Abstract Complex tectonic settings are generally considered to be unfavorable for shale gas accumulation, but a favorable desorption-gas content has been detected in Lower Cambrian Lujiaping Shales in Dabashan fold-thrust belt in northeastern Chongqing, Southern China, which suggests a good exploration potential. High-pressure (~30 MPa) and high-temperature (~120 °C) (HP-HT) methane adsorption isotherms were conducted on seven samples collected at 2665–2707 m below the ground surface from the Lower Cambrian Niutitang Shale (equivalent to the Lujiaping Shale) from northeast Guizhou Province, Southern China to assess methane adsorption capacity and the influence of total organic carbon (TOC) content, thermal maturity, mineralogy, and temperature-pressure conditions on methane adsorption in over-mature shales in complex tectonic areas. The samples contain high TOC contents, ranging from 5.1% to 8.4%, and equivalent vitrinite reflectance Ro values ranging from 3.62% to 3.85%. Over the experimental pressure range up to 30 MPa, Langmuir volumes correlate positively with TOC contents, which may be related to the increase in specific surface area and micropores (

中文翻译：

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黔东北复杂构造区页岩甲烷吸附特征：实验结果及地质意义

摘要 复杂的构造环境一般被认为不利于页岩气成藏，但在重庆东北大巴山褶皱冲断带下寒武统陆家坪页岩中发现了有利的解吸气含量，具有良好的勘探潜力。对从下寒武统牛蹄塘页岩（相当于贵州省东北部陆家坪页岩）评估甲烷吸附能力以及总有机碳（TOC）含量、热成熟度、矿物学和温压条件对复杂构造区过成熟页岩中甲烷吸附的影响. 样品含有高 TOC 含量，范围为 5.1% 至 8.4%，等效镜质反射率 Ro 值范围为 3.62% 至 3.85%。在高达 30 MPa 的实验压力范围内，Langmuir 体积与 TOC 含量呈正相关，这可能与比表面积和微孔的增加有关（