Welcome to our periodic newsletter that aims to highlight recent changes and additions to Shearwater Reveal. In this issue we discuss new tools we have added and updates to existing tools.
User Group Meetings
2018 Houston User-Group Meeting
The 2018 Houston User-Group Meeting took place at the Omni Hotel, West Houston in April. Presentations were given to update clients on new geophysical and GUI & infrastructure developments. FWI, statics updates, and Depth updates were also discussed. One-on-one sessions and beverages followed the scheduled presentations.
Shearwater at EAGE
Shearwater is attending the EAGE conference in Copenhagen in June 11-14. The Reveal team will be demonstrating the latest developments, so feel free to come by stand 920 for a demonstration or contact us to arrange a private viewing.
Tips & Tricks
A document is available on our website displaying pre-defined hot-keys for Reveal software. Please follow this link to download the PDF file
Parallelizing PreStackTime and PreStackDepth flows
Both PreStackTime and PreStackDepth flows are mainly parallelized by using replication for OFFBINS: one OFFBIN per replica. Workers can be used to manage the replica execution. Each OFFBIN can be further parallelized by using multiple ranks (MPI). When using MPI, selecting “All ranks read all data” in Input allows the migration tools to internally split the OFFBIN in an efficient manner that balances the computational load between the ranks working on that OFFBIN. In some cases the extra I/O can add to runtime overhead compared to running on a single rank. In PreStackTime using MPI in a given OFFBIN also allows for migrating OFFBIN volumes that do not fit in the memory of a single rank. (This is not yet available in PreStackDepth.) Note that MPI should not be used if the Input sort defines a gather that contains more than one OFFBIN.
New Analysis Tools
FWI is a new tool for performing full waveform inversions and modeling data. Both modeling and inversion modes support VTI (TTI is available). In addition there are QC modes for validation, e.g., initial models, source wavelets and shot selection. The tool is licensed separately for 2D and 3D. (The 3D version is limited to members of the Imperial College led Fullwave consortium.)
Fig. 1: Left: Initial model used in FWI. Middle: FWI update after 106 iterations using a variable grid size. Right: Correct model. The model is a modified Marmousi model courtesy of Imperial College.
HeaderMapMigration is a new tool for migrating horizons. It supports remigrating and demigrating depth horizons and migrating time horizons. It is available in the Model Building package.
Fig. 2. HeaderMapMigration results: SEAM (SEG SEAM Phase I) sediment model horizon before (left) and after (right) remigration with a modified velocity model. Background shows the original stack (left) and a PostStackMigration result of remigrating the original horizon (right).
SmartHorizonPicker is a new tool that picks horizons on seismic data using user-selected seed points. The tool uses a pre-trained machine learning dataset to select picks adjacent to already-selected locations on a stack. SmartHorizonPicker is available in the Model Building Package.
Fig. 3. Stack with auto-picked horizon overlayed.
FillTracesFromDB is a new tool intended to give more QC options when checking a database that has multiple pick values for each location. It replaces the values of an input seismic file with values extracted from the database file and then interpolates across the seismic volume.
Fig. 4. Tomography picks, colored by QC_Gamma, overlaid on the input gather (left) versus the gather filled with interpolated QC_Gamma pick values (right).
Additional Functionality Updates
Points mode rendering now has the capability to add/remove/modify points graphically for CSV files. With this functionality, it is possible to pick multiple points at a given location.
Fig. 5. Points mode rendering with multiple picks at a single (ILINE, XLINE) location.
FirstBreakPicking has been updated to include a stack-seeded option. The new workflow is described in the “Workflows” section of the manual and a flow with the new option is included in the land example flows.
Refractor Assignment Wizard
A new refractor assignment wizard has been created. This wizard allows a user to assign refractors to first breaks after running the FirstBreakPicking tool. A snapshot of the new wizard is included below and a description of the wizard is located in the “Workflows” section of the manual.