Seismic attributes 3D distributed

Calculating seismic attributes

Theory

Seismic Attributes 3D (Distributed) module is used to generate different seismic attributes from a 3D seismic volume. These attributes help in enhancing geological and structural features that are not easily visible in the original seismic data.

Seismic attributes describe various characteristics of the seismic signal such as:

amplitude strength
phase behavior
frequency variations
attenuation effects
structural discontinuities

These attributes are commonly used for interpretation tasks like:

fault detection
channel identification
thin bed detection
fracture zones
possible hydrocarbon indicators

The attributes are computed using a user-defined time window and trace window around each seismic sample.

For this module, the input data should be a 3D volume. This module generates one or more 3D attribute volumes with the same size and geometry as the input seismic data.

Input data

Input SEG-Y data handle

this will be a 3D post stack volume. Connect/reference to Output SEG-Y data handle or Output gather.

Parameters

Attributes - there are many attributes that can be calculated by using this module, however, the user has the option to select either one or all of the attributes to calculate at a time. For this, the user should select the required/all attribute from the below list and provide the output file name and path. This resultant attribute will be generated and stored at the user specified path. By default, all attributes are checked (TRUE) and will be calculated.

Envelope

calculates the instantaneous amplitude of the seismic trace. Envelope represents the strength of the seismic reflection independent of polarity.

Commonly uses for

bright spot identification
channel detection
general amplitude anomaly analysis

Envelope derivative

calculates the first derivative of the envelope. This highlights rapid changes in reflection strength.

Commonly uses for

thin bed detection
sharp impedance contrasts
stratigraphic boundaries

Second derivative of envelope

calculates the second derivative of the envelope. This further enhances subtle amplitude variations and thin-bed effects.

Commonly uses for

thin bed interpretation
subtle stratigraphic features

Instantaneous phase

calculates the instantaneous phase of the seismic signal. Phase shows reflector geometry independent of amplitude.

Commonly uses for

horizon tracking
structural interpretation
reflector continuity analysis

Cosine of instantaneous phase

calculates the cosine of the instantaneous phase. This represents the normalized in-phase component of the signal.

Commonly uses for

structural enhancement
reflector continuity

Instantaneous unwrap phase

calculates the unwrapped instantaneous phase. Phase unwrapping removes discontinuities caused by phase wrapping.

Commonly uses for

stable frequency computation
advanced phase analysis

Instantaneous frequency

calculates the local frequency of the seismic signal. This represents how fast the waveform oscillates at each sample.

Commonly uses for

thin bed detection
frequency shadow identification
lithology variation

Frequency derivative

calculates the rate of change of instantaneous frequency. This highlights rapid frequency variations.

Commonly uses for

thin bed tuning analysis
subtle stratigraphic features

Dominate frequency

calculates the dominant frequency of the seismic signal within the analysis window. This represents the frequency with the strongest spectral energy.

Commonly uses for

lithology variations
attenuation studies

Instantaneous bandwidth

calculates the frequency bandwidth of the signal around the instantaneous frequency. This indicates how wide the frequency spectrum is.

Commonly uses for

attenuation analysis
thin bed detection

Thin bed indicator

calculates an attribute designed to highlight thin layers below seismic resolution. This attribute uses frequency and amplitude information.

Commonly uses for

thin reservoir identification
stratigraphic interpretation

Instantaneous Q

calculates the instantaneous Q factor, which represents seismic attenuation. Low Q values indicate higher attenuation.

Commonly uses for

gas detection
fracture zones
reservoir quality analysis

Amplitude

displays the original seismic amplitude. This represents the reflection strength at each sample.

Commonly uses for

general seismic interpretation
amplitude anomaly detection

Coherence

calculates the similarity of neighboring seismic traces. Low coherence values usually indicate structural discontinuities.

Commonly uses for

fault detection
fracture identification

Similarity

measures waveform similarity between adjacent traces. This attribute highlights subtle discontinuities.

Commonly uses for

channel boundaries
stratigraphic features

Chaos

calculates a measure of seismic waveform disorder. High chaos values indicate disrupted or chaotic reflectors.

Commonly uses for

gas chimneys
fracture zones

Seismic relief

generates a relief-style visualization of seismic amplitude. This enhances reflector geometry and structural edges.

Commonly uses for

structural interpretation
visualization of seismic features

Time window - defines the vertical time interval used in attribute computation. A larger time window uses more samples and produces smoother results.

Typical values depend on the seismic bandwidth.

Trace window - defines the number of neighboring traces used in multi-trace attributes. A larger trace window increases spatial smoothing. Used mainly for attributes such as coherence, similarity & chaos.

V0 - reference velocity parameter used in certain frequency-related calculations. This parameter helps stabilize attribute estimation when velocity information is required.

Folder for output files

specify the calculated attribute output file name and path. The output file will be in internal file format.

Settings

Distributed execution

if enabled: calculation is on coalition server (distribution mode/parallel calculations).

Bulk size

chunk size is RAM in megabytes that is required for each machine on the server (find this information in the Information, also need to click on action menu button for getting this statistics).

Limit number of threads on nodes

limit numbers of of threads on nodes for performing calculations.

Job suffix

add a job suffix.

Set custom affinity

an axillary option to set user defined affinity if necessary.

Set custom affinity - true

Affinity

add your affinity to recognize you workflow in the server QC interface.

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.

Run scripts

it is possible to use user's scripts for execution any additional commands before and after workflow execution.

Script before run

path to ssh file and its name that will be executed before workflow calculation. For example, it can be a script that switch on and switch off remote server nodes (on Cloud).

Script after run

path to ssh file and its name that will be executed before workflow calculation.

Skip

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

Output data

There are no output vista items available for this module.

Information

There is no information available for this module.

Examples

In this example workflow, we are reading a 3D stack volume by using Read SEG-Y traces module.

Make the necessary connections/references to Seismic attributes 3D distributed module.

Choose the desired attributes from the Attributes section and the corresponding trace and time windows.

Actions

There are no action items available for this module.

Video lesson

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

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

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