scholarly journals Seismic Applications of Downhole DAS

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2897
Author(s):  
Ariel Lellouch ◽  
Biondo L. Biondi
Keyword(s):  
Temporal Resolution ◽  
Review Article ◽  
Seismic Signals ◽  
Acoustic Sensing ◽  
Continuous Sampling ◽  
Distributed Acoustic Sensing ◽  
Seismic Applications

Distributed Acoustic Sensing (DAS) is gaining vast popularity in the industrial and academic sectors for a variety of studies. Its spatial and temporal resolution is ever helpful, but one of the primary benefits of DAS is the ability to install fibers in boreholes and record seismic signals in depth. With minimal operational disruption, a continuous sampling along the trajectory of the borehole is made possible. Such resolution is highly challenging to obtain with conventional downhole tools. This review article summarizes different seismic uses, passive and active, of downhole DAS. We emphasize current DAS limitations and potential ways to overcome them.

Observing avalanche dynamics with Distributed Acoustic Sensing

2021 ◽  
Author(s):  
Andreas Fichtner ◽  
Pascal Edme ◽  
Patrick Paitz ◽  
Nadja Lindner ◽  
Michael Hohl ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Flow Regimes ◽  
Dynamic Strain ◽  
Seismic Signals ◽  
Fibre Optic ◽  
Snow Avalanches ◽  
Acoustic Sensing ◽  
Fibre Optic Cable ◽  
Distributed Acoustic Sensing ◽  
Seismic Instrumentation

<p><span>Avalanche research requires comprehensive measurements of sudden and rapid snow mass movement that is hard to predict. Automatic cameras, radar and infrasound sensors provide valuable observations of avalanche structure and dynamic parameters, such as velocity. Recently, seismic sensors have also gained popularity, because they can monitor avalanche activity over larger spatial scales. Moreover, seismic signals elucidate rheological properties, which can be used to distinguish different types of avalanches and flow regimes. To date, however, seismic instrumentation in avalanche terrain is sparse. This limits the spatial resolution of avalanche details, needed to characterise flow regimes and maximise detection accuracy for avalanche warning.</span></p><p><span>As an alternative to conventional seismic instrumentation, we propose Distributed Acoustic Sensing (DAS) to measure avalanche-induced ground motion. DAS is based on fibre-optic technology, which has previously been used already for environmental monitoring, e.g., of snow avalanches. Thanks to recent technological advances, modern DAS interrogators allow us to measure dynamic strain along a fibre-optic cable with unprecedented temporal and spatial resolution. It therefore becomes possible to record seismic signals along many kilometres of fibre-optic cables, with a spatial resolution of a few metres, thereby creating large arrays of seismic receivers. We test this approach at an avalanche test site in the Valleé de la Sionne, in the Swiss Alps, using an existing 700 m long fibre-optic cable that is permanently installed underground for the purpose of data transfer of other, independent avalanche measurements.</span></p><p><span>During winter 2020/2021, we recorded numerous snow avalanches, including several which reached the valley bottom, travelling directly over the cable during runout. The DAS recordings show clear seismic signatures revealing individual flow surges and various phases/modes that may be associated with roll waves and avalanche arrest. We compare our observations to state-of-the-art radar and seismic measurements which ideally complement the DAS data.</span></p><p><span>Our initial analysis highlights the suitability of DAS-based monitoring and research for avalanches and other hazardous granular flows. Moreover, the clear detectability of avalanche signals using existing fibre-optic infrastructure of telecommunication networks opens the opportunity for unrivalled warning capabilities in Alpine environments.</span></p>

scholarly journals Deep Deconvolution for Traffic Analysis with Distributed Acoustic Sensing Data

2021 ◽  
Author(s):  
Martijn van den Ende ◽  
André Ferrari ◽  
Anthony Sladen ◽  
Cédric Richard
Keyword(s):  
Real Time ◽  
Temporal Resolution ◽  
Heavy Traffic ◽  
Simultaneous Detection ◽  
Detection Accuracy ◽  
Acoustic Sensing ◽  
Traffic Conditions ◽  
Real Time Traffic ◽  
Vibration Sensing ◽  
Distributed Acoustic Sensing

