A three-component optical sensor for borehole seismic applications

2021 ◽  
Vol 40 (6) ◽  
pp. 447-453
Author(s):  
Jakob B. U. Haldorsen ◽  
Caleb Christensen ◽  
D. Rick Metzbower ◽  
Audrius Berzanskis ◽  
Jorge Machnizh ◽  
...  
Keyword(s):  
High Temperatures ◽  
Optical Sensor ◽  
Field Data ◽  
Sensor Array ◽  
Fiber Optic ◽  
Hybrid Fiber ◽  
Receiver Array ◽  
Operational Temperature ◽  
Distributed Acoustic Sensing ◽  
Borehole Seismic

We describe a new optical three-component accelerometer for borehole applications. Field data acquired in early 2020 in a fiber-optic-instrumented well in Houston, Texas, show that the new optical accelerometer is a viable borehole seismic sensor, measuring signals at frequencies from subhertz to hundreds of hertz. It is argued that an array of these sensors could be used to complement distributed acoustic sensing (DAS) technology to compensate for the inability of DAS sensors to measure wavefield polarization. This hybrid fiber-optic receiver array would be a fully optical wide-bandwidth sensor array without any electronics in the well. With a maximum operational temperature expected to exceed 200°C, this array would not be affected significantly by possible high temperatures in the near-reservoir section of the well.

scholarly journals Investigation of the Effects of Surrounding Media on the Distributed Acoustic Sensing of Helically-Wound Fiber-Optic Cable with Application to the New Afton Deposit, British Columbia

2020 ◽  
Author(s):  
Sepidehalsadat Hendi ◽  
Mostafa Gorjian ◽  
Gilles Bellefleur ◽  
Christopher D. Hawkes ◽  
Don White
Keyword(s):  
British Columbia ◽  
Numerical Modeling ◽  
Analytical Model ◽  
Field Data ◽  
Fiber Optic ◽  
Incident Angle ◽  
Acoustic Sensing ◽  
Distributed Acoustic Sensing ◽  
Straight Fiber

Abstract. Fiber optic sensing technology has recently become popular for oil and gas, mining, geotechnical engineering, and hydrogeology applications. With a successful track record in many applications, distributed acoustic sensing using straight fiber optic cables has become a method of choice for seismic studies. However, distributed acoustic sensing using straight fiber optic cables is not able to detect off-axial strain, hence a helically wound cable design was introduced to overcome this limitation. The helically wound cable field data in New Afton deposit showed that the quality of the data is tightly dependent on the incident angle (the angle between the ray and normal vector of the surface) and surrounding media. We introduce a new analytical two-dimensional approach to determine the dynamic strain of a helically wound cable in terms of incident angle in response to elastic plane waves propagating through multilayered media. The method can be used to quickly and efficiently assess the effects of various materials surrounding a helically wound cable. Results from the proposed analytical model are compared with results from numerical modeling obtained with COMSOL Multiphysics, for scenarios corresponding to a real installation of helically wound cable deployed underground at the New Afton mine in British Columbia, Canada. Results from the analytical model are consistent with numerical modeling results. Our modeling results demonstrate the effects of cement quality, and casing installment on the quality of the helically-wound cable response. Numerical modeling results and field data suggest that, even if reasonably effective coupling achieved, the soft nature of the rocks in these intervals would result in low fiber strains for the HWC. The proposed numerical modeling workflow would be applied for more complicated scenarios (e.g., non-linear material constitutive behaviour, and the effects of pore fluids). The results of this paper can be used as a guideline for analyzing the effect of surrounding media and incident angle on the response of helically wound cable, optimizing the installation of helically wound cable in various conditions, and to validate boundary conditions of 3-D numerical model built for analyzing complex scenarios.

Field testing a three-component fiber-optic borehole seismic sensor array

2014 ◽  
Author(s):  
Martin Karrenbach* ◽  
Victor Yartsev ◽  
Melissa Emuh ◽  
Ekaterina Hardin ◽  
Lisa LaFlame ◽  
...  
Keyword(s):  
Sensor Array ◽  
Fiber Optic ◽  
Field Testing ◽  
Borehole Seismic

Vibration Control of a Flexible Link Manipulator Using an Array of Fiber-Optic Curvature Sensors and Piezoelectric Actuators

2007 ◽  
Author(s):  
Kerem Gurses ◽  
Bradley J. Buckman ◽  
Edward J. Park
Keyword(s):  
Motion Control ◽  
Sensor Array ◽  
Fiber Optic ◽  
Element Model ◽  
Flexible Manipulator ◽  
Flexible Link ◽  
Velocity Feedback ◽  
Lyapunov Approach ◽  
Single Link ◽  
Actuator Control

This paper presents a novel feedback sensing approach for actively suppressing vibrations of a single-link flexible manipulator. Slewing of the flexible link by a rotating hub induces vibrations in the link that persist long after the hub stops rotating. These vibrations are suppressed through a combined scheme of PD-based hub motion control and proposed piezoelectric (PZT) actuator control, which is a composite linear and velocity feedback controller. Lyapunov approach was used to synthesize the controller based on a finite element model of the system. Its realization was possible due to the availability of both linear and angular velocity feedback provided by a unique, commercially-available fiber optic curvature sensor array, called ShapeTape™. It is comprised of an array of fiber optic curvature sensors, laminated on a long, thin ribbon tape, geometrically arranged in such a way that, when it is embedded into the flexible link, the bend and twist of the link’s centerline can be measured. Experimental results show the effectiveness of the proposed approach.

