宽方位地震资料方位各向异性处理——以大庆长垣三分量地震数据为例

地震纵波在HTI介质中传播时,沿垂直于裂缝方向的速度小于沿平行于裂缝方向,且反射强度降低和频率变低;横波在HTI介质中传播时分裂成快、慢横波。以大庆长垣喇嘛甸地区的宽方位三分量地震资料为基础,分析了方位各向异性的表现特征、影响及不同方位角范围内属性的变化,并根据这些性质的变化利用椭圆拟合对该地区的各向异性的方位和强度进行定量预测,与利用横波分裂预测的结果一致。为了消除方位各向异性对地震成像分辨率的影响,利用椭圆拟合准确求出了HTI介质的方位速度,进行方位速度动校正,消除了方位各向异性引起的快慢波时差,提高了资料的成像质量。

Azimuth anisotropic wide-azimuth seismic data processing: A case study of three-component data from Daqing Placanticline

For HTI media,P-waves run slower in the direction perpendicular to fractures than in the direction parallel to fractures; meanwhile,reflection strength and frequency decrease with propagation.S-waves split into fast and slow waves.Bosed on the wide-azimuth three-component data in Lama-dian,Daqing Placanticline,we analyzed the perfor-mance characteristics,influence of azimuthal aniso-tropy,and attribute variation with azimuth.Ellipse fitting is then utilized to quantitatively predict the azimuth and intensity of anisotropy in this area.Our results are consistent with those obtained using shear wave splitting.To mitigate the influence of azimuthal anisotropy on the resolution of imaging,we calculate the accurate azimuthal velocity of HTI media through ellipse fitting to accomplish NMO correction.This corrects the time difference between fast and slow waves caused by azimuthal anisotropy and consequently improves seismic imaging.