Multipole logging in a formation with stress-relief-induced anisotropy

Journal Article · Thu Dec 01 04:00:00 EST 1994 · Geophysics; (United States)

DOI:https://doi.org/10.1190/1.1443568· OSTI ID:6677170

Renlie, L ^[1]

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1. IKU Petroleum Research, Trondheim (Norway)

The stress relief associated with the drilling of a borehole may induce a mechanically damaged zone with radial transverse isotropy (RTI), where the properties in the radial direction differ from those in the axial and tangential directions. The effect of such a zone on multipole acoustic full-waveform logging is investigated using a numerical model based on the frequency-axial-wavenumber method. Calculations of the spectral behavior show that the fundamental mode associated with the multipole source behaves the same way in a TRI zone as it does in a damaged zone with isotropic properties. In a slow virgin formation, calculations of full waveforms show that the presence of a damaged zone with RTI is more difficult to detect than a damaged zone with isotropic elasticity because the refracted P-wave encounters an isotropic zone but not a RTI zone. The results indicate that a damaged zone with RTI, which is a precursor to destructive events such as borehole instability and sand production, can be detected only by analyzing the spectral behavior of the fundamental mode.

• OSTI ID: 6677170
• Journal Information: Geophysics; (United States), Journal Name: Geophysics; (United States) Vol. 59:12; ISSN GPYSA7; ISSN 0016-8033
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ANISOTROPY
BOREHOLES
CAVITIES
DATA ANALYSIS
FORMATION DAMAGE
INDUSTRY
MATHEMATICAL MODELS
PETROLEUM INDUSTRY
SONIC LOGGING
WELL LOGGING