南海北部白云凹陷浅层气的地球物理识别、成因和运移模式的研究

发布时间：2018-03-16 09:16

本文选题：白云凹陷　切入点：浅层气　出处：《中国科学院大学(中国科学院海洋研究所)》2017年硕士论文　论文类型：学位论文

【摘要】：本文对南海北部珠江口盆地白云凹陷浅层气的地球物理特征、气体来源、运移模式及其分布规律进行了研究。利用三维地震数据,结合测井数据对研究区域的浅层气进行地球物理识别;收集研究区域地球化学数据来讨论浅层气的气体来源;利用含气地层反射异常特征,识别白云凹陷浅层气的分布规律;以及通过建立地质模型分析了研究区域处浅层气的运移模式。利用三维地震资料,在井LW3-1-1数据的约束下,解释了2000km2的地震数据,识别出研究区域有大量浅层气的存在。根据地震资料解释可以看出含气地层具有弱相干性、高反射振幅、低层速度、低瞬时频率等特点。根据含气地层的地震波反射特征,在研究区域反射地震剖面上大量出现强反射、声波哑区、气烟囱、底辟、亮点以及极性反转等异常反射现象。根据测井数据解释可以看出含气地层测井响应特征:高电阻率、高时差、低密度、低中子孔隙度、高中子伽马等。通过地震剖面解释,可以看出研究区域有大量的气体垂向运移通道,可以判断大量浅层气的来源是深部天然气藏。又通过收集的地球化学资料,发现珠江口盆地浅部含气砂层含有生物成因气。因此,地球物理特征和地球化学分析表明,浅层沉积物中气体的积累被认为是生物成因气和热成因气的混合。在研究区域中,基于大型三维地震数据解释,我们提出三种浅层气运移模型。模型显示了气藏、聚焦流体迁移途径和浅层气积累。当气藏达到一定压力时,气体可能沿着烟囱垂直运输或浅层断层,形成浅层气积累。浅层气的分布基本特性,根据研究区域地震剖面解释的大型正断层、气烟囱、泥底辟构造、多边形断层、以及浅小正断层、迁移峡谷等,可以判断出浅层气的分布特征。可以看出研究区域浅层气的分布与深部气藏、断层分布和浅部岩层泥质含量密切相关。
[Abstract]:In this paper, the geophysical characteristics, gas source, migration model and distribution of shallow gas in Baiyun sag of Pearl River mouth basin in the northern part of the South China Sea are studied. Geophysical identification of shallow gas in the study area based on log data, discussion on gas source of shallow gas by collecting geochemical data, identification of shallow gas distribution in Baiyun sag by abnormal reflection characteristics of gas-bearing formation; The migration model of shallow gas in the study area is analyzed by establishing a geological model. The seismic data of 2000km ~ 2 are interpreted by using three-dimensional seismic data and the constraint of well LW3-1-1 data. According to the seismic data interpretation, we can see that the gas-bearing formation has the characteristics of weak coherence, high reflection amplitude, low layer velocity, low instantaneous frequency, etc. According to the seismic wave reflection characteristics of gas-bearing formation, A large number of abnormal reflection phenomena such as strong reflection, acoustic mute area, gas chimney, diapir, bright spot and polarity reversal appear in the study area reflection seismic profile. According to the interpretation of logging data, the logging response characteristics of gas-bearing formation can be seen: high resistivity, high resistivity, and so on. High time difference, low density, low neutron porosity, high and middle gamma, etc. Through seismic profile interpretation, we can see that there are a large number of vertical gas migration channels in the study area. It can be judged that the source of a large amount of shallow gas is deep natural gas reservoir. Based on the geochemical data collected, it is found that the shallow gas-bearing sand bed in the Pearl River mouth basin contains biogenic gas. Therefore, geophysical characteristics and geochemical analysis show that, The accumulation of gas in shallow sediments is considered to be a mixture of biogenic and thermal gases. In the study area, based on the interpretation of large 3D seismic data, three shallow gas migration models are proposed. When the gas reservoir reaches a certain pressure, the gas may be transported vertically along the chimney or along a shallow fault to form shallow gas accumulation. According to the large normal faults, gas chimneys, mud diapir structures, polygonal faults, shallow normal faults, migration canyons, etc. It can be seen that the distribution of shallow gas in the study area is closely related to the distribution of deep gas reservoirs, fault distribution and shallower shale content.
【学位授予单位】：中国科学院大学(中国科学院海洋研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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