Accurate interval velocity/depth modeling is demanding and computation of depth images challenging. However, pre-Stack Depth Migration offers significant benefits over time imaging. Pre-Stack Depth Imaging is a collaborative effort, involving the interpreter and his/her understanding of the geology in the process from the start. Interpreters will find the results are usually both simpler and more geological-plausible, and which generally correlate better with sub-surface structures when tested by the drill-bit. The interval velocity/depth model itself provides important rock physics information for reservoir characterization studies. In addition, 'Illumination’ maps allow a quantified understanding of where interpretations, time or depth, can be trusted and where caution should be exercised.
FSI was an early entrant to pre-Stack Depth Migration services, developing its own technology from the early 1990's onward. Internal software development continues, but FSI has also extended the range of software available to its depth teams by licencing industry-leading third-party applications, both modeling and migration, designed to increase the range of options available to Clients.
In summary, pre-Stack Depth Migration offers the following benefits:
• Accurate structural images Images more faithfully represent geological structures, improved and more confident interpretation
• Improved volumetrics Accurate determination of the physical dimensions, area and thickness, of target structures
• Well calibrated Borehold-data calibrated seismic-geological model
• Illumination analysis Quantified assessment of the trustworthiness of interpretations
Offshore, FSI has undertaken depth imaging work in many basins – particularly in the Gulf of Mexico, and also in Brazil, West Africa, Greenland, Barents Sea, the UK, Dutch and Norwegian sectors of the North Sea, India and Australia. FSI has also developed considerable expertise in depth imaging onshore datasets, particularly in overthrust areas from eastern Europe through to Pakistan and in transition zones, such as coastal West Africa.