Fracture discrimination using borehole frequency response of stoneley waves
US6192316A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 26, 1999 |
| Grant date | Feb 20, 2001 |
| Priority date | — |
| Expiry date | May 26, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V1/50
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A computer system (30) and method of operating the same to analyze well log data so as to distinguish fractures from drilling artifacts, such as caves, washouts, and breakouts, is disclosed. According to the disclosed system and method, a Stoneley wave well log obtained at a plurality of depths is analyzed at a low and a high frequency, to generate a low frequency reflection coefficient trace over depth and a high frequency reflection coefficient trace over depth. Comparison of these reflection coefficient traces with one another will indicate whether a reflecting feature includes a fracture (as indicated by good low frequency response) or a cave, washout, or other artifact (as indicated by good high frequency response), or both. The particular methods disclosed include the generation of the reflection coefficient traces through back-projection stacking of deconvolved impulse traces at both frequencies, and applying and evaluating an envelope function to the stacked traces.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.