Abstract To gain a better understanding of the gas-bearing property of Lower Cambrian Niutitang Formation shale and its influencing factors, the shale gas-bearing conditions, gas content, and composition in the Cengong block were investigated in this work based on wells CY1, TX1, and TM1. The Niutitang shale reservoir is characterized by large thickness, abundant organic matter with an average total organic carbon content of 4.74%, and high quartz content averaging 53.9%; therefore, it has good shale gas-bearing potential. The results of water immersion and ignition tests intuitively revealed the existence of shale gas based on the occurrence of continuous dense clusters of bubbles and long flames of 1–2 m. The Langmuir volumes of shale samples from well TM1, which ranged from 1.70 to 5.53 m3/t, were positively associated with TOC content and Brunauer–Emmett–Teller surface area, indicating a strong adsorption capacity and significant adsorbed gas potential. However, large differences were observed among the three wells with regard to gas-bearing properties; wells CY1 and TX1 had average total gas contents of 1.25 and 0.33 m3/t, respectively; the gas composition of well TM1 was dominated by nitrogen (N2), with contents generally exceeding 95%. Furthermore, the gas from well TX1 was mainly composed of methane with an average content exceeding 80%. Burial depth and TOC and quartz contents had significant control on the vertical distribution of gas content, and local tectonic preservation conditions resulted in differences of gas-bearing properties among various wells. The measured, lost, and total gas contents all presented positive correlations with TOC, quartz contents, and porosity, and were negatively related to clay content. The shale formed in deep-water shelf environments had better gas-bearing properties than that formed in shallow-water shelf environments. The broad axis of the box syncline in the Cengong block is a favorable location for shale gas accumulation, and fault development affects the shale gas plane distribution. Because of the influence of faults, the shale of well TM1 had low hydrocarbon content. Furthermore, based on the combined patterns of folds and faults as well as other special specific factors, a classification scheme of shale gas accumulation patterns in South China was developed.

中文翻译：

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下寒武统牛蹄塘组页岩含气性及其影响因素——以黔北岑公区块为例

摘要 为更好地了解下寒武统牛蹄塘组页岩的含气性及其影响因素，以CY1、TX1井为研究对象，对岑公区块页岩含气条件、含气量及组成进行了研究。 , 和 TM1。牛蹄塘页岩储层厚度大，有机质丰富，总有机碳含量平均为4.74%，石英含量高，平均为53.9%；因此，它具有良好的页岩气蕴藏潜力。水浸和点火试验结果基于连续密集的气泡簇和1-2 m长火焰的出现，直观地揭示了页岩气的存在。TM1 井页岩样品的朗缪尔体积为 1.70 至 5.53 m3/t，与 TOC 含量和 Brunauer-Emmett-Teller 表面积呈正相关，表明具有很强的吸附能力和显着的吸附气体潜力。然而，在含气特性方面，三口井之间观察到很大差异；CY1和TX1井的平均总含气量分别为1.25和0.33 m3/t；TM1井气体成分以氮气（N2）为主，含量普遍超过95%。此外，TX1井的天然气以甲烷为主，平均含量超过80%。埋藏深度、TOC 和石英含量对含气量的垂直分布有显着控制，局部构造保存条件导致各井含气性存在差异。被测量的，丢失的，和总气体含量均与 TOC、石英含量和孔隙度呈正相关，与粘土含量呈负相关。深水陆棚环境中形成的页岩比浅水陆棚环境中形成的页岩具有更好的含气性。岑公区块箱向向宽轴线是页岩气聚集的有利位置，断层发育影响页岩气平面分布。受断层影响，TM1井页岩油气含量较低。进而，基于褶皱、断裂的组合模式以及其他特殊的特殊因素，制定了华南地区页岩气成藏模式分类方案。深水陆棚环境中形成的页岩比浅水陆棚环境中形成的页岩具有更好的含气性。岑公区块箱向向宽轴线是页岩气聚集的有利位置，断层发育影响页岩气平面分布。受断层影响，TM1井页岩油气含量较低。进而，基于褶皱、断裂的组合模式以及其他特殊的特殊因素，制定了华南地区页岩气成藏模式分类方案。深水陆棚环境中形成的页岩比浅水陆棚环境中形成的页岩具有更好的含气性。岑公区块箱向向宽轴线是页岩气聚集的有利位置，断层发育影响页岩气平面分布。受断层影响，TM1井页岩油气含量较低。进而，基于褶皱、断裂的组合模式以及其他特殊的特殊因素，制定了华南地区页岩气成藏模式分类方案。断层发育影响页岩气平面分布。受断层影响，TM1井页岩油气含量较低。进而，基于褶皱、断裂的组合模式以及其他特殊的特殊因素，制定了华南地区页岩气成藏模式分类方案。断层发育影响页岩气平面分布。受断层影响，TM1井页岩油气含量较低。进而，基于褶皱、断裂的组合模式以及其他特殊的特殊因素，制定了华南地区页岩气成藏模式分类方案。