【摘要】 空白带现象是人工地震方法识别含天然气水合物沉积地层的重要标志之一。针对水合物沉积物的 3种微观模式 ,首先采用度量振幅空白程度的振幅比方法 ,计算并分析了水合物饱和度不随孔隙度变化 ,以及水合物的饱和度随孔隙度变化 (即CGHC和VGHC)两种情况 ,然后对上述两种情况设计了地震模型 ,合成了水合物沉积物地震纪录 ,获得了地震空白带现象。研究结果表明 :水合物沉积物饱和度的变化是振幅空白的主要原因。对孔隙度和饱和度都不固定的复杂情况 ,沉积物的岩性存在多解性 ,需用各种方法的多元信息进行对比研究 ,才能更好地解释空白带的产生及其特征。更多还原

【Abstract】 The blanking zone is an important seismic indicator of gas hydrate sediment. From three kinds of micro model for hydrate sediment we chose the amplitude ratio method for measuring the blanking degree to be used in modeling and analyzing the sediment with constant and variable gas hydrate concentration, respectively. Seismic models were designed to synthesize the seismic response under these two circumstances, and the seismic blanking zone was observed. The results demonstrate that the variable gas hydrate concentration is the main cause of the amplitude blanking. There are multiple interpretations for the sediment structure with variable porosity and concentration; therefore, extra available information should be used to study and interpret the cause and the characteristics of the blanking zone.更多还原