VSP detection of interbed multiples using inside‐outside corridor stacking

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1628-1635 ◽  
Author(s):  
Andrew Burton ◽  
Larry Lines
Keyword(s):  
Well Log ◽  
Multiple Reflections ◽  
Log Data ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Long Period ◽  
Multiple Attenuation ◽  
Predictive Deconvolution ◽  
Short Period ◽  
And Inversion

One of the most difficult problems in the exploration of Devonian reefs is the separation of primaries and short period interbed multiples. This is especially true in cases where weak primary reflections from porous reefal carbonates can be easily masked by interbed multiples generated from stronger shale/carbonate reflections above the reef. This problem of primary‐multiple separation is difficult since there are small normal moveout differences between the primary and short‐period multiple reflections, thus stacking might not be as effective at suppressing multiples as one would hope. Also, predictive deconvolution may be ineffective if it is difficult to design an accurate prediction distance for the deconvolution filter. The ineffectiveness of stacking and deconvolution in some cases has caused us to look for other alternatives. A recent paper by Lines (1996) advocates the use of shaping deconvolution and inversion methods that use well log information. Since reliable well log data are not always available, we examine a vertical seismic profiling (VSP) corridor stacking method for multiple identification proposed in Hardage (1983, 154–155) which obviates some of the conventional problems and which does not require well log data. A variation of this concept was applied to long‐period multiple attenuation by Hampson and Mewhort (1983).

LONG-PERIOD SURFACE-RELATED MULTIPLE SUPPRESSION IN 2D MARINE SEISMIC DATA USING PREDICTIVE DECONVOLUTION AND COMBINATION OF SURFACE-RELATED MULTIPLE ELIMINATION AND PARABOLIC RADON FILTERING

2021 ◽  
Author(s):  
Pimpawee Sittipan ◽  
Pisanu Wongpornchai
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Petroleum Reservoirs ◽  
The United States ◽  
Multiple Reflections ◽  
Long Period ◽  
Predictive Deconvolution ◽  
Short Period ◽  
Marine Seismic ◽  
Multiple Elimination

Some of the important petroleum reservoirs accumulate beneath the seas and oceans. Marine seismic reflection method is the most efficient method and is widely used in the petroleum industry to map and interpret the potential of petroleum reservoirs. Multiple reflections are a particular problem in marine seismic reflection investigation, as they often obscure the target reflectors in seismic profiles. Multiple reflections can be categorized by considering the shallowest interface on which the bounces take place into two types: internal multiples and surface-related multiples. Besides, the multiples can be categorized on the interfaces where the bounces take place, a difference between long-period and short-period multiples can be considered. The long-period surface-related multiples on 2D marine seismic data of the East Coast of the United States-Southern Atlantic Margin were focused on this research. The seismic profile demonstrates the effectiveness of the results from predictive deconvolution and the combination of surface-related multiple eliminations (SRME) and parabolic Radon filtering. First, predictive deconvolution applied on conventional processing is the method of multiple suppression. The other, SRME is a model-based and data-driven surface-related multiple elimination method which does not need any assumptions. And the last, parabolic Radon filtering is a moveout-based method for residual multiple reflections based on velocity discrimination between primary and multiple reflections, thus velocity model and normal-moveout correction are required for this method. The predictive deconvolution is ineffective for long-period surface-related multiple removals. However, the combination of SRME and parabolic Radon filtering can attenuate almost long-period surface-related multiple reflections and provide a high-quality seismic images of marine seismic data.

Rapid map and inversion of P-SV waves

Geophysics ◽  
1991 ◽  
Vol 56 (6) ◽  
pp. 859-862 ◽  
Author(s):  
Robert R. Stewart
Keyword(s):  
Spatial Resolution ◽  
Seismic Data ◽  
P Wave ◽  
Rock Properties ◽  
Low Velocity ◽  
P Waves ◽  
Near Surface ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
And Inversion

Multicomponent seismic recordings are currently being analyzed in an attempt to improve conventional P‐wave sections and to find and use rock properties associated with shear waves (e.g. Dohr, 1985; Danbom and Dominico, 1986). Mode‐converted (P-SV) waves hold a special interest for several reasons: They are generated by conventional P‐wave sources and have only a one‐way travel path as a shear wave through the typically low velocity and attenuative near surface. For a given frequency, they will have a shorter wavelength than the original P wave, and thus offer higher spatial resolution; this has been observed in several vertical seismic profiling (VSP) cases (e.g., Geis et al., 1990). However, for surface seismic data, converted waves are often found to be of lower frequency than P-P waves (e.g., Eaton et al., 1991).

