Noble gas geochemical characteristics of shallow hydrate in the deep water of the Qiongdongnan Basin and their significance

被引：0
|
作者：
Sun T. [1 ,2 ]
Wu T. [3 ]
Ge Y. [1 ,2 ]
Fan Q. [1 ,2 ]
Li L. [1 ,2 ]
Lu X. [1 ,2 ]
机构：
[1] CNOOC Research Institute Ltd., Beijing
[2] State Key Laboratory of Natural Gas Hydrates, Beijing
[3] CNOOC China Ltd., Haikou
来源：
Earth Science Frontiers | 2022年 / 29卷 / 05期
关键词：
coal-type gas; gas hydrate; gas source; noble gases; Qiongdongnan Basin;
D O I：
10.13745/j.esf.sf.2022.2.59
中图分类号：
学科分类号：
摘要：
The deep water area of the Qiongdongnan Basin possesses favorable geological condition for gas hydrate accumulation and is one of the leading demonstration areas for marine gas hydrate exploration and development. Based on geochemical analyses of natural gas and noble gases, this paper selects the shallow surface hydrate of the deep water area to carry out a comparative study relating to deep conventional natural gas reservoirs. The results show that shallow surface gas in the study area shares similar carbon isotope characteristics with deep conventional natural gas. The gas source is mainly deep thermogenic gas, with no obvious contribution from biogas, and genetically relates to coal-type gas. It is speculated that the gas source is the coal measure strata of the Yacheng Formation. The Ar isotopic compositions of light noble gases show that the gas source rock is related to the Tertiary formation, whilst the high 3He/4He ratios in samples indicate certain contributions from mantle derived gas. Therefore, under the background of gas-rich depression, it is of great significance to discuss the deep thermogenic gas for hydrate accumulation. The deep thermogenic gas reservoir and shallow hydrate reservoir can form a vertical three-dimensional gas reservoir, which lends theoretical support in future "multi-gas exploitation" for improving economic benefits of gas hydrate reservoir development in deep water areas. © 2022 Science Frontiers editorial department. All rights reserved.
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页码：476 / 482
页数：6
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