A Brief Introduction
For
Multi-Component Seismic Data Processing
Submitted by
BGP Jakarta Data Processing Center
January 16, 2006
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1. Introduction
Since 1983 BGP has experimented and developed multi-component
technology. This expertise has evolved into a series of integrated
techniques which have been tested and have proved to be reliable suite
of exploration and development seismic services.
BGP Jakarta Data Processing Center is fully supported by Geophysical Research
Institute (GRI) of BGP, China. GRI is a reputed international Geophysical services
company having very sound research and development background in Geophysical
industry. It has employed and developed highly advanced technologies and therefore
has become a world level service and research company in geophysical prospecting
industry.
The data was processed using PROMAX,GEODEPTH and GRISYS as the main
Geophysical application processing software (version 6.0), which was developed by
GRI of BGP. In addition to GBSYS seismic processing software for pre-stack time
migration developed by Globe Company of Houston USA is also available. The
seismic application software package is comprised of several geophysical data
processing modules, which are capable of undertaking full 2D and 3D interactive and
batch processing functions.
Integrated Techniques
Z component processing
Statics
Pre-stack noise attenuation
Surface consistent processing
Velocity analysis, NMO, stack
Imaging
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X,Y component processing
S wave statics
CCP binning
P-SV velocity analysis
P-SV wave NMO
P-SV wave imaging
Extraction of attributes
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before
after
S-wave Statics
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PSV
Super gather
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NMO
Conventional NMO
Non-hyperbolic NMO
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P-P
PSV
Final processing results
Gas-bearing sandstone
Lithology prediction using Vp/Vs ratio
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2. 3 Component Seismic Data Processing
1. Required input data
We will request COMPANY with the following data:
 2D 3C Field seismic tapes (vibroseis correlated) and additional data (observer
report, coordinates and elevations (SPS), uphole data)
 P-wave velocity model from anisotropic pre-stack time or depth migration of
P-P wave data (depth maps, velocity file, VTI parameters)
 Final processing results of P-P wave data
 Well data
 Other data required for data processing
2. Pre-Processing and Preparations
1. Data loading.
3. Shot gathers and all near traces display.
2. Geometry updating: The geometry can be defined with SPS file. The linear
NMO and shot gathers displays will be performed to check the result of the
defined geometry.
3. Component separation: V, H1, H2
4. Construction of a Vp/Vs (1-D) background model from VSP and/or well log
data.
3. P-P Wave Processing
5. Edit bad traces/shots, de-spiking (manually and/or automatically). Shot gather
display. The signal and noise amplitude analysis at different times.
6. Elevation static correction, stack sections with the elevation static correction
are applied to compare with refraction static correction
7. First break picking, Refraction Static Computation and Refraction Static
Application. QC: shot gathers and stack section using a preliminary velocity,
before and after refraction static application.
8. Spherical divergence correction. Shot gathers display.
9. Surface consistent amplitude compensation. Shot gather display.
10. Inverse Q filter(optional). Q will be calculated by estimating the spectral
change with different time. Suited QC plots for testing and application .
11. Surface consistent deconvolution or predictive deconvolution ( parameter tests,
QC plots).
12. CMP gathers sort. Fold display.
13. First pass velocity analysis (at 500m interval). Preliminary stack.
14. First pass residual statics. QC products.
15. Second pass velocity analysis.
16. Second pass residual statics.
17. Kirchoff pre-stack time migration( parameter tests, QC plots).
18. NMO inverse (second velocity).
19. Third pass velocity analysis
20. Kirchoff pre-stack time migration (third velocity).
21. NMO inverse (third velocity).
