Johan Sverdrup Imaging Part 2: Vp Update with RTM Gathers Using Multilayer Tomography

There are two main imaging challenges in the North Sea: complex overburden and strong velocity contrast between the layers. We can address these issues with recently developed model building techniques, full-waveform inversion resolving the shallow and multilayer tomography accurately representing the borehole velocities, and geological layering. However, in areas of structural complexities, using Kirchhoff gathers for multilayer tomography may not give results as good as with wavefield continuation techniques.

We present the use of reverse time migration subsurface azimuth angle gathers for model building using multiazimuth multilayer tomography in a North Sea environment and compare the imaging uplift from this workflow to the standard model building approaches with global tomography.

This study was performed to improve the compressional velocity and, hence, the shear-wave velocity for PS imaging to explore the potential of shear-wave data for characterizing the Johan Sverdrup reservoir in the North Sea.