Sensitive Multimeter, user manual, service guide made by AVO, Model CY-68. Army Navy numberDescripción completa
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Descripción: In this thesis, we apply AVO technique to map the attribute anomalies of the reservoir to survey the capability of AVO technique to indicate the exact location of the gas zones in approved hydroc...
AVO analysis and Impedance Inversion Okey Ileka
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AVO Analysis • • • • • • • •
Introduction AVO Pr Pre-processing AVO modeling AVO parameters AVO crossplot analysis AVO attributes Some ap application of of AV AVO Prob robabilis listic AV AVO an analysis 2
AVO Analysis • • • • • • • •
Introduction AVO Pr Pre-processing AVO modeling AVO parameters AVO crossplot analysis AVO attributes Some ap application of of AV AVO Prob robabilis listic AV AVO an analysis 2
Impedance Inversion • • • • • •
Post Post stac stack k 1D 1D Impe Impeda danc nce e Inv Inver ersi sion on FarFar-of offfset set ela elast stic ic Imp mped edan ance ce Lambda-mu-rho es estimation ion P to to S elastic In Inversion Anis Anisot otro ropi pic c ela elast stic ic Im Impe peda danc nce e Inte In terp rpre reta tati tion on of of Ro Rock ck phy physi sics cs tem templ plat ate e
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Introduction • AVO AVO is is the the amp amplilitu tude de vari variat atio ion n with with of offs fset et
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Introduction
Castagna lecture notes 5
Introduction
Castagna lecture notes
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Simplified Shuey (1985) Form of the Richards and Frazier (1976) Approximation
R (θ ) ≈ A + B sin θ 2
A = R p 1 ⎛ ΔV p
⎞ Δ ρ ⎟ A≈ ⎜ + 2 ⎜⎝ V p ρ ⎠⎟
B ≈ R p − 2 Rs 2 Δ V V s Δ ρ 1 V s ΔV s p + −4 2 B ≈ −2 2 2
V p ρ
2 V p
V p 7 V s
Third Order Approximation
R (θ ) ≈ A + B sin θ + C sin θ tan θ 2
1 ⎛ ΔV p
Δ ρ ⎞ ⎟ + A = ⎜ 2 ⎜⎝ V p ρ ⎠⎟
A − C ≈ Castagna lecture note
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C ≈
2
1 ΔV p 2 V p
1 Δ ρ 2 ρ 8
Hiltermann Approximation G
6 4 7 4 8
R(θ ) ≈ A cos θ + 2.25Δσ sin θ 2
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G = A + B Castagna lecture note
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AVO preprocessing
Castagna lecture notes
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Castagna lecture note
Factors that amplitudes • Earth effects • Acquisition related effects • Noise
Intercept Gradient Near and far stacks Curvature CDP stack Change in Poisson’s ratio Fluid Factor
Castagna lecture notes
• • • • •
Intercept minus Gradient Intercept plus Gradient Intercept times Gradient Rp-Rs P and S wave velocity contrast • Density Contrast • Amoco Indicator F(F-N) • Lamba-mu-rho
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Ca l cu l a t e d A V O A t t r i b u t e s
A = intercept B = gradient r² = correlation A×B (A + B)/2 ~ Rp - Rs (A – B)/2 ~ Rs A = intercept B = gradient C = curvature r² = correlation A×B (A + B)/2 ~ Rp - Rs (A – B)/2 ~ Rs A–C NI = normal intercept PR = Poisson reflectivity r² = correlation NI × PR
Shuey 2 Term
RC (θ) = A + B (sin²θ)
Shuey 3 Term
RC (θ) = A + B (sin²θ) + C (sin²θ)(tan²θ)
Verm-Hilterman
RC (θ) = NI(cos²θ) + PR (sin²θ)
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Roden, 2005
Some application of AVO • Residual gas saturation (converted waves) • Flat spot analysis • Overpressure detection • Density estimation 27
Probabilistic AVO analysis • In probabilistic AVO analysis the AVO parameters and attributes are assigned probability density function (PDF) or cumulative density function (CDF)
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Impedance Inversion • The goal of geophysical inversion is to estimate model parameter from observed data
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Impedance Inversion • • • • • •
Post stack 1D Impedance Inversion Far-offset elastic Impedance Lambda-mu-rho estimation P to S elastic Inversion Anisotropic elastic Impedance Interpretation of Rock physics template
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Poststack 1D impedance Inversion • Inversion of near stack traces
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Acoustic Impedance Inversion Near Angle Stack
Sonic,Density Logs
tie
Wavelet
tie
Bandlimited Inversion
Horizons
AI Earth Model
Trend Model
Merged AI
Castagna lecture note
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Far offset elastic Impedance • Inversion of far offset traces
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The Elastic Impedance E = Vp Vs = 1/cos2
= -8(Vs/Vp)2sin2 = 1 + /2
Castagna lecture notes
Sena, 1997
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Elastic Impedance Inversion Far Angle Stack
Sonic,Shear Sonic,Shear Sonic and Density Logs
tie
Wavelet
tie
Bandlimited Inversion
Horizons
EI Earth Model
Trend Model
Merged EI
Castagna lecture note
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Lambda Rho estimation
Hilter
’s lecture note
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P –to- S elastic Inversion
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Reflection Coefficients: Angle vs. Offset
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P-S Reflection Coefficient (Aki & Richards, 1980)
Rps
First Order Relative S-velocity change Stewart and Gasier lectu
ote
39 Relative density change
Anisotropic elastic Inversion
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Anisotropy
Hilterman course notes
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Anisotropic Inversion
Hilterman course notes
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Interpretation of Rock Physics Template • The rock physics template is based on a compiled catalog or atlas of RPT’s calculated by a rock physics expert. • The seismic interpreter can interpret elastic inversion results without in-depth knowledge about rock physics theory