22. Higher order NMO, mute and Stack.
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4. Poststack processing (for PP and PS)
23. Deconvolution after stack. QC products.
24. Time variant filter. QC products.
25. FK filter. QC products.
26. F-X deconvolution
27. Time variant gain. QC products.
28. Phase analysis, phase shift: zero-phasing filter to be derived statistically or by
matching the seismic to a supplied well reflection series. QC products.
29. Generation of final deliverables.
5. P-S Wave Processing
For the processing of the horizontal components, a modification of the P-P wave
processing will be applied. Differently from P-P wave processing there are no
restrictions of maximum offset or trace length (data as acquired shall be used).
Additional steps or modifications of steps are:
30. Restriction of maximum offset to 5 km.
31. Negative offset polarity reversal, reverse trace analysis and correction. Shot
gathers and all near traces will be displayed. Maps showing the amplitude of
the signal and noise at various times in the data set.
32. Rotation analysis and tests. QC products.
33. P-wave and S- wave static. QC products.
34. First Break Picking (manually and/or automatically), Refraction Static
Computation and Refraction Static Application. QC products.
35. Loop(s) of asymptotic binning, residual static computation, CCP velocity
analysis. Vp/Vs ratio sections are the most important deliverable to
achieve the project objective. Therefore adequate steps / iterations have to
be performed to achieve this goal. QC products.
36. CCP operations instead of CMP operations. QC products.
37. Inverse Qs filter. Qs to be calculated by estimating the spectral change with
different time. Suited QC plots for testing and application.
38. Offset separation (positive and negative offsets) prior to PSTM.
39. Kirchoff pre-stack time migration( parameter tests, QC plots).
40. NMO inverse using Kirchoff .
41. PSTM velocity analysis
42. Kirchoff pre-stack time migration .
43. NMO inverse .
44. Higher order NMO, mute and Stack.
6. Optional / additional Processing
45. PS DMO with N offset planes. QC products.
46. Higher order non-hyperbolic NMO corrections. QC products.
47. Trim statics. QC products.
48. FD Migration with PS average velocities (2*VpVs/(Vp+Vs)). QC products.
49. Generation of SPS.
50. Computation of velocities from raw uphole data and building of static model.
51. Noise attenuation. The contractor is asked to propose available suited
techniques and to provide technical details. COMPANY will choose the
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method to be applied. Suited QC products: prestack and stack gathers before
/ after.
52. Multiple attenuation. The contractor is asked to propose available suited
techniques and to provide technical details. This step includes sufficient
velocity analyses to generate an optimum filter. COMPANY will choose the
method to be applied. Suited QC products: prestack and stack gathers before /
after.
53. Posts-tack spectral whitening. QC: before/after.
7. Depth Processing
Pre-stack Depth Migration
In our seismic data processing center, we usually use GeoDepth software (developed
by Paradigm) to run the Pre-stack depth migration.
Geodepth software, a velocity analysis and depth imaging product, is designed to
allow interpreters and time and depth processors to perform highly accurate
time-to-depth conversion. Geodeprh software enables you to obtain a verified
depth/velocity model of the subsurface together with a consistent depth image and
depth migrated gathers for the multi-line marine and land surveys.
The key data sources for GeoDepth software are pre-stack CMP gathers and
navigation data for the 2D lines. The pre-stack gathers can be used after performing
time processing in another processing software. You can also load time and time
migrated stacks, CMP gathers, velocity sections, velocity functions and interpretation
picks. Alternatively, you can easily and accurately generate them from GeoDepth
software. It provides a wide variety of advanced, easy-to-use tools for data QC,
velocity analysis and time and depth imaging.
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8.
The Proposed Flow Chart of the 2D Seismic Data Processing
8.1
P-P Wave Basic Processing Sequence
Demultiplexing

