Depth Imaging and Velocity Model Construction
A complete imaging course, concentrating on visual concepts rather than equations. Difference between time and depth imaging, depth conversion.Wave and Ray based depth imaging correcting for velocity variation and complex sub-surface. Algorithm choice: Kirchhoff single/multi arrival, Beam versus wavefield methods (including reverse time migration), least-squares migration.
Role of interpreter in velocity model building and quality control
• Prestack migration, gather generation and velocity updates
• Anisotropy including VTI, TTI, orthorhombic cases.
• Full-Waveform Inversion
• Data preparation and initial quality controls
• Diving wave and reflection-based inversion schemes
• Quality control and common pitfalls.
• Tomography – grid or layer based, hybrid methods
• Case histories: Scott Field, North Sea Gas Basin, Sub-salt Gulf of Mexico.
• Additional uses of seismic velocities: e.g. imaging, pore pressure, depthing
Future developments: Imaging with multiples, Elastic imaging, Q migration