AVO Polynomial Fit

Description Fit a polynomial to amplitudes extracted along a horizon.
Module(s) Gather Attributes
Requirements Gathers, Gather horizon
Related Intercept/Gradient, AVA Stack Rotation
Works with Gathers

Extract amplitudes from a gather volume along a 4D horizon (i.e. IL/CL/gather dimension) and fit a polynomial to the extracted values. One map property is generated for each of the polynomial coefficients.

For each location, amplitudes are extracted from the gathers along the horizon. Using the least squares method, a polynomial of the specified order is calculated for the amplitude sequence. Each of the polynomial coefficients is stored as a map property in the original gather horizon.

With two terms, the polynomial coefficients are  analogous to I/G, but not the same. In this process, the independent variable (x) for the polynomial is linear in the gather domain (dependent on the gather type: angle or offset). For intercept and gradient, the independent variable is (sin2(x)) where x is the angle.

Create an AVO polynomial fit process

Create an AVO polynomial fit process
  1. In the Control Panel, open the Process tab.
  2. At the tab header, click the Add icon and select New Process.
  3. Double-click AVO Polynomial Fit.
  4. Type a new name for the process and click OK.
  1. In the Details Panel of the process, select a Gather horizon and Gather volume.
  2. Define the Polynomial order to fit at each location at which the volume is defined. As a result, a separate horizon property will be produced for each polynomial order, attached to the selected input horizon.
  3. At Output property name, type a name for the output horizon property that will be created.
  4. Click Run.

Viewing/Managing AVO horizon properties

Viewing/Managing AVO horizon properties
  1. In the Control Panel, open the Horizon tab.
  2. Right click on the horizon used for the AVO Polynomial Fit process and select Manage Custom Properties. The Custom Properties window will be displayed.
  3. Sort the order of the custom properties in alphabetical order by clicking on the header. The properties can also be renamed by clicking on the name and typing in a new name.
  4. Click OK to save and close the custom properties.

For more information, see Custom Horizon Properties.