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从弹性频散和固有衰减的角度出发,对Gypsy实验场地一地层内利用不同频率测得的速度值之间存在明显的不一致性作了解释。通过测井信息确定的简单模型,估算Gypsy砂岩之上一海相层段内部频散的弹性散射分量(38％)。任何比这个层段弹性散射的预测数大的频散被认为由固有衰减(62％)所造成。利用该井的垂直测量值,直接位于Gypsy砂岩之上的海相层段估算的固有Q_1=51,具有一个有效的Q数值,因为散射Q_(sc)=85。综合基质的总Q为32。利用固有Q=30并忽略散射作用的影响,可以解释Gypsy层内部非均质性砂岩和页岩的垂向测量值的频散。水平观察值需要进行更详细的模拟工作,以揭示路径和体积效应、弹性散射、衰减和固有各向异性的相对作用。声测井曲线上不太容易分辨的薄层在改善井间响应方面具有重要意义。频散可能是利用井间和地表地震资料作出储层属性图件的关键。
From the perspective of elastic dispersion and intrinsic attenuation, there is a clear explanation of the inconsistencies between the velocity values measured at different frequencies within a formation at the Gypsy site. Elastic scattering components (38%) of the internal dispersion above the Gypsy sandstone were estimated from a simple model determined by log information. Any dispersion greater than the predicted number of elastic scattering in this interval is believed to be caused by inherent attenuation (62%). Using the vertical measurements of this well, the intrinsic Q_1 = 51 estimated for the marine interval directly above the Gypsy sandstone has a valid Q value because of the scattering Q sc (sc) = 85. The total Q of the integrated matrix is 32. Using the intrinsic Q = 30 and ignoring the effects of scattering, it is possible to account for the dispersion of the vertical measurements of inhomogeneous sand and shale within the Gypsy layer. Horizontal observations require more detailed simulations to reveal the relative contribution of path and volume effects, elastic scattering, attenuation and intrinsic anisotropy. Thin layers that are not easily discernible on acoustic logs are of great importance in improving cross-well response. Dispersion may be the key to making maps of reservoir properties using crosswell and surface seismic data.