3D PP/PS Prestack Depth Migration on the Volve Field

Szydlik, Teresa; Way, S.; Smith, Patrick J.; Aamodt, Lars; Friedrich, Clemens

doi:10.3997/2214-4609.201402177

Cited by 35 publications

(46 citation statements)

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“…The size of the model is 12.3 (inline), 6.8, (crossline) and 4.5 km (depth). The initial velocity corresponds to a generally increasing velocity with depth with a mild low-velocity zone at approximately 3 km in the target reservoir area (Szydlik et al, 2007). Figure 9b and 9c shows the initial ϵ 1 and η 1 parameters.…”

Section: Orthorhombic Model Inversion C187mentioning

confidence: 99%

Full-waveform inversion in acoustic orthorhombic media and application to a North Sea data set

Masmoudi

Alkhalifah

2018

GEOPHYSICS

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Full-waveform inversion (FWI) in anisotropic media is challenging, mainly because of the large computational cost, especially in 3D, and the potential trade-offs between the model parameters needed to describe such media. By analyzing the trade-offs and understanding the resolution limits of the inversion, we can constrain FWI to focus on the main parameters the data are sensitive to and push the inversion toward more reliable models of the subsurface. Orthorhombic anisotropy is one of the most practical approximations of the earth subsurface that takes into account the natural horizontal layering and the vertical fracture network. We investigate the feasibility of a multiparameter FWI for an acoustic orthorhombic model described by six parameters. We rely on a suitable parameterization based on the horizontal velocity and five dimensionless anisotropy parameters. This particular parameterization allows a multistage model inversion strategy in which the isotropic, then, the vertical transverse isotropic, and finally the orthorhombic model can be successively updated. We applied our acoustic orthorhombic inversion on the SEG-EAGE overthrust synthetic model. The observed data used in the inversion are obtained from an elastic variable density version of the model. The quality of the inverted model suggests that we may recover only four parameters, with different resolution scales depending on the scattering potential of these parameters. Therefore, these results give useful insights on the expected resolution of the inverted parameters and the potential constraints that could be applied to an orthorhombic model inversion. We determine the efficiency of the inversion approach on real data from the North Sea. The inverted model is in agreement with the geologic structures and well-log information.

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Section: Orthorhombic Model Inversion C187mentioning

confidence: 99%

Full-waveform inversion in acoustic orthorhombic media and application to a North Sea data set

Masmoudi

Alkhalifah

2018

GEOPHYSICS

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“…We further verify the feasibility of envelope-based global correlation norm on real OBC data from North Sea (Szydlik et al, 2007;Alkhalifah et al, 2016). The initial P-wave velocity model (Figure 6b) is a smoothed version the layer-based tomographic model ( Figure 6a; Jones, 2003;Szydlik et al, 2007) obtained by applying a smoothing operator of length 1 km.…”

Section: Real Data Application: North Sea Obc Datamentioning

confidence: 99%

“…The initial P-wave velocity model (Figure 6b) is a smoothed version the layer-based tomographic model ( Figure 6a; Jones, 2003;Szydlik et al, 2007) obtained by applying a smoothing operator of length 1 km. The background density is 1 g/cm 3 .…”

Section: Real Data Application: North Sea Obc Datamentioning

confidence: 99%

Full waveform inversion using envelope-based global correlation norm

Alkhalifah

2018

Geophysical Journal International

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CitationOh J-W, Alkhalifah T (2018) Full waveform inversion using envelope-based global correlation norm. Geophysical Journal International. to recover long-wavelength structure in an early stage. In addition, the envelope-based global correlation norm maintains the advantage of the global correlation norm, which reduces the sensitivity of the misfit to amplitude errors so that the performance of inversion on real data can be enhanced when the exact source wavelet is not available and more complex physics are ignored.Through the synthetic example for 2D SEG/EAGE overthrust model with inaccurate source wavelet, we compare the performance of 4 different approaches, which are the least squares waveform inversion, least squares envelope inversion, global correlation norm and envelopebased global correlation norm. Finally, we apply the envelope-based global correlation norm on the 3D OBC data from the North Sea. The envelope-based global correlation norm captures the strong reflections from the high-velocity caprock and generates artificial lowfrequency reflection energy that helps us recover long wavelength structure of the model domain in the early stages. From this long-wavelength model, the conventional global correlation norm is sequentially applied to invert for higher-resolution features of the model.

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“…Each layer is updated by applying layer-based tomography and fitting check-shot data (Szydlik et al, 2007). Flattening common-image gathers and minimizing misties between seismic and well data are repeated until the model is optimized.…”

Section: Model With Heterogeneous Layersmentioning

confidence: 99%

“…As a result, CIGs are strongly destored ( The PP and PS OBS data were preprocessed using a standard sequence including wavelet shaping, noise and multiple attenuation techniques (Szydlik et al, 2007).…”

Section: Model With Heterogeneous Layersmentioning

confidence: 99%

Joint migration velocity analysis of PP- and PS-waves for VTI media

Cai

Tsvankin

2013

GEOPHYSICS

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Combining PP-waves with mode-converted PS reflections in migration velocity analysis (MVA) can help build more accurate VTI (transversely isotropic with a vertical symmetry axis) velocity models. To avoid problems caused by the moveout asymmetry of PS-waves and take advantage of efficient MVA algorithms designed for pure modes, I suggest to generate pure SS-reflections from PP and PS data using the PP+PS=SS method. Then the residual moveout in both PP and SS commonimage gathers is minimized during iterative velocity updates. The model is divided into square cells, and the VTI parameters V P 0 , V S0 , , and δ are defined at each grid point. The objective function also includes the differences between the migrated depths of the same reflectors on the PP and SS sections and a regularization term.Synthetic examples confirm that 2D MVA of PP-and PS-waves may be able to resolve all four relevant parameters of VTI media if reflectors with at least two distinct dips are available. The algorithm is also applied to a 2D line from 3D OBS (ocean bottom seismic) data acquired at Volve field in the North Sea. After the anisotropic velocity model has been reconstructed, accurate depth images can be obtained by migrating the recorded PP and PS data.

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3D PP/PS Prestack Depth Migration on the Volve Field

Cited by 35 publications

References 0 publications

Full-waveform inversion in acoustic orthorhombic media and application to a North Sea data set

Full-waveform inversion in acoustic orthorhombic media and application to a North Sea data set

Full waveform inversion using envelope-based global correlation norm

Joint migration velocity analysis of PP- and PS-waves for VTI media

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