An experimental comparison of three direct methods of marine source signature estimation

Abstract

Three methods for estimation of the pressure wavefield generated by a marine airgun array are tested experimentally and compared. In the trial a variety of radiation angles and array configurations were used and some large synchronization errors were deliberately introduced. The source was equipped with near‐field hydrophones and a subsource ministreamer. A tethered far‐field hydrophone was used so that the three estimated far‐field signatures could be compared with an independent measurement. The knowledge of the source signature is important for on‐board source array QC, deconvolution, multiple attenuation, stratigraphic trap prediction, modelling and inversion, AVO analysis and reservoir monitoring. The methods perform very well and give estimates whose frequency‐domain spectra match the measured spectra to within a few dB and within a few tens of degrees of phase over the tested bandwidth of 3.5–110 Hz. The time‐domain error‐energy is typically only a few per cent of the signal energy for radiation angles within about 30° of the vertical. The third method proved to be sensitive to an experimental shortcoming leading to overloading of the ministreamer and meaningful comparison was not possible for some test configurations.

Tools and Techniques: Marine Seismic Methods

“…Landr and Sollie (1992) constrained them to be solutions of the bubble equation of motion (described in the succeeding text); Amundsen (1993a) allowed them to be arbitrary functions. These two methods and that of Ziolkowski et al (1982) combined with Parkes et al (1984) were compared by Laws et al (1998) to measurements made with a farfield hydrophone, and the three methods were found to be of similar accuracy. Ziolkowski (1980) had proposed a method using 'scaled arrays,' but this involved doubling the shot interval and was not adopted.…”

Prediction of signatures of airgun arrays using dual near‐field hydrophones

“…In fact, the physics of oscillations of even a single air bubble in water remains the topic of intensive research (Keller and Miksis 1980;Geers and Hunter 2002;Wang 2013;King, Ziolkowski and Ruffert 2015). In this regard, direct measurement of wavelets of air bubbles becomes * E-mail: maksym.kryvohuz@shell.com the method of choice due to its accuracy and practical simplicity (Ziolkowski et al 1982;Hargreaves 1984;Ziolkowski 1991;Landrø and Sollie 1992;Amundsen 1993;Landrø et al 1994;Laws, Landrø and Amundsen 1998;Ziolkowski 1998).…”

Broad-band calibration of marine seismic sources used by R/VPolarsternfor academic research in polar regions

“…Laws et al 1998). Theoretical and experimental approaches for marine source signature estimation and calibration have been used (e.g.…”

“…Theoretical and experimental approaches for marine source signature estimation and calibration have been used (e.g. Laws et al 1998). The theoretical approaches usually compute the far-field signature from nearfield measurements, for example, either by single hydrophones (e.g.…”