Schlumberger

Technical Paper: Where is the Center of a Multi-Depth Marine Source Array?

Society: SEG
Paper Number:
Presentation Date: 2008
 

Abstract

In previous work, we discussed how to design a marine source array, using multiple source depths, that emits the same pulse shape (including the ghost reflection) in all directions. In this abstract, we address the question: Where is the (acoustic) center of a multi-depth source array? The acoustic center is the point from which the signal appears to have radiated. The center might be different for different frequencies; the one that minimizes the phase error across the whole bandwidth is termed the “phase center”. The phase center of a single depth array is at the sea surface. For multi-depth arrays, the optimum location of the center is complicated, because of the delay that is applied to the deeper elements in order to align the vertically propagating wavefields. In the examples discussed in this document, it is found that the optimum location (i.e., the phase center) varies from the depth of deepest source layer to about the same depth as the shallowest layer, depending on the ratio of the depths.

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