文章采用基于特殊处理数据的叠后谱反演方法对南海北部陆坡神狐海域的含水合物沉积层厚度进行预测。正演模拟结果表明, 谱反演技术可以精细识别异常地质体, 获取高分辨率的反射系数剖面。结合研究区高信噪比地震资料, 基于频谱分析, 发现在频率剖面上含水合物沉积层主要表现为低频高能、高频低能或高频盲区之上的低频低能、高频高能或高频低能区, 含水合物沉积层顶底界面均存在频率异常, 且含水合物沉积层底界衰减最为强烈, 通过谱反演, 发现获取的反射系数剖面比原始地震数据分辨率更高, 且与实际测井结果可对比, 通过定义-90°相位旋转后谱反演结果上振幅为零值的点之间的距离为地层厚度, 计算的过井含水合物沉积层厚度与测井估算结果吻合度高。研究表明, 该方法可以获取精度较高的含水合物沉积层厚度信息, 实现精度较高的水合物储量估算。
关键词：
南海; 神狐; 水合物; 时频; 资源量
Gas hydrate has attracted great interest from the scientists for the impact of its fossil fuel resource potential, the extent of submarine geohazard and global climate change. Thickness of a hydrate-bearing layer is an important parameter in resource evaluation. Quantitative identification of potential gas hydrate accumulation needs to pay urgent attention to the technology in pre-drilling assessment. Thickness of a hydrate occurrence can be identified by the time-frequency analysis method. The result suggests that the time-frequency analysis method, guiding by the logging data, may be an effective tool to identify thick hydrate-bearing layers. A hydrate-bearing layer tends to appear as a low-frequency low intensity zone, underlying a low-frequency high intensity and high-frequency low intensity zone.
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