Ghost-free imaging combining synchronized multi-level source and variable-depth streamer

Sablon, Ronan; Payen, Thierry; Tonchia, Helene; Siliqi, R.; Labarre, Xavier; Salaun, N.; Men, Yann Le

doi:10.1190/segam2013-0205.1

Cited by 11 publications

(2 citation statements)

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“…This type of acquisition and the corresponding processing provide possibilities to use the separated free‐surface reflections as useful signals, rather than treating them as noises (Carlson et al., 2007; Day et al., 2013; Kumar et al., 2016; Lu et al., 2014; Liu & Liu, 2019; Whitmore et al., 2010). As another option, the variable‐depth streamer is widely used in marine acquisition and related deghost processing (Soubaras & Dowle, 2010; Sablon et al., 2013; Soubaras & Lafet, 2013), which, compared to the conventional constant‐depth streamer, reduces the effects of free‐surface ghost waves. Similar techniques were developed for variable‐depth sources (e.g.…”

Section: Introductionmentioning

confidence: 99%

The effect of free‐surface reflections on depth images for acquisition with buried sources and receivers: Investigation through the point spread function#

Han

Xie

2023

Geophysical Prospecting

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In reverse time migration, if sources or receivers are buried at certain depths, the interference between the primary wave and the free‐surface reflection causes losing spectral contents in seismic data. If they are not properly compensated, errors will be carried to the target during the reverse time migration and cause a distorted image by so‐called ghost image. By invoking the point spread function, we investigate how distorted seismic data are mapped to the subsurface. Quantitative relations between the free‐surface parameters (i.e. source/receiver depth, free‐surface incident angle and near‐surface velocity) and wavenumber‐domain illumination can be created, which map missing frequency contents in seismic data to missing wavenumber contents in the point spread function. After transformed back to the space domain, we can investigate its effect on the image distortion. Numerical calculations expand the above approach to handle complex overburden structures and more realistic acquisition geometries. The proposed method provides us with a useful tool to investigate deghosting related problems, for example optimizing parameters of acquisition geometry, evaluating capabilities of existing acquisition systems and data processing technologies in suppressing the free‐surface reflection effect in the depth image, or developing new deghosting approaches.

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Section: Introductionmentioning

confidence: 99%

The effect of free‐surface reflections on depth images for acquisition with buried sources and receivers: Investigation through the point spread function#

Han

Xie

2023

Geophysical Prospecting

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“…However, deghosting of conventional seismic data, i.e., pressure measurements at constant streamer depth, also result in improvements of the final image compared with nondeghosted data (Zhou et al, 2012;Dhelie et al, 2014). The source-side deghosting algorithms used today rely on predictive deconvolution and/or using multilevel sources to avoid the notches introduced by the ghost reflection (Moldoveanu, 2000;Hopperstad et al, 2008;Halliday, 2013;Sablon et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Variable source depth acquisition for improved marine broadband seismic data

Haavik¹,

Landrø²

2015

GEOPHYSICS

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In marine seismic data acquisition, varying the source depth along a sail line gives diversity in sequential shot gather frequency spectra. Undesired alterations of the frequency spectra are created by the source ghost and by air-gun bubble oscillations. By deliberately varying the source depth along a sail line, it is possible to obtain a seismic data set that will have energy more evenly distributed within the main frequency band of the source output. This is obtained when data acquired with different source depths are stacked in imaging. We formulated a simple inverse problem that seeks to find the optimal distribution of source depths over a sequential series of shots that shape the amplitude spectrum of the final image into a desired shape. We assumed that the data are receiver-side deghosted, that designature could be applied to each shot gather, and that the shot gathers could be redatumed to a common datum prior to imaging.

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Marine, seabed, and land seismic equipment for broadband acquisition: a review

Mougenot¹

2017

Geophysical Prospecting

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The broadband capabilities of marine, seabed, and land seismic equipment are reviewed with respect to both the source and the receiver sides. In marine acquisition, the main issue at both ends of the spectrum relates to ghosts occurring at the sea surface. Broadband deghosting requires towing at variable depth to introduce notch diversity or using new equipment like multi‐component and/or low‐noise streamers. As a result, a doubling of the bandwidth from about three to six octaves (2.5–200 Hz) has been achieved. Such improvement is not yet observed for seabed surveys in spite of deghosting being a standard process on the receiver side. One issue may be related to the coupling of the particle motion sensor, particularly at high frequencies. For land acquisition, progress came from the vibrators. New shakers and control electronics using broadband sweeps made it possible to add two more octaves to the low‐frequency signal (from 8 to 2 Hz). Whereas conventional 10 Hz geophones are still able to record such low frequencies, 5 Hz high gain geophones or digital accelerometers enhance them to keep the signal above the noise floor. On the high end of the bandwidth, progress is not limited by equipment specifications. Here, the issue is related to a low signal‐to‐noise ratio due to the strong absorption that occurs during signal propagation. To succeed in enlarging the bandwidth, these improved equipment and sweeps must be complemented by a denser spatial sampling of the wavefield by point–source and point–receiver acquisition.

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Ghost-free imaging combining synchronized multi-level source and variable-depth streamer

Cited by 11 publications

References 1 publication

The effect of free‐surface reflections on depth images for acquisition with buried sources and receivers: Investigation through the point spread function#

The effect of free‐surface reflections on depth images for acquisition with buried sources and receivers: Investigation through the point spread function#

Variable source depth acquisition for improved marine broadband seismic data

Marine, seabed, and land seismic equipment for broadband acquisition: a review

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