Generating an Interface Model

Interface modelling parameters are relevant when performing interface modelling. These parameters include the angle of incidence at the interface for near and far offsets as well as noise parameters to account for the noise effects.  The generation of interfaces allows for the investigation of the AVO (Amplitude Variation with Offset), which is a useful fluid and lithology indicator.

  1. Interface Stochastic Model Parameters:
  • Depths: Insert depth range for the simulation run based on TVDBML (True Vertical Depth Below Mud Level); min-max [interval].
  • Error: Enter the error probability percentage.
  • Near Angle: The intercept angle at the interface to calculate near interface properties. Enter a value (usually less than 90°). There is an extra input box for standard deviation (±).
  • Far Angle: The intercept angle at the interface to calculate far interface properties. Enter a value (usually less than 90°). There is an extra input box for standard deviation (±).
  • Calculation: Click to see the following two options, and select the appropriate calculation.
    • SHUEY_TWOTERM: Calculates considerably faster and is only a valid approximation when the far angle is less than 35°.
    • SHUEY_THREETERM: Recommended calculation method to use in most cases. It calculates a non-linear AVO response, which is especially useful when modelling very far angles.
  • Iterations: Enter the desired number of iterations.

Note: Each iteration is based on probability theory whereby Insight runs a probability session for each parameter. The higher the iteration is set, the better the estimate of the models is. The higher the number of iterations, the longer it takes for Insight to run them.

  1. Interface Model PDFs: Select the horizontal and vertical axes of the PDF crossplot charts. To remove any chart, click the Remove Row icon. To add, click the Add icon.
  2. Interfaces: Make sure all the desired interfaces are included in the export. To remove any interface, click the green Show/Hide button, and the button will turn amber. The depth of the interfaces can optionally be overridden in the adjacent Min Depth Override and Max Depth Override boxes.

View in Crossplot: Click to view the crossplots in the Crossplot window.

Re-Run Simulations: Click to update the stochastic modelling output after changing any of the interface stochastic modelling parameters.

View Log/Warnings: Click to view successful generation and warning logs. A warning icon indicates issues the Stochastic Model window has run into and where the problem has arisen, normally relating to over-extrapolation of trends. This means that the stochastic modelling was performed at a depth that is much deeper or shallower than where the picks are available in the trending phase.

Export PDF: Click to export the interface model into .dustat format.