Open AccessEstimation of the anisotropy parameters of transversely isotropic shales with a tilted symmetry axis
Author(s) -
Nadri Dariush,
Sarout Joël,
Bóna Andrej,
Dewhurst David
Publication year - 2012
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2012.05545.x
Subject(s) - transverse isotropy , anisotropy , orientation (vector space) , isotropy , symmetry (geometry) , geology , axis of symmetry , geometry , a priori and a posteriori , inverse , oil shale , physics , optics , mathematics , paleontology , philosophy , epistemology
SUMMARY This paper reports a new approach for the estimation of Thomsen anisotropy parameters and symmetry axis orientation from ultrasonic P ‐wave traveltime measurements on transversely isotropic shale samples of arbitrary geometry. This approach can be used for core samples cut in any direction with respect to the bedding plane, because no a priori assumption regarding the symmetry axis orientation is made. This orientation is rather part of the solution of the inverse problem together with the anisotropy parameters themselves. Very fast simulated reannealing is used to search for the best possible estimate of the model parameters. The methodology is applied to spherical and cylindrical anisotropic shale samples.