孤南洼陷古近系沙三段中亚段可容空间转换系统研究

传统的层序地层学认为,在盆地演化过程中,海(湖)平面或可容空间的变化是统一的。然而根据对可容空间变化的分析研究发现,由于受到基底的差异沉降、沉积物的沉积以及绝对湖平面的变化三种因素的控制,断陷盆地内可容空间在时间和空间上的变化是非统一性的。根据可容空间的变化划分出的可容空间增加带、减小带以及转换带所组成的体系及其在平面和垂向上的空间展布称之为可容空间转换系统。文中首先从理论模型的角度分析了断陷盆地可容空间转换系统的构成要素及其相互关系,论述了可容空间转换系统的组成和划分方案,并以孤南洼陷沙三中亚段为研究对象,划分了一个三级可容空间转换系统并细分为7个四级可容空间转换系统。最后从石油地质学理论以及可容空间转换带处准层序垂向发育特征两方面阐述了转换带与油气成藏之间的关系,并结合典型油气藏实例解剖,认为可容空间转换带控制了有利的成藏组合的发育位置。

Research on the accommodation space transformation system in the Esz3 member of the Gu'nan sag

According to the traditional sequence stratigraphy,the change of the sea(lake) level or of the accommodation space of the basin is unified.However,based on the analysis and research on the accommodation space,we found that because of the influences of differential basement subsidence,sedimentary process and absolute lake level fluctuation,the changes of the accommodation space in a faulted basin are not unified.The accommodation-increasing,accommodation-decreasing and accommodation-transformation belts,and their three-dimensional distribution are called the accommodation space transformation system.Based on the theoretical model of the accommodation space transformation system,we have expatiated on its components and their relationship,and its division scheme.The Esz3 member of the Gu'nan sag as a research object has been divided into a 3rd-order accommodation space transformation system and seven 4th-order transformation systems.According to the petroleum geology and the vertical sequence characteristics of the transformation belt,we have discussed the relationship between the transformation belt and the formation of reservoir.In addition,with the analysis of classical reservoir,we propose that the transformation belt controls the distribution of the oil and gas.