Generalized Dix equation and analytic treatment of normal-movement velocity for anisotropic media
- Colorado School of Mines, Golden, CO (United States). Center for Wave Phenomena
Despite the complexity of wave propagation in anisotropic media, reflection moveout on conventional common-midpoint (CMP) spreads is usually well described by the normal-moveout (NMO) velocity defined in the zero-offset limit. In their recent work, Grechka and Tsvankin showed that the azimuthal variation of NMO velocity around a fixed CMP location generally has an elliptical form (i.e., plotting the NMO velocity in each azimuthal direction produces an ellipse) and is determined by the spatial derivatives of the slowness vector evaluated at the CMP location. This formalism is used here to develop exact solutions for the NMO velocity in anisotropic media of arbitrary symmetry. The high accuracy of the NMO expressions is illustrated by comparison with ray-traced reflection traveltimes in piecewise-homogeneous, azimuthally anisotropic models. The authors also apply the generalized Dix equation to field data collected over a fractured reservoir and show that P-wave moveout can be used to find the depth-dependent fracture orientation and to evaluate the magnitude of azimuthal anisotropy.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- OSTI ID:
- 346936
- Journal Information:
- Geophysical Prospecting, Journal Name: Geophysical Prospecting Journal Issue: 2 Vol. 47; ISSN GPPRAR; ISSN 0016-8025
- Country of Publication:
- United States
- Language:
- English
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