Geothermal energy is gaining traction as a sustainable and clean energy source, and recent research from Ying-chun Li at the Deep Underground Engineering Research Center at Dalian University of Technology sheds light on optimizing heat extraction efficiency in deep geothermal systems. The study, published in the journal ‘工程科学学报’ (Journal of Engineering Science), explores various stimulation techniques for geothermal reservoirs, emphasizing their impact on heat extraction performance.
As the world seeks greener energy solutions, geothermal energy stands out for its vast reserves and minimal environmental footprint. However, the efficiency of extracting heat from these reservoirs can vary significantly based on the stimulation methods employed. Li’s research systematically compares four distinct reservoir stimulation modes, including EGS-D (conventional hydraulic fracturing), EGS-P (indirect heat exchange with U-shaped pipes), and EGS-E (block caving). Each approach presents unique challenges and advantages in terms of heat transfer and production.
Li’s findings reveal that high-permeability reservoirs, stimulated through EGS-E, exhibit the most promising heat extraction efficiencies. “By caving the reservoir into smaller fractured blocks, we can significantly enhance permeability, leading to higher heat extraction efficiency and greater overall heat production,” Li explains. This insight could be a game-changer for energy companies looking to maximize output from geothermal sites.
The research also delves into the interplay between mechanical, hydraulic, and thermal factors within the reservoir. It highlights that the evolution of crack apertures—essential for heat transfer—depends on the balance between matrix contraction and hydraulic pressure. Interestingly, when the spacing between the rock matrix is minimized, the thermal effects can lead to crack apertures that are significantly larger than those induced by hydraulic pressure. “When we reduced the matrix spacing to 50 meters, the thermal effect-induced crack aperture was nearly five times larger than the hydraulic effect-induced aperture,” Li notes.
These insights have substantial commercial implications. For energy developers, understanding the optimal conditions for reservoir stimulation can lead to more efficient geothermal systems, ultimately reducing costs and increasing energy output. As the industry strives to meet growing energy demands while adhering to sustainability goals, this research paves the way for more effective geothermal energy exploitation.
The findings from Li’s study not only enhance our understanding of geothermal reservoir dynamics but also provide actionable strategies for energy companies. By optimizing reservoir design and operation, stakeholders can tap into the full potential of geothermal energy, contributing to a more sustainable energy future.
For more information on this groundbreaking research, visit the Deep Underground Engineering Research Center at Dalian University of Technology: lead_author_affiliation.
