Method for characterizing shear wave formation anisotropy
US7310285B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 2005 |
| Grant date | Dec 18, 2007 |
| Priority date | — |
| Expiry date | Nov 10, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V2210/626
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of characterizing shear wave anisotropy in a formation includes obtaining crossed-dipole waveforms from a borehole penetrating the formation over a range of depths and frequencies, determining far-field slowness in a fast-shear and slow-shear direction using a low-frequency portion of the crossed-dipole waveforms, and determining near-wellbore slowness in the fast-shear and slow-shear directions using a high-frequency portion of the crossed-dipole waveforms. The method also includes marking a selected depth of the formation as having intrinsic anisotropy if at the selected depth the far-field slowness in the fast-shear direction is less than the far-field slowness in the slow-shear direction and the near-wellbore slowness in the fast-shear direction is less than the near-wellbore slowness in the slow-shear direction. The selected depth is marked as having stress-induced anisotropy if the far-field slowness in the fast-shear direction is less than the far-field slowness in the slow-shear direction and the near-wellbore slowness in the fast-shear direction is greater than the near-wellbore slowness in the slow-shear direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.