Nonlinear Semblance Processing For The Evaluation Of An Acoustic Altered Zone Around The Borehole
Author(s)
Tezuka, Kazuhiko![Thumbnail](/bitstream/handle/1721.1/75233/1994.10%20Tezuka.pdf.jpg?sequence=3&isAllowed=y)
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Other Contributors
Massachusetts Institute of Technology. Earth Resources Laboratory
Metadata
Show full item recordAbstract
This paper describes a simple method to evaluate an acoustic altered zone around the
borehole using an array of sonic waveforms. The method is based on a semblance velocity
analysis and a nonlinear travel time window is introduced. On the assumption that a
velocity gradient of the altered zone may be linear, the nonlinear travel time window is
calculated as a function of averaged velocity and a normalized velocity gradient. The
method is applied to the synthetic acoustic data calculated by finite difference modeling. Case studies with several altered formation models confirmed that this method is a good estimator of the velocity gradients around the borehole.
Date issued
1994Publisher
Massachusetts Institute of Technology. Earth Resources Laboratory
Series/Report no.
Earth Resources Laboratory Industry Consortia Annual Report;1994-10