We develop a workflow to estimate elastic attributes ( $V_p$ and $V_s$) of Pre‐Salt carbonate reservoirs using the Xu and Payne rock physics model in a depth‐variant multimineralogic fashion and apply it to one calibration and four extrapolation wells in a field in the Brazilian Santos Basin. Some of the parameters were stochastically simulated in a Bayesian framework to handle the model non‐uniqueness. Nuclear magnetic resonance porosity and mineralogic logs and x‐ray powder diffraction data from the studied wells and literature reference values were used for elastic solid media and dual‐porosity network modelling, bringing geological reasoning to the proposed workflow. Using rock physics templates, we improved our understanding of the reservoir petroelastic trends and devised alternative model parameterizations. Since the model was parameterized in a multimineralogic fashion with depth‐variant mineralogic information (e.g. volumes of carbonate, quartz and clay) as input, we improved elastic attribute estimations within the reservoir, increasing the model predictive power, compared to the common practice of allowing only porosity to vary with depth and representing the matrix properties by a depth‐invariant homogeneous or mixed mineral. We also investigated the workflow robustness and non‐uniqueness by studying its dependence on the choice of calibration well.

中文翻译：

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贝叶斯框架中多矿物碳酸盐岩石物理建模的工作流程：巴西盐下储层案例研究

我们开发了一个工作流程来估算弹性属性（ $V_p$ 和 $V_s$）使用Xu和Payne岩石物理学模型以深度变异多矿物学的方式将盐下碳酸盐储层应用于巴西桑托斯盆地的一个油田中的一个定标井和4个外推井。在贝叶斯框架中随机模拟了一些参数以处理模型的非唯一性。来自研究井的核磁共振孔隙度和矿物学测井资料以及X射线粉末衍射数据和文献参考值被用于弹性固体介质和双孔隙度网络建模，从而为拟议的工作流程带来了地质原因。使用岩石物理学模板，我们提高了对储层岩石弹性趋势的理解，并设计了替代模型参数化。由于使用多变矿物学信息（例如碳酸盐，石英和粘土的体积）作为输入以多矿物学方式对模型进行参数化，因此与通常的做法相比，我们改进了储层内的弹性属性估计，提高了模型的预测能力。孔隙度仅随深度而变化，并由深度不变的均质或混合矿物表示基质性质。我们还通过研究工作流对校准井选择的依赖性来研究工作流的鲁棒性和非唯一性。与仅允许孔隙度随深度变化并通过深度不变的均质或混合矿物表示基质特性的常规做法相比。我们还通过研究工作流对校准井选择的依赖性来研究工作流的鲁棒性和非唯一性。与仅允许孔隙度随深度变化并通过深度不变的均质或混合矿物表示基质特性的常规做法相比。我们还通过研究工作流对校准井选择的依赖性来研究工作流的鲁棒性和非唯一性。