Creating a virtual geometry for a 2D marine data

Theory

Before the actual field deployment of the marine seismic data equipment like the seismic vessel, sources (air guns) and receivers (streamers/cables) a detailed pre-planning survey takes place. This is pretty much mandatory to understand the actual field requirements.

Virtual marine geometry helps in fulfilling the pre-survey planning. With this, the user can design a survey with source and receiver parameters. This will simulate the real world scenario how the source and receivers are placed etc.

Input data

For this module, there is no input data requirements so the user can ignore this part.

Parameters

Source params

Design the source parameters

Source line length

This parameter deals with the length of the source line. Specify the total line length in meters.

Distance between sources

This is nothing but a source point interval. Define the SP interval.

Distance between source lines

This is the between source lines. In case of 3D survey, we usually have 2 sources which are alternatively works. So define a distance between two source lines like 100 m, 200 m. In case of a 2D line, you can keep it as zero.

Number of source lines

For 2D it is one and for 3D it should be 2.

Direction of source line

This is the sail line direction.

1st source line - X co-ordinate of 1st source

Provide any virtual x-coordinate value like 100000

1st source line - Y co-ordinate of 1st source

Provide any virtual y-coordinate value like 2500000

Receiver params

This section relates to the receiver parameters

Receiver line length

Provide the cable/streamer length.

Distance between receivers

This is nothing but the receiver point interval. Define the Receiver interval value in meters.

Distance between receiver lines

In case of 3D survey, this is the distance between two adjacent receiver lines. Usually 100 meters is the distance between two receiver lines.

Number of receiver lines

Specify total number of receiver lines. In case of 2D, it will be 1. For 3D survey, it could be 4, 6 etc.

Distance between one source and active receivers

This is the near offset distance between the active source and the 1st active receiver/hydrophone/channel.

Other params

Constant topography value

Zero. For any survey, we've a reference datum i.e. MSL (Mean Sea Level). Since it is a marine seismic survey, the topography/elevation value becomes zero.

Settings

Skip

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

Output data

Trace headers

We get the out put trace headers with the specified source and receiver parameters.

Examples

This is a very simple workflow, where we add "Virtual geometry marine (2D)" module inside the Flow and provide various parameters.

For this module, we get only one vista item i.e. the location map. It will display the source and receivers with the above mentioned parameters. Red lines are Sources and Blue lines are Receivers.

Actions

There are no action items available for this module so the user can ignore it.

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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