Elastic anisotropy of core samples from the Taiwan Chelungpu Fault Drilling Project (TCDP): direct 3-D measurements and weak anisotropy approximations

0369989 - GFÚ 2012 RIV GB eng J - Journal Article
Louis, L. - David, Ch. - Špaček, Petr - Wong, T. - Fortin, J. - Song, S. R.
Elastic anisotropy of core samples from the Taiwan Chelungpu Fault Drilling Project (TCDP): direct 3-D measurements and weak anisotropy approximations.
Geophysical Journal International. Roč. 188, č. 1 (2012), s. 239-252. ISSN 0956-540X. E-ISSN 1365-246X
Institutional research plan: CEZ:AV0Z30120515
Keywords : microstructures * seismic anisotropy * acoustic properties
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 2.853, year: 2012

The study of seismic anisotropy has become a powerful tool to decipher rock physics attributes in reservoirs or in complex tectonic settings. We compare direct 3-D measurements of P-wave velocity in 132 different directions on spherical rock samples to the prediction of the approximate model proposed by Louis et al. based on a tensorial approach. The data set includes measurements on dry spheres under confining pressure ranging from 5 to 200 MPa for three sandstones retrieved at a depth of 850, 1365 and 1394 metres in TCDP hole A (Taiwan Chelungpu Fault Drilling Project). As long as the P-wave velocity anisotropy is weak, we show that the predictions of the approximate model are in good agreement with the measurements. As the tensorial method is designed to work with cylindrical samples cored in three orthogonal directions, a significant gain both in the number of measurements involved and in sample preparation is achieved compared to measurements on spheres.
Permanent Link: http://hdl.handle.net/11104/0203917