全方位道集速度建模方法及应用

Full-azimuth gather velocity modeling method and application

为了提高宽方位地震成像精度,需要对宽方位数据进行OVT域全方位速度建模.全方位道集速度建模技术是宽方位OVT域层析反演的一种速度建模技术,该技术以宽方位地震数据为基础,在OVT域进行偏移,在偏移后的全方位各向异性道集上拾取剩余时差,进行射线追踪建立方程组,统一求解,迭代得到最优速度模型.与常规速度建模方法相比,OVT域全方位道集速度建模既可以保留方位角的信息,又能够减少人为分方位引起的覆盖次数不均衡性,在刻画速度模型细节变化和提高成像精度方面具有较大的优势.实际资料应用表明,OVT域全方位道集层析反演速度建模技术更高效、灵活,能够较好的消除剩余时差,有效的刻画速度变化的细节,提高地质体成像精度.

In order to improve the accuracy of wide-azimuth seismic imaging, it is necessary to perform full azimuth velocity modeling in OVT domain for wide-azimuth data. The full-azimuth gather velocity modeling technology is a velocity modeling technology for wide-azimuth OVT domain tomographic inversion, based on wide-azimuth seismic data, the migrating is performed in the OVT domain, the remaining time difference is picked up on the migrated full-azimuth anisotropic gathers, ray tracing is performed to establish a set of equations, which are solved uniformly, and the optimal velocity model is iteratively obtained. Compared with the conventional velocity modeling method, the OVT domain full-azimuth gather velocity modeling can not only retain the azimuth angle information, but also reduce the imbalance of the fold times caused by the artificial azimuth, which has a great advantage in describing the changes in the details of the velocity model and improving the imaging accuracy. The application of actual data shows that the OVT domain full-azimuth gather tomographic inversion velocity modeling technology is more efficient and flexible, can better eliminate the remaining time difference, effectively describe the details of velocity changes, and improve the imaging accuracy of geological bodies.