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Proceedings [EAGE Publications BV 76th EAGE Conference and Exhibition 2014 - Amsterdam, Netherlands (2014.06.16-2014.06.19)] Proceedings 76th EAGE Conference and Exhibition 2014 - Fundamentals of Vibration Sensing with Distributed Fibre Optic Sensors through Downscaled Experiments
摘要： In the past few years the Distributed Vibration Sensing of fibre optic sensors (also called Distributed Acoustic Sensing) has gained great interest in geophysics, despite the fundamentals of the measurement being poorly understood. The technology offers immense improvement in terms of efficiency when compared with current geophysical methods and also could be preferred for applications such as permanent reservoir monitoring. We present a method for downscaled experimentation that enabled us to define the fundamentals of the optical fibre measurement. We show seismic data that were recorded simultaneously by both the fibre optical interferometer and conventional geophones, thus enabling the comparison of sensor performance. We present results focused on wave-polarity sensitivity and the directionality of fibre measurements. The current interrogation method of optical fibre cables cannot distinguish between wavefields coming from opposite azimuthal directions, which can be an issue in certain applications where the identification of up-going and down-going wavefields is essential. Observations are also presented that describe the relationship between the velocity signal that is measured using a geophone array and the phase difference measurement from the fibre optic sensing system.
关键词： directionality,Distributed Vibration Sensing,Distributed Acoustic Sensing,optical fibre measurement,geophones,wave-polarity sensitivity,seismic data,fibre optic sensors,geophysics
更新于2025-09-11 14:15:04
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A Combined Events Recognition Scheme Using Hybrid Features in Distributed Optical Fiber Vibration Sensing System
摘要： In this paper, a high efficiency multiple events recognition scheme based on a hybrid feature extraction algorithm and a combined classifier for distributed optical fiber vibration sensing (DOFVS) system has been proposed and demonstrated. The hybrid feature vectors are extracted by using zero crossing rate, sample entropy, wavelet packet energy entropy, kurtosis, and multiscale permutation entropy. A combined classifier of support vector machine and radial basis function neural network is proposed to improve the reliability of the recognition results. The recognition result is given only when both of the two classifiers output same event types. The experimental results demonstrated that the average identification rate of five typical patterns (no intrusion, waggling the fence, climbing the fence, kicking the fence, and cutting the fence) over 97% is achieved through the combined classifier. Moreover, the whole recognition processing speed of the combined scheme is also good of real time performance, which can be limited in 1.1 s. Therefore, this kind of events recognition scheme has a quite promising application prospects in DOFVS system.
关键词： hybrid feature vectors,signal analysis,Distributed vibration sensing,events recognition,optical fiber,combined classifier
更新于2025-09-11 14:15:04