辽河西部凹陷古近系沙四上亚段沉积相研究

发布时间：2018-01-20 23:08

本文关键词： 辽河西部凹陷沙河街组滩坝辫状河三角洲沉积相　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：辽河西部凹陷古近系沙四上亚段储层油气产量在中国东部油田中占据重要地位,目前岩性-地层油气藏正成为勘探重点。但由于对沉积相认识上的局限性,影响了勘探进展。本文针对西部凹陷沙四上亚段沉积特征进行研究,通过沉积地质学、层序地层学和多种技术手段,建立了研究区沙四上亚段的层序地层格架,研究了各级次层序内沉积特征,探讨了沉积相平面展布与演化规律。本文首先根据研究区沙四上亚段层序边界特征,确定了西部凹陷沙四上亚段层序划分方案。将沙四上亚段划分为两个三级层序,自下而上为层序一和层序二。进而对体系域和准层序组进行划分,建立起研究区四级层序地层格架。在层序划分的基础上,综合区域地质背景、钻测井和地震资料的分析,明确西部凹陷沙四上亚段沉积相类型和分布规律。在西部凹陷识别出两种主要沉积相类型,分别是辫状河三角洲和湖泊相沉积。其中辫状河三角洲主要发育辫状河三角洲前缘亚相,分布于研究区中南部地区;湖泊相分为滨浅湖和半深湖-深湖亚相,广泛分布于全区,滨浅湖亚相主要发育滩坝沉积,分布于曙北地区、中南部沿岸弱物源区和远岸区,半深湖-深湖亚相分布于曙北深洼区。滩坝是本次研究新发现的沉积相类型,是下一步勘探重点领域。根据沉积特征,将滩坝分为侧缘改造型滩坝、前缘改造型滩坝、基岩改造型滩坝、淹没改造型滩坝和风暴改造型滩坝五种沉积模式。滩坝的控制因素包括古地貌、古水深、古物源和古风场等。本文以曙北滩坝发育区为例,提出了定量恢复“四古”的方法。古地貌采用“印模法”恢复,滩坝主要发育于水下低隆起部位;古水深采用“波痕法”和“坝厚法”恢复,形成滩坝水深大约8m;古物源采用镜下岩屑对比法分析,主力滩坝是由三角洲改造、古潜山剥蚀和岸线基岩侵蚀所形成的混源滩坝;古风场通过滩坝展布特征进行倒推分析,形成滩坝受南北季风影响,风力可达8级。关于滩坝的控制因素总结为“风-源-盆”三端元控制系统。古地貌对滩坝发育具有重要意义,按照古地貌特征将曙北滩坝发育区分为沿岸带、潜山带、潜山披覆带、北部斜坡带和深洼带五个带,阐述“风-源-盆”系统中各因素对每一个带砂体发育的控制作用,并对滩坝分布进行预测。
[Abstract]:The oil and gas production of the Upper submember of the Paleogene Sha 4 in the western depression of Liaohe plays an important role in the oil fields in eastern China. At present, lithology-stratigraphic reservoirs are becoming the focus of exploration, but due to the limitation of the understanding of sedimentary facies. This paper studies the sedimentary characteristics of the upper submember of Sha 4 in the western sag, and establishes the sequence stratigraphic framework of the upper member of the submember of Sha 4 by means of sedimentary geology, sequence stratigraphy and various technical means. In this paper, the sedimentary characteristics of subsequences are studied, and the distribution and evolution of sedimentary facies are discussed. Firstly, according to the sequence boundary characteristics of the upper sub-member of Sha 4 in the study area. The sequence division scheme of the upper submember of Sha4 in the western sag is determined. The upper submember of the fourth member of the depression is divided into two third-order sequences, the first and second sequences from the bottom to the top, and the system tracts and quasi-sequence sets are further divided. The fourth order sequence stratigraphic framework is established in the study area. On the basis of sequence division, the analysis of regional geological background, drilling logging and seismic data is carried out. The types and distribution of sedimentary facies in the upper submember of Sha 4 in the western sag are clarified. Two main sedimentary facies types are identified in the western sag. The braided river delta and lacustrine facies mainly developed braided river delta front subfacies and distributed in the central and southern part of the study area. The lacustrine facies are divided into shallow littoral and semi-deep lacustry-deep lacustrine subfacies, which are widely distributed in the whole area. The shoreline and dam deposits are mainly developed in shoreline and shallow lacustrine subfacies, which are distributed in Shubei area, weak source area and far shore area along the central and southern coast. Semi-deep lacustry-deep lacustrine subfacies are distributed in Shoubei Shenwa area. Beach dam is a new sedimentary facies type discovered in this study and is the next key area of exploration. According to the sedimentary characteristics, the beach dam is divided into lateral edge reformation type beach dam. There are five kinds of sedimentary models: front reformed beach dam, bedrock reconstruction beach dam, submerged reformed beach dam and storm modified beach dam. The controlling factors of beach dam include paleogeomorphology and ancient water depth. Taking the development area of Shubei beach dam as an example, this paper puts forward a method of quantitative restoration of "four ancient times". The paleogeomorphology is restored by "impression method", and the beach dam is mainly developed in the low uplift area under water. The ancient water depth was restored by "wave mark method" and "dam thickness method", and the water depth of beach dam was about 8 m. The source of antiquities is analyzed by contrast method of lithic debris under mirror. The main beach dam is formed by delta reconstruction, erosion of buried hill and erosion of shoreline bedrock. The paleo-wind field is analyzed by the distribution characteristics of beach and dam, and the beach and dam are influenced by the north and south monsoon. Wind power can reach 8 grade. The controlling factors of beach and dam are summarized as "wind-source-basin" three-terminal control system. Paleogeomorphology is of great significance to the development of beach and dam. According to the paleogeomorphic characteristics, the development of Shubei beach dam is divided into coastal zone. Five zones, including buried hill zone, buried hill drape belt, northern slope zone and deep depression zone, are discussed in this paper. The controlling effects of various factors on the development of sand bodies in each belt are discussed, and the distribution of beach and dam is predicted.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P618.13

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