Abstract On the account of the absence of modern analogues, the interpretation of evaporite-bearing basins relies extensively on seismic and well data. Recent studies describe the intrasalt kinematic, geometries and compositions, relating the change of reflection patterns in seismic data to variations in evaporite sequences. However, these interpretations are only qualitative. This study describes a step further in proceeding from qualitative to quantitative interpretation of an evaporite-dominated interval. It integrates geophysical and geological foundations by combining rock physics, seismic inversion and statistical techniques to deliver seismic-driven facies volume of the evaporite sequence in the Santos Basin, offshore Brazil. Synthetic seismogram demonstrate the ambiguities and uncertainties in relating the seismic amplitude to salt types. Rock-physics analysis indicates that acoustic impedance is an effective differentiator of salt types in comparison to seismic amplitude. Therefore, we perform seismic inversion to transform interface property into layer property. The acoustic impedance volume mitigated significantly the risk of seismic interpretation in the salt sequence. The Bayesian classification integrates acoustic impedance and rock-physics analysis to deliver the seismic-driven facies volume, which categorizes bittern salts, halite and anhydrite. This enables the refinement of the seismic-stratigraphic interpretation of intrasalt sequences of the Ariri Formation based on the sedimentary cycles of evaporites. Additionally, we calculate proportion maps to evaluate the spatial variability of salt deposition. We observe an increase in bittern salts and anhydrite proportions from the bottom to the top of the sequence. The comparison between well-based and seismic-based proportions testifies to the quantitative potential of seismic data. The approach provides quantitative analysis of the evaporite sequence and can be applied to other salt-bearing basins.

中文翻译：

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桑托斯盆地蒸发岩层序的定量地震地层解释

摘要 由于缺乏现代类似物，含蒸发岩盆地的解释广泛依赖于地震和井资料。最近的研究描述了盐内运动学、几何形状和成分，将地震数据中反射模式的变化与蒸发岩序列的变化联系起来。然而，这些解释只是定性的。本研究进一步描述了从蒸发岩主导层段的定性到定量解释的进一步发展。它通过结合岩石物理学、地震反演和统计技术来整合地球物理和地质基础，以提供巴西近海桑托斯盆地蒸发岩层序的地震驱动相体积。合成地震图显示了将地震振幅与盐类联系起来的模糊性和不确定性。岩石物理学分析表明，与地震振幅相比，声阻抗是盐类类型的有效区分因素。因此，我们进行地震反演以将界面属性转换为层属性。声阻抗体积显着降低了盐层序中地震解释的风险。贝叶斯分类整合了声阻抗和岩石物理分析，以提供地震驱动的相体积，对卤盐、岩盐和硬石膏进行分类。这使得基于蒸发岩沉积旋回的 Ariri 组盐内层序的地震地层解释得以完善。此外，我们计算比例图以评估盐沉积的空间变异性。我们观察到卤盐和硬石膏比例从序列的底部到顶部增加。基于井和基于地震的比例之间的比较证明了地震数据的定量潜力。该方法提供蒸发岩层序的定量分析，并可应用于其他含盐盆地。