论文部分内容阅读
为点散射体响应、水平分辨率限制以及2-D和3-D偏移成像的动态范围推导出几个远场公式。数值实验证明了这些公式在实际CDP观测系统中的正确性。我们的结果说明在深度比记录孔径宽度大得多的远场,偏移成像的水平分辨率限制与散射体的深度成正比,而与波数和孔径大小成反比。对于相同的记录孔径,2-D叠前偏移图像的水平分辨率限制与对应的2-D叠后偏移图像相同。如果孔径大小相同,3-D叠后偏移图像的分辨率就是震源和接收器分布在固定区域中的3-D叠前偏移的两倍。同时,叠前偏移图像的动态范围要好于叠后偏移图像,而动态范围会因记录孔径宽度的增大而得到改善。分辨率限制的基础就是类似瑞利的过零点准则。
Several far field formulas are derived for point scatterer response, horizontal resolution limit, and dynamic range for 2-D and 3-D offset imaging. Numerical experiments show the correctness of these formulas in the actual CDP observation system. Our results demonstrate that at far depths much deeper than the recording aperture width, the horizontal resolution limit of migration imaging is directly proportional to the depth of the scatterer, inversely proportional to the wavenumber and the aperture size. The 2-D pre-stack offset image has the same horizontal resolution limit as the corresponding 2-D post-stack post-migration image for the same recording aperture. If the aperture sizes are the same, the resolution of the 3-D poststack offset image is twice the 3-D prestack migration with the source and receiver distributed in a fixed area. At the same time, the dynamic range of the pre-stack offset image is better than that of the post-stack offset image, while the dynamic range is improved due to the increase of the recording aperture width. The basis of the resolution limit is similar to Rayleigh zero-crossing guidelines.