我国富氦盆地成藏模式对煤系氦气富集和勘探的启示

Implications of the helium-rich basin accumulation model in China for helium enrichment and exploration of coal-bearing gas resources

  • 摘要:背景】氦气是我国紧缺的战略性资源,加强其勘查对保障国家资源安全至关重要。我国煤系气资源丰富且伴生氦气成藏潜力显著,但相关研究尚处起步阶段。【方法】本文基于天然气藏氦气生成-运移-成藏理论总结和分析,系统揭示煤系氦气富集规律并提出勘探方向。【结果和结论】获得以下认识:(1)我国氦气资源呈现“南北分区、东西分带”的分布格局,可以分为东部幔源富氦区、中部壳源富氦区和西部壳-幔混合富氦区,其空间分异受控于盆地构造类型与区域演化背景;(2)氦气成藏遵循源岩析出-跨层运移-圈闭聚集的动态过程,受氦源封闭性、运移通道有效性(断裂系统与微孔毛细管作用)、流体动力场及储盖配置的复合控制,其中圈闭条件为主导因素,垂向运移以断裂系统为核心,岩性储盖组合提供辅助封存,溶解-析出机制形成局部富集补充;(3)含煤盆地氦气生成时效显著长于煤系烃类,但成藏高峰期呈现时空耦合特征,煤系兼具自生自储双氦源属性,与天然气藏构成多层立体叠置关系;(4)煤系氦气具有多源混合、广域伴生、立体富集及低浓度特性,其成藏机制涉及多源供氦贡献度、跨系统扩散动力学、构造控藏效应及低丰度资源评价等关键科学问题,未来勘查应聚焦构造活动带微构造系统、煤系多类型储层、深部储集层及盆地边缘气藏;(5)煤系氦气应坚持“以量补质”思路,优先在鄂尔多斯盆地、黔西滇东等代表性潜力区开展风险勘探,构建“靶区优选-煤系多储层协同开发”与“勘查-开发-利用”全链条技术体系,集成氦气提纯技术与“氦-煤-气”多资源协同开发模式,实现煤系氦气资源高效动用。研究成果为煤系氦气勘探提供理论参考和技术路径,助力国家氦气资源安全保障目标实现。

     

    Abstract: Background Helium is a scarce strategic resource in China, and enhancing its exploration is crucial for ensuring national resource security. While China's coal-bearing strata are rich in gas resources with significant helium accumulation potential, related research remains in its infancy. Methods This study systematically investigates the enrichment mechanisms and exploration strategies for coal-derived helium by integrating theories of helium generation, migration, and accumulation in natural gas reservoirs. Results and Conclusions Key findings include: (1) China's helium resources exhibit a “north-south zonal and east-west banded” distribution pattern, categorized into eastern mantle-derived enrichment zones, central crust-derived enrichment zones, and western crust-mantle mixed enrichment zones, with spatial differentiation controlled by basin tectonic types and regional evolutionary backgrounds; (2) Helium accumulation follows a dynamic process of source rock exsolution, cross-strata migration, and trap accumulation, governed by helium source confinement, migration pathway effectiveness (fault systems and microporous capillary interactions), hydrodynamic fields, and reservoir-caprock configurations. Trap conditions dominate accumulation processes, with vertical migration primarily facilitated by fault systems, assisted by lithological reservoir-caprock combinations, and supplemented by dissolution-exsolution mechanisms for localized enrichment; (3) Helium generation in coal-bearing basins significantly predates hydrocarbon generation but shares spatiotemporal coupling during peak accumulation periods. Coal measures demonstrate dual helium sourcing (self-generation and storage), forming vertically stacked configurations with natural gas reservoirs; (4) Coal-derived helium exhibits multi-source mixing, widespread symbiosis, three-dimensional enrichment, and low-concentration characteristics. Critical scientific challenges involve multi-source helium contributions, cross-system diffusion dynamics, structural controls on accumulation, and low-abundance resource evaluation. Future exploration should prioritize microstructural systems in tectonic zones, multi-type coal measure reservoirs, deep reservoirs, and basin-margin gas accumulations; (5) It is contended that for coal-derived helium, the concept of “compensating quality with quantity” should be firmly adhered to. Exploration efforts with potential risks should be preferentially carried out in representative potential regions such as the Ordos Basin and the western part of Guizhou and the eastern part of Yunnan. A comprehensive technical system encompassing “target area optimization-coordinated development of multiple coal-derived reservoirs” and the entire chain of “exploration-development-utilization” needs to be constructed. Integrate helium purification technologies and the collaborative development model of “helium-coal-gas” multi-resources, so as to achieve the efficient exploitation of coal-derived helium resources. The research results offer robust theoretical references and clear technical pathways for helium exploration in coal-bearing systems, thereby contributing significantly to the achievement of national helium resource security objectives.

     

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