【摘要】 具有水平对称轴的横向各向同性 (HTI)介质模型是用来描述含有平行垂直裂缝油气藏最简单方位各向异性介质的模型。针对任意各向异性程度的HTI介质水平反射界面 ,提出了D 剖面的概念 ,并由此得到任意方位角(测线方向与主轴方向的夹角 )的转换波正常时差 (NMO)速度公式。在多波多分量勘探中 ,利用P P、P S1、P S2方位变化的动校正速度 ,可以建立S1波、S2波的速度和各向异性参数 ,其中包括与裂缝密度关系最为密切的Thomsen参数γ。数值实例计算表明 ,对于中等各向异性程度的HTI介质 ,可以利用P P波和转换波动校正速度公式较精确地计算出S波正常时差速度 ,这为使用多波多分量资料进一步反演Thomsen参数γ提供了可靠的依据。更多还原

【Abstract】 Transverse isotropic model for HTI media with a horizontal symmetry axis is the simplest one used to describe the transverse isotropy of the fractured reservoirs containing parallel vertical cracks. A double profile for describing the horizontal reflectors in HTI media with any strength of anisotropy is proposed. Moreover, the equations for normal moveout (NMO) velocity of P S wave in HTI medium with arbitrary symmetry and any strength of anisotropy are obtained. The velocities of S1 wave and S2 wave, and anisotropy parameters including Thomsen parameter γ related with crack density are obtained using azimuthal NMO velocities of P P wave, P S1 wave and P S2 wave in multicomponent seismic data. The numerical results indicate that the NMO velocity of S wave can be comparatively exactly computed by using NMO velocities of P P wave and P S wave in HTI media with moderate strength of anisotropy, which provides a reliable basis for the inversion of Thomsen parameters using 2D multicomponent seismic data.更多还原