Prediction of signatures of airgun arrays using dual near-field hydrophones |
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Authors: | Maksym Kryvohuz Xander Campman |
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Affiliation: | 1. Shell International Exploration and Production Inc., 150 North Dairy Ashford Road, Houston TX 77079 USA;2. Shell Global Solutions International BV, Lange Kleiweg 40, 2288 GK Rijswijk, The Netherlands |
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Abstract: | Successful estimation of airgun-array signatures from near-field measurements depends on the accuracy of poorly controlled model parameters such as the effective sea surface reflection coefficient and source depth. We propose a method for prediction of robust source signatures, which are insensitive to fluctuations of the latter parameters. The method uses vertical pairs of near-field hydrophones to measure near-field pressure and its vertical gradient, combination of which eliminates sea surface reflections from the near-field data. This excludes the uncertainty related to the fluctuating sea state and source depth from the process of inversion of the near-field data for source signature. The method explicitly separates the recorded near-field pressure into its up and down going components, which allows one to measure the effective frequency- and angle-dependent sea surface reflection coefficient right at the source, as well as to estimate the actual source depth. Tests on synthetic and field data demonstrate robust performance of the method. |
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Keywords: | Acoustics Acquisition Modelling Multicomponent Signal processing |
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