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下寒武统牛蹄塘组与下志留统龙马溪组页岩是扬子地区发育的两套富有机质黑色页岩,由于其分布面积广、厚度大、有机质丰度高而成为页岩气勘探的重点层位.然而牛蹄塘组孔隙度表现出了与龙马溪组截然不同的规律,两套页岩的孔隙结构、有机碳含量、密度也存在显著差异.结合测井、埋深(上覆压力)、孔隙度、有机碳及成熟度测试数据进行了对比分析.结果显示,牛蹄塘组过高的有机碳含量和热演化程度严重影响了页岩的孔隙结构,使有机质碳化,有机质孔发生坍塌和充填;牛蹄塘组埋深大、上覆压力也大,导致无机孔被压实,因此其总孔隙度明显小于龙马溪组.
The Lower Cambrian Niutitang Formation and the Lower Silurian Longmaxi Formation are two organic-rich black shales developed in the Yangtze area. Due to their wide distribution, large thickness and high organic matter abundance, shale gas exploration However, the porosity of the Niutizi Formation shows a completely different pattern from that of the Longmaxi Formation, and there are also significant differences in the pore structure, organic carbon content and density between the two sets of shales Porosity, organic carbon and maturity.Results show that the excessively high organic carbon content and thermal evolution in Niutitang Formation seriously affect the pore structure of shale, resulting in the carbonization of organic matter, organic matter Hole collapse and filling; Niutitang group buried deep, overlying pressure is also large, resulting in inorganic pores are compacted, so its total porosity was significantly less than the Longmaxi Formation.