Methods and systems for performing azimuthal simultaneous elastic inversion

Abstract

An improved method for analyzing seismic data to obtain elastic attributes is disclosed. In one embodiment, a reflectivity series is determined for at least one seismic trace of seismic data obtained for a subterranean formation, where the reflectivity series includes anisotropy properties of a formation. One or more synthetic seismic traces are obtained by convolving the reflectivity series with a source wavelet. The one or more synthetic seismic traces are inverted to obtain elastic parameters estimates. According to one aspect, the data inputs are angle-azimuth stacks. According to another aspect, the data inputs are azimuthal Fourier coefficients un, vn.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of patent application Ser. No. 13 / 046,447, filed on Mar. 11, 2011, entitled “METHODS AND SYSTEMS FOR PERFORMING AZIMUTHAL SIMULTANEOUS ELASTIC INVERSION”, which is related to, and claims priority from, Provisional Patent Application Nos. 61 / 313,394 and 61 / 340,096, filed on Mar. 12, 2010, entitled “METHODS AND SYSTEMS FOR PERFORMING AZIMUTHAL SIMULTANEOUS ELASTIC INVERSION”, the disclosures of which are incorporated here by reference.TECHNICAL FIELD[0002]The present disclosure relates generally to geophysics and, in particular, methods and systems for performing inversion of seismic data. More specifically, the present disclosure concerns improved techniques of analyzing seismic data to obtain elastic attributes such as azimuthal anisotropy data, or data based on a transversely isotropic model with a horizontal axis of symmetry (HTI anisotropy).BACKGROUND OF THE INVENTION[0003]Typically, in the field of o...

AI Technical Summary

Benefits of technology

This approach provides reliable and accurate estimates of elastic parameters, overcoming the limitations of existing methods by handling anisotropic media effectively, reducing noise bias, and eliminating symmetry axis ambiguity, thereby improving fracture characterization and lithology prediction.

Problems solved by technology

The prior art seismic data processing methods have significant drawbacks and limitations.

For instance, conventional Azimuthal AVO inversions provide only band-limited fractional elastic parameters estimates with reduced resolution and quality.

There are, however, a number of limitations to this method.

It is not theoretically valid for the case of two anisotropic half-spaces.

Moreover, for noise stability reasons, this method is usually implemented using a near offset approximation, which leads to bias in the parameter estimates.

There are, however, still drawbacks to this method because it assumes an isotropic earth, thereby losing all the information associated with the anisotropic parameters such as fracture information.

Further, overlooking these anisotropic parameters introduce systematic errors into such method.

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