1. GDF Suez Holland E 16-4 VSP Part 1:
Vertical Stack of raw X, Y, Z traces
Removal of casing ringing on Z-axis traces
Fabio Ogliani
Schlumberger
Data and Consulting Services
July 2009

2. E 16- 4 VSP: Z AXIS STACK Time reference: source
Display amplitudes: trace normalized

3. E 16- 4 VSP: X AXIS STACK Time reference: source
Display amplitudes: trace normalized

4. E 16- 4 VSP: Y AXIS STACK Time reference: source
Display amplitudes: trace normalized

5. X AXIS STACK: Close-up in the casing ringing interval
Stack traces from raw data.
The first arrival time is manually picked on the 3 components:
X (no filter),
Y (no filter)
and Z with FK filtering to remove casing ringing.
Time reference: source
Display amplitudes: trace normalized

6. Y AXIS STACK: Close-up in the casing ringing interval
Stack traces from raw data.
The first arrival time is manually picked on the 3 components:
X (no filter),
Y (no filter)
and Z with FK filtering to remove casing ringing.
Time reference: source
Display amplitudes: trace normalized

7. Z AXIS STACK: Close-up in the casing ringing interval
Stack traces from raw data.
The first arrival time is picked at the first break.
Time reference: source
Display amplitudes: trace normalized

8. Z AXIS STACK: Close-up after the casing ringing removal
Stack of Z axis traces after FK filtering to remove the down and upgoing casing ringing waves. (Masked velocities: higher than 3600 m/s).
The first arrival time is manually picked on the 3 components:
X (no filter),
Y (no filter)
and Z with FK filtering to remove casing ringing.
Time reference: source
Display amplitudes: trace normalized

9. Z AXIS STACK: Close-up after the casing ringing removal
Stack of Z axis traces after FK filtering to remove the down and upgoing casing ringing waves. (Masked velocities: higher than 3600 m/s).
The first arrival time is manually picked on the 3 components:
X (no filter),
Y (no filter)
and Z with FK filtering to remove casing ringing.
Time reference: source
Display amplitudes: trace normalized

10. Z AXIS STACK: Close-up after the casing ringing removal
Stack of Z axis traces after FK filtering to remove the down and upgoing casing ringing waves. (Masked velocities: higher than 3600 m/s).
The first arrival time is manually picked on the 3 components:
X (no filter),
Y (no filter)
and Z with FK filtering to remove casing ringing.
Time reference: source
Display amplitudes: trace normalized

11. Part 2: Processing of True-Z traces
GDF Suez Holland E 16-4 VSP
Part 2:
Processing of True-Z traces
Fabio Ogliani
Schlumberger
Data and Consulting Services
July 2009

12. True-Z field Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)

13. Velocity Filter: Downgoing Field
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels

14. Predictive Decon: Downgoing Field
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec

15. Zero phase filter: Downgoing field
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec
Waveshape filter: zero phase 8-90 Hz. Filter length 0.15 sec. White noise 10 %.

16. Velocity Filter: First Residual
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field

17. Velocity Filter: Second Residual
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field

18. Predictive Decon: Second Residual
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field (2600 to m)
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec

19. Zero phase filter: Second Residual
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec
Waveshape filter: zero phase 8-90 Hz. Filter length 0.15 sec. White noise 10 %.

20. Zero phase filter: Upgoing enhancement
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec
Waveshape filter: zero phase 8-90 Hz. Filter length 0.15 sec. White noise 10 %.
Upgoing wave enhancement: median stack 7 levels
Normal polarity: acoustic impedance increase = through

21. Zero phase filter: Upgoing enhanc. + Amplitude recovery
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec
Waveshape filter: zero phase 8-90 Hz. Filter length 0.15 sec. White noise 10 %.
Upgoing wave enhancement: median stack 7 levels
Time varying amplitude recovery: exponent gain1.2.
Normal polarity: acoustic impedance increase = through

22. Zero phase Upgoing&corridor stack Normal polarity
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec
Waveshape filter: zero phase 8-90 Hz. Filter length 0.15 sec. White noise 10 %.
Upgoing wave enhancement: median stack 7 levels
Time varying amplitude recovery: exponent gain1.2.
Corridor stack: width: 0.1 s
AGC on display 0.4 ms
AGC
Normal polarity: acoustic impedance increase = through

