Description
Seismic loop is an interactive procedure designed for processing data in a gather by gather mode. Using this procedure, the user can create a sequence of specific processing modules that will be contained in the Seismic loop. Processing is performed on the seismic data based on the user specified sort order output from the Sort Traces module which must precede this module in the workflow, and must provide the sorted input trace headers.
This module can also be used for quality control of input seismic data. Traces are displayed in accordance with the input sorting. Vistas that are interactively connected allow the user to step through a data volume, reviewing the results of the processing modules included in the Seismic loop processing sequence. Interactivity between the Location Map Vista and the Seismic display Vistas allow for random access to all gathers in the input seismic data.
There are multiple ways to display the Vista items (location map, input gather etc.) of Seismic Loop.
• To display the Vista items of any module user should use MB3 (right mouse button) and select Vista Groups followed by All Groups. Now we have two options to choose
In current window – Vista items will be added to the View Manager however if there are any existing vista items are there then the new vista items will be added to the existing one and it is often times confusing. To avoid this user should select “In a new window” unless there are no existing Vista items
In a new Window – Vista items will be added in a separate window in View Manager with the module name as the title to identify the module and it’s vista items.
• The second method is click on the icon 
“Add module views in current window” on the top right corner of the Module Manager window as shown below.
When user add the Vista items using this method, it is very useful in Seismic Loop. When there are multiple modules existing inside the Seismic Loop module, user can interactively see the results of the individual modules by simply selecting the module and go back and forth to see the resulting output of that particular module. To replicate this user should do the following procedure.
Click/select Seismic Loop module and click the Add module views icon. It will display the vista items as shown below.
It is worth to mention that whenever user wants to add a new module after seismic loop by right mouse click on seismic loop it will give an option of Modules Inside, Modules Next besides the regular vista items etc. Modules inside option inserts the module within Seismic Loop where as Modules Next option inserts the module outside the Seismic Loop.
Now user added a new module LMO by using Modules inside option and it will be added under Seismic loop module. To display the vista items, we should click the icon “Add module views” instead of MB3 or right mouse button click to see the interactivity of the tool.
Now let’s add another module, Despike and follow the same procedure to add the vista items as we did earlier.
To see the animation of LMO and Despike outputs, we should select the individual modules and see the changes on the shot gathers.
In the above image, we selected LMO and it’s vista items were added using the icon like wise we selected Despike module and added the vista items (below image) the same way. When we select LMO and Depsike modules, we can see the animation of the individual modules output results.
Like this we can add many modules inside the seismic loop module . Use can randomly and interactively select the shot/receiver/bin locations on the location map and test the parameters to see the results instantly.
The third method to display the Vista items of any module is as described below. To display the vista items, user should select that particular module and then click on the icon
There are couple of other important features within the Seismic Loop module. If user adds any modules within the seismic loop, they need not to make the references since the reference connections are automatic process. As you see on the Settings tab, Auto-connection option is checked. In the above example, Input to the seismic loop is from the Read seismic traces module, this will act as an input to the LMO module. After the LMO operation, output gather of LMO will act as an Input to the Despike module. Likewise output of Depsike will be Input to the next module. User should remember that, to save the output within the Seismic loop, they must use the “Save seismic by gather"module only.
Scenario : What if the job stopped due to some reason? Do we need to rerun the entire line?
You don’t have to. In the Seismic Loop Parameters tab, we can see the First seq. gather and Last seq. gather. If you know the last seq. gather number then we can replace the First seq. gather with that number and keeping the Last seq. gather unchanged. Now the most important task is NOT to overwrite the existing output file name. This can be done at the Save seismic by gather module where we should select the option “append” and uncheck the RewriteFile option. So the process will continue from the new seq range and append to the existing gather of output file name.
To explain in simple way, in the current gather we have sequences 1 to 251 and we submitted the job. Due to some reason our job didn’t finish. In the seismic loop parameters tab, we can see the Sequential gather number of the last sequence where the job failed. In this case we have 117. Now we replace the First seq. gather with 118 and keep the Last seq. gather 251 as it is.
There is another important option available in Seismic Loop i.e. Interpolated params. As shown in the image, we can see the Interpolated params at eh bottom of the Parameters tab. Whenever user wants to apply specific process like band pass filter/deconvolution etc to a particular FFID/Shot/CMP range then they can use this option to interpolate the respective parameters. Let us explain how it works. Within the seismic loop, let’s say user wants to apply deconvolution only to certain part of the line. In this case, they have to select the starting and ending points of the line and accordingly provide the parameters as shown below. To select these points, user should add vista items of the seismic loop. In addition to that we need to add an additional vista item i.e. Fixed points table. Initially it will be blank and nothing visible. As the user added the Decon predictive module inside the seismic loop and go to Seismic loop parameters tab and click on the 
button. It will add a row named “Parameter”. Here user has to select the first location on the location map. Now double click on Parameter of Interpolated params and it will open the reference window and assign the appropriate item. In this case, we selected the Prediction interval as parameter.
Once we click OK, then it will make the reference connection and display the first interpolation point on the Fixed points table as shown below.
Now we can see that the interpolated points map is displaying the interpolation points on the far left side of the image. Next to it is the location map where we select a point (green dot). Next to that one is the Fixed points table where it added the information like procedure, item (predictive interval), x, y and value fields. Likewise, we have to add predictive length also. For that, we have to click the + button again on the Interpolated params and add another Parameter row to the existing one.
After this, we have to choose the other location point to do the interpolation between these two selected points as shown below.
To do the interpolation, we need to change the decon predictive parameters to new values at this new location.
If we observe the above interpolated points map, it will interpolate the values between those two triangle only. This way we can able to interpolate parameters using seismic loop.
Input data
Input DataItem
Input SEG-Y data handle
Input sorted headers
Parameters
First
Indicate on primary sorting of input data (from “Sort traces” module).
This parameter is filled automatically with sorting header attribute
Second
Indicate on secondary sorting of input data (from “Sort traces” module).
This parameter is filled automatically with sorting header attribute.
Sequential gather number
Number of current iteration
Can also be used for selection of gather in accordance with data sorting
First seq. gather
Number of first iteration
Last seq. gather
Number of last iteration
Seq. gather increment
Iteration step
Auto increment
If unchecked, the gather of the current iteration will not change
Stop in error case
If checked, execution of the Seismic loop will stop if an error occurs
Movie time delay
Time delay between the iterations
It used for automatic review of seismograms in movie mode
Auto Start On Click
If checked, clicking on a gather location on the location map will run all of the procedures in the loop for the selected point.
Super gather aperture
Grid parameters
Iteration step first
Iteration step second
Advanced
Advanced usage parameters
Buffer read size
Number of traces to read
Interpolated params
Settings
Recursive GUI Update
If checked, Seismic loop will automatically update the Vistas after each gather iteration
Update. Time delay
Time delay between recursive Vista updates