论文详情
随着国内油气勘探目的层向深层快速延伸,对地震资料的信噪比、分辨率和成像精度要求更高,从而对检波器的灵敏度、带宽要求越来越高。采用窄线宽的分布反馈光纤激光器(DFB-FL)为振动敏感元件,设计了一种井中三分量光纤激光地震检波器,并采用相干探测方式实现微弱地震信号的检测。在实验室开展了频响灵敏度、噪声测试,并与高温动圈检波器2400进行对比试验,同时对井下光纤检波器的耐高温、耐高压性能进行了测试。经试验验证,所设计的井中三分量光纤激光检波器在1~400Hz内具有良好的信号探测能力,灵敏度达到34dB re pm/g,交叉灵敏度小于-25dB,可耐155℃高温及50MPa的高压。该检波器结构紧凑、灵敏度高、频带宽、一致性好,且耐高温高压,在井下勘探等恶劣工作环境具有良好的应用前景。
With the rapid expansion of deep exploration layers in domestic oil and gas exploration targets,more stringent requirements have become necessary in terms of signal-to-noise ratio,resolution,and imaging accuracy of seismic data.Therefore,geophones with higher sensitivity and bandwidth performance are needed.In this work,a distributed feedback fiber laser (DFB-FL) with a narrow linewidth and low noise is used as the sensing element.An all-fiber three-component fiber laser geophone for downhole exploration is developed on the basis of the vibration sensing units,and a coherent detection method is adopted to detect weak seismic signals.Frequency response sensitivity and noise tests were carried out in the laboratory,and a comparison with the high-temperature moving-coil geophone 2400 is carried out.The temperature and pressure resistance performance of the downhole fiber optic geophone are also evaluated.The experimental results show that the three-component fiber laser geophone has good signal detection capability within 1~400Hz,the sensitivity reaches 34dB re pm/g,the cross sensitivity is less than -25dB,and it can withstand temperatures as high as 155℃ and pressures up to 50MPa.The advantages of the three-component fiber laser geophone are its compact structure,high sensitivity,wide-band frequency response,good consistency,high temperature and pressure resistance,and good application prospects in underground exploration and other harsh working environments.
山东省自然科学基金(ZR2021MF127)、山东省重点研发计划(2019GGX104030)、山东省重大科技创新工程(2019JZZY010113)、齐鲁工业大学(山东省科学院)科教产融合项目(2020KJC-CG01,2020KJC-ZD17)、齐鲁工业大学(山东省科学院)产学研基金(2019-CXY4)、山东省泰山学者工程项目(tsqn20161061)和济南市创新团队项目(2019GXRC028)共同资助。