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Abstract

Anisotropy in rock layer is manifested in seismic data as anomalies in travel time, waveform<br>and amplitudes. Seismic wave travels generally in anisotropic medium, as the earth is<br>fundamentally anisotropic, but most of the processing algorithms assume the ideal condition of<br>isotropy. This faulty assumption leads to erroneous imaging and thus wrong interpretation. The<br>anisotropy is hidden inside the hyperbolic moveout velocity and moveout looks hyperbolic, even<br>though the layer is aniosotropic. Incorporation of velocity anisotropy in routine processing<br>improves the character of the reflector with proper focusing of amplitude and provides more<br>geological meaning to acoustic impedance and different attributes. Better accuracy, higher<br>resolution, wider spread length and improved ties between seismic and log require understanding<br>and application of anisotropy, if conflicting results of the routine processing and interpretation<br>objectives are to be reconciled. Hence, in many situations it becomes necessary to include the<br>effect of anisotropy for obtaining correct images and rock properties from seismic data.<br>Thomsen (1986) derived equations to account for anisotropy and these simplified equations<br>are widely used for solving important seismological problems effectively in anisotropic medium.<br>The purpose of this study is to estimate the Thomsen’s anisotropy parameter d(Delta), for<br>transversely isotropic medium from common mid point gather. Here, we describe a new approach<br>for determination of d(Delta) based on optimum moving window velocity analysis within<br>common mid point gather for different offset ranges to extend anisotopic normal move out<br>correction in processing steps. Further, parameters,d(Delta), are calibrated at well to resolve the<br>depth uncertainties. We shall demonstrate our technique and show the results from a field data set<br>from Cauvery basin, Southern India.

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/content/papers/10.3997/2214-4609-pdb.38.F017
2003-09-01
2020-09-22
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http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609-pdb.38.F017
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