Shear waves, multiple reflections, and converted waves found by a deep vertical wave test (vertical seismic profiling)

Geophysics ◽  
1980 ◽  
Vol 45 (9) ◽  
pp. 1373-1411 ◽  
Author(s):  
C. C. Lash
Keyword(s):  
Traveling Waves ◽  
Wave Energy ◽  
S Wave ◽  
Multiple Reflections ◽  
P Waves ◽  
S Waves ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Converted Waves ◽  
Set Up

Evidence that shear (S) waves are much more important in seismic surveys than currently believed was found in each of two deep well tests conducted some time ago. Wave tests were recorded along vertical lines, following procedures which are now designated “vertical seismic profiling.” The results may be divided into (1) evidence that shear (S) waves are produced by in‐hole dynamite charges and by the resulting compressional (P) waves, and (2) evidence that the S‐waves subsequently produce P‐waves. The proof of S‐wave production is quite conclusive. Even if we say that only P‐waves are set up in the immediate vicinity of the shot, some S‐waves are then generated within a radius of 10 to 100 ft to form what we will call a direct or “source S wave.” Other S‐waves are set up by conversion of P‐wave energy to S‐wave energy at interfaces hundreds and thousands of feet from the dynamite charge. In contrast to the P to S conversion, the evidence for S to P conversion is less conclusive. The source S‐wave generated near the shot was found to have a long‐period character, with many cycles which are believed to be controlled by the layering near the shot. The PS converted waves, which appear later, resemble the P‐waves that produce them. The interference to primary reflections by multiple reflections and/or converted waves produces complex signals at points deep in the well which require directional discrimination to separate up‐traveling waves from down‐traveling waves.

Comparison of VSP and sonic-log data in nonvertical wells in a heterogeneous structure

Geophysics ◽  
2008 ◽  
Vol 73 (4) ◽  
pp. U19-U25 ◽  
Author(s):  
Petr Bulant ◽  
Luděk Klimeš
Keyword(s):  
Seismic Waves ◽  
Heterogeneous Structure ◽  
Geologic Structure ◽  
Log Data ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Sonic Log ◽  
Vertical Propagation ◽  
Well Trajectory ◽  
The Difference

To compare the results of sonic-log measurements and of vertical seismic profiling (VSP), sonic-log velocities are used to estimate the corresponding traveltime in the geologic structure, which is then compared with the VSP traveltime. We show how to calculate the sonic-log traveltime in the geologic structure from the sonic-log velocities while taking into account the effects of the nonvertical propagation of seismic waves, resulting from the VSP-source offset and from heterogeneous velocity in the structure, together with the effects of the well trajectory deviating from strictly vertical. Errors caused by the commonly used assumption of vertical propagation may considerably exceed the difference of the measured VSP traveltimes from the sonic-log traveltimes.

scholarly journals Attenuation of long period multiple using F-k filter and surface-related multiple elimination methods on 2D broadband seismic data from Morowali Waters, Sulawesi

2021 ◽  
Vol 944 (1) ◽  
pp. 012005
Author(s):  
G L Situmeang ◽  
H M Manik ◽  
T B Nainggolan ◽  
Susilohadi
Keyword(s):  
Seismic Data ◽  
Seismic Waves ◽  
Frequency Bandwidth ◽  
Long Period ◽  
Time Migration ◽  
Predictive Deconvolution ◽  
Short Period ◽  
Wide Range ◽  
Marine Seismic ◽  
Multiple Elimination

Abstract Wide range frequency bandwidth on seismic data is a necessity due to its close relation to resolution and depth of target. High-frequency seismic waves provide high-resolution imaging that defines thin bed layers in shallow sediment, while low-frequency seismic waves can penetrate into deeper target depth. As a result of broadband seismic technology, its wide range of frequency bandwidth is a suitable geophysical exploration method in the oil and gas industry. A major obstacle that is frequently found in marine seismic data acquisition is the existence of multiples. Short period multiple and reverberation are commonly attenuated by the predictive deconvolution method on prestack data. Advanced methods are needed to suppress long period multiple in marine seismic data. The 2D broadband marine seismic data from deep Morowali Waters, Sulawesi, contains both short and long period multiples. The predictive deconvolution, which is applied to the processing sequences, successfully eliminates short period multiple on prestack data. The combination of F-k filter and Surface Related Multiple Elimination (SRME) methods are successful in attenuating long period multiple of the 2D broadband marine seismic data. The Prestack Time Migration section shows fine resolution of seismic images.

