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Version: 3.4.20 (unreleased)

Discrete Fracture Network

Right-click commands for a DFN under the DFN branch of the Interpretation Tree. Each DFN carries an Attributes node (DFN Attribute). The branch appears only when the licence includes the DFN feature; its header shows the standard group menu.

Source resources: IDR_IT_DFN.

Item Context Menu​

Right-click a DFN.

Actions​

  • Navigate To — Navigate to the item in the 3D view (ID_POPUP_ITEM_GOTO)

  • Make Active — Make this the active DFN, shown in bold, or make it inactive if it already is. Only one DFN is active at a time. Seed From DFN on a DEM model takes its fractures from the active DFN. (ID_PCLPOPUP_MAKEACTIVE)

  • Regenerate — Re-run the stochastic generator for this DFN using the current per-set statistics and spatial model. Mapped fractures keep their positions and count toward each set's target intensity; the rest are drawn afresh. Attributes, intersection lines and the fracture graph of the old fractures are cleared. (ID_DFN_REGENERATE)

  • Grow — Grow the existing fractures without regenerating: extend their tips under a preset stress field using the propagation engine (step 0.5 m, max 50 m per tip, sigma1 oriented N-S) (ID_DFN_REGENERATE_GROW)

  • Delete — Delete this DFN from the project. (ID_POPUP_ITEM_DELETE)

  • Fracture Intersections — Compute the 3D fracture-fracture intersection line segments and build the connectivity graph (required before topology/connectivity attributes) (ID_DFN_FRACTUREINTERSECTIONS)

  • Mesh Intersections — Intersect the DFN against the visible outcrop mesh and store the resulting synthetic trace polylines on the DFN (used by scoring and synthetic-trace export) (ID_DFN_MESHINTERSECTIONS)

  • Truncate Against Boundary — Does nothing at present. To clip fractures to the domain, set a set's Termination Rule to Truncate at Boundary and Regenerate. (ID_DFN_TRUNCATEAGAINSTBOUNDARY)

  • Fit Model Domain to Displayed Data — Set the domain of the selected DFNs to the box around the data displayed in the active 3D window, leaving out other DFNs, cameras and navigation objects, and offer to regenerate. See Setting the Domain. (ID_DFN_FITDOMAINTODISPLAYED)

  • Derive DFN Statistics... — Fit each fracture set's orientation, length and intensity statistics from measurements, in a dialog. The fractures themselves do not change, so VRGS offers to regenerate afterwards — otherwise the network on screen no longer follows from the statistics that describe it. Needs a DFN that already has sets. (ID_DFN_DERIVESTATS)

  • Model Surfaces... — Choose the bounding surfaces the network is confined between, so fractures are bed-confined rather than filling a box. Surfaces change both the model's shape and the volume its intensity is measured against, so VRGS offers to regenerate. See Implicit Surfaces for which surfaces are accepted. (ID_DFN_SETSURFACES)

  • Override P32 from Selected Traces... — Measure P21 (trace length per unit outcrop area) from the selected trace polylines, convert to P32 via the stereological factor, and replace each fracture set's intensity. Stores the source mesh name for provenance. (ID_DFN_OVERRIDEP32FROMTRACES)

  • Set Region Mask Source from Selection — Use the selected mesh, trace folder, or fault as a region-mask source for placement biasing. Fractures will be sampled with probability falling off as exp(-d^2/falloff^2) from the source geometry; clears the mask if no source is selected. (ID_DFN_SETREGIONMASKSOURCE)

  • Score DFN against Selected Traces... — Compare the DFN to observed traces and report a match score in 0..1. Combines a Kolmogorov-Smirnov length-distribution test, Fisher mean/K orientation distance, and a |P21_syn - P21_obs|/P21_obs intensity term as a weighted geometric mean. (ID_DFN_SCOREAGAINSTTRACES)

  • Re-derive from Source Orientation Groups — Re-run Fisher and length-distribution fits on the orientation groups and Sets originally used to build this DFN, in the domain it has, then regenerate. A set using its length-height fit goes on using it, refitted. Useful after editing the sources or adding measurements. (ID_DFN_REDERIVEFROMSOURCES)

  • Show Outcrop-Constrained Fractures Only — Show only the fractures that actually cut the outcrop — the ones that would leave a trace, and so the ones directly comparable with your interpretation. The rest of the network is hidden, not removed. Available once the DFN has been cut against an outcrop by Mesh Intersections or Score DFN against Selected Traces...; the command explains itself rather than emptying the view if it has not. (ID_DFN_SHOWOUTCROPCONSTRAINED)

Export submenu​

  • Fractures to FAB... — Write the fracture geometry as a FracMan .fab file. (ID_DFN_EXPORT_FAB)
  • Fractures to 3DEC (Itasca Geometry)... — Write the fractures as an Itasca geometry file (.geom) for 3DEC: one polygon per fracture, its set as a group and its set number, radius, dip and dip direction as extra values. See Export. (ID_DFN_EXPORT_ITASCA)
  • Set Statistics to CSV... — Write each fracture set's statistics to CSV. (ID_DFN_EXPORT_SETSTATS_CSV)
  • Fractures to CSV... — Write one row per fracture to CSV. (ID_DFN_EXPORT_FRACTURES_CSV)
  • Intersection Lines as Polylines — Turn the fracture–fracture intersection segments into polylines in the project. Run Fracture Intersections first, or there is nothing to export. (ID_DFN_EXPORT_INTERSECTIONS)

Analysis submenu​

  • Virtual Scanlines to CSV... — Run three virtual scanlines through the domain centre, one along each axis, and write raw and Terzaghi-corrected P10 per set to CSV. The counts and lengths also go to the Messages panel. (ID_DFN_ANALYSIS_SCANLINES)
  • Percolation Analysis — Cluster the network through its intersections and report how many fractures are isolated, how many clusters there are, how much of the network (by count and by area) the largest cluster holds, and whether it spans the domain in X, Y and Z. Needs Fracture Intersections first. (ID_DFN_ANALYSIS_PERCOLATION)
  • Oda Permeability Tensor... — Compute the Oda equivalent permeability tensor from the fracture geometry and a hydraulic aperture you supply in millimetres, using the cubic law. Reports P32, fracture porosity and the three principal permeabilities with their plunge and trend; the full tensor goes to the Messages panel. (ID_DFN_ANALYSIS_PERMEABILITY)
  • Connection Mesh for Flow... — Build one triangle mesh of the connected backbone of the network, with each fracture's aperture and transmissivity from a per-set aperture model. It can then solve steady flow along X, Y and Z, writing FlowRate and FlowShare layers back to the DFN, track particles, close apertures under stress, and run an ensemble of realisations. It runs in the background. See Connection Mesh for Flow. (ID_DFN_ANALYSIS_CONNECTIONMESH)
Oda assumes full connectivity

The Oda tensor is an upper bound: it sums fracture conductivities without asking whether they are connected. Run Percolation Analysis alongside it — a network that does not percolate will not deliver the permeability Oda reports — or solve the flow itself with Connection Mesh for Flow....

See also​