3-D converted shear wave rotation with layer stripping
US5610875A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 29, 1995 |
| Grant date | Mar 11, 1997 |
| Priority date | — |
| Expiry date | Sep 29, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V1/286
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for using a compressional-wave source to produce converted shear waves which are subjected to Alford 4-component rotation to align the observation coordinates with the natural coordinates of the principal anisotropic axes of a birefringent formation. The static time shift between the fast and the slow shear wavefields due to shear-wave splitting is determined so that they can be synchronized thereby to isotropize the birefringent formation. From those data, fracture-plane orientation can be determined. Based on those data, the direction of a deviated bore hole is aligned perpendicular to the fracture plane strike. For a deep-seated target formation, shallower layers are isotropized prior to rotation and synchronization of the converted shear wavefields originating from that deeper formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.