lithologic modeling :: Earth Volumetric Studio Help

lithologic modeling

The lithologic modeling module is an alternative geologic modeling concept that uses geostatistics to assign each cell’s lithologic material as defined in a pregeology (.pgf) file, to cells in a 3D volumetric grid.

There are two Estimation Types. Nearest Neighbor is a quick method that merely finds the nearest lithology sample interval among all of your data and assigns that material. It is very fast, but generally should not be used for final work. Kriging provides the rigorous probabilistic approach to geologic indicator kriging. The probability for each material is computed for each cell center of your grid, and the material with the highest probability is assigned to the cell. All of the individual material probabilities are provided as additional cell data components, allowing you to identify regions where the material assignment is somewhat ambiguous.

There are also two Lithology Methods when Kriging is selected. The Block method is the quickest since probabilities are assigned directly to cells and lithology is determined based on the highest probability among all materials, but the resulting model is blocky and requires high grid resolutions. The Smooth method assigns probabilities to nodes and then interpolates between them, cutting the blocky grid and forming a smooth grid. Much lower grid resolutions can be used with the Smooth method, often achieving superior results.

Ports

Direction	Name	Type	Description
Input	Input Geologic Field	Field	Accepts geologic field input to constrain kriging between two topographic surfaces.
Input	Input External Grid	Field	A field containing an external grid to use for the output.
Input	Input Filename	String	File used to generate the pre-geology file name.
Input	Input Refine Distance	Number	The refine distance for the pre-geology file.
Output	Output Filename	String	File used to generate the pre-geology file name.
Output	Output Refine Distance	Number	The refine distance for the pre-geology file.
Output	Geologic Legend Information	Geology Legend	Information required to properly label stratigraphic output or lithology within Legend.
Output	Output Field	Field	The main output field representing geologic materials.
Output	Status Information	String	Text containing the full status information output from the module.
Output	Variography	Renderable	A renderable object displaying the variography elements.
Output	Indicator Grid Data	Realization	Information required for direct exporting of raw indicator grid data.

Properties

Property	Type	Description
Allow Run	Boolean	Controls whether the module will run when applications are loaded or data changes.
Filename	File	The filename containing the data to interpolate onto the created grid.
New Variables	Boolean	Resets all expert system calculated variables to zero before each run, allowing multiple calculations without manual resetting.
Execute	Button	Forces the module to run. If pressed and the application saved, it will cause the module to run when the application is loaded.

Grid Settings

Property	Type	Description
Only Create Grid	Boolean	Forces the module to exit after gridding is complete with no interpolation done.
Grid Coordinates	Range 3D	Allows the user to define the coordinate domain within the data set in which kriging will be completed.
X Resolution	Integer	The number of grid nodes that will be included within the model horizontal domain.
Y Resolution	Integer	The number of grid nodes that will be included within the model vertical domain.
Z Resolution	Integer	The number of grid nodes that will be included within the model elevation domain when creating a single layer.
Cell Set Subdivision	Choice: Per Material, Stratigraphy or External Grid, All Categories	Allows the user to select whether the output is grouped into materials, grouped into layers, or not grouped.
Layers From Geology	Choice: Make Single Layer, Use all Horizons	Used with the input geology port. Can create a single layer or a layer for each horizon.
Proportional Gridding	Choice: Cells Per Layer, Proportional Z Resolution	When multiple geologic layers exist, cells are apportioned to layers in Z based on each layer’s average thickness.
Min Cells Per Layer	Integer	The minimum number of cells in the Z direction per layer when proportionally gridding an input geologic grid.
Cells Per Layer	Integer	The cells in the Z direction per layer when using the Cells Per Layer proportional gridding option.
Min Layer Thickness	Double	The smallest vertical height of each cell.
Reverse Surface Hierarchy	Boolean	Defines layers starting from the bottom to the top.
Rectilinear Offset	Double	Used to create a domain that is larger than the input data along all three axes.

Krig Settings

Property	Type	Description
Estimation Type	Choice: Kriging, Nearest Neighbor	Selects between the Nearest Neighbor and Kriging algorithms.
Lithology Method	Choice: Block, Smooth	Selects the unrefined (Block) or the refinement (Smooth) algorithm. The Smooth method requires lower grid resolutions to achieve great results.
Reach	Double	Defines the radial distance from any given model node that the kriging module will look for data points. Setting the reach to 0 causes automatic calculation.
Points In Reach	Integer	The maximum number of data points within the specified reach that will be considered for parameter estimation at a model node.
Octant Search	Boolean	When selected, searching is performed for each of the eight octants surrounding the point to be kriged.
Use All Points	Boolean	Causes the module to include samples up to the All Points Limit value. If the number of samples exceeds the limit, the Reach and Points In Reach settings are used.
All Points Limit	Integer	The maximum number of points to use when interpolating. If there are more samples than this value, the Reach and Points In Reach settings will be used.
Screen Refine Distance	Double	The distance used to discretize the lithologic intervals into points used in kriging.
Max Points Per Interval	Integer	Caps the number of points created between samples in PGF data.
Maximum Refined Points	Integer	Sets a limit on the total number of points created when refining a PGF file.
Variogram And Anisotropy	Variogram	Controls the variogram model and anisotropy parameters for kriging.

Data To Export

Property	Type	Description
Geologic Nodal Data	Multi-select: Layer Thickness, Depth, Elevation	Controls which data components to generate for the output field on a node-by-node basis.
Geologic Cell Data	Multi-select: Material ID, Geo Layer	Controls which data components to generate for the output field on a cell-by-cell basis.
Indicator Data Component Name	String	Sets the name of the calculated indicators, also used as a prefix for the generated Probability and Probabilities By Material data components.
Probability	Boolean	Exports a data value that describes the probability of that cell or node being the chosen material.
Probabilities By Material	Boolean	Exports a data value that describes the probability of that cell or node being each of the different materials.

Variography Display

Property	Type	Description
Variography Z Scale	Double	The vertical exaggeration to be applied to the output variography ellipsoid and line objects.
Display Variogram Ellipsoid	Boolean	Allows the user to display the variography ellipsoid.
Ellipsoid Opacity	Double	Sets the opacity of the ellipsoid directly.
Resolution	Integer	The resolution to use for the ellipsoid. Larger numbers create more detailed representations.
Ellipsoid Scale	Double	Scales the ellipsoid equally along each axis.
X Offset	Double	Translates the ellipsoid along the X axis.
Y Offset	Double	Translates the ellipsoid along the Y axis.
Z Offset	Double	Translates the ellipsoid along the Z axis.
Ellipsoid Color	Color	The color of the ellipsoid.
Display Variogram Lines	Boolean	Allows the user to display lines aligned with the variography ellipsoid.
Line Scale	Double	A scalar that sets the length of the variogram lines relative to the scale of the ellipsoid.
Primary Ratio Color	Color	The color of the primary ratio axis.
Secondary Ratio Color	Color	The color of the secondary ratio axis.
Tertiary Axis Color	Color	The color of the tertiary axis.

Drill Guide

Property	Type	Description
Create DG File	Button	Runs the module in a loop creating a synthetic boring at the maximum uncertainty location until it has reached the set Number Of Synthetic Samples.
Synthetic Sample Prefix	String	The prefix for the generated boring name of synthetic points.
Number Of Synthetic Samples	Integer	Controls how many times drill guide will run.
Boring Samples	Integer	Indicates how many samples to create at each synthetic boring.
User Points	Coordinate Array	Used to manage the number of points added to the grid for drill guide purposes, to help eliminate areas of high uncertainty that cannot be drilled.