23. Zero phase Upgoing&corridor stack Reverse polarity
Sequence of processing:
Stack (vertical sum) of raw traces ( tool-referenced X,Y and Z axes)
Casing ringing removal in Z axis stacks: depths from 1165 m to 1544 m
Transit time picking
Rotation of to True-Z axis
Band pass filter 4-98 Hz
Static correction: + 3 ms one way time
Normalization of first arrival amplitudes (window s from TT)
Velocity filter: Downgoing field enhancement: median stack 7 levels
First Residual: Subtraction of Down field
Second residual: Subtraction of downgoing Shear field
Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec
Waveshape filter: zero phase 8-90 Hz. Filter length 0.15 sec. White noise 10 %.
Upgoing wave enhancement: median stack 7 levels
Time varying amplitude recovery: exponent gain1.2.
Corridor stack: width: 0.1 s
AGC on display 0.4 sec
AGC
Reverse polarity: acoustic impedance increase = peak

24. GDF Suez Holland E 16-4 VSP Part 3: Shear velocities
The source of information for shear velocities are the two horizontal wavefields and the velocity filter residual field of the vertical component.
The recorded X and Y components (affected by the tool rotation) have been projected along the direction of maximum and minimum energy of the first arrival wave (HMX and HMN respectively).
The HMX waves are assumed to occur in the vertical plane of well deviation and are combined with the tool-Z traces to obtain the True horizontal response (True-X).
The HMN waves sense the response orthogonal to HMX-TrueX
The Shear time and velocities from HMX(TrueX), HMN and Z waves are tabulated separately. They do not show significant variations of S velocities and therefore do not provide indications shear anisotropy. The average Shear velocities and VPVS ratios are computed accordingly.
Fabio Ogliani
Schlumberger
Data and Consulting Services
July 2009

26. Horizontal Maximum Component (True-X)
The wavefield is obtained with the projection of tool-X and tool-Y data along the direction of maximum energy (tool-HMX).
The tool-HMX and tool-Z data are then rotated with the complementary of the well deviation angle to create the True-X horizontal component.
The shear time is picked along the blue line trends and refined with the yellow line trend.

27. Horizontal Minimum Component
The wavefield is obtained with the projection of tool-X and tool-Y data along the direction of minimum energy (tool-HMN).
The tool-HMN component is assumed to be orthogonal to the True-X component of the previous picture.
The shear time is picked along the blue line trends and refined with the yellow line trend.

28. Vertical Component (First residual field)
The wavefield is obtained with the tool-Z stacked traces and tool-HMX tarces. These wavfields are rotated with the well deviation angle to create the True-Z (vertical) component.
The shear time is picked along the blue line trends.

29. E 16-4 VSP: P & S interval velocities

30. GDF Suez Holland E 16-4 VSP Part 4: Examples of diffractions
The two horizontal components (Horizontal Maximum rotated to TrueX and Horizontal Minimum energy wavefields) and the TrueZ component show diffraction hyperbolae in addition to the usual Down/Up P/S content.
The following slides show the wavefields in the original version and after the removal of the removal of Down and Up events (residual fields).
The diffractions are visible in the residual fields.
All files are displayed with one-way first arrival time (i.e. no shift to two-way times is applied).
Therefore the diffraction apex indicates the diffractor depth.
The diffractor distance from the well is a function of P and S travel paths. Since the P or S nature of the diffraction is not analyzed in detail, the horizontal distance from the well, is not estimated in this report.
Fabio Ogliani
Schlumberger
Data and Consulting Services
July 2009

31. True-Y Horizontal Minimum Component
This horizontal wavefield shows well-developed diffraction hyperbolae, masked mostly by DownS waves
See next slide for DownS , DownP, UpP and UpS removal.
Time scale:
First arrival in one-way times from the SRD

32. True-Y Horizontal Minimum Component Residual after removal of Down&Up P&S events
This horizontal wavefield shows well-developed diffraction hyperbolae.
DownS, DownP, UpP and UpS fields have been removed with media stack filtering
Time scale:
First arrival in one-way times from the SRD

33. True-X Horizontal Maximum Comp.
This horizontal wavefield shows moderately -developed diffraction hyperbolae, masked mostly by DownS waves
See next slide for DownS , DownP, UpP and UpS removal.
Time scale:
First arrival in one-way times from the SRD

34. True-X Horizontal Maximum Comp
True-X Horizontal Maximum Comp. Residual after removal of Down&Up P&S events
The HMX horizontal wavefield diffraction hyperbolae somehow different from those of the HMN field.
DownS , DownP, UpP and UpS fields have been removed with media stack filtering
Time scale:
First arrival in one-way times from the SRD

35. True-Z component after Velocity filter Residual after removal of Down events
This field is taken from the main processing and is the velocity filter result.
The diffraction hyperbolae are masked by UpP waves
See next slide for UpP and removal.
Time scale:
First arrival in one-way times from the SRD

36. True-Z component Residual after removal of Down&Up P&S events
This field comes from the main processing and is obtained with an additional velocity filter step, removing the UpP waves.
Time scale:
First arrival in one-way times from the SRD