The 3D Supermesh format of FEFLOW 10.0 offers a new feature to include stratigraphic information in 3D models: the possibility to perform implicit modelling to define geological horizons from a set of points defined in borehole data. This allows to build structural models directly in FEFLOW.
The workflow is illustrated in the Figure below: from a group of (a) point set, representing the interface between geological units in different boreholes, FEFLOW is able to interpolate such data to create surfaces corresponding to (b) geological horizons.
Implicit modelling conceptual workflow: from (a) Point set, representing the depth of geological surfaces in borehole data, to the definition of (b) Geological horizons to be included in the FEFLOW model.
The Implicit modelling functionalities are available through the new Implicit Modelling Toolbar, which can be activated only in a 3D Supermesh file from the "View" menu:
Implicit Modelling Toolbar activation.
Implicit Modelling Toolbar.
The workflow for implicit modelling requires:
A 3D Boundary Representation of the domain, represented by at least one Block (i.e., volume), which can contain Surfaces, Lines and/or Points;
A definition of a Stratigraphic Pile (i.e., a valid sequence of lithologies);
Creating a number of Boreholes, where the Stratigraphic Pile is used;
Creating horizon points from Boreholes.
If the above information is provided and saved
in the 3D Supermesh, the resulting Structural model can be built by using
the "Generate
Implicit Surface" button (
) in the Supermesh
Processing Panel.
Implicit modelling workflow in 3D Supermesh.
A 3D representation of the model domain requires a volume which can contain one or more Blocks (e.g, if the volume is split by a fault plane), lines and/or points. In order to have a correct representation of the model domain, it is necessary to run the Surface repair Tool under in the Supermesh Processing Panel, to be sure all the 3D Supermesh Elements are correctly connected. Please refer to this page for details about this workflow.
The definition of the Stratigraphic Pile is automatic if Material Regions are defined in a Lookup Table, saved in the Supermesh through the Problem Settings window, as shown below:
Material Regions defined in a Lookup Table.
Definition of a Stratigraphic Pile in FEFLOW through Material Regions defined in a Lookup Table.
If no Lookup Table is defined, the user can manually add geological
units (i.e., materials) to the Stratigraphic
Pile by clicking on the star button (
) of
the Stratigraphic Pile. New materials will be created with a default name ("material", "material
1"...), which can be changed by the user from the Lookup Table in the
Problem Settings Window. In the same Lookup Table, material properties can be defined for
every geological unit.
Note that the Stratigraphic Pile defines the order of materials from top to bottom of the model, i.e., from the shallowest to the deepest geological unit.
 |
The current minimum number of geological units to use the Implicit modelling tool is 3. |
Boreholes can be either created manually or be imported from a file.
In order to create them manually, click on the
"Set/Clear Borehole"
button (
) of the Implicit
Modelling Toolbar. After activating the tool, the mouse pointer
will become green and the user can click anywhere on the model domain
to open the window "Create
Borehole", where the user can define the characteristics of
the Borehole.
Borehole creation.
The table above can be filled by the user with
the data of the boreholes. Location,
Azimuth and
Dip characterize
the geometrical definition of the the Borehole. The Borehole is created
by default with only one geological unit (i.e., the shallowest), but additional geological
units can be added by clicking on the star button (). The material column will
be automatically filled in order of the materials defined in the Stratigraphic
Pile. The user can click on the "Material"
column to
select another geological unit at certain depth. The columns "From" and "To"
allow the user to specify the thickness of each geological unit in the
borehole.
|
The user is responsible of defining a valid order of geological units in depth in the borehole, i.e., a deeper geological unit can't stand above a shallower one. |
The user can repeat the above workflow to create as many boreholes as necessary.
Boreholes can be also imported
from a file by clicking on the
"Edit Borehole Data" button in the Implicit
Modelling Toolbar (
)
and then clicking on the "Import" icon of the newly opened "Create Borehole"
window as shown below.
Option to import boreholes from the "Create Borehole" Window.
A window will then open to import a *.xyz file:
"Import boreholes..." option to import a *.xyz file.
The *.xyz file contains the list of the points along the boreholes which represent the contacts between distinct geological units.
An example of the structure of the *.xyz file is shown below: the file consists of five columns representing (in order from left to right): X, Y, Z (coordinates of the contact points between geological units), C (constant: 1 if material below the point is defined; 0 for the deepest point of the borehole), M (material corresponding to the geological unit; empty for the deepest point of the borehole). No column headers are necessary.
*.xyz file example.
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Note that the boreholes' vertical extension can be shorter than the thickness of the model domain. In that case, FEFLOW will extend the shallowest and deepest geological units until the top and bottom of the model domain, respectively. |
Once boreholes are created, either manually or by importing a file, they are listed in the "Spatial Entities" Panel, as shown below. From their context menu, each borehole can be renamed, edited, exported or deleted.
Boreholes are saved in the Spatial Spatial Entities Panel.
By double-clicking on their names in the Spatial Spatial Entities Panel, the boreholes can be visualised in the 3D Supermesh by activating the "Boreholes" option in the View Components Panel:
Visualization of Boreholes in 3D Supermesh.
The last step is to include the information contained
in the boreholes defined is to click
on the button 
to "Create Horizon Points from Boreholes". This operation creates
a list of point sets named Horizon Points
at the geological interfaces between consecutive stratigraphic units in
the Meshing panel.
Horizon Points created by clicking on "Create Horizon Points from Boreholes" button.