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Using Ghost Reflections Rather than Removing Them

Blacquiere, G. (author), Berkhout, A.J. (author)

In marine acquisition both a direct wavefield and a ghost wavefield are produced as well as recorded. Hence, the seismic data can be considered to be a natural blend of four wavefields related to the real sources, ghost sources, real detectors and ghost detectors respectively. We consider deghosting to be deblending ('echo-deblending'), leading...

conference paper 2015

document

Full wavefield migration: Utilization of multiples in seismic migration

Berkhout, A.J. (author), Verschuur, D.J. (author)

The next generation migration technology considers multiple scattering as vital information, allowing the industry to generate significantly better images of the subsurface. The proposed full wavefield algorithm (FWM) makes use of two-way wave theory that is formulated in terms of one-way wavefields. We show that the current migration algorithms...

conference paper 2012

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Toward the limits of deblending

Berkhout, A.J. (author), Blacquiere, G. (author)

If we bring sources closer together, they start to `sense' the nearness of each other and their physical behaviour will change. If the separation becomes smaller than half a wavelength, they start to act as one source with new properties (temporal bandwidth, directivity). This fusion process is very complex and nonlinear. To find out whether...

conference paper 2015

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Deghosting by echo-deblending

Berkhout, A.J. (author), Blacquiere, G. (author)

Because of the strong sea surface reflectivity, a marine source generates both a direct wavefield and a ghost wavefield. This corresponds to a blended source array, the blending process being natural. Consequently, deghosting becomes deblending ('echo-deblending'). We discuss source deghosting by an iterative deblending algorithm that properly...

conference paper 2015

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Utilization of Multiple scattering - The next big step forward in seismic imaging

Berkhout, A.J. (author)

Until today, seismic imaging is applied to primary reflections. This means that prior to imaging, the multiples need be removed from the measurements (‘data linearization’). However, multiples contain valuable information that should not be removed but should be utilized. The message of this presentation is that we should not adapt the measured...

conference paper 2015

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Blended acquisition with optimized dispersed source arrays

Berkhout, A.J. (author), Blacquiere, G. (author)

Until now, blended source arrays are configured with closely spaced source units, such as broadband airgun arrays (marine) and broadband vibrator arrays (land). In the latter case the source units are equal. We refer to this concept as homogeneous blending. In this paper the blending concept is extended to inhomogeneous blending, meaning that a...

conference paper 2012

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Focal transformation, an imaging concept for signal restoration and noise removal

Berkhout, A.J. (author), Verschuur, D.J. (author)

Interpolation of data beyond aliasing limits and removal of noise that occurs within the seismic bandwidth are still important problems in seismic processing. The focal transform is introduced as a promising tool in data interpolation and noise removal, allowing the incorporation of macroinformation about the involved wavefields. From a physical...

journal article 2006

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Development and assessment of two fixed-array microphones for use with hearing aids

Bilsen, F.A. (author), Soede, W. (author), Berkhout, A.J. (author)

Hearing-impaired listeners often have great difficulty understanding speech in situations with background noise (e.g., meetings, parties) . Conventional hearing aids offer insufficient directivity to significantly reduce background noise relative to the desired speech signal . Based on array techniques, microphone prototypes have been developed...

journal article 1993

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Seismic processing in the inverse data space

Berkhout, A.J. (author)

Until now, seismic processing has been carried out by applying inverse filters in the forward data space. Because the acquired data of a seismic survey is always discrete, seismic measurements in the forward data space can be arranged conveniently in a data matrix (P). Each column in the data matrix represents one shot record. If we represent...

journal article 2006

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The dynamics of statics

Turhan Taner, M. (author), Berkhout, A.J. (author), Treitel, S. (author), Kelamis, P.G. (author)

The statics problem, whether short wavelength, long wavelength, residual, or trim, has always been one of the more time-consuming and problematic steps in seismic data processing. We routinely struggle with issues such as poor signal-to-noise (S/N) ratio, cycle skipping, truncated refractors, wavelets with ambiguous first arrival times, etc....

