A Comprehensive Analysis of the Mutual Feedback Mechanisms between CO2 Geological Storage and Underground Coal Mining in the Ordos Basin

Abstract

The Ordos Basin, a representative sedimentary basin in China, possesses abundant underground coal and saline aquifer resources, which often overlap spatially. Complex mutual feedback mechanisms arise when the CO₂ geological storage (CGS) and underground coal mining (UCM) operate simultaneously. While previous studies have focused on CGS or UCM individually, the mutual feedback mechanisms between these activities remain poorly understood. To address this gap, this study comprehensively analyzes the mutual feedback mechanisms between CGS and UCM in the Ordos Basin. Specifically, this paper explores the necessity of CGS and UCM and the technological challenges they face while conducting rock laboratory experiments and establishing a mutual feedback model to analyze these mechanisms comprehensively. The results show that the deformation of the coal seam caused by a single reservoir CGS is 1.76 mm, and the deformation of the top of the reservoir caused by UCM is 0.39 mm, with both deformations at the millimeter scale. The safety distance between CGS and UCM is determined to be 500 m horizontally and 1187.26 m vertically. Beyond this safety distance, joint CGS and UCM operations can mitigate the magnitude of stress and displacement associated with UCM operations alone. Based on the Huaneng Zhengning power plant CCUS aquifer storage project, this study provides theoretical and technical guidance for integrating carbon capture, utilization, and storage (CCUS) with underground multiresource applications. This work aligns with global climate and energy security goals by improving resource utilization, reducing carbon emissions, and promoting environmental sustainability.