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

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

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

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

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

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

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

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

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

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

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

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 0.120 s from TT)

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 0.120 s from TT) Velocity filter: Downgoing field enhancement: median stack 7 levels

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 0.120 s from TT) Velocity filter: Downgoing field enhancement: median stack 7 levels Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec

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 0.120 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 %.

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 0.120 s from TT) Velocity filter: Downgoing field enhancement: median stack 7 levels First Residual: Subtraction of Down field

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 0.120 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: 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 0.120 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 4235 m) Predictive Decon. Prediction time: 2nd zero crossing. Autocorrelation length 1 sec

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 0.120 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 %.

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 0.120 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

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 0.120 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

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 0.120 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

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 0.120 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

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

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.

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.

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.

E 16-4 VSP: P & S interval velocities

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

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

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

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

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

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

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