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Gas Hydrate Research on the North Slope<br />
of the South China Sea, China<br />
Wu Nengyou 1) , Zhang Hongtao 2) , Huang Yongyang 1) , Yang Shengxiong 1) ,<br />
Zhang Haiqi 2) , Zhang Guangxue 1) , Zhao Hongwei 2) ,<br />
Liang Jinqiang 1) and Wang Hongbin 1)<br />
1) Guangzhou Marine Geological Survey, CGS, Guangzhou 510075, P. R. China<br />
2) China Geological Survey, Beijing 100011, P. R. China<br />
ABSTRACT: The north slope of South China Sea is a characteristic Cenozoic<br />
passive continental margin and is rich in oil and <strong>gas</strong> bearing basins. As a result, the<br />
geological and tectonic settings, the temperature and pressure regimes, and the<br />
methane-generating potential from the thick organic-rich sediments are all<br />
favorable for <strong>gas</strong> <strong>hydrate</strong> formation. Since 2001, the Guangzhou Marine<br />
Geological Survey (GMGS) has continuously carried out geological, geophysical<br />
and geochemical investigations for <strong>gas</strong> <strong>hydrate</strong> in the northern South China Sea. In<br />
this paper, the progress of <strong>gas</strong> <strong>hydrate</strong> research in the north slope of the South<br />
China Sea in the past five years is reviewed.<br />
The evidence for <strong>gas</strong> <strong>hydrate</strong>’s existence is currently considerable. Seismic data<br />
shows a well-developed BSR in profiles perpendicular to the SE-facing slope of the<br />
NE South China Sea. A certain degree of reprocessing and/or closer examination<br />
reveals the acoustic anomaly patterns. Studies of velocity structure of <strong>hydrate</strong>d<br />
sediments are useful for better understanding the distribution of <strong>gas</strong> <strong>hydrate</strong>s.<br />
The unambiguous images of bacterial mats, <strong>gas</strong> <strong>hydrate</strong>-derived carbonates and<br />
vent-clams have been obtained from a self-contained deep-towed photographic<br />
system. A lot of carbonate and clam samples were recovered by TV-guided grab.<br />
A number of geochemical anomalies may be related to the formation and<br />
dissociation of <strong>gas</strong> <strong>hydrate</strong>s, including the headspace <strong>gas</strong> in sediments, carbon<br />
isotopes of methane, downward and spatial profiles of Cl - , SO 4 2- and major cations<br />
(e.g., Ca, Mg, Ba, Sr, B, and NH 4 ) contents, and 18 O, D, 11 B, and 87 Sr/ 86 Sr ratios of<br />
the pore waters.<br />
New Energy Resources in the <strong>CCOP</strong> Region - Gas Hydrates and Coalbed Methane 25
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