In the quest to mitigate climate change, carbon capture, utilization, and storage (CCUS) has emerged as a critical technology. However, ensuring the safety and effectiveness of these projects is paramount, particularly when it comes to preventing CO2 leakage through geological faults. A recent study published in the *Journal of Carbon Dioxide Utilization* sheds new light on this very issue, offering insights that could significantly impact the energy sector.
Led by Haitao Yu from the State Key Laboratory of Disaster Reduction in Civil Engineering at Tongji University in Shanghai, the research focuses on the phase transition effects on CO2 leakage along faults during geologic carbon storage. The study proposes a non-isothermal hydro-thermal model to simulate CO2 phase transitions in fractured porous media, a complex process influenced by variations in pressure and temperature gradients.
“The interphase heat transfer is a crucial aspect of this model,” Yu explains. “It allows us to simulate CO2 leakage along faults and explore the pressure and temperature distribution and phase transition mechanism.”
The findings reveal that CO2 leakage progression can be divided into two stages: a pressure-dominated stage and a temperature-dominated stage. During the pressure-dominated stage, as the pressure difference between the reservoir and the fault decreases, the leakage flux decreases sharply. In the temperature-dominated stage, the liquid CO2 converts back to the gaseous phase, a process that has a negative effect on the leakage.
The sensitivity analysis conducted as part of the study indicates that CO2 leakage temperature determines the type of phase transition but has a limited impact on leakage mass flux. The reservoir overpressure and fault aperture, however, affect the extent and duration of the pressure-dominant phase transition, respectively. Moreover, increases in overpressure and fault aperture lead to higher leakage mass flux.
These findings have significant implications for the energy sector. “It is recommended that monitoring wells be preferentially deployed in areas characterized by high overpressure and large fault aperture,” Yu suggests. “This would enable early warning and targeted risk control in CCUS projects.”
The study’s insights could shape future developments in the field, particularly in enhancing the safety and effectiveness of CCUS projects. By understanding the phase transition effects on CO2 leakage, energy companies can make more informed decisions, ultimately contributing to more sustainable and secure carbon storage practices.
As the world continues to grapple with the challenges of climate change, research like Yu’s offers a beacon of hope, driving innovation and progress in the energy sector. The study’s publication in the *Journal of Carbon Dioxide Utilization* underscores its relevance and potential impact, paving the way for a more sustainable future.