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 picked horizons, assigns conformity relationships and fault constraints, and produces a consistent set of multi-Z 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)
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.
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: Select a fault model from the dropdown to constrain surfaces by faults. Leave empty for unfaulted modeling
•Border: Select a polygon to limit the modeling area. Leave empty to model the full extent of the input data
3. Select horizons
The left panel (Available Horizons) shows all horizons in the project. Use the Add and Remove buttons to move horizons between the available list and the selected table. Use Add all to include all horizons at once.
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 — type of stratigraphic relationship (Conformable, Erosion, Onlap, Base)
•Direction — erosion/onlap direction (Above, Below). Enabled only for Erosion and Onlap conformity types
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
Modeling Tab
This tab contains parameters that control the output grid resolution and surface smoothness.
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 geobodies from horizon pairs: When enabled, creates volumetric geobodies between each consecutive pair of horizons. These geobodies can be used for Volumetric calculations
Running the Model
After configuring all parameters, click Run to start the modeling process. The Run button becomes active only when at least two horizons are selected with valid data assignments.
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:
•Multi-Z surfaces for each horizon, available in Data Manager
•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