油气井下光纤光栅温度压力传感器

Fiber bragg grating temperature and pressure sensor for oil and gas well

温度和压力是石油开采过程中重要的参数,但油气井下高温高压环境苛刻,传统电子传感器很难实现长期稳定的工作。本文提出了一种基于碳纤维管增敏型的光纤光栅温度压力传感器。该传感器是以碳纤维丝编织成的中空管状结构作为骨架,通过耐高温环氧树脂固化成复合碳纤维管作为弹性体,并将表面嵌入耐高温光纤布拉格光栅作为感知元件,实现了井下温度和压力的同时测量。实验结果表明,该传感器可以在0~150℃和0~80 MPa环境下稳定工作,压力灵敏度最大可达到-50.02 pm/MPa,同时表现出很好的线性响应。通过外加参考光栅作为温度补偿光栅,解决了温度和压力同时测量过程中的交叉敏感问题,满足了井下开采过程中的精度要求,为油气井下高温高压光纤传感器的设计提供了实验依据。

Temperature and pressure are very important parameters in oil and gas well exploitation. The downhole environment is harsh so it is difficult for traditional electronic sensors to achieve long-term and stable monitoring of downhole parameters. In this paper, a fiber Bragg grating temperature and pressure sensor based on a carbon-fiber sensitized tube is proposed. The sensor is composed of a hollow tubular structure woven of carbon fibers as a skeleton. The composite carbon fiber tubes are cured by high-temperature resistant epoxy resin as an elastomer, and the high-temperature resistant fiber Bragg grating is embedded on the surface as a sensing element to realize the simultaneous measurement of downhole temperature and pressure. The experimental results show that the sensor can work stably in environments of 0~150 ℃ and 0~80 MPa, and the maximum pressure sensitivity can reach-50.02 pm/MPa. The sensor has a good linear response. By adding a reference grating as a temperature compensation grating, the cross-sensitivity problem in the process of the simultaneous measurement of temperature and pressure is solved, and the accuracy requirements in the process of underground mining are met. This technique provides an experimental basis for the design of high-temperature and high-pressure optical fiber sensors in oil and gas wells.