万安盆地重磁场特征研究与构造分析

发布时间：2018-01-10 09:10

本文关键词：万安盆地重磁场特征研究与构造分析　出处：《西安石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：万安盆地是位于南沙地块西侧,印支块体昆嵩地块东南缘的一个基底复杂的新生代走滑拉张型沉积盆地。上世纪八十年代国内外对万安盆地进行了不同程度的勘探研究,不同学者以地震资料为主对盆地地层、断裂系统和构造单元进行了划分。万安盆地在新生界经历了多次构造运动和六个阶段的构造演化,使得盆地内断裂极为发育,断裂体系对盆地构造单元划分起着重要作用。本文利用收集的万安盆地重磁力资料,结合前人相关研究,对万安盆地的构造、地层等方面有一个全面的认识,为万安盆地进一步的油气勘探工作提供基础的地球物理依据。本文主要收集了万安盆地重磁力资料,利用精度约为1:100万的重力数据,通过解析延拓、滑动平均、正则化滤波、总水平导数、垂向导数等方法对重磁力数据进行处理,得到不同的重磁力转换参数图件。结合区域地质资料,系统分析万安盆地重磁场特征,并对局部重磁异常成因进行解释;通过不同重磁力转换参数图件对盆地断裂体系进行了重新划分与解释,对与前人划分不同的新断裂进行解释,并系统划分了盆地的构造单元;利用4条主要剖面的重力拟合结果探讨了不同构造单元的地层展布。取得的主要成果和结论如下:(1)万安盆地布格重力异常依据其特征可划分为西部低值区、中部较高值区、南部较高值区和东部高值区,剩余重力异常较为复杂,重力高与重力低成带相间分布,基本反映新生界的凹隆格局,剩余重力异常特征多与新生界沉积厚度相关。局部磁异常在盆地内较为发育,主要分布在盆地南部和东侧,推测主要为中新世火山岩活动和基底岩浆岩侵入引起。(2)万安盆地断裂发育,断裂走向以北北东向和北东向为主,其次为北西向。与前人结果相比,万安断裂并没有延伸至盆地东南缘,在盆地中部终止;F2断裂和F4断裂是本次研究重新划出的断裂;F2断裂控制盆地南部的构造单元边界;南海西缘断裂带(万安盆地段)是印支地块南部与南沙地块的分界。(3)万安盆地基底由北西向南东呈凹隆相间分布格局,盆地整体新生界发育。万安盆地构造单元可划分为西北坳陷、北部隆起、中部坳陷、中部隆起、南部坳陷和东部坳陷6个构造单元。
[Abstract]:Nansha is located in the west of Wan'an Basin is a Cenozoic massif, a basal Indochina block of the southeastern margin of Kon Tum block complex strike slip extensional sedimentary basin. The last century at home and abroad in 80s of Wan'an Basin carried out exploration on different levels, different scholars mainly based on seismic data of strata, fault system and tectonic units of division of Wan'an Basin in Cenozoic experienced multiple tectonic movements and six tectonic evolution stages of the basin fractures highly developed, fracture system plays an important role in the division of tectonic unit. The collection of Wan'an Basin, gravity and magnetic data, combined with previous studies, structure of Wan'an Basin, a a comprehensive understanding of the formation and other aspects, to provide the basis for the Wan'an Basin further petroleum exploration geophysical basis. In this paper, the main collection of Wan'an Basin, gravity and magnetic data, Using gravity data accuracy is about 1:100 million, by analytic continuation, moving average filter, regularization, total horizontal derivative, the vertical derivative method of gravity and magnetic data processing, get the magnetic conversion parameters of different maps. Combined with regional geological data, the system analysis of magnetic field characteristics and the causes of an 000 basin. Abnormal local gravity and magnetic interpretation; through different magnetic conversion parameter maps were redivided and interpretation of Basin fault system interpretation of the previous and new fracture of different systems, and division of tectonic units of the basin; the results of strata distribution in different tectonic units by gravity fitting 4 main section. Results and conclusions are as follows: (1) the basin according to the characteristic of Bouguer gravity anomaly can be divided into the low value area, the central high value area, southern high value area and East high value areas, left Residual gravity anomaly is complex, high gravity and gravity low with alternate distribution, basically reflect Cenozoic depression uplift pattern, residual gravity anomaly characteristics associated with Cenozoic sedimentary thickness. Local magnetic anomaly in the basin is relatively developed, mainly in the South and east of the basin, the main push for measuring Miocene volcano rock the basal activity and magmatite intrusion caused. (2) the development of Wan'an Basin fracture, fracture to NNE and NE, followed by the North West. Compared with the previous results, and no fault Wanan extends to the southeast margin of basin, terminating in the central basin; F2 fault and F4 fault of the fault to draw the boundaries of tectonic units; F2 fracture control in southern basin; western margin fault zone of the South China Sea (Wan'an Basin area) is the boundary between the southern Indochina block and Nansha block. (3) the basin basement from North West to South East is concave and convex distribution pattern, The whole basin is developed as a whole. The structural units of the Wan An basin can be divided into 6 tectonic units: the northwest depression, the northern uplift, the central depression, the central uplift, the southern depression and the eastern depression.

【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13;P631

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