Creating table from Trace headers
Create Table module extracts trace header values from seismic traces and organizes them into structured tables. These tables provide a clear view of acquisition geometry and trace-level metadata for quality control, analysis.
Tables reflect the current values stored in trace headers. Any geometry or header edits should be followed by table regeneration. Large surveys may produce large full trace-header tables
Tables can be generated at source, receiver, bin (CMP), or trace level, for a single line or the entire survey.
Supported Table Types
Source Table – one row per unique source point
Receiver Table – one row per unique receiver location
Bin (CMP) Table – one row per unique midpoint or bin
Traces Table – one row per trace, for all traces
Output
The module outputs one or more tables that can be:
Viewed and filtered interactively
Used as input to other processing modules like Export Table.
Exported to external formats (e.g., ASCII)
Item (table data) - connect/reference to output trace headers where table data information is available. When the user connects/reference to Output trace headers of "Read seismic traces" and/or "Read SEG-Y traces" or any module where trace headers information contains tabular information that can be used.
Enum tables { Receivers, Sources, Bins, Traces } - this option allows the user to select the table(s) from the drop down menu. Sometimes, nothing is visible inside the drop down menu. In that case, click on "Parse common item info" in the action item menu and it display the tables.
Step X - specify X step size. By default, 1.
Step Y - specify Y step size. By default, 1.
Sparse -
Step X - specify X step size. By default, 1.
Step Y - specify Y step size. By default, 1.
Table settings - this option allows the user to adjust the table settings like which trace headers should be considered for output, value precision, deleting unnecessary trace headers etc.
As we mentioned, here the user can change the precision value from 1 to 3/4/5 etc and also, delete the unnecessary trace headers by simply clicking the -ve symbol.
Enabled table sorting - this option allows the user to sort the contents of the tables. By default, FALSE(Unchecked).
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.
Table out - outputs the cmp/bins trace headers information in a single table.
Tables - it outputs individual tables as per the user choice.
Receivers - outputs receiver trace header information as a receiver table.
Sources - outputs source trace header information as a source table.
Bins - outputs cmp trace header information as a cmp table.
Traces - outputs all the traces header(s) information as a trace table.
Pay attention this while creating a Traces table when dealing with large size 3D volumes.
There is no information available for this module.
In this example workflow, we are reading a geometry assigned shot gathers (3D survey). We would like to extract trace headers information for source, receiver and bin gathers in the form of Tables.
Here we are using the Output trace headers of Read seismic traces module as an Item (Input table) for the Create table module.
Output trace headers gives flexibility to get all of the gather(s) information like source, receiver, bin and traces whereas if the user chooses any other options from it it will possible only to that particular gather like source or receiver or bin/CMPs.
For each table i.e., source/receiver/bin/trace, the user should select the desired/required table from the drop down menu and execute the module. In case, the user wants to adjust/modify the output table information, click on "Table settings" option and try add/delete any particular trace header or adjust the precision value.
On the left hand side, it is the actual source information that is going to be created as a source table, however, if the user wants to increase the precision values of Z, Hole depth & Hole time, simply change the existing value to new value. Similarly, if the user doesn't want some of the trace headers in the final source table simply uncheck those trace headers in the Visible column. These column will not be output in the final source-table.
Parse common item info - this option allows the user to pull out all the common information from the trace headers. Sometimes,
YouTube video lesson, click here to open [VIDEO IN PROCESS...]
Yilmaz. O., 1987, Seismic data processing: Society of Exploration Geophysicist
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