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Ultrasonic Modeling: Application to Deep-water Multiples Imagingby Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on August 10, 199} in partial fulfillment of the requirements for the degree of Master of Science ABSTRACT
The technique of ultrasonic modeling is used to demonstrate the imaging of
subsurface deep-water multiples in typical marine seismic environment, using a
ray-based Kirchoff 2D pre-stack depth migration. Two separate experiments are
carried out in an ultrasonic water-tank. The first represents a two-layer structure
separated by a plane interface dipping 10 degrees. The model is constructed using
neoprene over aluminum. The recording geometry consists of an ocean –bottom
hydrophone (O.B.H.) and a line array of 72 sources. The image produced by combining
the primary reflection alone. The effect of post-critical reflections is studied.
In the second experiment, a three-layer model with a fault is imaged with a water
bottom streamer configuration. Joint migration of primaries and multiples improve
the image. For both models, synthetic seismograms are computed and migrated. These
are compared with the results of ultrasonic acquisition. Characteristics of ultrasonic
modeling such as scaling factor, transducers, signal to noise ratio, modeling
materials are studied and implemented in the actual experiment. Return to Theses Return to ERL Home Updated: June, 1999
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