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Ultrasonic Modeling: Application to Deep-water Multiples Imaging
Phillip Gurérendel
Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on August 10, 1990 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.
