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Title: Effects of single fractures on seismic wave propagation

Effects of single fractures on seismic wave propagation Detection and characterization of fractures, joints and faults remains an important problem in mining and geotechnical engineering, as well as in petroleum reservoir engineering. A theoretical model has been developed which predicts the amplitude and group time delay of the transmitted, reflected, and converted waves resulting from a plane wave incident upon a single fracture. It is assumed that seismic stresses are continuous across the interface. Seismic particle displacements, however, are assumed to be discontinuous. For completely dry conditions, the magnitude of the displacement discontinuity is given by the ratio of the seismic stress to the stiffness, {kappa}, of the fracture. If a fluid is present in the fracture, we postulate that, in addition to the displacement discontinuity, a velocity discontinuity exists which is equal to the ratio of the seismic stress to specific viscosity, {eta}. The wave equation has been solved for two sets of boundary conditions, with each set incorporating both specific stiffness and specific viscosity. These boundary conditions have been designated as Kelvin and Maxwell models. 12 refs., 5 figs.
Authors: ; ;
Publication Date:
OSTI Identifier:7041898
Report Number(s):LBL-28442; CONF-900640--4
ON: DE90009191
DOE Contract Number:AC03-76SF00098
Resource Type:Conference
Resource Relation:Conference: International conference on rock joints, Loen (Norway), 4-6 Jun 1990
Research Org:Lawrence Berkeley Lab., CA (USA)
Sponsoring Org:DOE/ER; DOE/RW
Country of Publication:United States
Language:English
Subject: 02 PETROLEUM; 03 NATURAL GAS; 58 GEOSCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; GEOLOGIC FRACTURES; MATHEMATICAL MODELS; ROCKS; WAVE PROPAGATION; SEISMIC WAVES; FLUID FLOW; OIL FIELDS; SEISMIC EFFECTS; STRESSES; VISCOSITY; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; MINERAL RESOURCES; PETROLEUM DEPOSITS; RESOURCES 020200* -- Petroleum-- Reserves, Geology, & Exploration; 030200 -- Natural Gas-- Reserves, Geology, & Exploration; 580000 -- Geosciences; 990200 -- Mathematics & Computers