四川盆地南部X地区五峰组–龙一₁亚段页岩储层有机质富集主控因素分析

Analysis on Main Controlling Factors of Organic Matter Enrichment in Shale Reservoir of Wufeng Formation - The First Sub-Member of Longmaxi Formation in X Area, Southern Sichuan Basin

摘要: TOC含量是评价烃源岩生烃能力的重要参数。为探讨研究区五峰组–龙一₁亚段页岩储层有机质富集的主控因素。针对研究区取得的岩心样品开展总有机碳分析实验以及主微量元素测定实验，基于此实验结果进行研究区页岩储层有机质富集主控因素分析。利用Ni/Co和U/Th微量元素丰度比值指示研究区水体氧化还原程度，利用P/Al和(Ni + Cu + Zn)/Al微量元素丰度比值对研究区的初始古生产力进行恢复评价，基于Al和Ti元素来评价研究区沉积岩中陆源输入碎屑含量。根据TOC与这些微量元素评价指标的相关性分析，明确研究区页岩储层有机质富集的主要控制因素是水体氧化还原程度，初始古生产力以及陆源碎屑输入含量相对影响较小。

Abstract: TOC content is an important parameter for evaluating hydrocarbon generation capacity of source rocks. To explore the main controlling factors of organic matter enrichment in shale reservoir of Wufeng Formation - The first sub-member of Longmaxi Formation in the study area. The total organic carbon analysis experiment and the determination experiment of main and trace elements were carried out on the core samples obtained in the study area. Based on the experimental results, the main control factors of organic matter enrichment in shale reservoir in the study area were analyzed. Ni/Co and U/Th trace element abundance ratios were used to indicate the degree of water REDOX in the study area, P/Al and (Ni + Cu + Zn) /Al trace element abundance ratios were used to assess the initial paleoproductivity of the study area, and terrigenous input debris content in sedimentary rocks in the study area was evaluated based on Al and Ti elements. According to the correlation analysis between TOC and these trace element evaluation indexes, it is evident that the primary controlling factors influencing organic matter enrichment in the shale reservoirs of the study area are water REDOX environment, initial paleo productivity, and the content of terrigenous clastic input.