An Imaging Note and the BP 2.5 Dimensional Data

Before providing some comparisons of one- and two-way migrations on complex data sets, it is worth discussing imaging data sets that, because of severe illumination or surface issues, might have wide ranging differences in both source generated and receiver suppressed energy levels. This issue was brought to light by several researchers at AMOCO and later BP. J. T. Etgen, Carl Regone and colleagues generated the model, which, when migrated, produced such a wide range of output reflection strengths that just displaying it was difficult.

Figure  5 shows how this reflection strength disparage can be overcome by a careful compensation for illumination. The bottom part of this figure shows a straightforward migration of the original input data. The middle part represents the illumination in space and depth. Simply dividing by this quantity produces the image at the top of Figure  5. Note that this process is not equivalent to an automatic gain control. It is actually based on being able to correctly handle energy differences specified by the Earth model and correct the output image for lateral and vertical differences.

Figure 5: Using illumination corrections to properly gain imaged data.