Vitesse des ondes ultrasonores, soniques et sismiques dans les argilites du tunnel de Tournemire. Effet de l’anisotropie et de la fracturation naturelle.

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31/12/2002

B. Zinszner, P. Meynier, J. Cabrera, P. Volant Oil & Gas Science and Technology – Rev. IFP, Vol. 57 (2002) N°4, pp. 341-353

Type de document > *Article de revue
Mots clés publication scientifique > faille/fracture , milieu argileux , ondes
Unité de recherche > IRSN/DEI/SARG/BERSSIN , IRSN/DEI/SARG/BEHRIG
Auteurs > CABRERA Justo , VOLANT Philippe

Abstract in english but full text in French. Elastic wave velocities in dense shale were measured at three scales of investigation: ultrasonic (laboratory), sonic (log) and seismic (tomography), using IPSN research facilities in the Tournemire tunnel (Aveyron, France).Tournemire shale exhibits a high transverse isotropy and the sonic/seismic measurements were performed in both a naturally fractured area (tectonic, near a subvertical fault) and a nonfractured area. This allows an investigation of the impact of fractures on wave velocity.Among the conclusions of practical importance for applied geophysics, one can point out:- the high P wave velocity anisotropy measured on centimetric samples is quantitatively the same that measured at decametric scale using seimics tomography;- the tectonic fractures have a noticeable impact on P wave velocity. The P velocity is lower in the fractured area. Unfortunately, the S-wave velocity could be measured at ultrasonic frequency only.

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