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Variation of reflectivity with angle (AVA)

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Proceedings Papers

Paper presented at the 2005 SEG Annual Meeting, November 6–11, 2005
Paper Number: SEG-2005-0281
... Summary AVO (amplitude variation with offset) and seismic attribute analyses often assume a flat model for the calculation of reflection angles from the offset distance. If the dip is not considered, the calculated AVA (amplitude variation with angle) will be incorrect in steeply dipping areas...
Proceedings Papers

Paper presented at the 2015 SEG Annual Meeting, October 18–23, 2015
Paper Number: SEG-2015-5814947
... Summary AVA inversion method utilizing angle information to obtain elastic parameters of subsurface rock is vital to reservoir characterization. Under the assumption of blocky layered media, a novel AVA inversion algorithm combining spectral reflectivity inversion with sparse Bayesian...
Proceedings Papers

Paper presented at the 2010 SEG Annual Meeting, October 17–22, 2010
Paper Number: SEG-2010-0398
... SUMMARY Certain seismic data anomalies, associated with low-Q targets, have recently been identified as instances of “absorptive reflectivity”. The anelastic reflection coefficients underlying this type of anomaly, and their variations with frequency (AVF) and/or angle (AVA), represent...
Proceedings Papers

Paper presented at the 2015 SEG Annual Meeting, October 18–23, 2015
Paper Number: SEG-2015-5899855
... offsets were recalculated to angles for AVA-analysis. Rpp was calculated for each CMP gather as amplitude of the reflected wave (zero-phase signal after deconvolution) normalized to the amplitude of the direct wave. Reflectivity values were averaged within the corresponding Fresnel zone which...
Proceedings Papers

Paper presented at the 2009 SEG Annual Meeting, October 25–30, 2009
Paper Number: SEG-2009-0256
...) , with predefined thresholds. reflection coefficient migration reservoir characterization international exposition seg houston 2009 accuracy alex malkin canning malkin fracture density gradient upstream oil & gas angle gather amplitude azimuthal ava analysis workflow inversion...
Proceedings Papers

Paper presented at the 2006 SEG Annual Meeting, October 1–6, 2006
Paper Number: SEG-2006-0466
... s lower peninsula. The survey was optimized for both reflection imaging purposes and the gathering of a wide range of incidence angles. With this we can do a highly detailed interpretation using the post stack migrated data, and utilizing the prestack data for AVA (amplitude variation with angle...
Proceedings Papers

Paper presented at the 2010 SEG Annual Meeting, October 17–22, 2010
Paper Number: SEG-2010-3263
... is then used as a reflectivity that is fed into a demigration process which creates modeled data. Remigration of such a data set then results in a gather on which any amplitude variation is a measure of illumination effects alone. The resulting illumination AVA signature can then be used to assess the effect...
Proceedings Papers

Paper presented at the 2012 SEG Annual Meeting, November 4–9, 2012
Paper Number: SEG-2012-0161
..., and interference of reflections. Angle-dependent RCs extracted at subsurface reflection points (RPs), by prestack migration, are better at handling these problems (Resnick et al., 1987; de Bruin et al., 1990). A specific example is the com- parison of amplitude variations with offset (AVO) and with an- gle (AVA...
Proceedings Papers

Paper presented at the 2007 SEG Annual Meeting, September 23–28, 2007
Paper Number: SEG-2007-2160
... is the high computational cost. INTRODUCTION Amplitude-preserving migration aims at making the AVO/AVA stud- ies for hydrocarbon detection quantitative and rigorous by reliably esti- mating angle-dependent reflection coefficients. Many factors affect the amplitude variations; here, we consider only...
Proceedings Papers

Paper presented at the 2005 SEG Annual Meeting, November 6–11, 2005
Paper Number: SEG-2005-0817
... Introduction Summary An integrated seismic interpretation project was performed using a pattern recognition toolkit to characterize the seismic signature and amplitude variation with angle (AVA) response of Tertiary oil sands encountered in a control well and identify other areas...
Proceedings Papers

