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Petroleum Seismological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
Seismic migration is a process by which an almost real image, in either space or time, of the underground structure is obtained from the observed seismic data recorded at the surface. It is the relocation of the seismic events to the real position rather than the location at which the event was observed at the surface. The purpose of seismic migration is to see the underground features in their proper locations both vertically and laterally. The concept of seismic migration is explained by citing a simple example of the geological non-conformity of dipping interface reflections. The recording of a seismic event (seismic reflection) from a dipping interface shows that the reflection point at the interface is displaced in an upward direction from its lower real position. The observed reflection point is not the real reflector.
Fault and fracture study by incorporating borehole image logs and supervised neural network applied to the 3D seismic attributes: a case study of pre-salt carbonate reservoir, Santos Basin, Brazil
Published in Petroleum Science and Technology, 2022
Amir Abbas Babasafari, Guilherme Furlan Chinelatto, Alexandre Campane Vidal
In the seismic migration sequence, the seismic events are moved to their actual subsurface locations. In the area of complex geometry, such as faults and salts, the migration process helps obtain more geologically consistent images. The bow-tie features after migration sequence in seismic data processing, particularly in salt formation, were converted to syncline, as is expected. The anticline and syncline-like features after migration become narrower and wider, respectively. In addition, the diffractions were collapsed after migration which can potentially mislead fault and fracture interpretation (Figures 7a and 7b).