited data as appropriate for pilot assessment (y-axis) and uncertainty (x-axis) of the system allows the user to arbitrarily studies. The expected users of the SRF three fundamental characteristics along with qualitaweight and assign uncertainty to the are geoscientists or hydrologists with tive regions of “poor,” “fair,” and “good” HSE risk for the Rio Vista gas field properties associated with the attribaccess to limited published information utes of the fundamental characteristics, about the site in reference books or to evaluate and rank two or more sites relative to each other. maps. In short, the framework is designed to answer the question, We emphasize that the SRF tool is intended to guide the selec“From a choice of several potential sites, which site has the lowtion of the most promising sites, for which more detailed risk est HSE risk?” assessment would be carried out. Testing and further developAPPROACH ment of the SR framework are under way. The approach stems from the realization that HSE risk is SIGNIFICANCE OF FINDINGS related to three fundamental characteristics of a geologic carThe SRF shows that comparative evaluations of prospective bon storage site: sites with limited characterization data can be accomplished, 1. Potential of the target formation for long-term containand that the ranking offers a way of screening sites based on ment of CO2 2. Potential for secondary containment, should the primary potential for CO2 leakage and seepage, as well as related HSE target site leak risk. 3. Potential of the site to attenuate and/or disperse leaking RELATED PUBLICATION CO2, should the primary formation leak and secondary Oldenburg, C.M., HSE screening risk assessment (SRA) for containment fail geologic CO2 sequestration. Fourth Annual Conference on The SRF tool is designed to provide a qualitative and indeCarbon Capture and Sequestration, Alexandria, Virginia, pendent assessment of each of these three characteristics, through May 2–5, 2005. Berkeley Lab Report LBNL-57280. a numerical evaluation of properties/values associated with varACKNOWLEDGMENTS ious attributes of the three general characteristics. For example, This work was supported in part by WESTCARB through the three attributes of the potential for the target formation to contain Assistant Secretary for Fossil Energy, Office of Coal and Power CO2 for long periods are (1) the nature of the primary seal, (2) the depth of the reservoir, and (3) the properties of the reservoir. The Systems, through the National Energy Technologies Laboratory properties of the primary seal attribute are thickness, lithology, (NETL), and Lawrence Berkeley National Laboratory, under demonstrated sealing capacity, and lateral continuity. Similar Department of Energy Contract No. DE-AC03-76SF00098.
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