# Dip Azimuth

 Description Calculate dip angle and azimuth of maximum dip from a dip field. Module(s) Explorationist Requirements Dip Field Related Dip Field, Curvature, Edges Works with Stacks, Gathers

This process analyses a 3D dip field to generate two attributes: maximum dip angle, and azimuth of the maximum dip angle. The azimuth of maximum dip is measured in degrees clockwise from map north. For an input dip field in depth this angle is in degrees. For input in time, this is a psuedo angle calculated with the assumption that 1 millisecond (TWT) is 1 metre.

## Create Dip azimuth and angle process

1. In the Control Panel, open the Process tab.
2. At the tab header, click the Add icon and select New Process.
3. Scroll down and double-click on Dip Azimuth.
4. Type a name for the process and click OK.

## Configure the Dip Azimuth 1. In the Details Panel, select Mode.
• Forward (convert dip field to azimuth/angle)
• Reverse (convert azimuth/angle to dip field)

## Forward Mode

• Select the Dip Volume (see Dips Field to create a dip volume).

Converts a DUG Insight 3D dip field volume (from Dip Field process) into two 3D output volumes:

• Azimuth of maximum dip, measured in degrees clockwise from map north.
• Maximum dip angle in the direction of increasing depth measured in degrees (0-90). Referenced from horizontal as per the diagram below. For inputs in time, this is a pseudo angle calculated by assuming that 1 millisecond (TWT) is 1 metre.

• If the dip field volume has a gather dimension, both output volumes will also have a gather dimension. ## Reverse Mode In reverse mode, this process creates a 3D dip field volume from two input volumes:

1. Dip Azimuth volume: a 3D volume with class Dip Direction
• Trace values should be between 0 (inclusive) and 360 (exclusive), otherwise a warning is displayed.
• See below for azimuth conversion parameters.
2. Dip Angle volume: a 3D volume with class Dip Angle
• Trace values should be between 0 (inclusive) and 90 (exclusive), otherwise a warning is displayed.
• See below for angle conversion parameters.

• Both volumes must have the same extents in all dimensions.
• If input volumes have a gather dimension, the resulting dip field volume will also have a gather dimension.
• The reverse process does not recreate the dip in the gather direction.

## Angle and azimuth input volumes conversion parameters

Insight uses these parameters to convert the input angle and azimuth values from the source convention to the DUG convention.

A number of presets are available for frequent conventions. Use the Custom... preset to define a custom convention.

Parameter Description DUG Convention
Azimuth unit Unit of the dip azimuth values in the Dip Azimuth input volume Degrees
Azimuth reference axis The azimuth value in the Dip Azimuth input volume is the angle between the reference axis and the projection of the normal to the dipping plane on the horizontal plane. This parameter defines the reference axis.
• From North clockwise towards East: the azimuth value is relative to the North axis clockwise towards the East axis.
• From Inline with Crossline at 90 degrees: the azimuth value is relative to the Inline axis, with the Crossline axis at 90 degrees.

From North clockwise towards East

Azimuth normal direction

The azimuth value in the Dip Azimuth input volume is the angle between the reference axis and the projection of the normal to the dipping plane on the horizontal plane. This parameter defines the direction of the normal to the dipping plane.

• Upward: the azimuth is the angle between the reference axis and the upward normal to the dipping plane.
• Downward: the azimuth is the angle between the reference axis and the downward normal to the dipping plane.
Upward
Angle unit
Unit of the dip angle values in the Dip Angle input volume
Degrees

## Dip Angle

Example of Pseudo Maximum Dip Angle generated from Dip Field provided in Dip Azimuth and Angle process. Generated from TWT Full Stack volume, calculated by assuming that 1 millisecond (TWT) is 1 metre.

This horizon is mainly dipping 0–4.8 degrees from the horizontal, with steeply faulted areas dipping from 9–16 degrees from the horizontal. ## Dip Azimuth

Example of Azimuth of maximum dip, measured in degrees clockwise from map north. As you can see most of the horizon is dipping between 288–350 degrees. Whereas the suspected faults are clearly dipping between 180–100 degrees. Faults are dipping SSE, opposite to the main NNW dipping horizon direction. 