The Impact of Inter-bed Multiple Attenuation on the Imaging of Pre-salt Targets in the Santos Basin Off-shore Brazil

Cypriano, Luis; Marpeau, Fabien; Brasil, R.; Welter, Guilherme Sausen; Prigent, H.; Douma, Huub; Boechat, João Batista; Carvalho, Paulo de Tarso Camillo de; Guerra, Claudio; Theodoro, Carlos Eduardo; Martini, Alvaro; Cruz, J. N.

doi:10.3997/2214-4609.201412691

Cited by 15 publications

(7 citation statements)

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“…Internal multiples generated by the overburden (figure 4a) have been removed, but later arriving internal multiples generated by interactions between the target area and the overburden (figure 4b) and internal multiples generated by the target area (figure 4c) remain. According to Cypriano et al (2015), the main internal multiples that contaminate the image of the target area in the Santos Basin are generated between the water bottom and the top of salt (see figure 1). By using double-focusing, we remove these internal multiples, while leaving some internal multiples below the target area behind.…”

Section: Marchenko Internal Multiple Attenuation By Adaptive Double-f...mentioning

confidence: 99%

“…The Santos Basin in Brazil is known for its oil-bearing carbonate reservoirs below a highly reflective stratified salt layer (see figure 1). The salt layer generates strong internal multiples that pose a problem for seismic imaging (Cypriano et al, 2015). Most imaging methods assume that the recorded wavefield was only reflected once and thus incorrectly interpret internal multiples as primaries from deeper reflectors.…”

Section: Introductionmentioning

confidence: 99%

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3D Marchenko internal multiple attenuation on narrow azimuth streamer data of the Santos Basin, Brazil

Staring¹,

Wapenaar²

2020

Preprint

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In recent years, a variety of Marchenko methods for the attenuation of internal multiples has been developed. These methods have been extensively tested on 2D synthetic data and applied to 2D field data, but only little is known about their behaviour on 3D synthetic data and 3D field data. Particularly, it is not known whether Marchenko methods are sufficiently robust for sparse acquisition geometries that are found in practice. Therefore, we start by performing a series of synthetic tests to identify the key acquisition parameters and limitations that affect the result of 3D Marchenko internal multiple prediction and subtraction using an adaptive double-focusing method. Based on these tests, we define an interpolation strategy and use it for the field data application.Starting from a wide azimuth dense grid of sources and receivers, a series of decimation tests is performed until a narrow azimuth streamer geometry remains. We evaluate the effect of the removal of sail lines, near offsets, far offsets and outer cables on the result of the adaptive doublefocusing method. These tests show that our method is most sensitive to the limited aperture in the crossline direction and the sail line spacing when applying it to synthetic narrow azimuth streamer data. The sail line spacing can be interpolated, but the aperture in the crossline direction is a limitation of the acquisition.Next, we apply the adaptive Marchenko double-focusing method to the narrow azimuth streamer field data from the Santos Basin, Brazil. Internal multiples are predicted and adaptively subtracted, thereby improving the geological interpretation of the target area. These results imply that our adaptive double-focusing method is sufficiently robust for the application to 3D field data, although the key acquisition parameters and limitations will naturally differ in other geological settings and for other types of acquisition.

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Section: Marchenko Internal Multiple Attenuation By Adaptive Double-f...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

3D Marchenko internal multiple attenuation on narrow azimuth streamer data of the Santos Basin, Brazil

Staring¹,

Wapenaar²

2020

Preprint

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“…The Santos Basin offshore Brazil is an excellent example of a region where internal multiples hinder accurate imaging (Cypriano et al, 2015). The region contains presalt carbonates that often hold significant amounts of oil.…”

Section: Introductionmentioning

confidence: 99%

Source-receiver Marchenko redatuming on field data using an adaptive double-focusing method

Staring

Pereira²,

Douma³

et al. 2018

GEOPHYSICS

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We have developed an adaptive double-focusing method that is specifically designed for the field-data application of source-receiver Marchenko redatuming. Typically, the single-focusing Marchenko method is combined with a multidimensional deconvolution (MDD) to achieve redatuming. Our method replaces the MDD step by a second focusing step that naturally complements the single-focusing Marchenko method. Instead of performing the MDD method with the directionally decomposed Green’s functions that result from single-focusing, we now use the retrieved upgoing Green’s function and the retrieved downgoing focusing function to obtain a redatumed reflection response in the physical medium. Consequently, we only remove the strongest overburden effects instead of removing all of the overburden effects. However, the gain is a robust method that is less sensitive to imperfections in the data and a sparse acquisition geometry than the MDD method. In addition, it is computationally much cheaper, more straightforward to implement, and it can be parallelized over pairs of focal points, which makes it suitable for application to large data volumes. We evaluate the successful application of our method to 2D field data of the Santos Basin.

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“…Here we demonstrate the successful application of the proposed method to 2D and 3D field data, where we can observe a clear improvement in the geological interpretability. We use a dataset from the Santos basin in Brazil, known for its pre-salt reservoirs, where accurate imaging of the targets is hindered by strong internal multiples generated in the overburden (Cypriano et al (2015)). The multiples are clearly visible (see figure 1), thus making it a suitable dataset to test adaptive double-focusing.…”

Section: Introductionmentioning

confidence: 99%

Marchenko redatuming by adaptive double-focusing on 2D and 3D field data of the Santos basin

Staring

Neut

Wapenaar

2018

SEG Technical Program Expanded Abstracts 2018

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The Santos basin in Brazil suffers from strong internal multiples that overlap with primaries from the pre-salt reservoirs. We propose an adaptive double-focusing method for the removal of these multiples to obtain a correct image of the target area. The proposed method applies a form of source-receiver Marchenko redatuming to the reflection response. The Marchenko method is used to achieve single-focusing, after which we convolve the retrieved downgoing focusing function and the upgoing Green's function to create double-focusing. This results in a base image that contains both primaries and internal multiples, and two models that predict the strongest internal multiples. Next, adaptive subtraction in the curvelet domain is used to remove these multiples from the base image. Some multiple interactions between the target area and the overburden remain, but we gain a robust method that is capable of dealing with a sparse acquisition geometry and imperfections in the (pre-processed) data. Also, this method is straightforward to implement and can be parallelized over pairs of focal points. These properties make adaptive double-focusing particularly suitable for the application to large volumes of field data. Tests on 2D field data and 3D field data show that the proposed method correctly predicts and removes the strongest internal multiples from the overburden, resulting in a clear improvement of the geological interpretability in the target area.

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The Impact of Inter-bed Multiple Attenuation on the Imaging of Pre-salt Targets in the Santos Basin Off-shore Brazil

Cited by 15 publications

References 1 publication

3D Marchenko internal multiple attenuation on narrow azimuth streamer data of the Santos Basin, Brazil

3D Marchenko internal multiple attenuation on narrow azimuth streamer data of the Santos Basin, Brazil

Source-receiver Marchenko redatuming on field data using an adaptive double-focusing method

Marchenko redatuming by adaptive double-focusing on 2D and 3D field data of the Santos basin

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