Full text loading...
-
AVOA Inversion of PP Reflections in Azimuthally Anisotropic Media Using Nonlinear Optimization
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, Tyumen 2017, Mar 2017, Volume 2017, p.1 - 5
Abstract
Summary
In this paper a new algorithm of nonlinear AVOA inversion of PP reflections in anisotropic media, based on optimization method, is proposed. We solve inverse problem by two methods: first, we use Ruger binomial approximation for plane-wave reflection coefficient at small offsets and determine the azimuth of symmetry axis φ_0 by the method of least squares, then we calculate elastic parameters V_p, V_s, ρ, and Thomsen anisotropy parameters ε^((V)), δ^((V)), γ by Nelder-Mead optimization method at long (pre-critical) offsets. Testing of the algorithms was conducted on the model data for the generalized 7 layers model of the Jurassic deposits of the Middle Ob in Western Siberia. The 7-th layer of the model that simulates the productive sands J2 is transversely isotropic with horizontal symmetry axis. The theoretical the reflection coefficients from the roof of the anisotropic layer were used to solve the inverse problem. It was shown that all parameters of the anisotropic layer can be determined by the nonlinear optimization method with reasonable accuracy for a signal/noise ratio ≥ 10.
© EAGE Publications BV