Paper presented at the 2007 SEG Annual Meeting, September 23–28, 2007
Paper Number: SEG-2007-0303
... Summary There are numerous publications about amplitude variation with offset (AVO) or with incident angle (AVA) in surface seismic data and their applications in the petroleum industry. However, this extended abstract demonstrates an AVA phenomenon in borehole sonic images of a horizontal...
Proceedings Papers

Paper presented at the 2007 SEG Annual Meeting, September 23–28, 2007
Paper Number: SEG-2007-0264
... estimated through Walden relations and angles computed with the kinematic de-migration. Variation of about 5° can be observed in a range of 40-60o. This represents significant variability for AVA studies. III. Offset to Angle transformation up to 60° incidence. IV. Common angle spectral harmonization...
Proceedings Papers

Paper presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, July 20–22, 2015
Paper Number: URTEC-2151459-MS
.... The variation of seismic reflection amplitude with angle of incidence (AVA) of seismic waves reflected from an interface between two geological layers may be used to obtain predrill information on RQ and CQ. The information from AVA inversion may be analyzed conveniently using rock physics templates, in which...
Proceedings Papers

Paper presented at the 2005 SEG Annual Meeting, November 6–11, 2005
Paper Number: SEG-2005-0242
... The physics to explain the variations of reflected seismic amplitudes as a function of the incidence angle (AVA) is well known. Under the assumption of two homogeneous and isotropic layers, AVA behavior is specified by the changes in P-wave velocities (Vp), S-wave velocities (Vs) and densities across...
Proceedings Papers

Paper presented at the Offshore Technology Conference, May 6–9, 2002
Paper Number: OTC-14147-MS
... to the angle volumes the seismic-wavelet effect is minimized thus reducing the likelihood of wavelet variations within the gathers causing false AVAs. Additionally inversion unravels both the amplitude shape and strength into an interval attribute as opposed to reflectivity that is an interface attribute...
Proceedings Papers

Paper presented at the SEG International Exposition and Annual Meeting, September 15–20, 2019
Paper Number: SEG-2019-3216604
... presents oil production data as evidence of aligned (or azimuthal or fracture) porosity connected to the borehole (fracture porosity) in an onshore naturally-fractured carbonate oil reservoir. The change with azimuth of the near-angle amplitudes (6-15) and the AVA gradient (amplitude variation with angle...
Proceedings Papers

Paper presented at the 2017 SEG International Exposition and Annual Meeting, September 24–29, 2017
Paper Number: SEG-2017-17467683
... sensitive to offset variation than reflection angle in CIGs. Mahmoudian and Margrave (2009) used angle-domain common image gathers (ADCIGs) for AVA analysis and found that they uniquely define ray couples for each point in the subsurface. The purpose of this paper is to delineate and compare the advantages...
Proceedings Papers

Paper presented at the 2008 SEG Annual Meeting, November 9–14, 2008
Paper Number: SEG-2008-2937
... at constant angles along each trace can be directly used to invert for reservoir lithology fluid properties using various amplitude-variation-withangle (AVA) inversion methodologies. Offset-to-angle transformation is straightforward for isotropic models. In the presence of anisotropy, such a transformation...
Proceedings Papers

Paper presented at the 2010 SEG Annual Meeting, October 17–22, 2010
Paper Number: SEG-2010-0409
... porous media model 1 ava variation velocity dispersion phase angle reflection coefficient incident angle reflection magnitude increase reservoir characterization upstream oil & gas reservoir reservoir model variation dispersion Frequency-dependent AVA variations in thinly layered...
Proceedings Papers

Paper presented at the 2008 SEG Annual Meeting, November 9–14, 2008
Paper Number: SEG-2008-2402
... variations of the velocity model. The attributes may be used at various steps of the processing sequence: stretch factor to design de- stretching operators, reflection angle to design partial angle stacks for AVO/AVA studies and kinematic invariants to perform reflection tomography. Introduction Pre-stack...

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