Insight’s automatic mistie analysis provides a fast and effective method for balancing multiple datasets
By running the mistie analysis wizard, we can adjust the amplitude, phase, and time shifts of our datasets to achieve a best-fit match between volumes
In this example, we’ll use the automatic mistie tool to correct the differences between a 3D and a 2D volume
This will enable us to pick a horizon through the original 2D and onto the newly-acquired 3D volume
To get started, let’s take a look at the two volumes side-by-side
In the map view, create an arbline along one of the 2D lines, then out into the surrounding 3D volume
Open the arbline view and look at the result
I’ll need a group to show both volumes at the same time
Here’s one that I prepared earlier
By putting the 2D volume above the 3D, it will be displayed where the two volumes overlap
In the centre, we can clearly see the transition between the volumes
On the left, we see the 2D data and on the right we see the 3D data
The status bar at the bottom of the window tells us information about the displayed volume below the mouse cursor
Okay, so we’re interested in picking this positive event
We’ll use the propagator-guided manual picker to pick this event.
Oh dear, that doesn’t look good! Picking is going to be difficult until we get this mistie sorted out
Let’s correct this before continuing to pick this horizon.
Go to View > Mistie correction - Automatic
Remember, each volume in Insight is assigned to a class
Insight uses this information to identify the data type and to control the display properties
Automatic mistie correction will only be applied to volumes of the same data type, so make sure the correct type has been assigned to your volumes before continuing!
Our data volumes are full stacks, so we’ll select the full stack as the class, and add the 3D and 2D volumes
We need to select which data to use as a reference
When performing misties, the reference data remains constant, and the other data volumes are adjusted to match it
The reference can be a single 2D line or an entire 3D volume
In this case, we’ll select our 3D volume, and have the 2D lines adjusted to match it
Choosing the right correlation window is critical to getting good results
You can use a fixed time interval for the comparison, or a window based on a horizon
In this case I will choose a fixed time interval near the horizon I am picking
We’ll keep the default values for everything else
The mistie correction will be calculated for the vertical shift, phase and amplitude
we can control what happens to each of these individually
The best match for each of these parameters can be determined for the entire volume, line-by-line, or not calculated at all
If we choose “Per volume”, all the lines in our 2D will share the same correction
If we choose “Per 3D volume / 2D line”, each line will have its own correction
In this case, were interested in calculating a separate vertical shift for each 2D line
so let’s use the Per 3D volume/2D line option
We also need to address phase and amplitude differences, so let’s set Phase and Amplitude to Per Volume
So what is Insight doing?
The mistie process first calculates the optimal correction for each intersection independently
It then determines an overall adjustment that best fits the individual corrections, to minimise the total residual mistie
Once complete, a table will appear with an overview of the proposed changes
If you need a record of the proposed changes, the data can be copied by right clicking and selecting copy to csv
Before applying these corrections, Insight gives you the option to QC the results at each intersection
These first two columns describe the intersection for that row
The Applied columns shows the adjustments made to the given line/volume
The residual columns show the remaining mistie at this intersection
You can double click on any row to open a view of that intersection
Here you can see a visual comparison between the uncorrected data, the ideal correction, and the final correction
These graphs show the impact of different shifts and phases on the correlation coefficient between the traces at the intersection
This final graph shows the spectra of the intersection traces
Before you continue, remember that mistie corrections are applied for all users of the data
Corrections are applied to the volumes, not just single Insight sessions
These changes may impact others, so be careful!
Once complete, the corrections will be applied whenever the volume is loaded or displayed
Phase rotation requires a lot of calculation
which can slow Insight down when reading traces, especially for time slices and horizon amplitude extraction
If you find that working with phase-rotated data is too slow, export a copy of the volume, which will store the data with the corrections applied
So, can we follow the event better?
Let’s have a look at our arbitrary line again
You can see that the newly-corrected volumes match significantly better
Picking across the volumes is much easier for the interpreter!
Manual corrections can be applied at any time through the Volume configure dialog, by double-clicking a volume in the Control Panel
Here you can see changes applied to the volume and make manual adjustments to the vertical shift, phase, and amplitude scale
Remember that you must be the owner of the volume in order to edit it!