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Title: On leakage and seepage from geological carbon sequestration sites

Abstract

Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO{sub 2} ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO{sub 2} 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 CO{sub 2} will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO{sub 2} rises until trapped by a confining caprock; (2) solubility trapping, for example when CO{sub 2} dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO{sub 2} reacts to produce stable carbonate minerals. When CO{sub 2} 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 CO{sub 2} seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant propertiesmore » of CO{sub 2} 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 CO{sub 2} 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 CO{sub 2} concentrations that will arise from variations in fundamental hydrogeological properties.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Assistant Secretary for Fossil Energy (US)
OSTI Identifier:
806116
Report Number(s):
LBNL-51130
R&D Project: 80TE02; TRN: US200303%%549
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 18 Jul 2002
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 58 GEOSCIENCES; BRINES; CARBON; CARBON DIOXIDE; CARBONATE MINERALS; NATURAL GAS; PERMEABILITY; POTENTIALS; SENSITIVITY; SIMULATION; SOLUBILITY; TRANSPORT; TRAPPING; GREENHOUSE GASES

Citation Formats

Oldenburg, C.M., Unger, A.J.A., Hepple, R.P., and Jordan, P.D. On leakage and seepage from geological carbon sequestration sites. United States: N. p., 2002. Web. doi:10.2172/806116.
Oldenburg, C.M., Unger, A.J.A., Hepple, R.P., & Jordan, P.D. On leakage and seepage from geological carbon sequestration sites. United States. doi:10.2172/806116.
Oldenburg, C.M., Unger, A.J.A., Hepple, R.P., and Jordan, P.D. Thu . "On leakage and seepage from geological carbon sequestration sites". United States. doi:10.2172/806116. https://www.osti.gov/servlets/purl/806116.
@article{osti_806116,
title = {On leakage and seepage from geological carbon sequestration sites},
author = {Oldenburg, C.M. and Unger, A.J.A. and Hepple, R.P. and Jordan, P.D.},
abstractNote = {Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO{sub 2} ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO{sub 2} 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 CO{sub 2} will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO{sub 2} rises until trapped by a confining caprock; (2) solubility trapping, for example when CO{sub 2} dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO{sub 2} reacts to produce stable carbonate minerals. When CO{sub 2} 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 CO{sub 2} seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant properties of CO{sub 2} 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 CO{sub 2} 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 CO{sub 2} concentrations that will arise from variations in fundamental hydrogeological properties.},
doi = {10.2172/806116},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {7}
}