3D Beam Prestack Depth Migration with Examples from Around the World

摘要

In 1999AGS started the commercial development of Beam Pre-Stack Depth Migration (BPSDM). The anticipated merits were simplicity, economy, flexibility and future development possibilities: the unknowns were the migration accuracy and quality. BPSDM consists of three important steps, decomposition, migration, and reconstruction. Decomposition is a multidimensional slant stack which decomposes the data into a basis of seismic wavelets. Each wavelet has a center location and determined dip components. These contribute to the properties of the wavelet. Migration computes a point to point mapping between the unmigrated and the migrated wavelet centers. Reconstruction composites each wavelet into its local region in migrated space and outputs seismic depth traces. Initial results, in 1999, were horrific but, with further development, BPSBM proved to have some superior aspects to Kirchhoff and wave equation migration. The quality and flexibility of BPSDM includes: capability for handling steep and overturned dip, demultiple options, the ability to reject coherent noise, incorporation of anisotropy, speed for migration iteration, calculation of residual 3D RNMO, extension to multi- and wide azimuth data acquisition, and the capacity to handle land and marine data. Data examples from around the world illustrate the quality and flexibility of the technique.