纵波与转换横波联合AVO反演估计横波速度和密度

Shear-wave velocity and density estimation from PP-and PS-waves joint AVO inversion

横波速度和密度是储层特征描述的重要弹性参数,然而,传统的仅用纵波资料三参数反演横波速度和密度的方法存在反演不稳定和反演结果不精确的问题。为此,文中提出纵波和转换横波联合AVO反演的方法来估计横波速度和密度,即推导出仅含有横波速度和密度参数的纵波反射系数近似式,该近似式和Aki-Richards的转换横波反射系数近似式有相同的目标参数。该方法充分利用了接收的多波多分量地震资料中的纵波、转换横波波场信息,减少了AVO反演结果的多解性,为储层特征描述提供更加准确的横波速度和密度参数。模型数据测试验证了该方法的准确性,在合成数据中加噪测试表明,该方法有较高的稳定性,同时实际资料测试表明该方法具有实用性。

Elastie parameters, such as S-wave velocity and density, are important for reservoir characterization. However, the conventional mcthods of S-wave velocity and density parameter estimation use P-wave data alone, which may be unstable and inaccurate in some case. In this papel, we propose a new method to estimate S-wave velocity and density by PP and PS-wave joint amplitude versus offset （AVO） inversion. We derive a new PP wave reflection coefficient approximation of the S-wave velocity and density, which has the same parameters as Aki-Richards＇s PS wave reflection coefficient approximation. Combining PP and PS waves of multi-wave and multi-component data, the S-wave velocity and density are estimated by a two parameter joint AVO inversion. This new method takes full advantage of longitudinal and converting waves of multi-component seismic data, which reduces multiple solutions of AVO inversion only using P-wave data. We apply this method to a layered model and real data by employing joint AVO inversion. The numerical examples demonstrate that our method is stable and robust to estimate the parameters.