宁东煤田地处我国西北干旱−半干旱区，是我国批准建设的14个亿吨级大型煤炭基地之一，目前存在高矿化度矿井水量大、处理技术成熟但成本高、综合利用率低等问题。为实现宁东煤田高矿化度矿井水的低成本资源化回注存储和水文生态环境保护，结合宁东煤田13座煤矿矿井水矿化度高的典型特征，因地制宜地提出在煤油资源重叠区，利用枯竭油层回注存储高矿化度矿井水这种宝贵的非常规水资源的技术思路，即利用枯竭油层孔−裂隙双重结构中储水空间、油田关停初期地层压力亏空和废弃油井/注水井低成本处置高矿化度矿井水经资源化利用后的余量水；系统阐述枯竭油层选择、回注工艺、储水潜力、预处理水质要求和环境的可行性；凝练出基础理论、法律法规政策和实时监测监管的研究展望。结果表明，提出的枯竭油层回注存储技术具有可行性，可实现宁东煤田高矿化度矿井水的低成本资源化处置，“如何精细刻画注水渗流过程”是回注处置技术瓶颈问题，科学实质是高矿化度矿井水−砂岩耦合化学作用下孔裂隙介尺度的枯竭油层注水渗流演化机理。同时，相关法律法规政策和实时监测监管方面亟需完善，以保障枯竭油层回注存储技术的顺利实施。研究旨在为高矿化度矿井水资源化回注存储提供新思路，为煤油气资源开发中二次水资源保护提供参考。

The Ningdong Coalfield is located in the arid and semi-arid region of northwest China, which is one of the 14 approved large-scale coal bases with a reserve of over 100 million tons in China. Currently, it faces challenges such as a large volume of highly-mineralized mine water, mature but costly treatment technology, and a low comprehensive utilization rate. To achieve the low-cost efficient reinjection and storage of highly-mineralized mine water in the Ningdong Coalfield and to protect the hydrological and ecological environment, this study, based on the typical characteristics of high mineralization in the mine water of 13 coal mines in the Ningdong coalfield, proposes a technical approach for the reinjection and storage of highly-mineralized mine water in depleted petroleum reservoirs in the coal and oil resources overlapping area. This approach utilizes the valuable unconventional water resource by making use of the pore-fracture dual structure and water storage space in the depleted petroleum reservoirs, the initial reservoir pressure vacuum during the shutdown of the oilfield, and the low-cost disposal of highly-mineralized mine water after resource utilization. The study systematically elaborates on the selection of depleted petroleum reservoirs, reinjection processes, water storage potential, pre-treatment water quality requirements, and the feasibility analysis of the environment. It also outlines prospects for fundamental theoretical research, legal regulations, policies, and real-time monitoring and control. The results indicate the feasibility of the proposed reinjection and storage technology in depleted petroleum reservoirs, which can achieve the low-cost efficient treatment of highly-mineralized mine water in the Ningdong coalfield. “How to finely characterize the water injection seepage process” is identified as a bottleneck issue in the reinjection treatment technology. In essence, it involves the evolution mechanism of water injection and seepage in the pore-fracture scale of the depleted petroleum reservoir under the coupled chemical action of highly-mineralized mine water and sandstone. Furthermore, there is an urgent need for improvement in related legal regulations, policies, and real-time monitoring and control to ensure the smooth implementation of the reinjection and storage technology in depleted petroleum reservoirs. This study aims to provide new insights into efficiently reinjecting and storing highly-mineralized mine water and to offer references for the protection of secondary water resources in the development of coal, oil, and gas resources.