Prediction of signatures of airgun arrays using dual near-field hydrophones
M. Kryvohuz and X. Campman
Journal name: Geophysical Prospecting
Issue: Vol 67, No 6, July 2019 pp. 1522 - 1546
Info: Article, PDF ( 9.6Mb )
Successful estimation of airgun-array signatures from near-field measurements de-pends 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 pres-sure 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.