Preliminary Investigation of Temperature and Pressure Measurement System for Down-hole Monitoring of Oil Wells Using FBG/EFPI Sensing Technique

摘要

To overcome the limitations of conventional electronic sensors currently used for downhole monitoring of oil and gas wells, including drastic reduction in reliability, long term instability and susceptibility to electromagnetic interference, a multiplexed fibre Bragg grating (FBG)/extrinsic Fabry-Perot interferometer (EFPI) sensor for simultaneous measurement of temperature and pressure is reported. Analysis of the spectral characterization is presented and a de-multiplexing mathematical model for the multiplexed sensor is proposed. This configuration is used to eliminate the issue of temperature-pressure crosssensitivity and effectively improve the resolution of the sensor system. Experimental results show good linearity between the Bragg wavelength shift and the physical parameters (temperature and pressure), high sensitivity and high accuracy.