Permeability of wellbore-cement fractures following degradation by carbonated brine

Stuart D.C. Walsh, Wyatt L. Du Frane, Harris E. Mason, Susan A. Carroll

Research output: Contribution to journalArticleResearchpeer-review

55 Citations (Scopus)

Abstract

Fractures in wellbore cement and along wellbore-cement/host-rock interfaces have been identified as potential leakage pathways from long-term carbon sequestration sites. When exposed to carbon-dioxide-rich brines, the alkaline cement undergoes a series of reactions that form distinctive fronts adjacent to the cement surface. However, quantifying the effect of these reactions on fracture permeability is not solely a question of geochemistry, as the reaction zones also change the cement's mechanical properties, modifying the fracture geometry as a result. This paper describes how these geochemical and geomechanical processes affect fracture permeability in wellbore cement. These competing influences are discussed in light of data from a core-flood experiment conducted under carbon sequestration conditions: reaction chemistry, fracture permeability evolution over time, and comparative analysis of X-ray tomography of unreacted and reacted cement samples. These results are also compared to predictions by a complementary numerical study that couples geochemical, geomechanical and hydrodynamic simulations to model the formation of reaction fronts within the cement and their effect on fracture permeability.

Original languageEnglish
Pages (from-to)455-464
Number of pages10
JournalRock Mechanics and Rock Engineering
Volume46
Issue number3
DOIs
Publication statusPublished - 1 May 2013
Externally publishedYes

Keywords

  • Carbon sequestration
  • Chemo-mechanical coupling
  • Fracture flow and transport
  • Wellbore integrity

Cite this