Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

SAMPLE-Seismic amplitude measurement for primary lithology estimation

Conference · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:6535245
SAMPLE is a method of seismic interpretation that extracts shear wave velocities or Poisson's ratios from the seldom used amplitude variations within a common-depth-point (CDP) gather. From a crossplot of pressure wave velocity and Poisson's ratio, lithologies and pore fluids are then estimated. The SAMPLE method works because reflection and transmission of elastic waves (seismic waves) at the boundary between two media are a function of 6 parameters. Three elastic parameters in each media are P-wave velocity, Poisson's ratio or S-wave velocity, and density. Given these 6 parameters and the angle of incidence of a plane elastic wave, the reflection and transmission amplitudes (coefficients) can be calculated using Zoeppritz's equations. SAMPLE is an inversion of this calculation. P-wave velocity is determined in a conventional manner (i.e., Dix interval velocities). Density is assumed to be a function of P-wave velocity. The unknown Poisson's ratios can be determined from the reflection amplitude variation with angle of incidence (offset versus amplitude variations within a CDP gather.) Having solved for P-wave velocities and Poisson's ratios, lithologies and fluids are estimated.
Research Organization:
Terra Linda Group, Inc., San Rafael, CA
OSTI ID:
6535245
Report Number(s):
CONF-8405216-
Conference Information:
Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 68:4
Country of Publication:
United States
Language:
English