【摘要】 对位于不同构造位置的两条下寒武统牛蹄塘组页岩采石场剖面进行了垂向系统采样研究,并进行了有机地球化学、矿物学及孔隙度测试。酉阳丹泉剖面富有机质层段集中在牛蹄塘组下部,厚度在25 m以上,总有机碳含量(TOC)均大于5.65%,遵义松林剖面仅对下部富有机质页岩进行采样,但基于富有机质层段地球化学垂向变化趋势可进行对比研究。结果表明,页岩微孔体积主要由有机孔提供,且基本不受构造作用影响。松林剖面TOC值越高,伊利石含量越低,介孔体积越小;而构造稳定区页岩介孔体积除部分样品与松林剖面重合外,仍有部分样品介孔体积明显偏高,说明构造位置的差异对页岩介孔具有明显的影响。宏孔体积在TOC大于6.4%时有减小的趋势,但不同构造位置的两剖面样品受构造应力差异影响不明显。构造应力对孔隙的影响主要与岩石的力学性质及伊利石矿物孔的保存能力有关。更多还原

【Abstract】 Shales were systematically sampled from the Niutitang Formation stone pits in different tectonic positions in the Upper Yangtze region and experiments were performed to characterize the organic geochemistry,mineralogy, and pore structure at different scales. Organic-rich shales in the Danquan profile, Youyang area, were mostly concentrated in the lower part of the Niutitang Formation; the thickness of organic-rich shale with total organic carbon(TOC) values greater than 5.65% is more than 25 m. Though only part of the organic-rich shales from the lower part of the Niutitang Formation in the Songlin profile, Zunyi area, were sampled, a comparison of the two profiles was conducted through vertical variation in the geochemical parameters. The results showed that the micropores in the shales were mostly composed of organic pores and basically not influenced by the tectonic movement. The mesopores in the shales in tectonically positive areas decreased with increasing TOC and decreasing illite content. Partial data of mesopores in tectonically stable areas were overlain with the Songlin profile and the remainder of the mesopore data were apparently higher than that of the shales in the tectonically positive areas, suggesting that tectonic position has a close relation with mesopores in shale. In addition, there is a negative correlation between the macropore volume and TOC in research areas when TOC > 6.4% and the macropores of two profiles have similar decreasing trends. As a result, the influence of tectonic stress on pores is mainly related to the mechanical properties of the rock and the preservation of illite mineral pores.更多还原