Model Builder

Description Build a model volume from a layer model and data at discrete locations.
Module(s) Lithofluids
Requirements 3D Survey, Window Model, Lithology Trends, Wells
Related LF Model (End Member Trends), LF Model (Ghost Horizon) , LF Model (Simple Krig), Window Models, Using Trends

Configure Output Extents

  1. Survey: Select a 3D output survey.
  2. Inline: Enter the output volume’s inline extents.
  3. Crossline: Enter the output volume’s crossline extents.
  4. TWT (ms) / TVDSS (m) / TVDSS (ft): Select a vertical dimension and enter the output volume’s vertical extents.

Configure Model Parameters

  1. Mode
    • Single volume: Creates a single volume
    • Single volume (Delta): Creates a single Delta volume
    • Single volume (Vint from Checkshots): Creates a single interval velocity volume from well T/D pairs
    • Elastic volumes: Creates P-impedance, S-impedance and density volumes and an optional Vp/Vs volume
  2. Layer Overrides: Select whether to override layers using formulae .
  3. End-member trends: Select whether to use end-member trends to build the model.
  4. Interpolation
    • Simple interpolation per layer: The values of the model within each layer are calculated from well and table data using inverse distance weighting or averaging.
    • Simple kriging: Constructs a blocky layered model from well and table data. At each location, each layer is populated with a single value.
    • 3D kriging: Constructs volumes using well data and supporting information using kriging.
    • Ghost horizon kriging: Constructs a detailed layered model from well and table data using kriging. Model layers are divided by ghost horizons using the conformability specified in the layer model.
  5. Horiz/Vert ratio: Set a horizontal/vertical ratio. For more information, refer to Understanding the Horizontal / Vertical Ratio.
  6. Layer Model: Select a layer model to control the structural behaviour of the model (see Creating a Windowing Model).
  7. Water bottom: Only required when using trends relative to the water bottom. Select a horizon or enter a constant.
  8. End-member trends: Select an end-member trend.
  9. Velocity: Select an input velocity volume.
  10. Velocity Type: Select the velocity type.
  11. Velocity Units: Select the unit of the velocity volume.
  12. Vp/Vs: Only available in the Elastic volumes mode. Select whether to create a Vp/Vs output volume.
  13. Trend volumes: Select whether or not to create Trend volumes for 3D/Ghost Horizon kriging methods.

Wells and Tables

Wells and tables contain the data used as input to the model calculations. They can be used separately or in conjunction.

Configure Wells

In this section, select the well curves to include in the model calculations.

  1. Add wells by clicking the blue "+" icon.
  2. For each well, select the log curves to use. In Single volume modes, select the log curve containing the type of data to model. In the Elastic volumes mode, select Compressional, Shear, and Density log curves. Insight will attempt to convert log curves based on their data class. For example, Slowness curves will be converted to Velocity.
  3. Specify well curve vertical extents: When enabled, the vertical extents can be specified separately for each well. In addition, the depth units (m or ft) can be specified for depth models (global setting for all wells).
  4. Temporarily exclude specific wells from the calculation by using the green/amber light button.

Configure Tables

In this section, select the tables to include in the model calculations. The Model Builder expects table data to be well-like data, containing values for the model at various (x, y, z) locations.

  1. Add tables by clicking the blue "+" icon.
  2. Table: Select a table containing well data.
  3. For each field, select the corresponding column from the table by clicking the drop-down arrow. The Well name column is optional. When a well name is specified, all data points are treated as if they belong to the same well. Map the required X, Y, and Z fields, and select the column(s) representing the model values depending on the selected mode.
  4. Adjust the data class and units for each of the model value columns.
  5. TWT (ms) / TVDSS (m) / TVDSS (ft): Select the vertical dimension of the data in the Z column.

Note: The Model Builder groups points in the table data using the Well name column. If no well name is specified, each point in the table is treated independently.

This section becomes available when one or more of the following options are selected under the Model parameters:

  • Layer Overrides: Use layer overrides
  • Interpolation: Simple interpolation per layer
  • End-member trends: Use end-member trends and Ghost Horizon Kriging interpolation.
  1. Layer Model: Select a layer model to control the structural behaviour of the model (see Creating a Windowing Model).
  2. End-member trends: Select whether to use end-member trends to use in the calculations.
  3. The table displays one row per layer in the model. For each row, select one or more lithologies (from the end-member trends) and the relative Proportion of that Lithology in the layer. Additional lithologies can be selected by clicking on the blue "+" icon next to each layer.
  4. Layer override:
    • Formula (default):Layer is overridden using
      • Constant value
      • Formula: Variables for the formula include:
        • "twt_ms" and "twt_s", defined to be the time of a sample in milliseconds or seconds, respectively
        • "tvdss_m" and "tvdss_ft", defined to be the true vertical depth (MSL) of a sample in metres or feet, respectively
        • "pi" or "e", the mathematical constants
        • Operators, conditions and maths functions are similar to those of the volume maths process.
        • Example: a V0+K function can be written as the following formula:1500 + twt_ms*0.5.
    • Volume: Layer is overridden using the values from the chosen volume
    • Horizon: Layer is overridden using the values from the horizon, calculated or custom properties

Configure Kriging Parameters

  1. Horizontal range (m): Specify the distance from the well up to which the well data influences the Kriging horizontally.
  2. Vertical range (ms): Specify the distance from the well up to which the well data influences the Kriging vertically.
  3. Collocated volumes: Select additional volumes to be used to guide the Kriging, for example, a seismic velocity volume when building a velocity model from well data. We recommend selecting volumes that have a range of values similar to the well data. Add the collocated volumes by clicking the blue "+" icon.

This section is only visible when a Kriging Interpolation method is used in the Model section.

  1. Constant trend: Select Add constant trend to include a constant trend term in the Kriging calculations.
  2. Depth-based trend
    • None: No depth-based trend
    • Depth: Linear trend based on depth. When selected, a velocity volume and velocity type must be specified.
    • Depth below water bottom: Linear trend based on depth below the water bottom horizon. When selected, velocity volume and velocity type must be specified, and a water bottom horizon must be selected in the Model section.
    • Water bottom depth: Linear trend based on the depth of the water bottom. When selected, a water bottom horizon must be selected in the Model section.
  3. Trend volumes: Select one or more volumes whose sample values will be used as trends. Add the trend volumes by clicking the blue "+" icon.