青海木里煤田聚乎更矿区煤系气耦合成藏机制及其盆地动力学控制

Multiple values of coal resources are the paragenetic association and symbiotic mining potential of various minerals in coal measures. In addition to coal itself, the closely related formation and distribution of unconventional natural gases (coal measure gases), including coalbed methane, shale gas, tight gas, gas hydrates, has attracted widespread attention. Selecting the Middle Jurassic coal measure of terrestrial facies of Juhugeng mine area, Muli coalfield in Qilian Mountains as the study object, and starting from exploring the basin geodynamic process control on formation and evolution of the coal measure gas system, this project carry out comprehensive study of coalbed methane - shale gas - tight sandstone gas - gas hydrates as "four in one". Identify the combinative accumulation features of different type of coal measure gases through detailed of drilling core observation and field survey, and systematic samples testing and multi-parameter thematic mapping. Reveal the coupling accumulation mechanism of coal measure gases in study area based on study of several key problems, such as basin deposit-filling control on development of source rocks and reservoirs, and tectonic-thermal events control on evolution of organic matters and migration and concentration of hydrocarbon materials, and coal measures deformation and displacement control on accumulating and positioning of unconventional gases. The solution of the above problems, in theory, the understanding of the coupling accumulation mechanism and the occurrence law of coal measure gases could be deepened, and in practice, the scientific basis will be provided to the comprehensive evaluation of coal gas resources, especially natural gas hydrate, in the areas.

煤炭资源的多重价值体现在含煤岩系中多种矿产资源的共生组合与共采潜力，除煤层自身之外，煤层气、页岩气、致密砂岩气、天然气水合物等煤系非常规天然气（煤系气）共生共存的现象已日趋受到业界的关注。本项目选择祁连山木里煤田聚乎更矿区中侏罗统陆相含煤岩系为研究对象，以煤系气系统形成和演化的盆地动力学过程为切入点，开展煤层气—页岩气—致密砂岩气—天然气水合物“四位一体”的综合研究。通过详细的钻孔岩心观察和野外调查、系统的样品测试分析和多参数专题制图，查明不同类型煤系气的共生组合特征；从盆地沉降-充填对烃源岩和储集层发育的控制、构造-热事件对有机质热演化和烃类物质迁移富集的控制、煤系变形-变位对非常规气成藏定位的控制等关键问题入手，建立研究区煤系气耦合成藏模式。上述问题的解决，在理论上，可以深化对煤系气成藏机制和赋存规律的认识；在实践上，将为本区煤系气资源综合评价尤其是天然气水合物调查提供科学依据。

煤系非常规天然气是煤系矿产资源的重要组成部分，其耦合成藏机制一直是当前煤炭资源领域亟需解决的重要科学技术难题之一。我国含煤盆地普遍遭受后期构造运动的改造，构造演化对于煤系非常规天然气的控制作用日益受到关注，从早期构造控煤研究拓展为适应当代煤地质学发展的构造控气（煤系非常规天然气）研究势在必行。.本基金选择祁连山木里煤田聚乎更矿区中侏罗统煤系和华北鄂尔多斯盆地石炭二叠系煤系和中侏罗统煤系为研究对象，以煤系气系统形成和演化的盆地动力学过程为切入点，开展煤层气—页岩气—致密砂岩气—天然气水合物“四位一体”综合研究。取得以下主要成果：（1）恢复了聚乎更矿区中侏罗世以来研究区构造演化过程，厘清了矿区现今构造格局，充实了木里盆地基础地质构造研究成果。（2）查明了聚乎更矿区烃源岩发育特征，划分了煤系气生储盖组合类型，揭示了其形成控制因素，支撑了研究区煤与煤系气的综合勘探。（3）对研究区烃源岩进行了评价，恢复了研究区烃源岩生烃及运移过程，解释了研究区天然气水合物的气体形成过程。（4）查明了研究区煤系储层物性特征，总结了煤储层、页岩储层以及砂岩储层的各自特点，为煤系气储层评价及煤系气开发提供了理论支撑。（5）阐明了聚乎更矿区煤系气富集条件，类比鄂尔多斯盆地煤系气富集成藏条件，强调构造控制下煤系气富集成藏的特点。（6）厘定了煤系矿产资源的概念，充实了煤炭资源的内涵，建立了煤系矿产资源组合分类系统，划分了5大赋煤区煤系矿产资源共生组合类型，强调煤系气的重要性和普遍性。（7）在国内外期刊发表学术论文共25篇，其中，SCI收录11篇、EI收录5篇、北大中文核心3篇；获省部级科技进步奖一等奖1项；培养研究生6名，其中，博士2名，硕士4名。.上述工作成果深化了对煤系气成藏机制和赋存规律的认识，可以为我国复杂构造区的煤系气资源综合评价提供科学依据。