Geofluid identification from seismic data are crucial for understanding reservoir characteristics. However, fluid indicators based on elastic parameter combinations show strong ambiguity in terms of geofluid identification. Although the effective pore-fluid bulk modulus proves to be the superior fluid indicator in geofluid discrimination, it is limited to empirical models such as the critical porosity model. The consolidation parameter model can evaluate the consolidation and compaction of sediments and is widely used due to its better applicability. Therefore, a novel fluid indicator considering consolidation parameter is proposed and a boundary-constrained inversion strategy for geofluid identification is developed. First, the novel fluid indicator is defined based on the poroelasticity theory. Then, the linearized AVA (amplitude variation with angle) approximation equation related to the new fluid indicator is derived to directly link seismic data and properties of pore-filling materials. The model analysis verifies the accuracy of the derived approximation equation at moderate incident angles, which can be used for parameter prediction by pre-stack seismic inversion. Furthermore, the contribution of each attribute of the novel equation to the reflectivity is analyzed to validate the feasibility of new fluid indicator inversion. Finally, a boundary-constrained AVA pre-stack inversion method is presented to enhance the robustness of the inversion results of the model parameter. The reliability of the improved method is proved by accurate inversion results of synthetic seismic records. After determining the consolidation parameter using well-log data combined with BGT (Biot–Gassmann Theory), the field data further demonstrated that the proposed approach is accurate and effective.

中文翻译：

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考虑固结参数的新型流体指标 AVA 反演

从地震数据中识别地质流体对于理解储层特征至关重要。然而，基于弹性参数组合的流体指标在地质流体识别方面表现出很强的模糊性。尽管有效孔隙流体体积模量被证明是区分地质流体的优越流体指标，但它仅限于经验模型，例如临界孔隙率模型。固结参数模型可以评价沉积物的固结压实作用，因其较好的适用性而被广泛应用。因此，提出了一种考虑固结参数的新型流体指标，并开发了一种用于地质流体识别的边界约束反演策略。首先，基于孔隙弹性理论定义了新型流体指示剂。然后，推导了与新流体指标相关的线性化 AVA（振幅随角度变化）近似方程，以直接将地震数据与孔隙填充材料的特性联系起来。模型分析验证了所推导的近似方程在中等入射角条件下的准确性，可用于叠前地震反演参数预测。此外，分析了新方程的每个属性对反射率的贡献，以验证新流体指标反演的可行性。最后，提出了一种边界约束的AVA叠前反演方法，以增强模型参数反演结果的稳健性。合成地震记录的准确反演结果证明了改进方法的可靠性。