COURSE CONTENT

1. SEISMIC PROPAGATION

• Media for wave propagation
• Types of waves
• Elastic constants
• Factors controlling Poisson’s ratio include:
• Propagation of waves
• Partitioning of energy.

2. ROCK PHYSICS FOUNDATION FOR AVO ANALYSIS: GASSMANN’S EQUATIONS AND FLUID SUBSTITUTION

• Gassmann’s equations
• Gassmann’s assumptions
• Using Gassmann’s equations
• Estimating K*
• The Fluid Substitution Paradox
• Fluid properties
• Raymer-Hunt-Gardner Equations
• Saturated versus frame moduli
• Low gas saturations
• Sensitivity and uncertainty
• Differences in frame modulus from inverted modulus and between brine and gas sands
• Alternatives to Gassmann’s Equations
• Conclusions and Discussion.

3. EARLY SEISMIC OBSERVATIONS: HISTORICAL DEVELOPMENTS LEADING TO THE BIRTH OF AVO

• Introduction
• Bright spot technology before AVO
• Increased understanding of conventional hydrocarbon indicators
• Shear wave exploration
• Other methods
• Birth of AVO
• AVO is widely used and lessons learned
• Studying offset dependence of reflection coefficients with ‘equal-angle particle stacks’
• Classification of AVO anomalies
• Commercialization of AVO
• Bright Spots: Oil versus Gas
• Rock physics analysis and AVO
• The Impact of 3D Seismic
• Crossplotting of AVO attributes
• Lambda-Mu-Rho analysis
• Application of AVO in exploration/development projects

4. ZOEPPRITZ EQUATIONS AND THEIR APPROXIMATIONS

• Bortfeld approximation
• Richards and Frasier (Aki and Richards) approximation
• Shuey’s approximation
• Hilterman’s approximation
• Smith and Gidlow approximation
• Fatti et al approximation
• Lamé parameter extraction
• Xu and Bancroft extraction
• Gray et al extraction
• Approximations for Converted-Wave and Anisotropic Reflectivity.

5. FACTORS AFFECTING SEISMIC AMPLITUDES AND PROCESSING FOR AVO

• Introduction
• Spherical spreading
• Transmission
• Influence of scattering attenuation in heterogeneous overburden on AVO
• Intrinsic attenuation and dispersion
• Mode conversions
• Effects of tuning and NMO stretch
• Removal of noise
• AVO in structurally complex areas
• Anisotropy
• Effects due to receiver coupling
• Effects due to array directivity
• Preprocessing for AVO
• 3-D AVO
• AVO attribute processing
• Estimation of intercept and gradient.

6. AVO INTERPRETATION

• Introduction
• Modeling
• AVO techniques
• Attribute stacks
• AVO combination indicators
• Classification of AVO responses
• Crossplotting
• Noise and AVO
• AVO and visualization
• AVO polarization attributes
• Lambda-Mu-Rho λμρ
• AVO and neural networks.

7. AVO and Anisotropy

• Introduction
• Anisotropy
• Weak anisotropy in rocks
• Physical meaning of anisotropy parameters
• Offset-dependent effects of anisotropy
• Numerical solution to Zoeppritz equations
• Moveout velocity analysis in anisotropic media
• Azimuthal anisotropy
• Methods for fracture analysis

8. SEISMIC INVERSION, CONVERTED WAVE AVO, AND UNCERTAINTY IN AVO ANALYSIS

• Seismic inversion
• Impedance inversion
• Band limited nature of seismic signal
• Sparse-spike inversion
• Model-based inversion
• Elastic impedance
• Local and global optimization in inversion
• Prestack versus poststack inversion
• Simultaneous inversion
• Poisson Impedance.

Converted-wave AVO

• Zoeppritz equations for PS reflections
• PS Elastic Impedance
• Simultaneous P-P and P-S inversion

Uncertainty in AVO

• Bayes theorem
• Monte Carlo simulation
• Quantifying uncertainty
• Quantifying uncertainty in practicen 

9. DISCUSSION AND CONCLUSIONS

• Introduction
• AVO Processing Issues
• Aspects of Seismic Data Acquisition for AVO Analysis
• Amplitude Calibration and Balancing
• AVO Attributes and Crossplotting
• The Rigidity Contrast Paradox
• Comments on Class IV Gas Sands
• Dynamic Elastic Moduli Determination
• Azimuthal AVO
• Carbonate AVO
• Tuning and Frequency Dependent AVO
• AVO Risking
• AVO in Practice
• The Future of AVO.