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Most seismic data is processed to optimize image quality for structural interpretation, with little regard to preserving characteristics essential for successful seismic reservoir characterization. No matter how sophisticated the inversion algorithm, use of inadequately processed seismic data will severely impact the quality of the final interpretation.

As a consequence, seismic data (and well logs) can rarely be used “as is” for seismic reservoir characterization without substantial pre-conditioning. Rock Solid Images uses our AVATAR toolkit to provide a complete suite of seismic data conditioning steps to optimize the quality of pre and post-stack seismic data prior to use in impedance, AVO and seismic facies classification applications. Similarly, Geophysical Well Log Analysis GWLA® is used to condition well-logs used for seismic modeling and Well Tie analysis in iMOSS®.

AVATAR may be applied to pre or post-stack seismic data and is composed of several interlinked steps:

HR_RADON– High Resolution Radon Demultiple (Pre-Stack)HR_Radon is a proprietary algorithm for conducting high resolution multiple suppression using an adaptive Radon scheme. The approach is designed to specifically address the issues of aliased events and limited differential move-out between primaries and multiples by use of an extension of the conventional Radon transform to enhance the focusing of energy in the transform domain.

SBALAN – Spectral Balancing of Gathers (Pre-Stack)Gabor-Morlet Joint Time-Frequency Analysis (JTFA) is used to separate the frequency spectra of each gather trace into a user-specified number of sub-bands. The sub-bands are calculated using a running Gaussian-shaped window which gives a slowly varying amplitude profile of each sub-band. Then each sub-band spectra is balanced against the corresponding sub-band of a user-specified pilot trace within the gather.

The primary advantage of this approach is two-fold: (1) the bandwidth of the gather at each time sample is determined by the pilot trace, and (2) the total energy contained in each reflector is held constant by computing its energy envelope and requiring that the energy of all sub-bands (after scaling) sum to the original energy envelope amplitude. This ensures that AVO character is not altered in this process.

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AVATAR®Seismic Data Conditioning

+1-713-783-5593 www.Rocksolidimages.com

ALIGN – Pre-stack Data Alignment (Pre-Stack)A fundamental assumption made in AVO inversion is that primary reflection events are horizontally aligned (flat) across each CDP gather. The presence of residual move-out, non-hyperbolic move-out, random noise, multiples, tuning effects etc. will violate this assumption and introduce noise (uncertainty) into the AVO results. The ALIGN module corrects for various residual move-out effects, resulting in a much-improved AVO signature.

ALIGN flattens gathers based on a conditional minimization of a reflector’s least-squares fit error by determining a local statics shift on each gather trace. The “condition” that is minimized can be either semblance or AVO fit.

EPS3D – Edge-Preserving Smoothing (Pre or Post-Stack)This program performs “edge-preserving smoothing” in 3D, which is a methodology to enhance S/N by means of noise reduction. It works in the offset domain by re-sorting the pre-stack seismic volume into offset volumes. This acts to preserve AVO effects because smoothing does not take place between adjacent offsets within the gather. It takes into account spatial dip of coherent reflections so that frequency and continuity are preserved. The “edge-preserving” characteristics result from user-defined semblance cutoffs so that summation and filtering do not occur across traces with different reflector characteristics (i.e. faults, angular unconformities, channel boundaries, etc.).

XTEND – Spectral Extension (Post-Stack)Data bandwidth is a well-known constraint on the resolving power of seismic data, with implications for both structural and stratigraphic interpretation. The objective of this process is to enhance seismic resolution by extending data bandwidth beyond the limits of current seismic processing techniques such as spectral whitening or deconvolution.

The process extends seismic bandwidth by first performing a form of sparse inversion, and then creating a bandwidth extended version of the input trace from the sparse inversion result. Sparse inversion is implemented by means of an orthogonal matching pursuits algorithm, which is comparable to constrained least-squares modeling of the input data, with constraints limiting the number of non-zero values of the derived reflectivity.

For more information please visit www.rocksolidimages.com/avataror contact Gareth Taylor: gareth.taylor@rocksolidimages.com

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