scholarly journals Deployment recommendation for Distributed Acoustic Sensing at the surface

2020 ◽  
Author(s):  
Pascal Edme ◽  
Patrick Paitz ◽  
Ana Nap ◽  
Francois Martin ◽  
Valentin Metraux ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Reservoir Characterization ◽  
Low Cost ◽  
Broad Band ◽  
Minor Amount ◽  
Acoustic Sensing ◽  
Reflection Seismic ◽  
Order Of Magnitude ◽  
Distributed Acoustic Sensing ◽  
A Minor

<p>Distributed Acoustic Sensing (DAS) is an optical interferometry based ground motion sensing technology which has the potential to revolutionize the field of seismological data acquisition. It offers the possibility to replace very large numbers of cost-intensive conventional point sensors (seismometers or geophones) by interrogating a single low-cost optic-fibre cable. Being unaffected by spatial aliasing, DAS is emerging as a potential next-generation broad-band geo-hazard (e.g. earthquakes, landslides) and reservoir (e.g. geothermal, oil and gas) seismic monitoring tool.</p><p>For borehole applications, with the cable appropriately coupled with the casing, the reliability and benefit of DAS-based VSP acquisition is now widely recognized. At the surface however, for reflection seismic for example, the adequate deployment procedure is less well documented, and experiments are performed with cables sometimes directly deployed on the surface, or sometimes buried quite deep (e.g. one meter) in the ground. Especially for non-permanent monitoring, the trenching effort can be substantial or unaffordable due to logistic or permitting issues. One may wonder if such an effort with its associated cost is actually beneficial.</p><p>We present here the results of a surface-based active seismic experiment conducted in Switzerland in the context of a geothermal reservoir characterization project with “co-located” stretches of cable deployed at different depths. The repeatability of the DAS measurements is quantified and compared to a dense array of conventional multi-component geophones. The study shows that deeply (50 cm) deployed cables offers only marginal data quality improvements compared to very shallow (2 cm) cables. In contrast, the parts of the cable directly laid down at the surface exhibit much larger noise levels and very poor repeatability (approximately one order of magnitude larger NRMS). Our study suggests that only a minor amount of elastic material covering the cable is enough to provide a good coupling and that a modest machine to conveniently perform such a shallow deployment would greatly benefit the growing DAS user community.</p>

Distributed Acoustic Sensing System for oil and gas exploration

2019 ◽  
Author(s):  
Tuanwei Xu ◽  
Shengwen Feng ◽  
Kaiheng Yang ◽  
Lilong Ma ◽  
Fang Li
Keyword(s):  
Oil And Gas ◽  
Acoustic Sensing ◽  
Oil And Gas Exploration ◽  
Sensing System ◽  
Distributed Acoustic Sensing

Dual wavefields from distributed acoustic sensing measurements

Geophysics ◽  
2016 ◽  
Vol 81 (6) ◽  
pp. D585-D597 ◽  
Author(s):  
Flavio Poletto ◽  
Daniel Finfer ◽  
Piero Corubolo ◽  
Biancamaria Farina
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Axial Direction ◽  
Borehole Data ◽  
Directional Information ◽  
Native Strain ◽  
Acoustic Sensing ◽  
Wavefield Separation ◽  
Seismic Acquisition ◽  
Distributed Acoustic Sensing

Distributed acoustic sensing (DAS) using fiber optic cables is an emerging seismic acquisition technology for the oil and gas industry, geothermal resource exploration, and underground fluid-storage monitoring. This technology offers the advantage of improving seismic acquisition by enabling massive arrays for monitoring of seismic wavefields at reduced cost with respect to conventional methods. In general, it is accepted that this method provides acoustic signals comparable with conventional seismic data, however, without the multicomponent directional information typical of geophones. We have developed a modified data extraction method and found that, as a result of the dense spatial distribution of recording points along the optic cable, DAS can provide two linked wavefield components in the axial direction, even when using a single 1D cable line. These signal pairs consist of dual components that are related to native strain rate (or strain) and particle acceleration (or velocity) fields at a given recording location. These dual signals are easily usable for wavefield separation purposes simply performing a trace-by-trace combination by appropriate scaling coefficient. The analysis performed with borehole data from linear and helically wound cables demonstrates the effectiveness of polarity recovery and dual-wavefield separation. We show real examples in which the data can be combined to provide separation of up- and downgoing wavefields. The ratio of the dual components provides information on local slowness properties in the formation.

