南海中建南盆地地震地层分析

Seismic stratigraphic analysis of Zhongjiannan basin in South China Sea

（广州海洋地质调查局，广州510760）

Guangzhou Marine Geological Survey, Guangzhou 510760,China

中建南盆地是发育于南海西部陆缘的大型新生代沉积盆地，勘探程度较低，综合地球物理调查表明盆地内具有形成油气圈闭的生储盖条件，有良好的油气勘探前景。利用多道地震调查资料和周边地区的地质资料对盆地进行了地震地层分析，解释了5个地震反射界面，划分出3个地震超层序和5个地震层序，并进行了较为详细的描述；对各地震层序的地质属性进行了分析探讨，认为盆地发育有全新统—上新统、上中新统、中中新统—下中新统、渐新统—上始新统、中始新统—古新统等5套地层；在地震相划分和沉积相分析的基础上，对各层序的沉积特征和沉积发育史进行了分析，认为盆地早期为陆相沉积，逐渐发展为现今的浅海—半深海相沉积。

Zhongjiannan basin,a large Cenozoic sedimentary basin developed in the west continental margin of South China Sea,is low in exploration degree.The integrative geophysical survey indicates that the basin has a good exploration potential for its favorable source-reservoir-cap conditions for forming traps.The multi-channel seismic data and geologic survey data surrounding the basin were used for seismic strata analysis.5 seismic reflection interfaces,3 seismic supersequences,and 5 seismic sequences were divided and described in detail.Geologic attributes of seismic sequences was analyzed and discussed.It was found out that there are 5 sets of stratum in the basin: Holocene-Pliocene, Upper Miocene, Middle Miocene-Lower Miocene, Oligocene-Upper Eocene, and Middle Eocene-Paleocene. Based on the classification of seismic facies and the analysis of sedimentary facies,the sedimentary characteristics and the depositional history of seismic sequences were analyzed.The results show that the sedimentary environment of the basin is continent deposit at early stage and shallow sea-bathyal facies nowadays.