Vertical seismic profiling system having vertical seismic profiling optical signal processing equipment and fiber Bragg grafting optical sensors
US6072567A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 12, 1997 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Feb 12, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V1/52
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system for vertical seismic profiling of an earth borehole includes an optical fiber having a plurality of Bragg grating sensors formed therein, each one of the Bragg grating sensors being tuned to reflect a respective bandwidth of light, each bandwidth having a different respective central wavelength. Each of the Bragg grating sensors are responsive to an input light signal, a static strain, a dynamic strain and a temperature strain for each providing a respective light signal indicative of static and dynamic forces and temperature at a respective sensor location. The physical spacing and wavelength spacing of the Bragg grating sensors are known such that each of the sensing light signals are easily correlated to a specific depth. The Bragg grating sensors are tuned such that when a sensor is subjected to a maximum static strain, maximum dynamic strain, and a maximum temperature strain, the maximum wavelength shift of a respective sensing light signal does not cause the frequency of the sensing light signal to enter the bandwidth of another one of the plurality of Bragg grating sensors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.