Recent research published in the journal “Underground Space” has shed light on how fluid injection affects the permeability of granite fractures, a critical factor in the extraction of geothermal energy. Led by Fengshou Zhang from the Department of Geotechnical Engineering at Tongji University in Shanghai, the study investigates the relationship between fracture roughness and permeability changes during fluid injection, which is essential for managing deep geothermal reservoirs.
The study reveals that the roughness of granite fractures plays a significant role in determining how these fractures react when fluid is injected. Specifically, the findings indicate that “a rougher fracture leads to a lower peak reactivated permeability.” This means that in geothermal projects, the physical characteristics of the rock can limit how easily fluids can flow through the fractures, impacting the efficiency of energy extraction.
Moreover, the research highlights that while the strategies used for fluid injection—such as confining pressure and injection rates—do influence permeability, their effect is less significant than that of the fracture’s roughness. This insight is crucial for energy companies looking to optimize their geothermal operations, as it suggests that a deeper understanding of the geological characteristics of a site can lead to better planning and implementation of fluid injection strategies.
The implications of this research extend beyond geothermal energy. Industries involved in underground construction, hydrocarbon extraction, and even waste disposal can benefit from understanding how fracture characteristics affect fluid dynamics. Enhanced permeability management could lead to safer operations, reduced risk of induced seismicity, and improved recovery rates, ultimately translating to cost savings and increased efficiency.
Zhang’s work emphasizes the importance of tailored approaches to fluid injection based on the specific geological conditions of a site. As the demand for renewable energy sources continues to rise, insights from studies like this one will be vital for developing sustainable geothermal energy solutions. The findings serve as a reminder that understanding the complexities of underground formations is crucial for maximizing the potential of geothermal resources and minimizing environmental risks.
