In the heart of China, researchers are revolutionizing the way we extract and understand deep coalbed methane, a critical resource in the global energy mix. Juntai Shi, a leading expert from the State Key Laboratory of Petroleum Resources and Engineering at China University of Petroleum Beijing, has developed a groundbreaking material balance equation that promises to enhance the efficiency and scientific rigor of deep coalbed methane extraction.
Deep coalbed methane, often found at significant depths, has seen rapid development in recent years, with some wells achieving daily production rates of tens of thousands of cubic meters. However, the complexity of these reservoirs, which include free gas, dissolved gas, and adsorbed gas, has posed significant challenges. Shi’s research, published in Meitan kexue jishu (translated as Coal Science and Technology), addresses these challenges head-on, providing a comprehensive framework for evaluating and optimizing coalbed methane reserves.
The material balance equation developed by Shi and his team considers multiple factors that were previously overlooked. “We’ve incorporated the pressure difference between micropores enriched with adsorption gas and mesopores occupied by free gas and water, as well as the changes in coal reservoir physical parameters caused by formation stimulation,” Shi explains. This holistic approach allows for a more accurate assessment of controlled reserves, average coal reservoir pressure, and the proportion of different types of gas production.
One of the most significant implications of this research is the potential to improve the recovery rate of coalbed methane. By understanding the production proportions of adsorbed gas, free gas, and dissolved gas, operators can optimize their extraction strategies. Shi’s methods also provide explicit calculations for average formation pressure and productivity evaluation, avoiding the need for complex computer programming.
The commercial impacts of this research are substantial. Enhanced recovery rates mean more gas extracted per well, reducing the need for new drilling and lowering operational costs. This is particularly important in the energy sector, where efficiency and cost-effectiveness are paramount. “Reducing the abandoned pressure is an effective way to improve the coalbed methane recovery rate,” Shi notes, highlighting the practical applications of his findings.
The research also introduces a novel EUR (Estimated Ultimate Recovery) prediction method, which organizes production data into a linear expression of apparent pressure p/Z* and Gp. This allows for accurate predictions of EUR given a certain abandoned pressure, providing valuable insights for long-term planning and investment.
Looking ahead, this research could shape the future of deep coalbed methane extraction. By providing a more accurate and comprehensive understanding of these complex reservoirs, Shi’s work paves the way for more efficient and sustainable extraction methods. As the energy sector continues to evolve, innovations like these will be crucial in meeting global demand while minimizing environmental impact.
For energy companies operating in deep coalbed methane reservoirs, Shi’s findings offer a roadmap to improved productivity and profitability. By adopting these new methods, operators can enhance their extraction strategies, optimize resource allocation, and ultimately, contribute to a more sustainable energy future. The publication of this research in Coal Science and Technology underscores its significance and potential impact on the industry. As the world seeks to balance energy needs with environmental concerns, breakthroughs like these will be instrumental in shaping the future of energy extraction.