Distributed Acoustic Sensing (DAS) is a novel vibration sensing technology that can be employed to detect vehicles and to analyse traffic flows using existing telecommunication cables. DAS therefore has great potential in future "smart city" developments, such as real-time traffic incident detection. Though previous studies have considered vehicle detection under relatively light traffic conditions, in order for DAS to be a feasible technology in real-world scenarios, detection algorithms need to also perform robustly under heavy traffic conditions. In this study we investigate the potential of roadside DAS for the simultaneous detection and characterisation of the velocity of individual vehicles. To improve the temporal resolution and detection accuracy, we propose a self-supervised Deep Learning approach that deconvolves the characteristic car impulse response from the DAS data, which we refer to as a Deconvolution Auto-Encoder (DAE). We show that deconvolution of the DAS data with our DAE leads to better temporal resolution and detection performance than the original (non-deconvolved) data. We subsequently apply our DAE to a 24-hour traffic cycle, demonstrating the feasibility of our proposed method to process large volumes of DAS data, potentially in near-real time.

Spectral Analysis of Surface Waves with Simultaneous Fiber Optic Distributed Acoustic Sensing and Vertical Geophones

2018 ◽  
Vol 23 (2) ◽  
pp. 183-195 ◽  
Author(s):  
R. Daniel Costley ◽  
Gustavo Galan-Comas ◽  
Clay K. Kirkendall ◽  
Janet E. Simms ◽  
Kent K. Hathaway ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Fiber Optic ◽  
Seismic Signals ◽  
Near Surface ◽  
Acoustic Sensing ◽  
Optical Cable ◽  
Unconsolidated Sand ◽  
Distributed Acoustic Sensing ◽  
Surface Wave Method ◽  
Seismic Measurements

Experiments were performed comparing the response of fiber optic distributed acoustic sensing (DAS) to vertical geophones installed on the surface. The DAS consisted of an optical interrogator attached to an optical fiber. The fiber was part of an optical cable that was installed at depths of 0.3 to 0.76 meters in a coastal environment composed of unconsolidated sand. Seismic signals generated with an impact hammer were recorded simultaneously with both systems and directly compared. Experiments were performed with two different configurations, broadside and end-fire, between the source and the fiber optic cable. The seismic signals recorded in the two configurations and with the two sensor systems were processed identically using the Spectral Analysis of Surface Wave method. The results demonstrate the suitability and limitations of using DAS for near-surface seismic measurements.

Distributed acoustic sensing for near-surface seismic applications

2018 ◽  
Vol 144 (3) ◽  
pp. 1702-1703
Author(s):  
Richard D. Costley ◽  
Gustavo Galan-Comas ◽  
Kent K. Hathaway ◽  
Stephen A. Ketcham ◽  
Clay K. Kirkendall
Keyword(s):  
Near Surface ◽  
Acoustic Sensing ◽  
Distributed Acoustic Sensing ◽  
Seismic Applications

Distributed Acoustic Sensing – a new tool for seismic applications

First Break ◽  
2014 ◽  
Vol 32 (2010) ◽  
Author(s):  
Tom Parker ◽  
Sergey Shatalin ◽  
Mahmoud Farhadiroushan
Keyword(s):  
Acoustic Sensing ◽  
Distributed Acoustic Sensing ◽  
Seismic Applications

Distributed Acoustic Sensing - A New Tool for Seismic Applications

2012 ◽  
Author(s):  
T. Parker ◽  
S. V. Shatalin ◽  
M. Farhadiroushan ◽  
Y. I. Kamil ◽  
A. Gillies ◽  
...  
Keyword(s):  
Acoustic Sensing ◽  
Distributed Acoustic Sensing ◽  
Seismic Applications
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