This document outlines a simple seismic data processing workflow consisting of 23 steps: 1) field data input, 2) geometry update, 3) trace editing, 4) amplitude recovery, 5) noise attenuation, 6) deconvolution, 7) CMP sorting, 8) NMO correction, 9) stretch mute, 10) demutiple, 11) migration, 12) stacking, and 13) post-stack processing. The workflow aims to reformat raw field data, remove noise, correct for geometric spreading and velocity variations, and stack the data to generate a final seismic section for client delivery and interpretation.

1. Simple Seismic Data Processing Workflow
Compiled by :
Hatem Refaat Abdel Mobdy Radwan
Senior Geophysics Student
Faculty of Science, Ain Shams university.
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2. Activities
-Affiliations:
- Active Member in The Society of Exploration Geophysicists Student Chapter "SEG" since july 2014.
- Active Member (MENTOR) in “SPWLA” Ain Shams University Student Chapter Since October 2015.
-Volunteering Experience:
- Formal volunteer at Egyptian food bank 2010-2012.
Personal Introduction
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3. Field Data Input
Geometry Update
Trace Editing
Amplitude Recovery
Noise Attenuation
Deconvolution
CMP sorting
NMO Correction
Demultiple
Stretch Mute
Migration
Stacking
Post Stack Sequence
Simple Processing
Workflow
overview
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4. Field Data Input
Raw field Data must be reformatted into the company internal format (software format).
Usually the raw field data comes with SEG-D Format !!
Field data format
SEG Y
SEG D
Internal format of SLB
Omega (DIO)
Internal format is usually more efficient and reduces data size by 40%
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5. Geometry Update
Update the X,Y coordinates, elevation, line & point numbering, source & receiver types, shooting pattern
information by merge the Navigation/SPS file with the data file header .
Elevation map
78 ft
117 ft
Fold Map
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6. Trace Edit
Aim:
1- Remove bad traces(very noisy traces).
2- Remove bad shots.
3- Edit Polarity Reversed traces.
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7. Trace Edit
Before AfterN.B:
AAA filter can easily attenuate these noise without killing the traces.
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8. Amplitude Recovery
Aim:
Compensate the effect of Trace amplitude decay, There are 3 main causes of attenuation(decay)
Geometric attenuation Absorption Transmission
Before After
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9. Noise Attenuation: Ground Roll
Generated by: surface waves
Characterized by: low velocity, low frequency, high amplitude
Can be attenuated using: f-k filter, radon
transform, wavelet transform, curvelet transform
BeforeAfter
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10. Noise Attenuation: Seismic interference(SI)
Caused by interference with another seismic survey in the same time in the
same area
can be attenuated by Tau-p mutes that isolate the (SI) in Tau-p domain
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11. Deconvolution (Decon)
Decon is an inverse filter that used to improve seismic resolution by removing the adverse filtering
effects encountered by Seismic Waves during their passage through the earth (which acts as a filter).
After Before
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12. CMP sorting
Data sorting is re-organising (reordering) the data, to perform a certain process.
CMP sorting performed in order to perform Velocity analysis to determine the stacking velocity.
CVSSemblance
CMPs in offset
planes
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13. Normal Move Out Correction (NMO)
NMO Correction uses the stacking velocity which is determined by velocity analysis to remove the NMO effect.
NMO effect increase with offset, decrease with time, depth and velocity.
(a) Event isn’t corrected
(b) Event correct with proper velocity
(c) Event is over-corrected (velocity is
too low)
(d) Event is under-corrected (velocity
is too high)
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14. Stretch Mute
Event after NMO correction, First arrivals stretch and become low frequency these two effects increase with offset
(occur at the far offset).
MuteCMP gather NMO
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15. Demultiple
Multiples cause by: multiple reflections of the primary wave.
Can be attenuated by: f-k filter, Tau-p filter, stacking, Deconvolution.
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16. Demultiple
Can be attenuated by: f-k filter, Tau-p filter, stacking, Deconvolution.
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17. Migration
Reposition the reflection points from their apparent location to their true location (in case of dipping reflectors
and complex structures)
Increasing
structure
complicity
Increasing
lateral
velocity
complicity
Post stack Time
Migration
Post stack Depth
Migration
Pre-stack Time Migration
Pre-stack Depth
Migration
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18. Pre-stack Migration
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19. Post stack Migration
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20. Stacking
Stacking is basically a summation process,
summing the traces to produce a stacked
section represent the subsurface.
Stacking depend on many factors, but the
most important factor is the stacking
velocity (determined by Velocity Analysis)
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21. Post Stack sequence
Filtering:
After stacking, filtering can remove high and low frequency noise !
Amplitude scaling:
Acquire the final section a suitable amount of gain for better interpretation.
Final product:
Ask client for final product list to deliver in SEGY format.
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22. Thank You !
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23. Any Questions ?!
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