team 6: deducing rock properties from spectral …...identify ways to use spectral decomposition...
TRANSCRIPT
![Page 1: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/1.jpg)
Team 6:Deducing Rock Properties from
Spectral Seismic DataMentor Jiajun Han, CGG
Maria-Veronica Ciocanel, Brown UniversityHeather Hardeman, University of CalgaryDillon Nasserden, Simon Fraser University
Byungjae Son, University of North Carolina, GreensboroShuai Ye, Texas A & M University
![Page 2: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/2.jpg)
ProblemThe aim of our investigations is to find evidence for subsurface reservoirs and valleys from geological data.
Spectral decomposition, which is called time-frequency decomposition, characterize the change in frequency of a seismic signal.
![Page 3: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/3.jpg)
Methods
Short-Time Fourier Transform (STFT)
Continuous Wavelet Transform (CWT)
![Page 4: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/4.jpg)
• Synchrosqueezing Transform (SST)
![Page 5: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/5.jpg)
• Basis Pursuit (BP)
![Page 6: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/6.jpg)
Seismic Attributes
Envelope of seismic trace:
𝐸𝐸 𝑡𝑡 = 𝑇𝑇2(𝑡𝑡) + 𝐻𝐻𝑇𝑇2(𝑡𝑡) The first and second time derivative of the envelope The phase attribute:
𝜃𝜃 𝑡𝑡 = arctan(𝐻𝐻𝑇𝑇 (𝑡𝑡)𝑇𝑇 (𝑡𝑡)
)
The first and second time derivative of the phase attribute
![Page 7: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/7.jpg)
Reservoir Data Set
Post-stack data Pre-stack data
![Page 8: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/8.jpg)
Post-stack Results – standard attributes
Attributes for the reservoir post-stack data: First derivative of the envelope (left) and second derivative of the envelope (right)
![Page 9: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/9.jpg)
Post-stack Results – amplitude and phase attributes
Constant frequency slices obtained by CWT for the amplitude (left) and phase (right) attributes at frequency approx. 5 Hz and 3 Hz respectively.
![Page 10: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/10.jpg)
Post-stack Results – amplitude and phase attributes
Constant frequency slices obtained by SST with regards to the amplitude (left) and phase (right) attributes at frequency approx. 60 Hz (left) and 55 Hz (right).
![Page 11: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/11.jpg)
Valley Data Set
Post-stack data
![Page 12: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/12.jpg)
Post-Stack Results – standard attributes
Attributes for the valley post-stack data: First derivative of the envelope (left) and second derivative of the envelope (right)
![Page 13: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/13.jpg)
Post-Stack Results – phase attribute
Constant frequency slices obtained with BP (basis pursuit) for the phase attribute at approx27 Hz (left), and 32 Hz (right)
![Page 14: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/14.jpg)
Preliminary/Future Work
Look into AVO (amplitude vs offset) analysis in order to identify bright spots for hydrocarbon reservoirs
Identify ways to use spectral decomposition information for pre-stack data analysis
Determine if frequency information from t-f analysis can provide insight into distinguishing between P and S-waves
![Page 15: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/15.jpg)
Pre-stack Results – AVO, A-B attributesP and S-Wave Velocities
Unlike density, seismic velocity involves the deformation of a rock as a function of time. This leads to two different types of velocities:
(1) P-wave (2) S-wave
![Page 16: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/16.jpg)
If q > 0°, an incident P-wave will produce both P and S reflected andtransmitted waves. This is called mode conversion.
Mode Conversion of an Incident P-Wave
Reflected P-wave = RP(θ1)
Reflected S-wave = RS(θ1)
Transmitted P-wave = TP(θ1)
Incident P-wave
Transmitted S-wave = TS(θ1)
VP1 , VS1 , ρ1
VP2 , VS2 , ρ2
θ1
φ1
θ1
θ2
φ2
q16
![Page 17: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/17.jpg)
AVO method
• AVO (Amplitude versus Offset) method ---- Interpret the amplitudes of the P-waves as a function of offset, or angle, which contain implied information about the S-waves.
• Converting from offset to angle domain
• To extract S-wave type information from P-wave reflections at different offsets ----(Wiggins’ Form of the Aki-Richards Equation)
: where,sintansin)( 222 θθθθ CBARP ++=
.21,24
21,
21
22
p
P
P
S
S
S
P
S
p
P
p
P
VVC
VV
VV
VV
VVB
VVA ∆
=∆
−
∆
−
∆=
∆+
∆=
ρρ
ρρ
![Page 18: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/18.jpg)
An example of evaluated attributes A and B
![Page 19: Team 6: Deducing Rock Properties from Spectral …...Identify ways to use spectral decomposition information for pre-stack data analysis Determine if frequency information from t-f](https://reader034.vdocuments.net/reader034/viewer/2022042916/5f55b47c8c5ea049e81cc51c/html5/thumbnails/19.jpg)
Pre-stack Preliminary Results
Attributes 𝑻𝑻𝟏𝟏 (left) and 𝑻𝑻𝟐𝟐 (right) at approx. 40 Hz as a function of time and offset. BP was performed with a Ricker wavelet dictionary.