陆相断陷盆地高精度层序地层研究现状与思路

陆相断陷盆地高精度层序地层研究常采用经典层序地层学和Cross高分辨率层序地层学两种分析方法,这两种方法存在明显的差别,主要体现在层序识别方法与适用范围、层序结构与对地层分布的认识等方面。由于都是基于可容空间的变化来识别层序,使得两种方法相结合解决断陷盆地层序研究问题有了理论上的依据。分析认为,以经典层序地层学方法和三分体系域的观点为基础,通过不整合面的识别和追踪,可建立宏观或区域层序地层格架,研究盆地沉积体系分布演化;以Cross的高分辨率层序地层学方法和二分体系域的观点,建立不整合面控制下的整合地层的高级次层序地层格架,研究沉积相和储层的分布,是陆相断陷盆地高精度的层序地层研究的有效方法。两种层序研究方法的结合点取决于断陷盆地区域性不整合面的分布和发育情况。

Current research situation and thinking on high accuracy sequence stratigraphy in the terrestrial rift basin

There are obvious differences between two analytical methods named classic sequence stratigraphy and Cross' high-resolution sequence stratigraphy on identification method, applicability, inner structure and the knowledge of formation distribution of the sequence in the terrestrial rift basin. These form theoretical basis for sequence studies in the terrestrial rift basin can be made by combining these two methods because both based on the sequence identification for the changes of the accommodation space. Analysis considered that based on the classic sequence stratigraphy method and standpoint of trichotomised system tract, and through i-dentification and trace of unconformity surface the macro- or areal-sequence stratum framework can be established for studying the distribution and evolution of the depositional system; based on Cross' high resolution sequence stratigraphy method and standpoint of dichotomized system tracts, the higher-order sequence formation framework controlled by unconformity surface for studying the distribution of sedimentary facies and reservoir. It is the effectual approach of high accuracy sequence stratigraphy study in the terrestrial rift basin. The combining point of the two methods depends on the development and distribution of the areal unconformity surface in the terrestrial rift basin.