Estimating a shear modulus of a transversely isotropic rock

Autor: K. J. Ellefsen, C. H. Cheng, Kenneth M. Tubman, M. N. Toksöz
Rok vydání: 2002
Předmět:
Zdroj: IEEE 1991 Ultrasonics Symposium.
DOI: 10.1109/ultsym.1991.234100
Popis: A method of estimating c/sub 66/, one of the shear moduli of a transversely isotropic rock, using a guided wave generated during acoustic logging is described. The symmetry axis of the anisotropy is assumed to be parallel to the borehole. The inversion for c/sub 66/ is based on a cost function which has three terms: a measure of the misfit between the observed and predicted wavenumbers of the guided wave (tube wave), a measure of the misfit between the current estimate for c/sub 66/ and its most-likely value, and penalty functions which constrain the estimate for c/sub 66/ to physically acceptable values. Estimates for c/sub 66/ from synthetic data are almost always within 1% of their correct value. Estimates for c/sub 66/ from field data collected in a formation with a high clay content are typical of transversely isotropic rocks. >
Databáze: OpenAIRE