Comparison of geophone and surface-deployed distributed acoustic sensing seismic data

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. A25-A29 ◽  
Author(s):  
Kyle T. Spikes ◽  
Nicola Tisato ◽  
Thomas E. Hess ◽  
John W. Holt
Keyword(s):  
Seismic Data ◽  
Fiber Optic ◽  
Single Strand ◽  
Near Surface ◽  
Acoustic Sensing ◽  
Surface Reflection ◽  
Reflection Seismic ◽  
Geophysical Surveys ◽  
Distributed Acoustic Sensing ◽  
High Level

The rapid and nonintrusive deployment of seismic sensors for near-surface geophysical surveys is of interest to make data acquisition efficient and to operate in a wide variety of environmental and surface-terrain conditions. We have developed and compared near-surface data acquired using a traditional vertical geophone array with data acquired using three different fiber optic cables operating in a distributed acoustic sensing (DAS) configuration. The DAS cables included a helically wrapped fiber, a nearly bare single-strand fiber, and an armored single-strand fiber. These three cables are draped on the ground alongside the geophones. Equivalent processing on colocated shot gathers resulted in a high level of similarity, in particular for reflection energy acquired through geophones and the helically wrapped cable. The single-strand fibers indicate much less similarity. Frequency content, however, differs in the raw and processed gathers from the geophones and the fiber optic cables. Nonetheless, results demonstrate that DAS technology can be used successfully to acquire near-surface reflection seismic data by deploying the cables on the surface. Potential applications for this technology include rapid deployment of active and/or passive arrays for near-surface geophysical characterization for various applications at different scales.

Illuminating seafloor faults and ocean dynamics with dark fiber distributed acoustic sensing

Science ◽  
2019 ◽  
Vol 366 (6469) ◽  
pp. 1103-1107 ◽  
Author(s):  
Nathaniel J. Lindsey ◽  
T. Craig Dawe ◽  
Jonathan B. Ajo-Franklin
Keyword(s):  
Ocean Dynamics ◽  
Sea State ◽  
Acoustic Sensing ◽  
Ocean Surface Waves ◽  
Sensing Technology ◽  
Northern Pacific ◽  
Distributed Acoustic Sensing ◽  
A Minor ◽  
Array Recordings

Distributed fiber-optic sensing technology coupled to existing subsea cables (dark fiber) allows observation of ocean and solid earth phenomena. We used an optical fiber from the cable supporting the Monterey Accelerated Research System during a 4-day maintenance period with a distributed acoustic sensing (DAS) instrument operating onshore, creating a ~10,000-component, 20-kilometer-long seismic array. Recordings of a minor earthquake wavefield identified multiple submarine fault zones. Ambient noise was dominated by shoaling ocean surface waves but also contained observations of in situ secondary microseism generation, post–low-tide bores, storm-induced sediment transport, infragravity waves, and breaking internal waves. DAS amplitudes in the microseism band tracked sea-state dynamics during a storm cycle in the northern Pacific. These observations highlight this method’s potential for marine geophysics.

scholarly journals Distributed Acoustic Sensing Using Chirped-Pulse Phase-Sensitive OTDR Technology