Shot Gathers Display

Geometry Update

Sort to Vertical Component

Edit bad traces/shots, de-spiking

Elevation Static Correction

First Break Picking, Refraction Static Correction

Spherical Divergence Correction

Surface consistent amplitude compensation

Surface consistent deconvolution

Sort to CMP gather

First pass velocity analysis (every 500 m) and stack

First Pass Surface Consistent Residual Statics Correction

Predictive Deconvolution or Inverse Q-filter

Second pass velocity analysis (every 250m) and stack

Second Pass Surface Consistent Residual statics Correction

Kirchhoff Pre-stack Time Migration

NMO Inverse

Third Pass Velocity Analysis

Kirchhoff Pre-stack Time Migration

NMO Inverse and SEGY RAW PSTM Gather

NMO, Mute and Stack
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
F-X deconvolution

Post-stack Deconvolution

Time variant filter

Scaling

Final Result
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8.2 P-S Wave Basic Processing Sequence
Demultiplexing

Shot Gather and Near Offset Display

Geometry Update

First Break Picking, Refraction Static Correction

Sort to Horizontal Component

Construction of a Vp/Vs

Negative offset polarity reversal, reverse trace analysis and correction

Rotation analysis and tests

PS static application

Edit bad traces/shots, de-spiking

FK Filter at Shot/Receiver Domain(Optional)

Spherical Divergence Correct

Surface consistent amplitude compensation

Surface consistent deconvolution

Sort to CCP

CCP velocity analysis (every 500 m) and stack

1st Surface Consistent Residual statics Correction

Predictive Deconvolution or Inverse Qs-filter

nd
2 velocity analysis (every 250m) and stack

2nd Surface Consistent Residual statics Correction

Offset separation (positive and negative offsets) prior to PSTM

Kirchhoff Pre-stack Time Migration

NMO Inverse
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
Third Pass Velocity Analysis

Kirchhoff Pre-stack Time Migration

NMO Inverse and SEGY RAW PSTM Gather

NMO, Mute and Stack

F-X deconvolution

Post-stack Deconvolution

Time variant filter

Scaling

Final Result
9. Key processing techniques for Multi-Component Seismic Data
 Automatic Vp/Vs Picker
 Co-Sensor Interpolation
 Co-Sensor Sum
 Common Conversion Point (CCP) Binning
 Multi-Component Cross-Equalization
 S-Wave 2-Component Rotation
 Vp/Vs Computation
 Vp/Vs Correlation
 Vp/Vs Transform
 P-Sv PSTM
 P-Sv DMO
10. Key Processing Technic Description
 Common Conversion Point (CCP) Binning
Pre-stack P-S converted wave data are rebinned to common conversion point (CCP)
location instead of common midpoint (CMP) location for subsequent processing. Each
input trace is segmented into user-specified time windows that are individually
rebinned and output as new traces. Velocity manager formatted files of velocities and
of Vp/Vs ratios are required.
 Multi-component Cross-Equalization
For land and marine multi-component data, this module cross-equalizes the amplitude
and phase spectra of the horizontal detector components for optimal vector wavefield
processing, including combination (rotation) using the S-Wave 2-component Rotation
module. The vertical detector component may be included in the computation and
may also be corrected to remove spurious S-wave energy.
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 S-Wave 2-Component Rotation
For land and marine multi-component data, the horizontal detector components of
shear-wave data are rotated to obtain the desired wavefield. The data may be rotated
to the source-detector direction, a common direction, or back to the original direction.
If the original field orientations of the horizontal components are not known, they
may be calculated so that subsequent rotation can be performed.
 Vp/Vs Transform
Stacked compressional-wave, converted-wave, or shear-wave reflection data two-way
traveltimes are transformed to two-way traveltimes of a different type. By correlating
a transformed version of one wave type to a recorded version of that wave type, an
analysis of the ratio of compressional-wave velocity (Vp) to shear-wave velocity (Vs)
can be made. This can aid in the interpretation of lithology and fluid properties from
seismic data. Input data is post-stack and trace selected as required. Output can be a
transformed stack from average Vp/Vs function or a set of transformed gathers, useful
for Vp/Vs correlation analysis. A complete input trace or a single window of data can
be transformed.
 P-SV DMO
P-SV DMO is performed with a space-time (x-t) Kirchhoff algorithm. The input data
are common-offset gathers which have not been NMO. Output obtained that consists
of common-offset gathers which approximate P-P data in an equivalent velocity
medium. Additional processing, such as a residual NMO correction, is typically
required after applying this process.
11. Final Products
 SEGY tapes of the PP and PS final stack and migration
 SEGY tapes of final filtered zero-phased PP and PS migration
 PP and PS PSTM or DMO gather tapes in SEGY
 PP and PS stacking and migration velocities in ASCII format
 SEGY tape of final Vp/Vs sections
Final report (3 paper copies plus 3 CDROM PDF file copies)
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