ATTENUATION OF SHORT-PERIOD MULTIPLES IN SEISMIC DATA PROCESSING OF THE JEQUITINHONHA BASIN, BRAZIL

2014 ◽  
Vol 32 (3) ◽  
pp. 395 ◽  
Author(s):  
Silmara L.R. Oliveira ◽  
Rosângela Corrêa Maciel ◽  
Michelângelo G. da Silva ◽  
Milton José Porsani
Keyword(s):  
Data Processing ◽  
Seismic Data ◽  
Time Windows ◽  
Fixed Time ◽  
Seismic Data Processing ◽  
Multiple Reflections ◽  
Seismic Line ◽  
New Approach ◽  
Predictive Deconvolution ◽  
Short Period

ABSTRACT. Short-period multiples attenuation is a difficult problem for shallow water marine seismic data processing. In the past few decades many filteringmethods have been developed to solve this problem and to improve the quality of seismic imaging. The Wiener-Levinson predictive deconvolution method is one of themost useful and well known filter methods used in the seismic data processing flow. It is a statistical approach to reduce redundancy along the time variable seismictrace, allowing us to both improve the time resolution and also attenuate multiple reflections of the seismic traces. One of the assumptions of the Wiener-Levinsonmethod is that the seismic wavelet is stationary along the entire seismic trace. However, this is not true for real seismic data and to bypass this limitation the methodis normally applied using fixed time windows, distributed along the seismic trace. The present study tested a new adaptive predictive deconvolution approach for theattenuation of short-period multiples. The new approach is based on a sliding window of fixed length that is shifted sample by sample along the entire seismic trace.At each position, a new filter is computed and applied. The implied systems of equations are solved by using a recursive Levinson-type algorithm. The main differencewith respect to the conventional Wiener-Levinson approach is that the filter is updated for each data sample along the trace and no assumption is imposed on the dataoutside the considered window. The new adaptive predictive deconvolution approach was tested using a seismic line of the Jequitinhonha Basin acquired by Petrobras.The results demonstrated that the new approach is very precise for the attenuation of short-period multiples, producing better results than the ones obtained fromthe conventional Wiener-Levinson predictive deconvolution approach. The results were obtained with filters of 25 coefficients, predictive distance of 5 samples andwindow length equal to 55 samples.Keywords: seismic processing, Jequitinhonha Basin, adaptive predictive deconvolution, multiple of attenuation, Wiener-Levinson deconvolution.RESUMO. A atenuação de reflexões múltiplas de curto período, presentes nos dados sísmicos adquiridos sobre lâmina d’água rasa, representa um grande problemado processamento de dados sísmicos marítimos. Nas últimas décadas, vários métodos de filtragem de dados sísmicos têm sido desenvolvidos com o propósito deatenuar reflexões múltiplas e melhorar a qualidade das seções sísmicas. O método de filtragem conhecido como deconvolução preditiva de Wiener-Levinson é bastante utilizado na indústria do petróleo. Ele permite melhorar a resolução temporal dos dados sísmicos e atenuar reflexões múltiplas, podendo ser visto como um método estatístico que remove a coerência temporal dos traços sísmicos. O método de Wiener-Levinson pressupõe que o pulso sísmico é estacionário, fato este que não ocorrenos dados sísmicos reais. Para contornar este problema, o método de Wiener-Levinson é normalmente aplicado utilizando-se janelas de tempo fixas, distribuídas ao longo do tempo de registro. No presente trabalho, empregamos um método de deconvolução preditiva adaptativa no qual as janelas de tempo deslizantes são deslocadas amostra a amostra ao longo de todo o traço sísmico. Os sistemas de equações são resolvidos com o algoritmo recursivo tipo-Levinson. Na deconvolução de Wiener-Levinson, com janelas de tempo fixa, os filtros são gerados e aplicados dentro de cada janela. Já na deconvolução preditiva adaptativa o algoritmo calcula um novo filtro a cada posição da janela deslizante. Para teste da nova abordagem utilizamos os dados sísmicos da Bacia de Jequitinhonha, cedidos pela Petrobras. Os melhores resultados foram obtidos com filtros de 25 coeficientes, distância de predição igual a 5 amostras e janela móvel de 55 amostras. Os resultados obtidos com a nova abordagem demonstram que a deconvolução preditiva adaptativa atua com eficácia na atenuação de múltiplas de curto período, apresentando resultados melhores queos gerados pelo método de deconvolução preditiva de Wiener-Levinson.Palavras-chave: processamento sísmico, Bacia do Jequitinhonha, deconvolução adaptativa, atenuação de múltiplas, deconvolução de Wiener-Levinson.

