GeoTomo VECON 4.9: Separating Survey Geometry from Target Illumination

A VSP layout with plenty of receivers can still miss the reflector that motivated the survey. VECON gives a geophysicist a way to test the source, borehole and geological model together before deciding where to acquire data. This research-based technical assessment draws on official sources checked on November 8, 2026 UTC; we did not independently install or test the software.

GeoTomo, LLC is the supplier identified on the current contact page. Its corporate overview describes a company founded in 1998 and focused on geophysical software. The current VECON product page labels 4.9 as its latest version and links release notes dated May 18, 2025. The older news listing still highlights 4.8; it should not override the product’s newer version evidence. An exact maintenance build, a later owner or a product renaming was not verified.

Build the geological case before optimizing the geometry

VECON is documented as a 2D/3D VSP and surface-seismic survey-design and forward-modeling system for land and marine applications. The product FAQ describes building 2D models from interpreted layers, faults and objects, SEG-Y sections or section images, and 3D models from intersecting sections, interface maps or digitized contours. P-wave velocities are required; density, Vp/Vs and velocity gradients can also be specified. The well trajectory and shot/receiver coordinates then define the acquisition problem.

Those inputs deserve more attention than the visual smoothness of the model. A section traced from an image needs a defensible spatial and depth basis, and default elastic properties remain assumptions even when the software permits them. For a walkaway VSP study, a useful sequence is to define the target and plausible velocity cases, generate candidate shot positions and borehole receiver levels, then compare ray paths and target coverage across those cases. This is an engineering study proposal, not evidence that a specific acquisition design has been validated.

The product documentation supports rotating imported geometries into local north/south coordinates, cropping larger reservoir models around the well or area of interest, and moving between 2D and 3D representations. Keep the transformation and crop boundary with the project deliverables. Otherwise, a locally convenient model can become difficult to reconcile with the acquisition crew’s coordinate system or the interpreter’s full-field model.

Geometry fold and modeled illumination are different evidence

One of the most useful 4.9 additions is the ability to display and save geometry fold without performing ray tracing. That makes the distinction explicit: a geometry statistic can be calculated before the subsurface propagation problem has been solved. The same release adds polygon-based selection for ray/shot displays, receiver-incidence-angle plotting without loaded geometry, raypath loading without shot/receiver geometry, and utilities for anisotropic raypath IDs and unit handling.

Use a fold plot to understand the layout, then use the selected propagation model to investigate how that layout sees the target. A high geometry-fold value is not by itself proof of favorable reflection angles or target illumination. Our OMNI 3D overview addresses the related acquisition-layout and QC task; evaluate any handover on the actual geometry and coordinate conventions rather than assuming equivalent outputs.

VECON documents 3D ray tracing for direct arrivals, reflections and converted reflections, as well as ray coverage and fold plots. It also offers finite-difference forward modeling. The synthetic-data FAQ distinguishes acoustic pressure responses from elastic vector responses and describes SEG-Y output. These are different physical representations, not interchangeable settings. Before comparing synthetic amplitudes or arrival patterns, specify the selected solver, wavefield components, source definition, sampling and model boundary assumptions.

The downloadable VECON brochure has a 2011 copyright and is useful for historical workflow context, not a current version-specific solver matrix. For example, its feature summary and broader prose differ in how they describe 3D finite-difference scope. Use the current product page, the intended build’s manual and a supplier-confirmed module list to settle the exact dimensionality, anisotropy and solver configuration required for the study.

Well-log and interpretation imports need a checked model basis

The 4.8 release notes, March 12, 2024, document improved model construction from well logs, density-log input and building 3D layers from ZMap files from Petrel. They also add a depth-versus-elevation option for user-supplied interfaces. The 4.9 notes extend well-log-based 2D grid building with smoothing options, update the Well Log Editor and correct a displayed-unit issue. These are version-scoped changes; they do not establish a live Petrel synchronization service.

For a proposed exchange, inspect the imported horizon at the well, check the depth/elevation sign and units, and document any smoothing applied to logs or layers. Ask the supplier to show how the model preserves the interfaces and property variations that matter to the target. SEG-Y synthetic traces can then be passed into a processing or interpretation test, while the product page documents SPS export of designed source and receiver coordinates to acquisition teams. A general automation API contract was not verified in the public sources reviewed.

VECON 4.9 is current; the public installation guidance is older

The 4.9 notes explicitly cover Linux and Windows versions. The product page also mentions Unix, but no current Unix build matrix was verified. The shared requirements page lists legacy systems including Windows 7 and older Linux distributions, with historical 64-bit CPU/RAM guidance. That is not sufficient evidence to recommend a new 4.9 installation on those OS releases or to promise support for a current Windows/Linux release. Obtain the supported OS, architecture, runtime libraries, graphics/remote-display configuration and storage requirements for the supplied build.

The same page warns that its minimum RAM figures concern average datasets and that larger data need more memory. Model dimensions, grid sampling and solver choice should therefore be part of a workload-based sizing discussion. Its GPU note is attached to another product’s FWI module; it should not be presented as VECON GPU entitlement. Neither the historical workstation figures nor vendor runtime adjectives establish the speed of a proposed 3D job.

The system FAQ documents GeoTomo’s license files and FlexNet/network-server arrangements, largely in dated troubleshooting articles. The VECON FAQ also describes host-specific keys. These support treating licensing and compute access as installation dependencies, but do not settle current floating/node-locked options, seat or concurrent-job counts, subscription/perpetual terms, offline transfers or VM/cloud permission. Confirm those commercially, together with maintenance and support response commitments. The support page remains available, while the public VECON guides page provides a brochure and a “Coming Soon” notice; the FAQ says detailed help manuals are bundled with the installed application.

Compare modeling methods on the same target

NORSAR-3D is a direct alternative for VSP/surface-seismic illumination and model-based survey evaluation. Its documented wavefront and Kirchhoff workflows offer a useful comparison around the same velocity model, target, shot/receiver geometry and required output. Our NORSAR Software Suite assessment explains the distinctions between illumination, simulated migrated images and monitoring-network design. Compare the required wave phenomena and solver assumptions first, then anisotropy representation, synthetic-component outputs, geometry exchange and deployment. Neither product’s public claims establish an independent performance or accuracy winner.

VECON deserves consideration when the task is to connect an explicit geological model with a candidate VSP or surface layout and generate interpretable rays or synthetic data. A different modeling environment may be preferable if its documented method or integration better matches the required wavefield and downstream processing test. Evidence is strong for the current 4.9 identity and specific model-building/geometry changes, and more limited for modern deployment, exact licensed solvers and automation. The next useful procurement step is a supplier demonstration using the team’s own target model, including units, solver settings, exported geometry and synthetic headers—not a generic promise that a survey is optimal.