GIM Tracking

Tracking generation interface

The tracking generation interface in opened up from Tools -> GIM Data Generation -> GIM Tracking. The interface has 4 different menus and works as a wizard with next and back buttons. The 4 menus are:

1. Input
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   This is where you decide which dataset to track, and which interval to use between inlines and crossline. The settings can also be adjusted so that only a subset of the cube is tracked.

2. Tracking parameters
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   This is where you sett the tracking parameters to obtain best possible result.

3. Output
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   This is where you decide if you want to track both inline and crossline or just one of them. You can also change the datasets name.

4. Status
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   This is where you get an overview of how the tracking generation is

Tracking parameters

The tracking parameters menu

The tracking parameters offered are:

• Snap mode
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  Tracks min (trough), max (peak) or minmax (both). Remember that when you generate surfaces from these trackings, minmax will generate twice as many surfaces as only min or max. On regional dataset, say more than 2000 inlines/xlines, it is recommended to start with only one polarity and see how many surfaces that are generated.

• Direction
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  Tracks increasing, decreasing or both ways. When using both ways, the tracker will try to connect to where the tracker stopped when it was tracking in the first direction.

• Gradient tracking
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• Backtrack quality control algorithm
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  Not used

• Deletion
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• Average
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  Not used

• Deviation
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  Not used

• Amplitude range
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• dT - Time difference
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• dT - dt between best and 2nd best
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  Not used

• d(dT) - Gradient
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• Look ahead
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  Not used

Output and status

Testing tracking parameters

Wether the objective of the GIM tracking is to generate GIM seismic or GIM tracking to create GIM surfaces, it is essential to first set the tracking parameters optimally. Since the tracking process only takes a few seconds on any given inline/xline, or 2D section, it is possible to effectively test the tracker interactively until the desired result is obtained. To test the tracker parameters, make sure a seismic section is displayed in the Geocap graphical window, and then click Tools->GIM Data Generation->GIM Tracking.

Generate tracking for surfaces

Generating surfaces is very much a balancing act. One wants the tracker to be generous and generate long lines giving us large surfaces. But at the same time we do not want the tracker to make mistakes. So we have to test to find the optimal settings.

Generate tracking for 3D bodies

To make 3D bodies, we want to omit the data which is interpretable. We invert the tracking so that all good data is removed, and we are left with the noisy bits of which we will make bodies. Often we use a medium tracking criteria (dT of 6ms) combined with a medium remove long setting (e.g. 6 traces).

Generate tracking for facies attribute

To make facies attribute, we only generate the tracking in one direction, either inline or crossline. One recommended method to get exiting results is to combine a strict tracking criteria, e.g. a dT of 3 ms, combined with a "remove short" set to 10 traces. This will make lots of breaks in the tracking as well as remove all parts of the data where GIM cannot generate interpretation lower than 10 traces.

Tracking the cube