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地下介质的地震波速度与岩石性质有密切的关系,反映岩石类别和其中含流体的状况。剩余层速度分析是在分析层速度数据基础之上,进行剩余层速度计算,突出局部速度异常,配合BSR分布及振幅异常分析,预测天然气水合物分布的范围。本研究通过对BSR层层速度和剩余层速度的计算,并且结合多种特殊地震属性以及BSR分布范围进行综合分析,进一步了解层速度和剩余层速度在水合物解释中的指示意义:①地层层速度能在一定程度上反映岩性分层、岩石类别和含流体状况,高值层速度与地层厚度、压实作用和岩石性质有关,含水合物地层的层速度往往比一般地层的层速度高;②剩余层速度消除了地层厚度和压实作用的影响,高值剩余层速度主要是由岩性的差别引起;③结合BSR和其他地震属性分析可判断剩余层速度是否由水合物引起;④含水合物地层中,剩余层速度越高水合物的含量越高;剩余速度越低,说明泥质含量越高或者是气体的含量越高。
The seismic wave velocity of underground media is closely related to the nature of the rock and reflects the rock type and the fluid-containing conditions in it. Residual layer velocity analysis is based on the analysis of the layer velocity data, the remaining layer velocity calculation, highlighting the local velocity anomalies, with the BSR distribution and amplitude anomaly analysis to predict the range of gas hydrate distribution. In this study, through the calculation of BSR layer velocity and residual layer velocity, and combined with a variety of special seismic attributes and BSR distribution range to make a comprehensive analysis, we can further understand the significance of layer velocity and residual layer velocity in hydrate interpretation: The velocity can reflect lithologic stratification, rock types and fluid-containing conditions to a certain extent. The velocity of high value layers is related to the thickness of strata, compaction and rock properties. The strata velocity of hydrate-bearing strata is often higher than that of normal strata ; ② the remaining layer velocity eliminates the effect of formation thickness and compaction, and the residual velocity of high value is mainly caused by the difference of lithology; ③ With the analysis of BSR and other seismic attributes, it can be judged whether the residual layer velocity is caused by hydrate; ④ In the hydrate-bearing formations, the higher the remaining velocity, the higher the hydrate content; the lower the residual velocity, the higher the mud content or the higher the gas content.