Distributed seismic energy source
US5109947A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 21, 1991 |
| Grant date | May 5, 1992 |
| Priority date | — |
| Expiry date | Jun 21, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V2210/161
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A drill string in a fluid-filled borehole acts as a waveguide for an extensional wavefield that is generated in the drill string when it is excited by the vibrations of a drill bit secured to the lower end of the drill string. The waveguide acts as a distributed acoustic energy source which initiates head waves in the surrounding formation. The head waves are detected at one or more discrete locations near the surface of the earth. The extensional wavefield is detected by a sensing means mounted at the top of the drill string. The detected head waves are cross-correlated with the detected extensional waves to create a cross-correlogram which may be displayed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.