Post on 14-Jan-2017
transcript
Simple Seismic processing workflow
By: Ali Ismael AlBaklishy Senior Student, Geophysics Department,
School of sciences, Cairo University
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
Processing Workflow:
References.
Q&A.
Content
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
Processing Workflow:
References.
Q&A.
Introduction
Seismic Prospecting
Seismic Interpretation
Seismic
acquisition
Seismic Processing
Seismic
Interpretation
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
Processing Workflow:
References.
Q&A.
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Data Reformat (Transcription)
Field data format SEG Y SEG D
Internal format of the co.
Ex.: DIO (Omega)
Data Initialization
Geometry update
Objective : • Insert the X,Y,Z coordinates for each
shot and geophone group by merge the Navigation/SPS file with the data file .
Data Initialization
Trace Editing
Objective :
1- Remove bad traces. 2- Remove bad shots. 3-Remove Duplicated traces. 4- Polarity Revers.
Data Initialization
Trace Editing
before
after
Data Initialization
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Amplitude Recovery And Gain
• Energy is attenuated due to the spherical divergence effect.
Amplitude Processing
Before after
• Before And After Amplitude Recovery
Amplitude Processing
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
1- Ground Roll Attenuation.
Before
Noise Attenuation
• Ground Roll Attenuation
After
Noise Attenuation
2- Swell Noise Attenuation.
Before After
Noise Attenuation
3- Liner Noise Attenuation By using FK filter & Radon (tau p)
Noise Attenuation
• Tau p Radon transform
Noise Attenuation
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Deconvolution
Objective: To get rid of the energy wavelet so that get the earth’s Reflectivity.
• Deterministic Deconv. (de-signature Deconv.) (known Wavelet)
Deconvolution
• Statistical Deconv. (Gap Deconv).
(Unknown Wavelet)
Before
Deconvolution
After
Deconvolution
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Multiple Attenuation
• Water Bottom Multiples Attenuation
Before After
• Surface Multiples Attenuation
Multiple Attenuation
Before After
• Interbed Multiples Attenuation
• Short period and residual Multiples Attenuation By using Deconvolution
Multiple Attenuation
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Velocity Analysis And NMO
Objective : 1- Determine NMO Velocity. 2- Determine stack velocity. 3- Determine Migration velocity.
Velocity Analysis And NMO
MVFS
• In case of wrong Velocity
Velocity Analysis And NMO
• Stretch Muting
Velocity Analysis And NMO
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Migration
Objective:
Is to reposition the data from its apparent reflection point (due to Non Horizontal Reflectors) to its true reflection point.
• Migration classification According to its position in the workflow
Post stack Migration
Pre-Stack Migration
• Take long time. • High cost. • No data losses.
• Less time. • Low cost. • Loss in data.
Migration
• Pre-stack and post stack Migration
Migration
• Migration classification According to its types:
Time Migration
Depth Migration
• Time and space Domain.
• Don’t takes ray bending & lateral velocity change into account.
• Take shorter time.
• Depth Domain.
• takes ray bending & lateral velocity change into account.
• require greater
computer time.
Migration
1- Time Migration • Time migration is the repositioning of reflected seismic data to their
true reflection points in space and time. Ex: Kirchhoff Migration
Migration
2- Depth Migration.
• In depth migration, data are migrated in depth domain and the input data for the process is unmigrated seismic data in time domain. The output is migrated data in the depth domain.
• take into account the bending of ray paths by refraction within a complex geology.
Migration
• Time Migration and depth Migration
Migration
• Migration Examples
Migration
• Migration Examples
Migration
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Stacking
Stacking
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
References.
Q&A.
Data Makeup
• Data Filtering
• Amplitude Scaling
Stacking
Stacking
Content Introduction.
• Data Initialization.
• Amplitude Processing.
• Noise Attenuation.
• Deconvolution.
• Multiple Attenuation. • Velocity Analysis and NMO. • Migration.
• Stack. • Data Makeup.
Processing Workflow:
Q&A.
References:
• Exploration Geophysics, Mamdouh R. Gadallah · Ray Fisher,2009.
• Seismic data Processing, OZ Yilmaz.
• Seismic Data Analysis And Techniques in Hydrocarbon Exploration, ENWENODE ONAJITE, 2014
• Seismic Reflections: Marine Processing - Part 5 | Direct Arrivals, Refractions, and Linear Noise
• Seismic Reflections: Marine Processing - Part 4 | Swell Noise Removal
Q&A