Investigation of multiple reflections and wave conversion by means of a vertical wave test (vertical seismic profiling) in southern Mississippi

Geophysics ◽  
1982 ◽  
Vol 47 (7) ◽  
pp. 977-1000 ◽  
Author(s):  
C. C. Lash
Keyword(s):  
Wave Train ◽  
Low Frequency ◽  
P Wave ◽  
Multiple Reflections ◽  
Low Velocity ◽  
P Waves ◽  
S Waves ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
Sonic Log

A vertical wave test employing the vertical seismic profiling (VSP) technique in southern Mississippi confirmed suspicions that apparent multiple reflections might include converted waves as well as multiply reflected compressional waves. Both compressional (P) and shear (S) waves generated near the source were observed to travel to great depths, and P‐to‐S conversions were apparent in deep zones as well as shallow. P‐wave reflections were observed in agreement with predictions from synthetic records based on the sonic log. Up‐traveling P‐waves were reflected a short distance below the surface, at the base of the low‐velocity layer, and were followed as down‐traveling P‐waves to 200 ft depth by means of a vertical spread. Below 2000 ft and following the first P wave train, the predominate energy appeared to be down‐traveling P‐waves which could not be traced back to the reflection of up‐traveling P‐waves. The continuity of wavelets indicated instead that the strong down‐traveling S‐waves generated near the source produced P‐waves by S‐to‐P conversion somewhere in the zone between 800 and 1400 ft. The interference on the recordings made with an individual seismometer, or a small group of seismometers, using dynamite shots as the source was generally of a low‐frequency nature, so that the signal‐to‐noise (S/N) ratio was improved by the use of a high passband filter. The interference was greatly reduced without the need for a filter on recordings in which the source was a distributed charge of 100 ft length. The distributed charge produced much less shear‐wave energy in the P reflection band, demonstrating that the interference encountered when using a concentrated charge source was the consequence of the generation of S‐waves near the source. The distributed charges were previously chosen as a means for effectively eliminating secondary (ghost) reflections, an unwanted form of multiple reflections.

Multiple attenuation: some current techniques

1989 ◽  
Vol 20 (2) ◽  
pp. 275 ◽  
Author(s):  
J. Wardell ◽  
P. Whiting
Keyword(s):  
Water Layer ◽  
Velocity Difference ◽  
Periodic Sequences ◽  
Multiple Attenuation ◽  
Predictive Deconvolution ◽  
Recent Approach ◽  
Short Period ◽  
Recorded Data ◽  
P Domain ◽  
Recent Variation

Multiple attenuation techniques have to be based on some difference between the multiples and the primary reflections. The two major differences that are exploited are firstly velocity, and secondly the fact that multiples are periodic sequences of events, and hence are predictable, while the primaries are non-periodic. The widely used frequency-wavenumber (F-K) domain techniques rely on velocity difference only, but a recent variation of this method also makes use of any difference in dip between primaries and multiples to give significantly greater multiple attenuation. For short period multiples, velocity differences may be insufficient for much attenuation, and the process has to be based on the multiple's periodicity, using some type of long predictive deconvolution operator. One problem with this approach is that the multiple period varies with time, particularly at long offsets. Transforming the record to the tau-p domain removes this variation however, allowing more effective deconvolution of the multiples. Another recent approach is to model a multiples-only record by wave equation methods, and subtract it from the recorded data. At present however, this is limited to well defined multiple generators, such as the water layer. With the variety of multiple attenuation processes available today, the geophysicist needs to understand the types of multiple problem to which each is most suited, in order to select the technique most applicable to his data.

