陆相断陷湖盆层序地层模式及控制因素研究——以惠民凹陷下第三系沙河街组为例
The sequence pattern and controlling factors in terrestrial rift-subsidence lacustrine basin——Taking the Shanhejie Formation of Lower Tertiary in Huimin Depression as example
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摘要: 惠民凹陷是一典型的陆相断陷湖盆,研究表明:下第三系沙河街组二、三、四亚段可划分为3种层序类型,即断陷初期型、强断陷期型和断陷后期型层序。本次研究采用了体系域的四分方案。断陷初期红色地层层序,受气候因素控制明显,在层序演化上有其独特的特点。研究区发育断陷初期型、强断陷期型和断陷后期型3种类型沉积密集段,不同类型的沉积密集段在层序中所处位置不同,控制着不同的烃源岩厚度和油气资源储量。Abstract: Huimin Depression is a typical terrestrial rift-subsidence lacustrine basin.The study results indicate that the 2,3 and 4 sub-members of Shahejie Formation of Lower Tertiary can be divided into three types of stratigraphic sequences, i. e. the stratigraphic sequence in primary rifting stage, the stratigraphic sequence in violent rifting stage and the stratigraphic sequence in the later rifting stage.The sequence stratigraphy indicated that it is more suitable to divide a sequence into four system tracts. The red beds stratigraphic sequence is mainly controlled by the climate and has unique characteristics in sequence evolution. The three kinds of stratigraphic sequence in this region formed three kinds of condensed sections that located in different section of each sequence.The different condensed section will influence the abundance of source rock and resources,and every condensed section controls the distribution and thickness of the source rock.