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大别造山带和合肥盆地是紧密相连的2个构造单元,在形成和时空演化上具有密切的关系。在大别造山带内发现的可燃天然气和发生燃烧的隧道具有明显的区域性,集中分布于磨子潭断裂以南的北大别杂岩带和舒城断裂附近的早石炭世变质石英片岩中,断裂是连通深部气源的通道;推覆体之下的寒武系凤台组和北淮阳型石炭系2套海相烃源岩是隧道可燃天然气的主力气源岩,其中下寒武统凤台组烃源岩具有有机碳含量高、镜质体反射率高、最高热解峰温高、氯仿沥青“A”含量低的特点,已进入热演化的过成熟阶段;北淮阳型石炭系烃源岩有机质丰度高,以Ⅲ型干酪根为主,热演化程度很高,已生成大量油气,在相对稳定的构造环境中,这种油气就可能保存下来,可作为有效烃源。大别造山带隧道可燃天然气的发现展示了合肥盆地深部海相层系良好的勘探前景,下步勘探重心应从“中新生代盆地系统”转移到深部海相层系,以寻找“古生古储”或“古生新储”类型油气藏为主。
The Dabie orogenic belt and the Hefei Basin are two closely connected structural units that are closely related to the evolution of space and time. The combustible natural gas and the burned tunnels found in the Dabie orogenic belt have obvious regional distribution, concentrated in the North Dabie complex belt south of the Mozhatan fault and the Early Carboniferous metamorphic quartz schist near the Shucheng fault, The fault is the channel connecting the deep gas source. Two sets of marine source rocks of the Cambrian Fengtai Formation and the Northern Huaiyang-type Carboniferous under the nappe are the main source rocks of the combustible natural gas in the tunnel. The Lower Cambrian Fengtai Formation The source rocks of the group have the characteristics of high organic carbon content, high vitrinite reflectance, high peak pyrolysis temperature and low content of chloroform bitumen “A”, which have entered the stage of thermal evolution over maturity. The Northern Huaiyang-type carbon The hydrocarbon source rocks have high abundance of organic matter and are mainly Type III kerogen with a high degree of thermal evolution. Large amounts of oil and gas have been formed, which may be preserved in a relatively stable tectonic setting and can be used as an effective hydrocarbon source. The discovery of combustible natural gas in the Dabie orogenic belt tunnel shows a good exploration prospect for the deep marine facies in the Hefei Basin. The next exploration center of gravity should be shifted from the Mesozoic-Cenozoic basin system to the deep marine facies in order to find Raw ancient “or” paleontology new reservoir "type of reservoirs.