A numerical simulation of the acoustic and elastic wavefields radiated by a source on a fluid-filled borehole embedded in a layered medium

Journal Article · Thu Apr 01 04:00:00 EST 1993 · Geophysics; (United States)

DOI:https://doi.org/10.1190/1.1443430· OSTI ID:5930947

Bouchon, M ^[1]

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1. Univ. Joseph Fourier, Grenoble (France). Lab. de Geophysique Interne et Tectonopysique

The authors present a method of calculation to simulation the propagation of acoustic and elastic waves generated by a borehole source embedded in a layered medium. The method is formulated as a boundary element technique where the Green's functions are calculated by the discrete wavenumber method. The restrictive assumptions are that the borehole is cylindrical and that its axis runs normal to the layer interfaces. The physics of the method rely on Huygens's principle that states that a diffracting boundary--the borehole wall in the present case--can be represented as a distribution of secondary sources. The borehole is discretized into small cylindrical elements and each element is represented by three sources: a volume source representing the wavefield diffracted in the fluid and two surface forces that give rise to the elastic wavefield radiated outside the borehole. The strength of each source is obtained by solving the linear system of equations that describes the boundary conditions at the borehole wall. The method is used to generate synthetic acoustic log s and to investigate the wavefield radiated into the formation. The simulations considered display the Stoneley wave reflections at the bed boundaries and show the importance of the diffraction that takes place where the borehole wall intersects the layer interfaces.

• OSTI ID: 5930947
• Journal Information: Geophysics; (United States), Journal Name: Geophysics; (United States) Vol. 58:4; ISSN GPYSA7; ISSN 0016-8033
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ATTENUATION
BOREHOLES
CAVITIES
DATA ANALYSIS
FUNCTIONS
GEOPHYSICAL SURVEYS
MATHEMATICS
NUMERICAL ANALYSIS
RESPONSE FUNCTIONS
SEISMIC SOURCES
SEISMIC SURVEYS
SEISMIC WAVES
SIMULATION
SONIC LOGGING
SOUND WAVES
SURVEYS
WAVE PROPAGATION
WELL LOGGING