Full Waveform Inversion

Full Waveform Inversion (FWI) is a methodology that seeks to find high-resolution, high-fidelity velocity models of the subsurface capable of matching individual synthetic seismic waveforms with an original raw field dataset. This is achieved iteratively by determining and minimizing a residual; the difference between modeled and recorded data.

PGS FWI utilizes the full wavefield, so both diving waves (wavefronts continuously refracted upwards through the earth due to the presence of a vertical velocity gradient) and reflections. FWI is successful in resolving small scale features; in particular, in shallow-water environments where reflection based tomographic inversion methods are limited.

FWI Fundamentals

  • Full Waveform Inversion is a velocity model building tool 
  • Earth models are refined by minimizing the difference between recorded data and the modeled data  
  • Historically only refractions were used and penetration depth was limited
  • PGS FWI uses the full wavefield for deeper modeling

PGS FWI Benefits

  • Uses diving waves, refractions and reflections together to reduce dependence upon very long offsets and provide high-fidelity velocity models
  • Avoids cycle-skipping artifacts and delivers models with correct long wavelength information
  • Removes migration isochron artifacts resulting in accurate deep velocity models
  • High-resolution deep velocity updates translate to improved subsurface images and robust reservoir characterization

 

PGS FWI
PGS FWI overcomes geological complexity to provide excellent resolution of a Paleocene canyon in deepwater Côte d’Ivoire.