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Title: Numerical studies of CO 2 and brine leakage into a shallow aquifer through an open wellbore

Abstract

Industrial-scale geological storage of CO 2 in saline aquifers may cause CO 2 and brine leakage from abandoned wells into shallow fresh aquifers. This leakage problem involves the flow dynamics in both the wellbore and the storage reservoir. T2Well/ECO2N, a coupled wellbore-reservoir flow simulator, was used to analyze CO 2 and brine leakage under different conditions with a hypothetical simulation model in water-CO 2-brine systems. Parametric studies on CO 2 and brine leakage, including the salinity, excess pore pressure (EPP) and initially dissolved CO 2 mass fraction, are conducted to understand the mechanism of CO 2 migration. The results show that brine leakage rates increase proportionally with EPP and inversely with the salinity when EPP varies from 0.5 to 1.5 MPa; however, there is no CO 2 leakage into the shallow freshwater aquifer if EPP is less than 0.5 MPa. The dissolved CO 2 mass fraction shows an important influence on the CO 2 plume, as part of the dissolved CO 2 becomes a free phase. Scenario simulation shows that the gas lifting effect will significantly increase the brine leakage rate into the shallow freshwater aquifer under the scenario of 3.89% dissolved CO 2 mass fraction. The equivalent porous media (EPM) approachmore » used to model the wellbore flow has been evaluated and results show that the EPM approach could either under- or over-estimate brine leakage rates under most scenarios. The discrepancies become more significant if a free CO 2 phase evolves. Therefore, a model that can correctly describe the complex flow dynamics in the wellbore is necessary for investigating the leakage problems.« less

Authors:
 [1];  [1];  [2];  [2]
  1. Beijing Normal Univ., Beijing (China). College of Water Sciences, Engineering Research Center of Groundwater Pollution Control and Remediation of Ministry of Education
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Energy Geosciences Division
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1476630
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Hydrogeology Journal
Additional Journal Information:
Journal Volume: 26; Journal Issue: 2; Journal ID: ISSN 1431-2174
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES

Citation Formats

Wang, Jingrui, Hu, Litang, Pan, Lehua, and Zhang, Keni. Numerical studies of CO2 and brine leakage into a shallow aquifer through an open wellbore. United States: N. p., 2017. Web. doi:10.1007/s10040-017-1685-y.
Wang, Jingrui, Hu, Litang, Pan, Lehua, & Zhang, Keni. Numerical studies of CO2 and brine leakage into a shallow aquifer through an open wellbore. United States. doi:10.1007/s10040-017-1685-y.
Wang, Jingrui, Hu, Litang, Pan, Lehua, and Zhang, Keni. Thu . "Numerical studies of CO2 and brine leakage into a shallow aquifer through an open wellbore". United States. doi:10.1007/s10040-017-1685-y. https://www.osti.gov/servlets/purl/1476630.
@article{osti_1476630,
title = {Numerical studies of CO2 and brine leakage into a shallow aquifer through an open wellbore},
author = {Wang, Jingrui and Hu, Litang and Pan, Lehua and Zhang, Keni},
abstractNote = {Industrial-scale geological storage of CO2 in saline aquifers may cause CO2 and brine leakage from abandoned wells into shallow fresh aquifers. This leakage problem involves the flow dynamics in both the wellbore and the storage reservoir. T2Well/ECO2N, a coupled wellbore-reservoir flow simulator, was used to analyze CO2 and brine leakage under different conditions with a hypothetical simulation model in water-CO2-brine systems. Parametric studies on CO2 and brine leakage, including the salinity, excess pore pressure (EPP) and initially dissolved CO2 mass fraction, are conducted to understand the mechanism of CO2 migration. The results show that brine leakage rates increase proportionally with EPP and inversely with the salinity when EPP varies from 0.5 to 1.5 MPa; however, there is no CO2 leakage into the shallow freshwater aquifer if EPP is less than 0.5 MPa. The dissolved CO2 mass fraction shows an important influence on the CO2 plume, as part of the dissolved CO2 becomes a free phase. Scenario simulation shows that the gas lifting effect will significantly increase the brine leakage rate into the shallow freshwater aquifer under the scenario of 3.89% dissolved CO2 mass fraction. The equivalent porous media (EPM) approach used to model the wellbore flow has been evaluated and results show that the EPM approach could either under- or over-estimate brine leakage rates under most scenarios. The discrepancies become more significant if a free CO2 phase evolves. Therefore, a model that can correctly describe the complex flow dynamics in the wellbore is necessary for investigating the leakage problems.},
doi = {10.1007/s10040-017-1685-y},
journal = {Hydrogeology Journal},
issn = {1431-2174},
number = 2,
volume = 26,
place = {United States},
year = {2017},
month = {11}
}

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