In the heart of China’s Ordos Basin, a pressing challenge has emerged for coal mines grappling with the disposal of highly mineralized mine water. Enter Longfei Feng, a researcher from the China Coal Research Institute in Beijing, who has pioneered a solution that could revolutionize water management in the energy sector. His groundbreaking work, published in the journal *Meitan xuebao* (translated to *Coal Science*), focuses on deep-well reinjection technology, offering a cost-effective and scalable approach to handling large volumes of mine water.
Feng’s research delves into the dynamics of deep-well reinjection, utilizing numerical simulations based on thermal-hydraulic-mechanical (THM) coupling governing equations. By examining a case study from an Ordos mine, Feng and his team investigated how varying branch numbers and well spacings in multi-lateral well systems affect reinjection flow rates and pore water pressure in target layers. “Multi-lateral wells exhibit significantly higher reinjection capacities than vertical wells,” Feng explains. This finding alone could reshape the way the energy sector approaches mine water management.
The study reveals that reinjection flow rates in multi-lateral systems are jointly controlled by branch numbers and well spacing. Feng’s team developed a theoretical model for flow rate and drawdown in inclined boreholes and fitted a functional relationship between well spacing and flow rate. “Flow rates initially increase with spacing and stabilize beyond critical thresholds,” Feng notes. For instance, with a branch inclination of 5°, flow rates stabilize when spacings exceed 200, 300, and 400 meters for two, three, and four-branch wells, respectively.
One of the most compelling aspects of Feng’s research is its focus on cost efficiency. By integrating well construction lengths, the team established a relative cost function per unit reinjection flow rate. This allowed them to propose a methodology for optimizing well configuration and spacing. “Relative construction cost per unit flow rate is proportional to well spacing,” Feng explains. “Costs escalate more rapidly with additional branches under fixed spacing.” This insight is crucial for the energy sector, where cost-effectiveness is paramount.
Feng’s research provides a scientific basis for the design of mine water geological storage engineering. His findings suggest that two-branch wells are optimal for flow rates between 77−149 cubic meters per hour, three-branch wells are preferred for flow rates between 149−201 cubic meters per hour, and four-branch wells are recommended for flow rates between 201−306 cubic meters per hour. These guidelines could significantly impact the commercial viability of deep-well reinjection technology in the energy sector.
The implications of Feng’s research extend beyond immediate cost savings. By optimizing well configurations and spacing, the energy sector can enhance the efficiency and sustainability of mine water management. This could lead to reduced environmental impact and improved operational performance, ultimately benefiting both the industry and the communities it serves.
As the energy sector continues to evolve, the need for innovative solutions to water management challenges becomes increasingly apparent. Feng’s work, published in *Meitan xuebao*, offers a promising path forward. His research not only addresses the pressing needs of coal mines in the Ordos Basin but also provides a blueprint for future developments in the field. By embracing deep-well reinjection technology and optimizing well configurations, the energy sector can achieve greater efficiency, sustainability, and cost-effectiveness in its operations.