“富集有机质”成烃作用再认识:以东营凹陷为例

A restudy on the hydrocarbon occurrence of “ enriched organic matter” : A case study of Dongying Depression

从沉积特征、微观结构和有机质赋存状态等方面,分析了东营凹陷富集有机质烃源岩不同于分散有机质烃源岩的特征,探讨了其对成烃过程的影响。相对于分散有机质烃源岩,富集有机质烃源岩纹层理非常发育,岩性组合和微观沉积特征表现出较强的韵律性和非均质性,且易于形成顺层的有机质网络。上述特点决定了富集有机质烃源岩物理性质存在较强的各向异性,易形成平行层面的微裂隙,具有相对较高的侧向渗透率。这从一定程度上表明富集有机质烃源岩的侧向排烃过程比较容易实现。该认识对于深入研究和评价东营凹陷乃至整个中国东部陆相断陷盆地烃源岩具有重要意义。

On the base of sedimentary characteristics, microstructure, and organic matter occurrence analysis, differences between enriched organic matter and dispersed organic matter source rocks are described, and the factors that affect hydrocarbons generation and migration are investigated. Most of the enriched organic matter source rocks are paper-laminated with strong rhythm and strong heterogeneity, and the organic networks can be easily formed since the relatively high abundance and horizontally distributed organic matter. The heterogeneity results in anisotropy in rock physical characteristics, and can lead the rocks to produce horizontal fractures. The experimental results also show that the enriched organic vertical permeability. From the above, it is concluded matter source rocks have higher horizontal permeability than that hydrocarbons migration process can be achieved more easily than it was expected before. This conclusion is of great importance to Dongying Depression and the other terrestrial rift basins in East China in restudy and evaluation of hydrocarbon source rocks.