journal article 2007

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Acquisition geometry analysis in complex 3D media

Van Veldhuizen, E.J. (author), Blacquiere, G. (author), Berkhout, A.J. (author)

Increasingly, we must deal with complex subsurface structures in seismic exploration, often resulting in poor illumination and, therefore, poor image quality. Consequently, it is desirable to take into consideration the effects of wave propagation in the subsurface structure when designing an acquisition geometry. We developed a new, model-based...

journal article 2008

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The concept of double blending: Combining incoherent shooting with incoherent sensing

Berkhout, A.J. (author), Blacquiere, G. (author), Verschuur, D.J. (author)

Seismic surveys are designed so that the time interval between shots is sufficiently large to avoid temporal overlap between records. To economize on survey time, the current compromise is to keep the number of shots to an acceptable minimum. The result is a poorly sampled source domain. We propose to abandon the condition of nonoverlapping shot...

journal article 2009

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Effect of noise in blending and deblending

Berkhout, A.J. (author), Blacquière, G. (author)

We show that deblended shot records have a better background-related S/N than shot records in unblended surveys. This improvement increases with increasing blending fold and decreasing survey time. An interesting consequence of this property is that blended surveys can be carried out under more severe noise conditions than unblended surveys. It...

journal article 2013

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Recursive prestack depth migration using CFP gathers

Thorbecke, J. (author), Berkhout, A.J. (author)

The common-focus-point technology (CFP) describes prestack migration by focusing in two steps: emission and detection. The output of the first focusing step represents a CFP gather. This gather defines a shot record that represents the subsurface response resulting from a focused source wavefield. We propose applying the recursive shot-record,...

journal article 2006

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Effect of noise in blending and deblending

Berkhout, A.J. (author), Blacquière, G. (author)

If simultaneous shooting is carried out by incoherent source arrays, being the condition of blended acquisition, the deblending process generates shot records with a very low residual interference (blending noise). We found, theoretically and numerically, that deblended shot records had a better background-related signal-to-noise ratio than shot...

journal article 2013

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The road ahead in seismic processing

Berkhout, A.J. (author)

The next generation seismic processing system will comprise a chain of unified algorithms, from preprocessing to reservoir characterization. All these algorithms are formulated in terms of a closed-loop estimation problem, showing a great similarity with each other. A critical module in each algorithm is forward modeling, allowing feedback...

journal article 2013

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Changing the mindset in seismic data acquisition

Berkhout, A.J. (author)

Seismic acquisition surveys are designed such that the time intervals between shots are sufficiently large to avoid the tail of the previous source response interfering with the next one (zero overlap in time). To economize on survey time and processing effort, the current compromise is to keep the number of shots to some acceptable minimum. The...

journal article 2008

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Blended acquisition with dispersed source arrays

Berkhout, A.J. (author)

Blended source arrays are historically configured with equal source units, such as broadband vibrators (land) and broadband air-gun arrays (marine). I refer to this concept as homogeneous blending. I have proposed to extend the blending concept to inhomogeneous blending, meaning that a blended source array consists of different source units....

journal article 2012

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Multiscattering illumination in blended acquisition

Berkhout, A.J. (author), Blacquiere, G. (author), Verschuur, D.J. (author)

In traditional seismic surveys, the firing time between shots is such that the shot records do not interfere in time. However, in the concept of blended acquisition, the records do overlap, allowing denser source sampling and wider azimuths in an economic way. A denser shot sampling and wider azimuths make that each subsurface gridpoint is...

journal article 2012

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Combining full wavefield migration and full waveform inversion, a glance into the future of seismic imaging

Berkhout, A.J. (author)

The next generation seismic migration and inversion technology considers multiple scattering as vital information, allowing the industry to derive significantly better reservoir models — with more detail and less uncertainty — while requiring a minimum of user intervention. Three new insights have been uncovered with respect to this fundamental...

journal article 2012