Numerical Modeling Studies of The Dissolution-Diffusion-Convection ProcessDuring CO2 Storage in Saline Aquifers Metadata

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Title

  • Main Title Numerical Modeling Studies of The Dissolution-Diffusion-Convection ProcessDuring CO2 Storage in Saline Aquifers

Creator

  • Author: Pruess, Karsten
    Creator Type: Personal
  • Author: Zhang, Keni
    Creator Type: Personal

Contributor

  • Sponsor: Lawrence Berkeley National Laboratory. Earth Sciences Division.
    Contributor Type: Organization

Publisher

  • Name: Lawrence Berkeley National Laboratory
    Place of Publication: Berkeley, California
    Additional Info: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

Date

  • Creation: 2008-11-17

Language

  • English

Description

  • Content Description: For purposes of geologic storage, CO2 would be injected into saline formations at supercritical temperature and pressure conditions, and would form a separate phase that is immiscible with the aqueous phase (brine). At typical subsurface temperature and pressure conditions, supercritical CO2 (scCO2) has lower density than the aqueous phase and would experience an upward buoyancy force. Accordingly, the CO2 is expected to accumulate beneath the caprock at the top of the permeable interval, and could escape from the storage formation wherever (sub-)vertical pathways are available, such as fractures or faults through the caprock, or improperly abandoned wells. Over time, an increasing fraction of CO2 may dissolve in the aqueous phase, and eventually some of the aqueous CO2 may react with rock minerals to form poorly soluble carbonates. Dissolution into the aqueous phase and eventual sequestration as carbonates are highly desirable processes as they would increase permanence and security of storage. Dissolution of CO2 will establish phase equilibrium locally between the overlying CO2 plume and the aqueous phase beneath. If the aqueous phase were immobile, CO2 dissolution would be limited by the rate at which molecular diffusion can remove dissolved CO2 from the interface between CO2-rich and aqueous phases. This is a slow process. However, dissolution of CO2 is accompanied by a small increase in the density of the aqueous phase, creating a negative buoyancy force that can give rise to downward convection of CO2-rich brine, which in turn can greatly accelerate CO2 dissolution. This study explores the process of dissolution-diffusion-convection (DDC), using high-resolution numerical simulation. We find that geometric features of convection patterns are very sensitive to small changes in problem specifications, reflecting self-enhancing feedbacks and the chaotic nature of the process. Total CO2 dissolution rates on the other hand are found to be quite robust against modest changes in problem parameters, and are essentially constant as long as no dissolved CO2 reaches the lower boundary of the system.

Subject

  • Keyword: Diffusion
  • STI Subject Categories: 58
  • STI Subject Categories: 54
  • Keyword: Abandoned Wells
  • Keyword: Dissolution
  • Keyword: Simulation
  • Keyword: Storage
  • Keyword: Fractures
  • Keyword: Carbonates
  • Keyword: Plumes
  • Keyword: Convection
  • Keyword: Specifications
  • Keyword: Security
  • Keyword: Aquifers

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Report

Format

  • Text

Identifier

  • Report No.: LBNL-1243E
  • Grant Number: DE-AC02-05CH11231
  • DOI: 10.2172/944124
  • Office of Scientific & Technical Information Report Number: 944124
  • Archival Resource Key: ark:/67531/metadc898341