东营凹陷永8地区沙三段沉积体系研究

Sedimentary systems in the third member of the Shahejie Formation, Yong-8 region, Dongying depression

关键词:  永8地区  沙三段  层序地层格架  沉积相  沉积体系

Key words:  Yong-8 region  third member of the Shahejie Formation  sequence stratigraphic framework  sedimentary facies  sedimentary system

摘要:

综合运用岩心、测井、录井、地震、古生物等资料,对东营凹陷永8地区沙三段进行层序地层划分和沉积相研究。将沙三段划分为上、中、下3个长期旋回,进一步将沙三上亚段和沙三中亚段各分为4个短期旋回,沙三下亚段分为2个短期旋回。古近纪沙三期主要发育2种沉积相类型,即三角洲、半深湖-深湖相。对研究区沉积相的演化特征分析表明,构造位置、古地貌和物源方向对沉积相具有重要的控制作用。研究区沙三段发育了前三角洲-三角洲前缘-三角洲平原-河流相-浅湖亚相纵向演化序列,沉积体系在纵向上表现为湖泊-河流-湖泊体系的分布特点,具有明显的周期性纵向演化特征。在平面上,河流、三角洲从东向西逐渐推进。通过对该地区的沉积体系研究,为储层评价及油气勘探起到指导作用。

Abstract:

The sequence stratigraphic division and sedimentary facies analysis of the third member of the Shahejie Formation in the Yong-8 region, Dongying depression are based on the core examination, well logs, seismic and palaeontological data. The third member of the Shahejie Formation is divided into three long-term cycles and two sedimentary facies types, including the delta and bathyal-abyssal facies. The main controlling factors of sedimentary facies comprise tectonic settings, palaeogeomorphical features and provenances. Vertically, the third member of the Shahejie Formation exhibits the evolutionary sequences of the prodelta, delta front, delta plain, river and shallow lake subfacies, representing the lake, river and lake sedimentary systems. Laterally, the river and delta facies are developed gradually from the east to the west of the study area. The results of research for the sedimentary systems may facilitate the reservoir assessment and hydrocarbon exploration in the study area.