Structural modeling is the process of building a three-dimensional geological framework from interpreted horizons and faults. In g-Space, the Structural Modeling wizard takes interpreted horizons – or the geological objects organized in the Conceptual Model – assigns conformity relationships and fault constraints, and produces a consistent set of TIN surfaces that honor all input data. The resulting structural model serves as the foundation for property modeling, volumetric calculations, and reservoir characterization.

Purpose

The Structural Modeling wizard is designed for:

• Building a 3D structural framework from interpreted horizons
• Incorporating fault geometry to create geologically consistent surfaces
• Defining conformity relationships (conformable, erosion, onlap) between horizons
• Generating geobodies from horizon pairs for volumetric analysis
• Creating multi-Z surfaces that handle complex geological structures

Requirements

• At least two interpreted horizons available in Data Manager
• A velocity model for depth conversion (if working in depth domain)
• Optionally, a fault model for fault-constrained modeling
• Optionally, a border polygon to limit the modeling area

Launching the Wizard

Launch methods:

• Through Ribbon menu → Modelling → Structural Modeling
• Through Wizards panel (if activated)

[image: placeholder_Structural_Modeling_wizard_launch_from_R.png]

The wizard opens as a dialog window with two tabs (Input data and Modeling). Navigate between tabs using the Back and Next buttons at the bottom of the dialog.

Step-by-Step Guide

Input Data Tab

This tab is where you select horizons, define their stratigraphic order, assign conformity relationships, and specify fault constraints.

[image: placeholder_Input_data_tab_of_the_Structural_Modelin.png]

1. Select the domain

• Choose between Depth (default) and Time domain using the radio buttons at the top of the dialog
• The domain determines which horizon data (depth maps or time maps) will be used for modeling

2. Select fault model and border

• Fault model: The dropdown lists Ignore faults followed by the available fault models. When the Conceptual Model has a fault model linked to it, that model is preselected here; you can still pick another one, or choose Ignore faults to model unfaulted surfaces
• Border: The dropdown lists No border followed by the available border polygons. When the project contains polygons, the first one is selected by default; choose No border to model the full extent of the input data. If the project has no polygon at all, a warning is shown when you run the model and a border is created automatically (see Running the Model below)

3. Select horizons or objects

The left panel provides the input list. When the Conceptual Model contains objects for the selected domain, the panel is titled Available Objects and lists those objects, each prefixed with its conformity ([Depositional], [Unconformity] or [Intrusion]); only objects whose data matches the selected domain are shown. When there are no conceptual objects for the domain, the panel falls back to Available Horizons and lists the project horizons directly.

Use the Add → and ← Remove buttons to move items between the available list and the selected table. Use Add all → to include everything at once, or ← Remove all to clear the selected table. Multiselection works the same way as in the Fault Modeling wizard.

4. Configure the selected horizons table

The right panel shows the selected horizons with columns for:

• Horizon name — the name of the selected horizon
• Points — usage of horizon picks (No data / Soft / Hard)
• Maps — usage of horizon maps (No data / Soft / Hard)
• Multi-Z — select a multi-Z surface if available
• Markers — usage of well markers (No data / Soft / Hard)
• Conformity — stratigraphic role of the horizon/object: Depositional, Unconformity or Intrusion
• Direction — for unconformities, Top truncated or Bottom truncated. This cell is active only when Conformity is set to Unconformity

Use Move up and Move down buttons to set the correct stratigraphic order. Horizons should be ordered from shallowest (top) to deepest (bottom).

Data usage modes:

• No data — this data type is not used for the horizon
• Soft — data is used as a trend guide but the surface may deviate from it
• Hard — the surface is forced to pass exactly through these data points

Each usage cell is colour-coded for quick review: No data is grey, Soft is green and Hard is blue. Data types that are not available for a horizon or object appear as a disabled No data cell.

5. Set the vertical modeling limits

Use the Top and Bottom spin boxes to define the vertical extent of the modeling box. The labels show the current project unit (for example Top (m) / Bottom (m) in the depth domain, or the time unit in the time domain). By default Top is set to the project datum and Bottom to the deepest value across the selected horizons/objects; enter your own numeric values to override them. Only the interval between these limits is modeled, so the result maps and TIN surfaces are clipped to this box, which focuses the calculation on the zone of interest and reduces computation time.

Modeling Tab

This tab contains parameters that control the output grid resolution and surface smoothness.

[image: placeholder_Modeling_tab_of_the_Structural_Modeling_.png]

Parameters:

• Step X: Grid cell size in X direction (default: 50). Smaller values produce higher resolution but slower computation
• Step Y: Grid cell size in Y direction (default: 50). Typically set equal to Step X
• Smoothing (%): Surface smoothing percentage (0–100, default: 0). Higher values produce smoother surfaces but may lose detail at fault intersections
• Generate layers from horizon pairs: Enabled by default. Creates volumetric layers (geobodies) between each consecutive pair of horizons. These can be used for Volumetric calculations
• Generate fault blocks: Enabled by default. Splits the model into separate fault blocks based on the selected fault model, so each block can be analyzed independently

Running the Model

After configuring all parameters, click Run to start the modeling process. The Run button becomes active only when at least one horizon/object is selected with valid (non-No data) data assignments.

If the project contains no polygon at all, a warning is shown before the model is built: "No polygon border is available in the project. The modeling border will be created automatically from the largest area extent of the selected objects." The border is then generated automatically from the largest area extent of the selected horizons/objects.

To save the structural model for later reuse, click Save Structural Model As... to store the complete configuration including horizon selection, conformity relationships, and modeling parameters.

Results:

• A resulting surface for each horizon/object, calculated and stored as a TIN surface and available for display in section and 3D views through Data Manager
• Gridded result maps for each horizon/object, which behave as normal maps and can be used with the standard map operations
• Geobodies between horizon pairs (if enabled)
• Surfaces are fault-constrained if a fault model was specified

Recommendations

• Start with a coarse grid (larger Step X/Y) for quick preview, then refine
• Use Hard constraint for well markers to ensure the model honors well data exactly
• Use Soft constraint for maps to allow the model to adjust where map data may be less reliable
• Set conformity types carefully — Erosion and Onlap relationships significantly affect how surfaces interact
• Define a border polygon to reduce computation time and focus on the area of interest
• Review results in 3D view to verify fault-horizon intersections

See Also

• Conceptual Model
• Horizon picking
• Fault picking
• Geological modeling
• Volumetric calculations
• Properties modeling
• Data Manager