泌阳凹陷核三段T-R旋回层序地层与沉积体系研究

Study on sequence-stratigraphy and sedimentary system of the Eh3 in Biyang Depression

泌阳凹陷为一陆相断陷湖盆,运用T-R旋回原理对泌阳凹陷下第三系核桃园组核三段地层进行层序划分,这种层序由湖进体系域(LTST)与湖退体系域(LRST)组成。根据详细的相分析、地震地质解释以及区域地质方面的研究,将核三段划分为一个T-R旋回(相当于经典层序地层学的Ⅱ级层序)和3个次级T-R旋回。识别出扇三角洲、远(近)源三角洲、水下扇及浅湖、深湖-半深湖等沉积体系。在此基础上,弄清不同体系域中沉积体系的发育规模及其展布有明显的差异,总结出泌阳凹陷T-R旋回沉积层序模式,为下步油气勘探提供了理论指导。

The suhsident mechanism and basin shape and other features of the continental fault lacustrine basin are different from other sedimentary basins, which results in the difference of the interior constitution of sedimentary sequence and the feature of sequence boundary. Biyang Depression is a fault basins. This paper has a study on the stratigraphy partition of the member Eh3 in Biyang Depression with the principle of T-R cycle. The sequences are composed of lower lacustrine trangressive system trace ( LTST) and supper lacustrine regressive system trace (LRST). On the basis of detailed facies analysis, seismology interpretation and regional geologic survey. The member Eh3 in Biyang Depression is divided into one lacustrine transgressive and lacustrine regressive cycle (T-R cycle) and three lower T-R cycle. The sedimentary systems in the T-R cycle: fluvial fan, fan delta, common delta and lacustrine sedimentary system. On the basis of which, the great difference of the developed scale and the distribution of the sedimentary in different system trace is recognized, the model of T-R cycle sedimentary sequence in Biyang Depression is summarize. The theory guide for the next oil-gas exploration is given in this paper.