南海北部白云凹陷浅层气的识别、成因和运移模式的研究

IOCAS-IR > 海洋地质与环境重点实验室

	南海北部白云凹陷浅层气的识别、成因和运移模式的研究
	秦芹1,2
学位类型	硕士
导师	吴时国
	2017-05-23
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	海洋地质
关键词	白云凹陷浅层气气烟囱
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。
其他摘要	In this paper, the geophysical characteristics, source, migration pattern and distribution of shallow gas in the Baiyun Sag of the Pearl River Mouth Basin in the northern South China Sea are studied. Based on the three-dimensional seismic and well logging data, the geophysical characteristic of the shallow gas in the study area are identified; the geochemical data are collected to discuss the gas source of the shallow gas; the distribution features of the shallow gas are identified according to the seismic reflector characteristic of the gas-bearing layer; and the migration model of the shallow gas in Baiyun Depression was analyzed by establishing geological model. Based on the three - dimensional seismic data, more than 30 lines were interpreted under the constraints of well logging LW3-1-1, and a large amount of shallow gas in the study area was identified. According to the seismic data, the gas-bearing strata has the characteristics of the weak coherence, strong amplitude reflector, low velocity, low instantaneous frequency, etc. According to the characteristics of seismic reflection of the gas - bearing strata, anomalous reflections such as strong reflection, acoustic dumb zone, gas chimney, gas channel, bright spot and polarity reversal are occurred in the seismic profile of the study area. The gas-bearing layer was recognized by the interpretation of the well logging data. Through the interpretation of the seismic profile, it can be seen that a large number of gas vertical migration channels are developed in the study area, and it can be concluded that the shallow gas origins from deep gas-bearing reservoir. And based on the collected geochemical data, the biogenic gas was discovered in the gas-bearing sand of the Pearl River Mouth Basin. Thus, the geophysical and geochemical analyzes indicate that the gas of the shallow sediment are regarded as a mixture of biogenic and thermogenic gas. In the study zone, we establish a migration model of the shallow gas based on the three-dimensional seismic data. The model shows the gas-bearing reservoir, the focused fluid migrating pathway and the accumulation of the shallow gas. Based on the faults, gas chimneys, mud diapirs mud volcano, pipeline, shallow superficial fault and migration canyon which are interpreted from seismic profile, can explain the distribution features of shallow gas. It can be seen that the distribution of the shallow gas in the study area is closely correlated with the deep gas reservoir, faults and the mud content of shallow rocks.
学科领域	海洋科学
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/136616
专题	海洋地质与环境重点实验室
作者单位	1.中国科学院海洋研究所 2.中国科学院大学
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	秦芹. 南海北部白云凹陷浅层气的识别、成因和运移模式的研究[D]. 北京. 中国科学院大学,2017.

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