Seismic Frequency Loss Mechanisms: Direct Observation
M. Batzle, R. Hofmann, G. Kumar, L. Duranti and De-H. Han
Event name: 67th EAGE Conference and Exhibition - Workshops
Session: WS 2: Seismic Q: Observations, Mechanisms and Interpretation
Publication date: 13 June 2005
Info: Extended abstract, PDF ( 336.77Kb )
Price: € 20
Direct measurement of seismic attenuation (1/Q) and velocity dispersion in the laboratory point to several independent loss mechanisms. A forced deformation technique allows measurement at both seismic frequencies and amplitudes. Fluid motion is the primary mechanism in porous, permeable clastics. In shales, bulk fluid motion is inhibited and clay particle interaction with bound water may dominate. Another mechanism usually not considered is losses in the fluid phase. Heavy, viscous fluids themselves show bulk losses independent of a rock matrix. These loss mechanisms are frequency dependent, so observations of 1/Q made at seismic frequencies usually will not agree with sonic log measurements, which, in turn, will not agree with ultrasonic data.