Delayed-shot migration in TEC coordinates

Abstract:

This paper extends the analytical Riemannian wavefield extrapolation (RWE) approach to 3D coordinate systems. I formulate an inline delayed-shot migration procedure in tilted elliptical-cylindrical (TEC) coordinate systems. When inline coordinate tilt angles are well-matched to the inline source ray parameters, the TEC coordinate extension affords accurate propagation of both steep-dip and turning-wave components. I show that wavefield extrapolation in TEC coordinates is no more complicated than propagation in elliptically anisotropic media. Impulse response tests illustrate the accuracy and lack of numerical anisotropy of the implemented scheme. I apply this approach to a realistic 3D wide-azimuth synthetic derived from a field Gulf of Mexico data set. The resulting images demonstrate the imaging advantages made possible through 3D RWE implementations, including the improved imaging of steeply dipping salt flanks, potentially at a reduced computational cost. Narrow-azimuth migration results demonstrate the applicability of the approach to typical Gulf of Mexico field data.

Delayed-shot migration in TEC coordinates