Multiple anisotropic parameter inversion for a tti earth model

Abstract

A method for determining values of anisotropic model parameters of a Tilted Transversely Isotropic (TTI) Earth model, the anisotropic parameters including P-wave velocity (Vp0) along a tilted symmetry axis, the Thomsen anisotropy parameters delta and epsilon (or eta =( epsilon-delta) / (1+2delta)) representative of variations of wave velocities as a function of wave propagation angle from the symmetry axis, the method including acquiring input data for a geological volume of interest; determining a theoretical relationship between the input data and the anisotropic model parameters; ; and calculating the values of the anisotropic model parameters at each of a plurality of subsurface locations in the geological volume of interest based on the theoretical relationships and the input data using workflows involving iterative or sequential combinations of processes including input data preprocessing, conventional tomographic inversion, three dimensional tomographic inversion based on a tilted transversely isotropic model, and three dimensional pre-stack depth migration using a tilted transversely isotropic model.

Description

technical field [0001] The present invention relates to a method for determining values ​​of anisotropic model parameters of a Tilted Transversely Isotropic (TTI) earth model. Background technique [0002] To analyze the geological structure of subsurface formations, exploration geophysicists make many assumptions. One of them is that the subsurface formation is isotropic, when in reality, it's basically anisotropic. Such incorrect assumptions can lead to incorrect imaging and interpretation of geological structures. In order to extend seismic processing techniques to anisotropic media, it is desirable to obtain measures of the anisotropy of geological structures. [0003] Seismic anisotropy can be defined as the correlation between seismic velocity and wave propagation direction. It is well known that the tilted-axis transverse isotropic earth model or TTI earth model can be used to simulate wave propagation in anisotropic media and to obtain images of subsurface formati...

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Problems solved by technology

However, drilling and coring are very expensive processes, and direct measurements are only possible at very few well locations

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