摘要
渤海湾盆地济阳坳陷渤南洼陷的主要含油层系为古近系的沙河街组。沙河街期各时段沉积相的展布各具特征 ,并具清晰的演化序列。沙四早期以发育扇三角洲相为特征 ,分布于洼陷南部 ;北部边缘则发育近岸水下扇沉积 ;东部及西部均存在辫状河三角洲相 ;中部有盐湖沉积。沙四晚期以盐湖相发育为特征 ,主要占据湖泊深水部位 ,其周围依次分布半深湖、浅湖及滨湖亚相。此外 ,局部见及小型辫状河三角洲沉积。沙三期是辫状河三角洲发育的全盛时期 ,主要分布于洼陷东南部 ,物源来自孤岛凸起。这些沉积长期以来被认为是浊积岩 ,近期研究表明它们属辫状河三角洲沉积。辫状河三角洲前缘砂体构成了渤南洼陷最主要的储层成因类型 ,渤南洼陷绝大部分油气均储存在该类砂体中。沙三期湖泊相沉积也始终发育 ,且深湖、半深湖亚相发育良好。经过沙三期后的抬升剥蚀和填平补齐作用 ,沙二期湖盆变浅 ,以浅湖为主 ,研究区东南部及西北部均发育面积较大的辫状河三角洲沉积。沙一期发生大规模湖侵 ,物源区向后退缩 ,研究区仅存在单一的湖泊相 ,其中半深湖。
The Paleogene Shahejie Formation is the main petroliferous stratum in the Bonan Sag of Jiyang Depression in Bohai Gulf Basin.The features of the distribution of sedimentary facies of every Member of the Shahejie Formation are various and the evolution of sedimentary facies is clear. During the early time of the fourth subage of the Shahejie Age, it was characterized by well developed fan delta facies, which located in the south part of the Bonan Sag. Inshore submerged fan was developed in the north margin, braided delta facies located in the east and west, and deposits of salty lacustrine was located in the center. During the late time of the fourth subage, it is characterized by well developed salty lacustrine facies, which located in the deep water area of the Bonan Sag. Semi deep lake subfacies, shallow lake subfacies and lake hore subfacies were developed respectively around the salty lacustrine facies. Moreover, there were some small scale braided deltas locally. The third subage of the Shahejie Age was the time of full bloom of the braided deltas. During this time, the braided deltas located in the southeast part of Bonan Sag. The main source area was Gudao Salient. Sandstone bodies of the braided delta front are the most principal reservoir in which almost oil of Bonan Sag was preserved. The lacustrine facies was also developed throughout the third subage, especially the deep lake subfacies and semi deep lake subfacies were well developed. Through the uplift, erosion and sedimentation during the post third subage, the lacustrine basin of the second subage shallowed and was mainly composed of the shallow lake subfacies. The braided deltas with an extensive area were developed in the southeastern and northwestern of the study area. During the first subage, source area retreated with a large scale transgression of the lake. There only was the lacustrine facies developed in the study area, in which the deep lake subfacies and semi deep lake subfacies were over prevailed.
出处
《古地理学报》
CAS
CSCD
2002年第4期19-29,共11页
Journal of Palaeogeography：Chinese Edition
关键词
沉积相
古近系
沙河街组
渤南洼陷
济阳坳陷
sedimentary facies, evolution of sedimentation, Paleogene, Shahejie Formation, Bonan Sag
