Full text loading...
-
Orthorhombic Elastic Reflection FWI for AVO and Long Length-Scale Parameter Estimations
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
We develop an algorithm for orthorhombic elastic Full Waveform Inversion (FWI) in the reflection domain. We constrain the inversion from a full orthorhombic system through the use of a chain rule, in order to solve for shear (vs) and compressional (vp) velocities within a fixed orthorhombic-anisotropic background model. We are able to achieve not only short length-scale model updates, but interestingly, relatively long wavelength as well, both of which are required for AVO inversion of target reservoirs. We analyze two mechanisms for long length-scale updates under the regime of elastic reflection FWI: a local amplitude-induced long length-scale domain-of-influence effect, and an intrinsic tomographic component contained within FWI. We illustrate our method on a 3D subsalt model, and obtain good parameter recovery for subsalt reservoir targets that extend vertically over a long distance compared to the extent of a gradient or imaging imaging wavelet.