张洪涛 付威 王春骞 张广玉 王振龙

摘 要：针对油井动液面不能实时监测的问题，采用一种将压力测量和温度剖面测量相结合的方法对油井动液面进行实时监测。设计了基于偏心推杆结构的光纤压力计，采用多模光纤测量温度剖面，根据温度剖面上的拐点确定动液面初始位置，通过初始压强及动液面初始位置计算井中液体密度，之后仅利用压力计随后测得的数据即可求出动液面的实时位置。实验结果表明，光纤压力计有很好的线性度和重复性，其线性度为0.999，压力灵敏度达到230.9pm/MPa，满足井下压力测量要求，同时多模光纤所测温度剖面拐点明显，易于读取，将两种方法结合可对油井动液面数据进行实时准确的监测。

关键词：光纤传感;光纤压力计;温度剖面;偏心推杆;实时动液面监测

DOI：10.15938/j.jhust.2018.06.001

中图分类号： TN253

文献标志码： A

文章编号： 1007-2683（2018）06-0001-06

Abstract：Real-time monitoring of dynamic liquid-level of oil-well is very important in oilfield. A novel method combining pressure measurement and temperature profile measurement is proposed in this paper to measure dynamic liquid-level of oil-well in real-time. A fiber Bragg grating pressure sensor based on an eccentric-pushrod structure is used to measure downhole pressure and the multimode fiber is used to measure temperature profile. The initial position of the dynamic liquid-level can be determined by the inflection point of the temperature profile. The density of the liquid in the well is calculated from the initial pressure and the initial position of dynamic liquid-level. Base on this data the real-time position of the dynamic liquid-level can be obtained only by using the pressure data. Experimental results show that the method that the fiber Bragg grating sensor has a good linearity and repeatability the sensitivity of the sensor can reach 230.9pm/MPa wich meets the requirements of downhole pressure measurement and the inflection point of the temperature profile measured by multimode fiber is obvious and easy to read. The combination of the two measurements methods can be used for real-time and accurate monitoring of oil well liquid level data.

Keywords：optical fiber sensing; fiber optic pressure sensor; temperature profile; eccentric-pushrod; real-time dynamic liquid-level monitoring

0 引 言

在油田的生產开发过程中，动液面数据是一项关键的油田管理基础资料，直接反映油井的供液能力，被誉为“油井的脉搏”。通过对动液面数据的实时监测，可以分析出油井的工作情况以及井下供排状况，并以此为依据优化工作参数，这对降低能耗，提高采收率，减少油井事故，延长油井寿命具有重要的意义。

目前，油井动液面测量方法主要有浮筒法、压力传感器法和声波法3种。浮筒法受到自身重量和体积的限制，只适合在环空井和敞开井中使用。压力传感器法通常采用存储式电子压力计，测量一段时间后将压力计从井筒中取出获取数据，无法进行实时监测。……