光纤F-P腔压力传感器在高温油井下的应用研究

针对高温、高压油井的测量环境,设计研制了基于光纤非本征型Fabry-Perot(F-P)腔的波长解调型光纤压力传感器系统.该系统采用激光熔接制作的光纤F-P传感头,具有测量动态范围大、温度敏感性小、耐高温和长期工作稳定等优点,在压强0～30 MPa范围内,系统压力测量分辨率达到0.003 MPa,温度敏感性小于0.002 MPa/℃.光纤传感头采用光纤-厚壁石英管激光熔接的无胶封装方式,解决了高温环境下的传感器高压密封和光纤保护问题.

Fiber Optic Pressure Sensor System Based on Extrinsic Fabry-Perot Interferometer for High Temperature Oil Well Measurement

To meet the need of the pressure measurement in high temperature oil wells,an extrinsic Fabry-Perot(F-P)interferometer(EFPI)based optical fiber pressure sensor is developed.The F-P cavity sensor fabricated by laser thermal bonding technique has characteristics of large dynamic gauge range,low temperature sensitivity,high temperature resistance and long term operation stability.The pressure resolution of 0.03 MPa over the full scale from 0 to 30 MPa has been achieved.Solutions for some key problems in the downhole measurement have been proposed:by optimizing the structure of the F-P sensor the cross-sensitivity of temperature and pressure is effectively reduced;for prolonging the life time of sensor head and polyamide coated fiber an epoxy-free package method based on hermetical bonding of quartz ferrule and fiber is used.The sensor system has been successfully applied to downhole pressure measurement in Liaohe oil field.