VTI介质角度叠加逆时偏移

常规各向同性逆时偏移方法在处理各向异性问题时会导致层位成像不准确、同相轴能量不聚焦等问题，并且利用拉普拉斯滤波算子等简单滤波方法不能彻底去除成像结果中的强振幅低频噪声。针对这些问题，首先应用声波近似方程模拟qP波在各向异性VTI介质中的传播，在震源激发位置设定平滑的各向同性或椭圆各向异性震源环以压制qSV波的影响；在此基础上提出了VTI介质逆时偏移的角度叠加实现策略，利用角度域共成像点道集中不同角度成像结果的叠加压制低频噪声，提高成像精度。模型试算和应用实例偏移结果表明，该方法能够对高陡复杂构造准确成像，且能量均衡、低频噪声压制效果较好。

Reverse time migration in VTI media based on ADCIGs

Conventional isotropic reverse time migration(RTM) method can lead to inaccurate imaging and unfocused seismic event energy when dealing with the anisotropic problem,and the strong amplitude and low frequency noise in the RTM imaging results cannot be completely removed by simple filtering methods such as Laplace filter operator.In order to solve these problems,we apply acoustic approximate equation to simulate the wavefield propagation of qP wave in VTI medium,eliminate the influence of qSV wave through setting smooth isotropic or elliptic anisotropic source ring at source locations.On this basis,the angle domain common imaging gathers(ADCIGs) superposition implementation strategies of RTM in VTI medium has been developed,which use the superposition of imaging results with different angles in ADCIGs to suppress the low-frequency noise and improve the imaging precision.Model tests and real dataset examples verify that the proposed approach can obtain the accurate imaging in complex steep structures with better energy balance and lower low-frequency noise.