The Anchang syncline is a complex tectonic area for shale gas exploration in South China, located in the northern part of Guizhou Province. The shale of the Upper Ordovician Wufeng-Lower Silurian Longmaxi formations in the well Anye 1 in Zunyi area of Guizhou Province was studied using argon ion polishing, scanning electron microscopy, N2 low-temperature low-pressure adsorption experiments and organic geochemical, rock and mineral analysis and other supporting experiments to portray microscopic pore type, structure and their controls on the gas content of marine shale reservoirs. There are many kinds of micro and nano pores in the Wufeng-Longmaxi shale, and organic pores and micro cracks are the most abundant. The shale hosts mainly nano pores, and the micro pores are mostly filled with calcite. Organic pores are the main pore types of the Longmaxi shale, and micro cracks are the main pore types of the Wufeng shale. There are two kinds of N2 adsorption-desorption isotherms: type IV-H4 hysteresis loop and type V-H3 hysteresis loop, which are slit pores with a flat structure. The BET specific surface area is between 7.87 and 14.83 m2/g, the total pore volume of BJH is between 0.002 6 and 0.005 2 cm3/g, mainly mesopores, and the average pore diameter is concentrated at 2-5 nm. In the longitudinal direction, microscopic pores have a significant control on the gas content of the Wufeng-Longmaxi shale in the well Anye 1. The shale adsorption amount is positively correlated with the TOC content, and the other parameters have no obvious correspondence with the gas content. Compared with the Wufeng-Longmaxi shale in the Jiaoshiba area,%黔北安场向斜为我国南方页岩气勘查复杂构造区.为深入研究页岩微观孔隙特征及对含气性的影响,以贵州遵义安页1井上奥陶统五峰组—下志留统龙马溪组页岩为研究对象,通过氩离子抛光扫描电镜、N2低温低压吸附实验及有机地化、岩矿分析等配套实验,刻画了海相页岩储层微观孔隙类型、结构及对含气性的控制作用.五峰—龙马溪组页岩存在多种微纳米孔隙,以有机孔和微裂缝最为发育.页岩主要为纳米孔隙,微米孔隙多被方解石充填;有机质孔隙为龙马溪组页岩的主要孔隙类型,微裂缝为五峰组页岩的主要孔隙类型.N2吸附—脱附等温线有2种:Ⅳ型-H4滞后环和Ⅴ型-H3滞后环,为平板结构的狭缝孔;BET比表面积介于7.87～14.83㎡/g,BJH总孔容介于0.002 6～0.005 2 cm3/g,以介孔为主,平均孔径集中在2～5 nm.纵向上,微观孔隙对安页1井五峰—龙马溪组页岩的含气量有显著控制作用,页岩吸附量与TOC正相关,含气量与其他参数无明显对应关系;横向上,通过与焦石坝五峰—龙马溪组页岩对比,安页1井在页岩厚度、孔渗及孔喉直径上存在差异,是影响储层含气性的关键因素.通过安页1井单井分析,显示黔北安场向斜五峰—龙马溪组地质条件优越,具有较好的页岩气勘探前景.
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