Reverse Time Migration
Advanced two-way wave-equation prestack migration
Accurately image in and below areas with great structural and velocity complexity.
Gulf of Mexico WAZ
Nearly continuous coverage across the most active portions of three major deepwater exploration plays
Our multiclient wide-azimuth surveys provide nearly continuous coverage across the most active portions of three major Gulf of Mexico deepwater exploration plays:
- subsalt Lower to Middle Miocene
- Lower Tertiary (Wilcox)
- emerging subsalt Pliocene.
Primary exploration targets in most of these areas are at depths from 20,000 to 35,000 ft beneath a complex and highly variable allochthonous salt canopy. These areas are characterized by various structural styles and trap types, from four-way closures associated with turtle structures or salt-cored folds to three-way traps against salt keels, feeders, or welds.
Wide-azimuth acquisition in the Gulf of Mexico.
Survey challenges, processing and interpretation
- Complex salt bodies
- Poor subsalt imaging
- Multiples
- Anisotropic velocity model building
Continuous survey coverage in deep water
Merge of raw SB3 RTM data from E-Octopus VIII, IX, and X surveys.
Acquisition technology and technique
Wide-azimuth acquisition is one of the primary techniques being used in Gulf of Mexico surveys. It addresses the imaging issues common to this area by recording a wider range of azimuths and offsets than conventional narrow-azimuth acquisition techniques. This acquisition technique employs
- four vessels equipped with point-receiver marine seismic system: two source and two recording boats
- ten 8-km steerable streamers per recording boat.
- Latest acquired data—wide-azimuth streamer acquisition survey; acquisition with point-receiver marine seismic system
Processing highlights
Our data processing techniques for subsalt imaging include use of reverse time migration (RTM) angle gathers for subsalt update tomography, 3D GSMP general surface multiple prediction methodology for improved attenuation of multiples, and multiazimuth tomography for construction of anisotropic velocity models.
