Earth and Environmental Sciences Area Logo Earth and Environmental Sciences Area Logo
Lawrence Berkeley National Laboratory Logo
Menu
  • About Us
    • Contact Us
    • Organizational Charts
    • Virtual Tours
    • EESA Strategic Vision
  • Our People
    • A-Z People
    • Alumni Network
    • Area Offices
    • Committees
    • Directors
    • IDEA Working Group
    • Paul A. Witherspoon
    • Postdocs & Early Careers
    • Search by Expertise
  • Careers & Opportunities
    • Careers
    • Intern Pilot w/CSUEB
    • Mentorship Program
    • Recognition & Funding Opps
    • EESA Mini Grants
    • S&E Metrics for Performance and Promotion
    • Student Opportunities
    • Supervisor EnRichment (SupER) Program
    • Promotion Metrics (Scientific)
  • Research
    • Our Divisions
    • Climate & Ecosystem Sciences Division
      • Environmental & Biological Systems Science
        • Programs
        • Environmental Remediation & Water Resources
        • Ecosystems Biology Program
        • Bioenergy
      • Biosphere-Atmosphere Interactions
        • Programs
        • Climate Modeling
        • Atmospheric System Research
        • Terrestrial Ecosystem Science
      • Climate & Atmosphere Processes
        • Programs
        • Climate Modeling
        • Atmospheric System Research
      • Earth Systems & Society
        • Programs
        • Climate Modeling
    • Energy Geosciences Division
      • Discovery Geosciences
        • Programs
        • Basic Energy Sciences (BES) Geophysics
        • Basic Energy Sciences (BES) Geochemistry
        • Basic Energy Sciences (BES) Isotope
      • Energy Resources
        • Programs
        • Geologic Carbon Sequestration
        • Hydrocarbon Resources
        • Geothermal Systems
        • Nuclear Energy & Waste
      • Resilient Energy, Water & Infrastructure
        • Programs
        • Water-Energy
        • Critical Infrastructure
        • Environmental Resilience
        • Grid-Scale Subsurface Energy Storage
    • Projects
    • Research at a Glance
    • Publication Lists
    • Centers and Resources
    • Technologies & National User Programs
  • Departments
    • Climate Sciences
    • Ecology
    • Geochemistry
    • Geophysics
    • Hydrogeology
    • Operations
  • News & Events
    • News
    • Events
    • Earth & Environment Newsletter
  • Intranet
  • COVID & Safety
    • EESA Safety
    • EESA COVID-19
  • Search

  • all
  • people
  • events
  • posts
  • pages
  • projects
  • publications

Laboratory and Numerical Simulation Studies of Convectively Enhanced Carbon Dioxide Dissolution3 min read

by ESD News and Events on February 22, 2011

Geologic Carbon Sequestration Program Hydrogeology Department Research Highlight

Timothy J. Kneafsey and Karsten Pruess

As a possible means of reducing CO2 emissions into the atmosphere, ESD’s Timothy J. Kneafsey and Karsten Pruess have recently studied the injection of carbon dioxide (CO2) into deep saline aquifers and the benefits of enhanced CO2 dissolution into the local brine. The method involves CO2 being injected into a permeable, porous zone confined beneath a low-permeability cap rock, so that the CO2 would remain in the aquifer for an extended period of time. Injected CO2 would be in a supercritical state (scCO2) and have lower density than the local existing brine; consequently, it would tend to rise to the top of the permeable interval and spread beneath the cap rock. After CO2 is injected into the subsurface, it would either (1) exist in a mobile, separate, supercritical phase; (2) manifest itself as trapped scCO2; (3) be dissolved in the host brine; or (4) be precipitated as solid minerals. The storage security and permanence increase as CO2 is trapped, then dissolved, and then eventually chemically bound to solid phases, but the expected time scale of each of these modes increase sequentially as well. Any enhancement of the rate or magnitude of processes increasing security or permanence would be desirable.

Injected CO2 will tend to spread under a confining cap rock, and at some distance from the injection well, there would likely be a nearly horizontal interface between a free CO2 phase above and the aqueous phase below. At the CO2/water interface, CO2 will dissolve into the aqueous phase, and if the aqueous phase were immobile, the rate of CO2 dissolution would be limited by the rate at which CO2 could be removed from the interface by molecular diffusion. This process is slow, and the rate of CO2 dissolution would decrease with time.

