TX盆地西部凹陷渐新统-中新统沉积体系研究

发布时间：2018-12-15 00:36

【摘要】：TX盆地位于我国某海域内,是我国海上油气勘探程度较低的含油气盆地之一。本论文研究区为TX盆地内的西部凹陷,其勘探及研究程度较低,是否存在良好油气资源条件是目前需要解决的问题。本论文的研究目的层为渐新统-中新统,研究内容为其内部沉积体系的展布特征描述。前人已有的研究成果表明,该研究层段主要为海相沉积地层,内部发育的优质砂岩储层与下部深湖相烃源岩及上部区域性盖层形成一套良好的生、储、盖油气系统。因此,刻画研究区内中新统-渐新统层位内部砂体分布特征,恢复相应沉积体系,对TX盆地西部凹陷油气地质条件的研究具有较大意义。针对该问题,从前人对TX盆地西部凹陷地质构造背景、地层与沉积特征、盆地构造特征等研究成果出发,通过与邻区相关地震特征、地层、层序对比,以地震资料为基础,应用地震线描方法进行沉积盆地原始结构重建,确定沉积环境。在此基础上,选取研究区内典型地震剖面来识别目的层内部砂体,刻画地震相并圈定优质砂体,确定其发育规律及展布特征。利用源控+相控的方法,建立三角洲-斜坡-深水扇的沉积体系脉络关系,并结合相应的沉积环境、水流体系等,实现研究区沉积体系综合分析。最终基于沉积体系的研究,开展一定程度的油气地质条件研究分析。通过本次论文研究,取得了以下几方面认识:(1)根据地震资料分析,初步确定调查区新生界存在8个主要地震反射界面,其中T3、T6、T8-1、T9、Tg为五个区域性大型角度不整合面,并依此划分、识别出研究区第三系发育Ⅰ-1,Ⅰ-2,Ⅱ-1,Ⅱ-2和Ⅱ-3五个构造层序。(2)在对地震剖面精细解释刻画的基础上,通过地震线描方法进行沉积盆地原始结构的重建,确定研究区渐新统当时的沉积环境为浅海陆架和半深海陆架内洼陷环境、中新统为大陆边缘陆架环境;又通过对地震反射特征的识别与归类,在研究区共识别、划分出6种优势地震相,并对每一种地震相进行了地质意义分析,确定了研究区的优势沉积相分布,为沉积环境特征分析提供了重要依据。(3)通过波形分析,结合邻区已验证实例,确定研究区骨架砂体岩相的波形特征,在研究区目的层位进行砂体扫描,确定不同类型砂体的时空展布,再结合沉积相分布与沉积环境特征分析,确定研究区目的层位中新统、渐新统的沉积体系,划分出三角洲、浅海陆架、斜坡等相带,确定三角洲-深水扇的脉络关系。
[Abstract]:The TX basin, which is located in a certain sea area of China, is one of the oil and gas bearing basins in China. The research area of this paper is the western sag in the TX basin, its exploration and research degree is low, whether there is good oil and gas resource condition is the problem that needs to be solved at present. The purpose of this paper is the Oligocene-Miocene, and the research content is to describe the distribution characteristics of the internal sedimentary system. The results of previous studies show that the studied formation is mainly marine sedimentary formation, and the high quality sandstone reservoir developed in the interior forms a good system of generation, reservoir and cap oil and gas with deep lacustrine source rocks and upper regional caprocks in the lower part. Therefore, it is of great significance to study the oil and gas geological conditions in the western sag of TX basin by characterizing the distribution characteristics of sand bodies inside the Miocene-Oligocene horizon and restoring the corresponding sedimentary systems in the study area. In order to solve this problem, the previous studies on the geological structure background, stratigraphic and sedimentary characteristics and basin structural characteristics of the western sag of the TX basin, based on seismic data, are based on the correlation of seismic characteristics, stratigraphy and sequence with adjacent areas. The original structure of sedimentary basin was reconstructed by seismic line drawing method, and the sedimentary environment was determined. On this basis, the typical seismic profiles in the study area are selected to identify the sand bodies in the target layer, to depict seismic facies and to delineate the high-quality sand bodies, and to determine the development and distribution characteristics of the sand bodies. By means of source-controlled facies control, the sedimentary system of delta-slope-deep-water fan is established, and the sedimentary system in the study area is analyzed synthetically by combining the corresponding sedimentary environment, flow system and so on. Finally, based on the study of sedimentary system, a certain degree of oil and gas geological conditions research and analysis. Based on the analysis of seismic data, it is preliminarily determined that there are 8 main seismic reflection interfaces in the Cenozoic region of the survey area, among which T3T6 T6-T8-1T9; Tg is a regional large angle unconformable surface, according to which, the Tertiary development 鈪，

本文编号：2379610