3-D Grid Based Seismic Velocity Modeling
Pre-requested data:
Seismic Surfaces: mapped and contoured with no gaps or faults. They should have the same areal
extension and have the same gridding parameters. Surfaces should represents the whole dynamic
range of the data and include the near surface velocity reflector if possible.
Well tops: well tops should be reviewed and QC. Faulted tops should not be included in the
velocity model.
Stacking/migration velocity file as SEGY or point file with attributes. This file should be
converted into interval velocity through Dix conversion prior of using.
Wells velocity surveys (if any).
Idea of the workflow:
The idea is to create a 3D grid and layer this grid. Then sample the interval velocity (derived
after Dix conversion of the stacking velocity) into this simple grid (up scaling). The last step is to
populate the interval velocity as a property into the grid through Kriging.
Pseudo-velocity 2-D Modelin
Pre-requested data:
Seismic Surface: with or without faults.
Well tops: well tops should be reviewed and QC. Faulted tops should not be included in the
velocity model.
Sparsely distributed wells (usually in developed oil fields).
Idea of the workflow:
The idea is to use the depth of tops in the wells (stratigraphic well tops) and the interpreter’TWT
of the surface at the well location to calculate velocity values (velocity indicator) at the well’s
location. Then these values are gridded and contoured then multiplied to the original time grid to
get depth grid. The resulted depth grid is an interpreter input dependent, so velocity is a pseudovelocity.