Optoelectronics Technology Consortium 32-Channel Parallel Fiber Optic Transmitter/Receiver Array Testbed

1996 ◽  
Vol 7 (12) ◽  
pp. 33
Author(s):  
Casimer DeCusatis ◽  
Terrence Quinn ◽  
Petar Pepeljugoski ◽  
Daniel Kuchta ◽  
John Crow
Keyword(s):  
Fiber Optic ◽  
Parallel Fiber ◽  
Receiver Array

Capturing Glacier-Wide Cryoseismicity With Distributed Acoustic Sensing

2021 ◽  
Author(s):  
Fabian Walter ◽  
Patrick Paitz ◽  
Andreas Fichtner ◽  
Pascal Edme ◽  
Wojciech Gajek ◽  
...  
Keyword(s):  
Fiber Optic ◽  
Flow Line ◽  
Ground Deformation ◽  
Sensor Coverage ◽  
Mountain Glacier ◽  
Acoustic Sensing ◽  
Alpine Glacier ◽  
Glacier Ice ◽  
Distributed Acoustic Sensing ◽  
Ice Sheet Dynamics

<p>Over the past 1-2 decades, seismological measurements have provided new and unique insights into glacier and ice sheet dynamics. At the same time, sensor coverage is typically limited in harsh glacial environments with littile or no access. Turning kilometer-long fiber optic cables placed on the Earth’s surface into thousands of seismic sensors, Distributed Acoustic Sensing (DAS) may overcome the limitation of sensor coverage in the cryosphere.</p><p>First DAS applications on the Greenland and Antarctic ice sheets and on Alpine glacier ice have highlighted the technique’s superiority. Signals of natural and man-made seismic sources can be resolved with an unrivaled level of detail. This offers glaciologists new perspectives to interpret their seismograms in terms of ice structure, basal boundary conditions and source locations. However, previous studies employed only relatively small network scales with a point-like borehole deployment or < 1 km cable aperture at the ice surface.</p><p>Here we present a DAS installation, which aims to cover the majority of an Alpine glacier catchment: For one month in summer 2020 we deployed a 9 km long fiber optic cable on Rhonegletscher, Switzerland, and gathered continuous DAS data. The cable followed the glacier’s central flow line starting in the lowest kilometer of the ablation zone and extending well into the accumulation area. Even for a relatively small mountain glacier such as Rhonegletscher, cable deployment was a considerable logistical challenge. However, initial data analysis illustrates the benefit compared to conventional cryoseismological instrumentation: DAS measurements capture ground deformation over many octaves, including typical high-frequency englacial sources (10s to 100s of Hz) related to crevasse formation and basal sliding as well as long period signals (10s to 100s of seconds) of ice deformation. Depending on the presence of a snow cover, DAS records contain strong environmental noise (wind, meltwater flow, precipitation) and thus exhibit lower signal-to-noise ratios compared to conventional on-ice seismic installations. This is nevertheless outweighed by the advantage of monitoring ground unrest and ice deformation of nearly an entire glacier. We present a first compilation of signal and noise records and discuss future directions to leverage DAS data sets in glaciological research.</p><p> </p><p> </p><p> </p>

Seismic Observations of Four Thunderstorms Using an Underground Fiber-Optic Array

2021 ◽  
Author(s):  
Samuel Hone ◽  
Tieyuan Zhu
Keyword(s):  
Fiber Optic ◽  
Seismic Velocity ◽  
Ground Surface ◽  
State College ◽  
Full Waveform ◽  
Penn State ◽  
Distributed Acoustic Sensing ◽  
Back Azimuth ◽  
Optic Array ◽  
The Waves

Abstract Thunderstorms are a common atmospheric phenomenon that cause abundant acoustic disturbances, which can interact with the ground surface, creating a link between atmospheric and solid Earth processes. This article reports seismological observations of four thunderstorms through the spring and summer of 2019, as recorded by the distributed acoustic sensing fiber-optic array (4.9 km) on the Penn State campus in State College, Pennsylvania. With a dense sensor array in the local region, we are able to construct the seismic full waveform response of the thunderstorm events (hereafter referred to as thunderquakes) and track the wave propagation across the array. We use a time-domain grid search to obtain the back azimuth and slowness of the waves, and a modified Geiger’s method to pinpoint source locations of the thunderquakes. Correlated with the time of the recorded signal, this data allows reconstruction of thunderstorm movement as well as offering measurements of the seismic velocity.

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