An investigation into CO2-brine-cement-caprock interactions for wellbore integrity in CO2 geological storage

Amir Jahanbakhsh, Montserrat Recasens, Nazia Mubeen Farooqui, M. Mercedes Maroto-Valer, Mojgan Hadi Mosleh, Harshit Agrawal, Anna Korre, Sevket Durucan

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Abstract

Geological storage in saline aquifers and depleted oil and gas reservoirs can help mitigate CO2 emissions. However, CO2 leakage over a long period remains a major concern. Poorly cemented borehole and cement degradation after CO2 injection can provide pathways for CO2 leakage to groundwater and the atmosphere. Accordingly, it is critical to thoroughly understand the interactions between CO2-brine and cement caprock/reservoir rock to assess the possible risk of CO2 leakage. In this work, we performed a series of experiments simulating deep wellbore environments in order to investigate the alteration of chemical,
physical and mechanical properties of cement and rock. Here, we present the characterisation of composite cement-caprock core samples, including porosity, permeability and mechanical properties measured before and after exposure to CO2-brine. Some of the composite samples were further analysed by micro CT, XRD and SEM-EDX. Moreover, the variation of ions concentration in brine at different time-scales was studied by performing ICP-OES analysis. It was observed that dissolution and precipitation of some minerals started from early stage of exposure and continued as time passed, and, as a result, cement and cement-caprock interface were affected.
Original languageEnglish
Publication statusPublished - 2018
Event14th International Conference on Greenhouse Gas Control Technologies 2018 - Melbourne, Australia
Duration: 21 Oct 201826 Oct 2018

Conference

Conference14th International Conference on Greenhouse Gas Control Technologies 2018
Abbreviated titleGHGT-14
Country/TerritoryAustralia
CityMelbourne
Period21/10/1826/10/18

Keywords

  • CO2
  • Cement
  • caprock
  • wellbore integrity
  • CCS
  • Geological sequestration

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