Source signature determination from ministreamer data

Landrø, Martin; Langhammer, Jan; Sollie, R.; Amundsen, Lasse; Berg, Eivind

doi:10.3997/2214-4609.201411641

Cited by 7 publications

(13 citation statements)

References 10 publications

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“…Since the MBI method is based on forward modelling of the pressure output from each airgun, the algorithm will not attempt to model 'unexpected' sea-bottom reflections. In fact it was shown by Landrø et al (1994) that the sea-bottom reflections did not corrupt the signature estimation, and that the sea-bottom reflections remained unchanged in the ministreamer residual data.…”

Section: Description Of the Mbi Methodsmentioning

confidence: 97%

“…Ziolkowski et al (1982) proposed a gun-to-hydrophone distance of 1 m. marine seismic array. They are: the notional-source method (Ziolkowski et al 1982;, ministreamer bubble inversion (Landrø and Sollie 1992;Landrø et al 1994) and ministreamer monopole inversion (Amundsen 1993;Landrø et al 1994). We refer to these as NS, MBI and MMI, respectively. Our study is the first where all three methods are used at the same time so that a direct comparison is possible.…”

Section: Introductionmentioning

confidence: 99%

“…He neglected the relative motions of ministreamer and bubbles, which are not expected to be significant in comparison with the source-ministreamer separation, in order to obtain a time-invariant problem amenable to linear least-squares techniques. Landrø et al (1994) demonstrated experimentally the methods of Landrø and Sollie (1992) and Amundsen (1993) and proposed some modifications to the methods.The notional-source method is proprietary to Schlumberger (European Patent number 0-066-423, US Patent number 4476553). The ministreamer bubble inversion method is proprietary to Statoil (Norwegian Patent 176227).In this study, we compare three methods for estimating the far-field signature of a 354 R. Laws, M. Landrø and L. Amundsen…”

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confidence: 99%

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confidence: 99%

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

Laws

Landrø

Amundsen

1998

Geophysical Prospecting

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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.

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Section: Description Of the Mbi Methodsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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

Laws

Landrø

Amundsen

1998

Geophysical Prospecting

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“…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).…”

Section: Introductionmentioning

confidence: 99%

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

Kryvohuz

Campman

2019

Geophysical Prospecting

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

Breitzke

Boebel

Naggar

et al. 2008

Geophysical Journal International

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SUMMARY Air guns and air‐gun arrays of different volumes are used for scientific seismic surveys with R/V Polarstern in polar regions. To assess the potential risk of these research activities on marine mammal populations, knowledge of the sound pressure field of the seismic sources is essential. Therefore, a broad‐band (0–80 kHz) calibration study was conducted at the Heggernes Acoustic Range, Norway. A GI (2.4 l), a G (8.5 l) and a Bolt gun (32.8 l) were deployed as single sources, 3 GI (7.4 l), 3 G (25.6 l) and 8 VLF™Prakla‐Seismos air guns (24.0 l) as arrays. Each configuration was fired along a line of 3–4 km length running between two hydrophone chains with receivers in 35, 100, 198 and 263 m depth. Peak‐to‐peak, zero‐to‐peak, rms and sound exposure levels (SEL) were analysed as functions of range. They show the typical dipole‐like directivity of marine seismic sources with amplitude cancellation close to the sea surface, higher amplitudes in greater depths, and sound pressure levels which continuously decrease with range. Levels recorded during the approach are lower than during the departure indicating a shadowing effect of Polarsterns's hull. Backcalculated zero‐to‐peak source levels range from 224–240 dB re 1 μPa @ 1 m. Spectral source levels are highest below 100 Hz and amount to 182–194 dB re 1 μPa Hz–1. They drop off continuously with range and frequency. At 1 kHz they are ∼30 dB, at 80 kHz ∼60 dB lower than the peak level. Above 1 kHz amplitude spectra are dominated by Polarstern's self‐noise. From the rms and sound exposure levels of the deepest hydrophone radii for different thresholds are derived. For a 180 dB rms‐level threshold radii maximally vary between 200 and 600 m, for a 186 dB SEL threshold between 50 and 300 m.

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Source signature determination from ministreamer data

Cited by 7 publications

References 10 publications

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

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

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

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

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