Predicting stress-induced velocity anisotropy in rocks

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Geophysics

DOI:https://doi.org/10.1190/1.1443836· OSTI ID:100743

Mavko, G; Mukerji, T; Godfrey, N ^[1]

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1. Stanford Univ., CA (United States). Rock Physics Lab.

A simple transformation, using measured isotropic V{sub P} and V{sub S} versus hydrostatic pressure, is presented for predicting stress-induced seismic velocity anisotropy in rocks. The compliant, crack-like portions of the pore space are characterized by generalized compressional and shear compliances that are estimated form the isotropic V{sub P} and V{sub S}. The physical assumption that the compliant porosity is crack-like means that the pressure dependence of the generalized compliances is governed primarily by normal tractions resolved across cracks and defects. This allows the measured pressure dependence to be mapped form the hydrostatic stress state to any applied nonhydrostatic stress. Predicted P- and S-wave velocities agree reasonably well with uniaxial stress data for Barre Granite and Massillon Sandstone. While it is mechanically similar to methods based on idealized ellipsoidal cracks, the approach is relatively independent of any assumed crack geometry and is not limited to small crack densities.

• DOE Contract Number: AC21-91MC28087
• OSTI ID: 100743
• Journal Information: Geophysics, Journal Name: Geophysics Journal Issue: 4 Vol. 60; ISSN GPYSA7; ISSN 0016-8033
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
ANISOTROPY
CALCULATION METHODS
GEOLOGIC FRACTURES
GEOLOGIC STRATA
PETROLEUM INDUSTRY
POROSITY
RESERVOIR ROCK
RESPONSE FUNCTIONS
SANDSTONES
SEISMIC WAVES
STRESS ANALYSIS
WAVE PROPAGATION