Controlling factors for gas hydrate occurrence in Shenhu area on the northern slope of the South China Sea

查看全文 作　　者：WANG [1,2]HongBin;YANG [1]ShengXiong;WU [2,3]NengYou;ZHANG [1]GuangXue;LIANG [1]JinQiang;CHEN [2,3]DuoFu

机构地区：[1]Key Laboratory of Marine Mineral Resources of Ministry of Land and Resources, Guangzhou Marine Geological Survey;[2]Guangzhou Research Center for Gas Hydrate, Guangzhou Institute of Energy Conversion of Chinese Academy of Sciences;[3]CAS Key Laboratory Marginal Sea Geology, Guangzhou Institute of Geochemistry of Chinese Academy of Sciences

出　　处：《Science China Earth Sciences》索引2013年第56卷第4期,共8页

基　　金：supported by National Basic Research Program of China(Grant No. 2009CB219508);Chinese Academy of Sciences (Grant No.KZCX2-YW-GJ03);National Natural Science Foundation of China(Grant No. 91228206) 摘　　要：Temperature and pressure on seafloor of the northern slope in the South China Sea are suitable for gas hydrate formation, but bottom simulation reflector (BSR), an indication of gas hydrate occurrence, only occurred in limited areas of the slope. Drillings in the BSR-distributed area (the District S) on the northern slope of the South China Sea suggested that gas hydrate only occurred at Sites SH2, SH3, and SH7 with high saturation (up to 20%-40%), and there is no hydrate at Sites SH1 and SH5 although the distance between SH1 to SH3 is only 500m. In this paper, we investigated seafloor gradient, fault development, temperature, and pressure in the District S on the northern slope of the South China Sea to understand the possible factors con- trolling BSR distribution and gas hydrate occurrence. The District S is a structurally fractured continental slope zone and its seafloor gradient varied greatly. The BSR-occurred areas have an average gradient of 19.89×10 2 whereas the BSR-free zone has the average gradient of 10.57×10 2 . The calculated relative structural intensities from fault densities and displacements show that the BSR-distributed areas tend to occur in the areas with a moderately high structural intensity, where faults frequently developed close to the seafloor that are possibly favored for lateral migration of gases. On the basis of temperatures and pressures at drilling sites, hydrate-occurred Sites SH2, SH3, and SH7 are located within the thermodynamically stable area for methane hydrate, and hydrate-absent Sites SH1 and SH5 are out of the thermodynamically stable area for methane hydrate formation, suggesting that both BSR and the thermodynamic stability are necessary for hydrate occurrence in the subsurface. 关键词：海域天然气水合物南海北部陆坡控制因素中国热力学稳定性甲烷水合物海底坡度结构强度

相关文献

参考文献（31）
引证文献（11）
耦合文献（598）

参考文献(31)

引证文献(11)

耦合文献(598)

互联网出版许可证新出网证(渝)字10号全国400电话 - 免长途话费

Controlling factors for gas hydrate occurrence in Shenhu area on the northern slope of the South China Sea

参考文献(31)

引证文献(11)

耦合文献(598)

用户提示