CO2 dissolution into brine causes the brine density to increase on the order of 0.1% to 1%, depending on pressure, temperature, and salinity. This causes denser CO2-rich brine to overlie the less dense local brine, inducing a gravitational instability. This instability can result in fluid convection, which could significantly increase the rate at which dissolved CO2 is transferred from the interface with the overlying free CO2, accelerating CO2 dissolution. Kneafsey and Pruess have performed visualization and quantitative laboratory tests and numerical modelling to study this phenomenon.

In these laboratory visualization tests, CO2 gas is introduced above the brine contained between two sheets of glass. The space between the sheets of glass is an analogue for the pore space within the reservoir in which the CO2 would be emplaced. The brine contains water and a pH sensitive dye, sensing the CO2 reaction with the water that forms an acidic solution. Initially, a diffusive front develops at the CO2/water interface. This denser brine becomes unstable and forms fingers, which penetrate deeply into the cell, causing fresh brine to flow to the surface and enhancing CO2 dissolution (Figure 1).

Kneafsey and Pruess have compared their experimental results to a numerical model using TOUGH2 and found good agreement (Figure 2). They are now looking at enhanced CO2 dissolution in heterogeneous systems using both visualization and quantitative measurements, under conditions that are similar to natural reservoirs—to better understand this dissolution process. These measurements, when extended using numerical simulation, will be used to estimate how enhanced CO2 dissolution resulting from density driven convection will affect geologic CO2 sequestration at the field scale.

Kneafsey_fig1

Figure 1. Experimental setup and the effects of CO2 dissolution and density-driven convective at 1 minute, 35 minutes, and 68 minutes (clockwise from top left).

Kneafsey_fig2

Figure 2. Comparison between density-driven convection in the modeled system (left) and experimental system (right).


News & Events

EGD Postdoc Fellow Receives Young Researcher Presenter Award1 min read

January 21, 2021

Pramod Bhuvankar, an EGD postdoctoral fellow working with research scientist Abdullah Cihan, received a Young Researcher Presenter Award during the 2020 Computational Methods in Water Resources conference in December. His presentation, “Pore-scale simulations of permeability decline in porous media due to fines migration,” described a pore-scale CFD study of clay mobilization in porous media due…

Berkeley Lab Partners with International Collaborators in Geothermal Energy Research1 min read

January 20, 2021

  Scientists from the Energy Geosciences Division have begun working with European partners on three new geothermal research projects through the Department of Energy’s membership in GEOTHERMICA, a transnational consortium that combines the in-country financial resources and research expertise of 15 participating countries to demonstrate and validate novel concepts in geothermal energy use. This marks the…

EESA Senior Scientist Talks Earthquake Building Resilience1 min read

Berkeley Lab senior scientist David McCallen leads a subproject called Earthquake Sim, or EQSIM, for the DOE’s Energy Exascale Computing Project. He is also professor and director of the Center for Civil Engineering Earthquake Research in the Department of Civil and Environmental Engineering at the University of Nevada, Reno. McCallen recently spoke with Scott Gibson of…

EESA Scientist Coauthors New Comprehensive Guide on Removing CO2 from the Atmosphere2 min read

January 18, 2021

Berkeley Lab researchers are working on ways to sequester more carbon in soil, including through agricultural practices. (Credit: Berkeley Lab) Scientists say that any serious plan to address climate change should include carbon dioxide removal (CDR) technologies and policies, which makes the newly launched CDR Primer an especially vital resource, says Berkeley Lab scientist Margaret Torn, one…

  • Our People
    • Area Offices
    • Committees
    • Directors
    • Organizational Charts
    • Postdocs
    • Staff Only
    • Search by Expertise
  • Departments
    • Climate Sciences
    • Ecology
    • Geochemistry
    • Geophysics
    • Hydrogeology
  • Research
    • Climate & Ecosystem Sciences Division
    • Energy Geosciences Division
    • Program Domains
      • Programs
    • Projects
  • Contact
    • 510 486 6455
    • [email protected]
    • Our Identity

Earth and Environmental Sciences Area Logo DOE Earth and Environmental Sciences Area Logo UC

A U.S. Department of Energy National Laboratory Managed by the University of California

Lawrence Berkeley National Laboratory · Earth and Environmental Sciences Area · Privacy & Security Notice