TY - THES

T1 - Improved Research Technique on the Influence of CO2 on Wellbore Cement under Downhole Conditions

AU - Plessing, Elias

N1 - no embargo

PY - 2024

Y1 - 2024

N2 - Carbon Capture and Storage (CCS) is essential for achieving carbon neutrality, especially in hard-to-decarbonize industries. One of the main challenges in CCS is ensuring that CO2 is permanently contained in geological storage sites. Cement is crucial for sealing the wellbore and preventing leaks. To evaluate durability of cement against CO2, traditional tests like API Specification RP 10 are used, which test cement in pressurized conditions and analyze its properties after exposure. However, these methods have their limits and new ways of testing are to be developed for more realistic results. This thesis consists of two parts. One is about the development of a new permeability testing setup to monitor the changes in permeability and strength of different types of cement that have been exposed to super-critical CO2 for 2 weeks, 4 weeks or not at all. The changes were significant and widely depending on what type of cement was used. The second part deals with the improvement of an experimental setup that has been developed to advance the evaluation of the interaction of cement with CO2. In this setup, cement slurry is placed in an annulus between a rock cylinder and metal. It is then exposed to CO2 radially through the rock. In this method a CT scanner is used to monitor the carbonation front in real-time. It measures CO2 consumption and makes it possible to implement new sensors such as ultrasonic. Furthermore, it provides immediate insights into cement integrity and the interactions between cement and CO2, thus enhancing the security of CO2 storage in CCS applications.

AB - Carbon Capture and Storage (CCS) is essential for achieving carbon neutrality, especially in hard-to-decarbonize industries. One of the main challenges in CCS is ensuring that CO2 is permanently contained in geological storage sites. Cement is crucial for sealing the wellbore and preventing leaks. To evaluate durability of cement against CO2, traditional tests like API Specification RP 10 are used, which test cement in pressurized conditions and analyze its properties after exposure. However, these methods have their limits and new ways of testing are to be developed for more realistic results. This thesis consists of two parts. One is about the development of a new permeability testing setup to monitor the changes in permeability and strength of different types of cement that have been exposed to super-critical CO2 for 2 weeks, 4 weeks or not at all. The changes were significant and widely depending on what type of cement was used. The second part deals with the improvement of an experimental setup that has been developed to advance the evaluation of the interaction of cement with CO2. In this setup, cement slurry is placed in an annulus between a rock cylinder and metal. It is then exposed to CO2 radially through the rock. In this method a CT scanner is used to monitor the carbonation front in real-time. It measures CO2 consumption and makes it possible to implement new sensors such as ultrasonic. Furthermore, it provides immediate insights into cement integrity and the interactions between cement and CO2, thus enhancing the security of CO2 storage in CCS applications.

KW - CO2

KW - Carbon Dioxide

KW - Cement

KW - Carbon Capture and Storage

KW - CCS

KW - CCUS

KW - Well Integrity

KW - CO2

KW - Zement

KW - Durchlässigkeit

KW - CO2 Stabilität

KW - CO2 Speicherung

KW - CO2 Reaktion mit Zement

M3 - Master's Thesis

ER -