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<< Click to Display Table of Contents >> Navigation: Best Practice Flows > Velocity model workflow > Setting up the velocity model > From Vrms |
The From Vrms method converts stacking / RMS velocity gathers produced by seismic processing into an interval velocity cube using the Dix equation, optionally smoothing the result along horizons. Use it when seismic velocity data are the main constraint and well control is sparse.
•Vrms seismic data — 2D lines and/or 3D cubes in the time domain, tagged as VELOCITY type with RMS option. The wizard searches the project automatically and merges all available Vrms data.
•Time horizons (optional) — used as smoothing targets when Smooth along horizons is enabled.
•Datum — elevation reference (editable).
•Max Depth — lower bound of the cube (default 4000 m).
•Depth Step — vertical sampling (default 10 m).
•Smooth along horizons — when enabled, applies lateral smoothing parallel to the selected horizons to remove noise introduced by the Dix conversion.
•Smooth along horizons window — size of the spatial smoothing kernel, expressed in traces (default 20).
1.Select From Vrms in the velocity model wizard.
2.Set Datum, Max Depth and Depth Step.
3.Enable Smooth along horizons if needed and choose a window size.
4.Run the model. The wizard collects all Vrms seismic data in the project, applies Dix conversion per trace, and writes the resulting interval velocity cube.
Interval velocity cube derived from Vrms; depth and time maps consistent with the input gather coverage.
•Areas with good Vrms coverage (for example fresh processing results) and limited well data.
•Starting model for later refinement with well- or marker-based methods.
•High-lateral-resolution use cases where seismic velocities capture features unavailable from sparse wells.
For well-tied models, combine this initial cube with Checkshot + markers + horizons in a second pass.
•Setting up the velocity model