Reversing the channel/Offsets of an input gather

Theory

Reverse Gather module reverses the trace order within each gather without modifying trace amplitudes or header values (other than sequence order). This operation is used to change the directional ordering of traces for consistency, visualization, or compatibility with downstream processing modules.

The gather structure (shot, CMP, receiver, etc.) is preserved while the internal trace sequence is inverted. No resampling or amplitude modification is performed. Traces in each gather are reordered from last to first. Gather boundaries remain unchanged. Reversing offset order (far-to-near or near-to-far)

Input data

Input DataItem

Input gather

connect/reference to the Output gather that needs to be reversed. The input gather could be a pre or post-stack gather. It could be a Shot/Receiver/CMP gather.

Parameters

There are no parameters associated with this module.

Settings

Auto-connection

By default, TRUE(Checked).It will automatically connects to the next module. To avoid auto-connect, the user should uncheck this option.

Bad data values option { Fix, Notify, Continue }

This is applicable whenever there is a bad value or NaN (Not a Number) in the data. By default, Notify. While testing, it is good to opt as Notify option. Once we understand the root cause of it, the user can either choose the option Fix or Continue. In this way, the job won't stop/fail during the production.

Fix

It will fix the bad values and continue executing the workflow.

Notify

It will notify the issue if there are any bad values or NaN. This will halt the workflow execution.

Continue

This option will continue the execution of the workflow however if there are any bad values or NaN, it won't fix it.

Number of threads

One less than total no of nodes/threads to execute a job in multi-thread mode. Limit number of threads on main machine.

Skip

By default, FALSE(Unchecked). This option helps to bypass the module from the workflow.

Output data

Output DataItem

Output gather

generates the trace/offset reversed gather as an output.

Information

There is no information available for this module.

Examples

In this example workflow, we reverse a simple common shot gather. The channels starting from 1 to 120 (left to right). After reversing the gather, the channels starts from 120 to 1 (left to right). The user can annotate the OFFSET headers and check the same.

Execute the module and generate the vista items. It will display Input gather and Output gather. Annotate Channel and/or OFFSET trace headers by using View Properties.

Actions

There are no action items available for this module.

Video lesson

YouTube video lesson, click here to open [VIDEO IN PROCESS...]

Related articles

Yilmaz. O., 1987, Seismic data processing: Society of Exploration Geophysicist

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