Yuqia depression in northern Qaidam Basin, as a potential continental shale gas exploration target of Northwest China, is a sedimentary center of Jurassic lacustrine strata with thick dark mudstone and shale layers. Based on such means as the analysis of total or⁃ganic carbon (TOC), hydrogen index (HI), vitrinite reflectance (Ro), porosity and permeability of shale, scanning electron microscope analysis (SEM), mineral composition and isothermal adsorption features of cores from the well Chaiye-1, the authors investigated natu⁃ral gas reservoir forming conditions of Yuqia depression. The assessment results show that the organic types and maturity are favorable for the development of organic-matter pores and microfractures. The gas content of Dameigou Formation shale is high because of high TOC content. Clay mineral content has hindered the development of the cracks of the shale but accelerated its adsorption capacity. The shale of the Middle Jurassic Dameigou Formation is thus a significant target of the shale gas exploration in northern Qaidam Basin.%柴达木盆地北缘鱼卡凹陷发育的侏罗系泥页岩是中国北方陆相页岩气勘探的目的层系之一。为进一步明确鱼卡凹陷侏罗系泥页岩地化-储集条件，系统采集了柴页1井泥页岩岩心样品，开展了总有机碳、热解氢指数、镜质体反射率、孔隙度和渗透率、扫描电镜、矿物组成及等温吸附特征实验分析。结果表明，柴页1井中侏罗统大煤沟组泥页岩有机质类型和成熟度利于有机质孔隙发育，较高的总有机碳含量利于页岩气富集；粘土矿物的存在虽然抑制了泥页岩微孔隙的发育，但对其吸附能力有促进作用。鱼卡凹陷具有良好的页岩气生成和储集条件，是页岩气勘探的有利地区。
展开▼
