【摘要】 黔北地区下古生界发育多套富有机质页岩层系，具有良好的页岩气勘探前景，但区内构造展布复杂、页岩储层品质差异较大，且保存条件认识尚浅，制约了该区页岩气的高效勘探开发。为了深入认识上述因素对区内页岩气勘探开发的影响，以黔北地区奥陶系五峰组—志留系龙马溪组和寒武系牛蹄塘组页岩为研究对象，系统梳理了研究区2套海相页岩的沉积及地球化学特征、储层孔隙结构及储集能力特征以及保存条件等，明确了2套海相页岩成藏条件差异，指出了页岩气有利勘探方向。研究结果表明：(1)五峰组—龙马溪组页岩以深水陆棚相硅质页岩、碳质页岩为主，有机质丰度高，有机质类型好，该套页岩分布局限于残留向斜内，热演化程度适中，物性好，有机质孔隙发育；(2)牛蹄塘组页岩分布范围广，热演化程度高，物性差，储集空间以无机孔为主；(3)五峰组—龙马溪组页岩的顶底板条件良好，页岩气富集主要受控于构造变形强度，其中遵义—南川断裂东侧的向斜东翼构造变形较弱，是页岩气勘探有利区；(4)牛蹄塘组页岩的底板条件整体较差，热演化程度相对适中的古隆起区域、发育硅质岩底板的构造弱变形区是页岩气勘探有利区。结论认为，研究成果明确了区内下古生界页岩气成藏地质条件，并指出了页岩气勘探开发有利区，为盆外复杂构造区页岩气的勘探指明了方向，有助于此类页岩气产业的高质量发展。更多还原

【Abstract】 The northern Guizhou area contains multiple suites of organic-rich shales in the lower Paleozoic, which is promising for shale gas exploration. However, the complex distribution of structures, varying qualities of shale reservoirs, and insufficient knowledge of preservation conditions in this area restrict the efficient exploration and development of shale gas. To ascertain how these factors affect the shale gas exploration and development, this paper studies two suites of marine shales in the northern Guizhou area, i.e. the Ordovician Wufeng Formation–Silurian Longmaxi Formation(Wufeng–Longmaxi Formations), and the Cambrian Niutitang Formation, in terms of their sedimentary and geochemical characteristics, reservoir pore structure, storage capacity, and preservation conditions, and analyzes their differences in shale gas accumulation conditions. Furthermore, the shale gas exploration prospects in this area are proposed. The following results are obtained. First, shales in the Wufeng–Longmaxi Formations are dominantly deepwater continental shelf facies siliceous shales and carbonaceous shales, with high TOC contents and good organic matter types. This suite of shales is only distributed in residual synclines,with moderate thermal maturity, good reservoir properties, and well-developed organic pores. Second, shales in the Niutitang Formation are widely developed in the study area, with high thermal maturity, poor reservoir properties, and inorganic pores as the main storage space.Third, the Wufeng–Longmaxi Formations generally have good roof and floor conditions, where shale gas enrichment is mainly controlled by the intensity of tectonic deformation. The eastern wing of synclines to the east side of the Zunyi-Nanchuan fault is a potential shale gas prospect due to its weak tectonic deformation. Fourth, the Niutitang Formation has generally bad floor conditions. The paleo-uplift areas containing shales with relatively moderate thermal maturity and the weak tectonic deformation areas with siliceous rocks as floors are the shale gas exploration prospects of this formation. The research results clarify the geological conditions of the lower Paleozoic shale gas reservoirs in the northern Guizhou area and propose the shale gas exploration prospects in this area. This research is referential for exploration of shale gas in complex structural areas in other basins, and can facilitate the high-quality growth of the shale gas industry.更多还原