Modeling, Migration and Velocity Analysis in Simple and Complex Structure

Dr. J. Bee Bednar


Introduction
Target audience
Overview

Seismic Modeling

Primary Concerns
Three Earth Models
Seismic Acquisition: The Basic Idea
Why Model?
Waves and Wavefields
The Scalar Wave Equations
Stress-Strain Equations
Algorithms
Variational Formulation and Finite Elements
Finite Differences
Model Boundaries
Fourier Based Methods
A Word About Sources
Huygens Principle and Integral Methods
Raytracing
Raytrace Modeling
Zero Offset Modeling
History
Data Acquisition
Zero Offset Hand Migration
Shot Profile Hand Migration in Two Dimensions
Curved Rays
Shot Profile Hand Migration in Three Dimensions
Remarks about Migration
Redundant Data
Swing Arms
Non-Zero Offsets
Stacking and DMO
Historical Summary

Zero Offset Migration Algorithms
The Migration Algorithm Hierarchy
Migration in Depth
Migration in Time
Migration Summary

Exploding Reflector Examples
Canadian Glauconitic Channel Play
Gulf of Mexico Salt Model
Granitic Overthrust

Prestack Migration
Wavefield and Wave-Motion Hierarchies
Shot Profile Prestack Migration
Partial Prestack Migratio–Azimuth Moveout (AMO)
Velocity Independent Prestack Time Imaging
Double Downward Continuation—Common Azimuth Migration
Common Offset Kirchhoff Ray-Based Methods
Beam and Plane Wave Migrations
Algorithmic Differences

Prestack Migration Examples
Common Azimuth on the SEG/EAGE C3-NA Synthetic
Kirchhoff versus One-Way on a Gulf of Mexico 2D Salt Synthetic
A North Sea Sill Synthetic
Marmousi Case Study
An Imaging Note and the BP 2.5 Dimensional Data
BP 2.5 D Data
BP 2004 Salt Structure Data
SEG AA' Data Set
Migration from Topography
The SMAART JV Sigsbee Model
SMAART JV Pluto Data Set
SEG/EAGE C3-NA Data Imaging
Anisotropic Earth Models

Data Acquisition
Array Effects
Aperture
Aliasing
Modern Acquisition Geometries
Data Acquisition Summary

Migration Summary
Computational Complexity
Velocity Sensitivity
Amplitudes
Conclusions

Isotropic Velocity Analysis
Migration Velocity Analysis Geometry
Constant Velocity Migration Velocity Analysis
Velocity Independent Migration Velocity Analysis
Migrated Common Image Gathers
Semblance-Based Isotropic MVA on CIGs, CAGs, and SMIGs
Painless (No Horizons) Velocity Model Construction
Horizon-Based Velocity Analysis
Residual Tomography
SEG AA' Case Study
Marmousi Case Study

Anisotropic Velocity Analysis
Anisotropic Earth Models
The Anisotropic Earth
Anisotropic Normal Moveout
Depthing
A VTI example

Case Studies
Salt Flood and Body Insert
Amplitude Preservation
Which One Should I Use?
Land Data PSTM Versus PSDM Comparison
Autopicking PSTM
Tomography
South Texas Fault Shadow
Blessing Texas Case Study
Data Mapping through AMO on the Blessing data

Course Summary