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南海北部陆坡神狐海域是中国天然气水合物勘探最具潜力的区域之一.对该海域53个站位的孔隙水硫酸盐梯度、硫酸盐-甲烷界面(Sulfate-Methane Interface,SMI)和硫酸盐通量等进行计算和综合分析,结果显示孔隙水SO42-浓度梯度范围为0.33～4.43mmol L-1m-1,SMI深度范围为7.7～87.9mbsf.计算得出硫酸盐通量范围为2.0～26.9mmol m-2a-1,平均为11.7mmol m-2a-1.53个站位的SMI深度与甲烷通量相关系数为-0.80,表明SMI深度受甲烷通量影响,甲烷通量控制了甲烷厌氧氧化反应(Anaerobic Methane Oxidation,AMO)的速率以及SMI的深度和硫酸盐通量.似海底反射(Bottom Simulating Reflector,BSR)基本上分布于SMI埋深小于50m bsf或硫酸盐通量大于3.5mmol m-2a-1的区域,钻探获得水合物实物样品的SH2B,SH3B和SH7B三个钻孔的BSR埋深和SMI埋深的比值分别为8.36,8.60和9.94.结合地球化学和地球物理方法进行综合分析,认为白云凹陷和南部隆起是神狐海域天然气水合物发育的有利区.
One of the most potential areas for gas hydrate exploration in China is one of the most potential areas for gas exploration in China, including the Sulfate-Methane Interface (SMI) and sulphate Flux, etc. The results show that the SO42- concentration gradient of pore water ranges from 0.33 to 4.43 mmol L-1m-1, and the SMI depth ranges from 7.7 to 87.9 mbsf. The calculated sulfate flux ranges from 2.0 to 26.9 The correlation coefficient between the SMI depth and methane flux was 11.8 mmol mmol-2a-1 with an average of 11.7 mmol m-2a-1.53 stations, indicating that the SMI depth is affected by methane flux and methane flux controls methane anaerobic oxidation (AMO) rate and SMI depth and sulphate flux.The Bottom Simulating Reflector (BSR) is basically distributed in the SMI buried depth less than 50m bsf or sulfate flux greater than 3.5mmol m- 2a-1, the ratios of BSR depth to SMI buried depth of the three drilled SH2B, SH3B and SH7B drilled hydrate samples were 8.36, 8.60 and 9.94, respectively. The combined analysis of geochemistry and geophysical methods , That Baiyun depression and southern Long Shenhu area is favorable areas of gas hydrate development.