Elastic impedance parameterization and inversion with Young's modulus and Poisson's ratio
Elastic impedance parameterization and inversion with Young's modulus and Poisson's ratio
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DOI：
10.1190/geo2012-0529.1
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发表时间：
2013-10
期刊：
影响因子：
3.3
通讯作者：
Z. Zong;Xingyao Yin;Guo-chen Wu
中科院分区：
文献类型：
--
作者：
Z. Zong;Xingyao Yin;Guo-chen Wu
杨氏模量和泊松比与孔隙度、岩石强度、矿物和总有机碳含量等储层定量属性有关，可用于推断优选钻井位置或甜点。通常，它们是根据岩石物理规律计算和估计的，包括纵波、横波阻抗/速度和密度，这些规律可以通过叠前地震数据直接反演。然而，杨氏模量中的密度项由于对地震振幅变化的敏感性较低而难以估计，而且间接方法会给杨氏模量和泊松比的估计带来更多的不确定性。本研究将杨氏模量和泊松比的弹性阻抗方程和弹性阻抗变化与入射角反演相结合，在不需要叠前地震资料的密度信息的情况下，给出了杨氏模量和泊松比估计的表格和直接方法。我们首先导出了一种新的基于杨氏模量和泊松比的弹性阻抗方程。然后，为了提高估计的稳定性，我们提出了弹性阻抗随入射角变化的阻尼奇异值分解（EVA-DSVD）反演方法来估计杨氏模量和泊松比。该方法实现了两步反演：弹性阻抗反演和参数估计。在参数估计中引入模型约束和DSVD算法，使得EVA-DSVD反演更加稳定。对合成数据的测试表明，在噪声适中的情况下，杨氏模量和泊松比的估计仍然是合理的。在实际数据集上的测试表明，估计结果与井解释结果吻合较好。
Young’s modulus and Poisson’s ratio are related to quantitative reservoir properties such as porosity, rock strength, mineral and total organic carbon content, and they can be used to infer preferential drilling locations or sweet spots. Conventionally, they are computed and estimated with a rock physics law in terms of P-wave, S-wave impedances/velocities, and density which may be directly inverted with prestack seismic data. However, the density term imbedded in Young’s modulus is difficult to estimate because it is less sensitive to seismicamplitude variations, and the indirect way can create more uncertainty for the estimation of Young’s modulus and Poisson’s ratio. This study combines the elastic impedance equation in terms of Young’s modulus and Poisson’s ratio and elastic impedance variation with incident angle inversion to produce as table and direct way to estimate the Young’s modulus and Poisson’s ratio, with no need for density information from prestack seismic data. We initially derive a novel elastic impedance equation in terms of Young’s modulus and Poisson’s ratio. And then, to enhance the estimation stability, we develop the elastic impedance varying with incident angle inversion with damping singular value decomposition (EVA-DSVD) method to estimate the Young’s modulus and Poisson’ sr atio. This method is implemented in a two-step inversion: Elastic impedance inversion and parameter estimation. The introduction of a model constraint and DSVD algorithm in parameter estimation renders the EVA-DSVD inversion more stable. Tests on synthetic data show that the Young’s modulus and Poisson’s ratio are still estimated reasonable with moderate noise. A test on a real data set shows that the estimated results are in good agreement with the results of well interpretation.