Method to compensate measurement error of fiber Bragg grating sensor caused by hydrogen darkening
US10408694B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 2016 |
| Grant date | Sep 10, 2019 |
| Priority date | — |
| Expiry date | Jun 7, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/07
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method is described for compensating measurement errors of fiber Bragg grating (FBG) sensors installed in fiber cables in down-hole oil and gas environments due to hydrogen darkening. The method involves loading a fiber of known length and multiple FBG sensors in a hydrogen chamber with control of temperature, hydrogen concentration, pressure, and time and adjusting each of the variables through a test matrix while continuously measuring and recording the fiber transmission loss and FBG spectrum changes, then creating a correlation map of fiber transmission loss vs. Bragg wavelength shift, and using that map for compensating the wavelength shift of downhole installed fiber cables as a function of their hydrogen induced transmission loss through time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.