Real-Time Monitoring of the Effect of Carbon Dioxide on the Cement Sheath

Paul Wagner

Research output: ThesisMaster's Thesis

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Abstract

Global warming is one of the most significant issues the world is facing. Capturing carbon dioxide from the atmosphere or industrial processes and storing it in geological formations can help counteract climate change. Nevertheless, the interaction between well barrier elements such as cement, casing, tubulars, packers, and valves can lead to possible leakages. To accomplish successful carbon dioxide sequestration, injecting the carbon dioxide in its supercritical state is necessary. The supercritical carbon dioxide can corrode steel and elastomers and react with the calcium compounds in the cement, dissolving them and forming calcium carbonate and bicarbonate in the process. This carbonation can lead to channels forming on the cement-to-rock interface or cracking due to the carbonate precipitation, resulting in a loss of well integrity. This study focusses on finding ways that enable the continuous monitoring of well integrity under in-situ conditions. The construction of an autoclave, capable of withstanding supercritical conditions of carbon dioxide, facilitates the in-situ monitoring. This autoclave also makes CT-scans of the pressurized sample possible, as well as acoustic measurements, using state-of-the-art piezo elements. The first tests will establish a baseline using neat Class G Portland cement to verify the design and sensors. The set up consists of a rock core in the middle of the autoclave cell surrounded by a cement sheath. Drilling a channel in the middle of the core expedites the distribution of the carbon dioxide. Once the ability of the sensors to monitor the integrity is verified, different cement compositions and their interaction with supercritical carbon dioxide can be studied. The experimental setup and the procedure discussed here closely simulate the downhole condition. Hence, the results obtained using this setup and procedure is representative of what could be observed downhole. The direction is not to remove the sample from the cell and analyze it under in-situ conditions. Digitalization is powering the in-situ analysis in this experiment. After the carbonation, samples from the autoclave undergo a thorough chemical and physical analysis. The correlation of the data from the sensors and chemical analysis aids in further developing real-time monitoring. The results from this study can lead to the prevention of leakage of carbon dioxide to the environment and other formations, which defeats the purpose of carbon dioxide sequestration. These results should improve the economics of these wells as well as the health, safety, and environmental aspects.
Translated title of the contributionEchtzeitüberwachung des Einflusses von Kohlendioxid auf den Zementmantel
Original languageEnglish
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Ravi, Krishna, Supervisor (internal)
Award date22 Sept 2020
Publication statusPublished - 2020

Bibliographical note

embargoed until null

Keywords

  • Cement
  • Carbonation
  • Real-Time Monitoring
  • Well Integrity
  • Carbon Capture and Storage

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