南海东北部陆坡水合物钻探区海底表层热导率分布特征

发布时间：2018-04-27 02:38

本文选题：天然气水合物 + 热导率　；参考：《海洋地质与第四纪地质》2016年02期

【摘要】：依据获取的热导率测量数据和多波束数据所反映的海底地貌特征,分析了南海东北部陆坡天然气水合物钻探区表层沉积物矿物组成、粒级以及区域地貌特征对热导率分布的控制作用。研究结果表明,钻探区表层沉积物热导率平均值为(1.26±0.12)W/(m·k),相对于南海北部陆坡热导率背景偏高,沉积物组分中既含有陆源浊流沉积体中的高热导率矿物,也含有由甲烷等为主要气源的生物化学反应而形成的具有高热导率特性的碳酸盐。钻探区表层沉积物热导率区域细节分布具有非常明显的特征,2区和5区属于海台地貌,海底表层分布有大面积的碳酸盐结壳,由于底流的剥蚀作用导致沉积物粒级相对较粗,呈现高值热导率(1.32±0.06)W/(m·k)和(1.34±0.06)W/(m·k),并以此为中心向周缘逐级降低;位于海底海槽处的1区和8区则属于海槽地貌,海底表层易于接受来自海台的过滤沉积物,粒级相对较细但压实程度较低,呈现低值热导率,分别为(1.10±0.06)W/(m·k)和(1.01±0.06)W/(m·k)。钻探区表层沉积物热导率偏高主要受控于内生地质作用控制下高流体疏导所携带的化学组分,而热导率的非均匀分布则受控于外生地质作用诸如地貌地形变化导致的粒级分布状况。
[Abstract]:The mineral composition of surface sediments in the natural gas hydrate drilling area on the northeast slope of the South China Sea is analyzed according to the geomorphological characteristics of the seabed reflected by the obtained measurements of thermal conductivity and multi-beam data. The effect of grain size and regional geomorphology on the distribution of thermal conductivity. The results show that the average thermal conductivity of surface sediments in the drilling area is 1. 26 卤0.12)W/(m / KG, which is higher than that in the northern slope of the South China Sea. The composition of the sediments contains both high thermal conductivity minerals from terrestrial turbidite sediments. It also contains carbonates with high thermal conductivity formed by biochemical reactions of methane and other main gas sources. The detailed distribution of the thermal conductivity of surface sediments in the drilling area is very obvious. Area 2 and area 5 belong to the sea platform geomorphology. There is a large area of carbonate crusts in the surface layer of the seabed, and the sediment grain size is relatively coarse due to the denudation of the bottom flow. The results show that the thermal conductivity is 1.32 卤0.06)W/(m ~ (k) and 1.34 卤0.06)W/(m ~ (KN), and this decreases gradually to the peripheral margin. The first and eighth zones located at the bottom trough belong to the trough landform, and the surface layer of the seabed is easy to accept the filtered sediments from the sea platform, and the surface layer of the sea is easy to accept the filtered sediment from the sea platform. The grain size is relatively fine but the compaction degree is low, showing a low thermal conductivity of 1.10 卤0.06)W/(m ~ (k) and 1.01 卤0.06)W/(m / KG, respectively. The high thermal conductivity of the surface sediment in the drilling area is mainly controlled by the chemical components carried by the high fluid dredging under the control of the endogenetic geological process. The non-uniform distribution of thermal conductivity is controlled by the grain-level distribution caused by exogenetic geological processes such as geomorphologic changes.
【作者单位】：中国地质调查局广州海洋地质调查局;国土资源部海底矿产资源重点实验室;
【基金】：国土资源部国家专项(GZH201100303;GZH201100305) 国家高科技研究发展计划“863”项目(2013AA092501) 国家自然科学基金项目(91428205)
【分类号】：P744.4

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