Demultiple strategies in the submarine slope of Taiwan accretionary wedge

2020 ◽  
Author(s):  
Feisal Dirgantara ◽  
Andrew Tien-Shun Lin ◽  
Char-Shine Liu ◽  
Song-Chuen Chen
Keyword(s):  
Shallow Water ◽  
Seismic Data ◽  
Sampling Rate ◽  
Water Layer ◽  
Noise Removal ◽  
Accretionary Wedge ◽  
Reflection Seismic ◽  
Multiple Attenuation ◽  
Predictive Deconvolution ◽  
Short Period

<p>Reducing multiple contaminations in reflection seismic data remains one of the greatest challenges in seismic processing and its effectiveness is highly dependent on geologic settings. We undertook two-dimensional reflection seismic data crossing the upper and lower accretionary wedge slopes off SW Taiwan to test the efficiency of various multiple-attenuation scenarios. The area has resulted from an incipient arc-continent collision between the northern rifted margin of the South China Sea and the Luzon volcanic arcs. The wedge extends from shallow water to deep water bathymetries, hence promoting both short-period and long-period multiples within the seismic records. The multichannel seismic data were achieved under 468 hydrophones, 4-ms sampling rate, 12.5-m channel spacing, 50-m shot spacing and 15-second recording length. Preprocessing flow includes swell noise removal, direct wave mute, and missing channel and shot restoration. A subset of demultiple methods based on the periodicity nature and the spatial move-out behavior of multiples were explored to attenuate multiples energy under different geologic environments. The first step relies on the simultaneous subtraction of surface-related multiples, which combined wave-equation multiple attenuation (WEMA) and surface-related multiple elimination (SRME). WEMA is a shot domain multiple attenuations based on a combination of numerical wave extrapolation through the water layer and the water bottom reflectivity. This method was capable to partially suppress the water layer multiples. SRME was applied to attenuate the residual multiple energy at near-offset. This method assumes surface-related multiples can be kinematically predicted by convolution of prestack seismic traces at possible surface multiple reflection locations. Some primary reflections seem to be better retained after the combined subtraction process than using WEMA or SRME filtering independently. The second step lies on parabolic Radon transform to attenuate far-offset multiples by subtracting the noise energy in <em>tau-p</em> on input gathers that have been corrected for normal move-out and inverse transform the remaining primary energy back to CMP-offset domain. Predictive deconvolution in the <em>x-t</em> domain was performed to attenuate low-frequency reverberations in the upper wedge slope. A double-gap deconvolution operator was extended to predict reverberations with correct relative amplitudes, followed by time-variant bandpass filtering to reduce much of residual multiple energy. In general, WEMA and predictive deconvolution were more effective in attenuating the multiples energy at the upper wedge slope where the water depths are shallower; whereas SRME and parabolic Radon were capable of reducing the energy of multiples at the lower wedge slope. Nevertheless, multiples energy could not be fully eliminated due to several factors. The dependency of some demultiple methods (e.g. parabolic Radon, WEMA, SRME) on velocity function may perturb the forward multiple predictions before subtraction as primary velocities might not be present due to the highly tilted strata in the thrust belts domain. Furthermore, parabolic Radon may not perform well in shallow water and area with slowly increasing velocities with depth (e.g. the upper wedge slope). Since the reflection seismic dataset spans various tectonic environments and water depth, results suggest there was no single demultiple method capable to suppress multiples in all environments.</p>

A novel approach to seismic signal processing and modeling

Geophysics ◽  
1981 ◽  
Vol 46 (10) ◽  
pp. 1398-1414 ◽  
Author(s):  
Jerry M. Mendel ◽  
John Kormylo ◽  
Fereydoun Aminzadeh ◽  
Ja Sung Lee ◽  
Farroukh Habibi‐Ashrafi
Keyword(s):  
Seismic Source ◽  
Seismic Signal ◽  
Well Log ◽  
Seismic Profiling ◽  
Vertical Seismic Profiling ◽  
State Variable ◽  
Novel Approach ◽  
Wiener Filters ◽  
Seismic Signal Processing ◽  
Spherical Divergence

This paper demonstrates some results obtained using state‐variable models and techniques on problems for which solutions either cannot be or are not easily obtained via more conventional input‐output techniques. After a brief introduction to state‐variable notions, the following seven problem areas are discussed: modeling seismic source wavelets, simultaneous deconvolution and correction for spherical divergence, simultaneous wavelet estimation and deconvolution, well log processing, design of recursive Wiener filters, Bremmer series decomposition of a seismogram (including suppression of multiples and vertical seismic profiling), and estimating reflection coefficients and traveltimes.

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