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4368 ◽  
Author(s):  
María R. Fernández-Ruiz ◽  
Luis Costa ◽  
Hugo F. Martins
Keyword(s):  
Direct Detection ◽  
Low Cost ◽  
High Sensitivity ◽  
Coherent Detection ◽  
Simple Method ◽  
Acoustic Sensing ◽  
Chirped Pulse ◽  
Distributed Sensor ◽  
Phase Sensitive ◽  
Distributed Acoustic Sensing

In 2016, a novel interrogation technique for phase-sensitive (Φ)OTDR was mathematically formalized and experimentally demonstrated, based on the use of a chirped-pulse as a probe, in an otherwise direct-detection-based standard setup: chirped-pulse (CP-)ΦOTDR. Despite its short lifetime, this methodology has now become a reference for distributed acoustic sensing (DAS) due to its valuable advantages with respect to conventional (i.e., coherent-detection or frequency sweeping-based) interrogation strategies. Presenting intrinsic immunity to fading points and using direct detection, CP-ΦOTDR presents reliable high sensitivity measurements while keeping the cost and complexity of the setup bounded. Numerous technique analyses and contributions to study/improve its performance have been recently published, leading to a solid, highly competitive and extraordinarily simple method for distributed fibre sensing. The interesting sensing features achieved in these last years CP-ΦOTDR have motivated the use of this technology in diverse applications, such as seismology or civil engineering (monitoring of pipelines, train rails, etc.). Besides, new areas of application of this distributed sensor have been explored, based on distributed chemical (refractive index) and temperature-based transducer sensors. In this review, the principle of operation of CP-ΦOTDR is revisited, highlighting the particular performance characteristics of the technique and offering a comparison with alternative distributed sensing methods (with focus on coherent-detection-based ΦOTDR). The sensor is also characterized for operation in up to 100 km with a low cost-setup, showing performances close to the attainable limits for a given set of signal parameters [≈tens-hundreds of pe/sqrt(Hz)]. The areas of application of this sensing technology employed so far are briefly outlined in order to frame the technology.

scholarly journals High Temperature Adsorption of SO2 on Mixed Oxides Derived from CaAl Hydrotalcite-Like Compounds

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 325
Author(s):  
Hailin Wang ◽  
Run Hao ◽  
Meiping Gao ◽  
Zhongshen Zhang ◽  
Zhengping Hao
Keyword(s):  
High Temperature ◽  
Air Pollutants ◽  
High Efficiency ◽  
Mixed Oxides ◽  
Low Cost ◽  
Minor Amount ◽  
So2 Adsorption ◽  
Temperature Programmed ◽  
Calcination Method ◽  
A Minor

SO2 which is usually emitted at high temperature is one of the most important air pollutants. It is of great significance to develop high temperature SO2 adsorbent with high efficiency and low cost. In this work, a series of hydrotalcite-like compound-derived CaAlO and CaXAlO(X = Ce, Co) were prepared by coprecipitation and calcination method, and were employed as adsorbents for SO2 adsorption at high temperature (700 °C). The structure and surface properties of these adsorbents were characterized by XRD, Brunauer–Emmett–Teller (BET), Derivative thermogravimetric analysis (DTG) and CO2-TPD (temperature programmed desorption) measurement. Addition of a minor amount of Ce, Co (5 wt%) could significantly increase the number of weak alkalinity sites. CaO in CaCeAlO showed the best SO2 adsorption capacity of 1.34 g/g, which is two times higher than that of CaO in CaAlO (0.58 g/g).

scholarly journals Current and Future Applications of Distributed Acoustic Sensing as a New Reservoir Geophysics Tool

2015 ◽  
Vol 8 (1) ◽  
pp. 272-281 ◽  
Author(s):  
Meng Li ◽  
Hua Wang ◽  
Guo Tao
Keyword(s):  
Low Cost ◽  
Seismic Profile ◽  
Precise Determination ◽  
No Production ◽  
Acoustic Sensing ◽  
Seismic Detection ◽  
Exploration And Production ◽  
Distributed Acoustic Sensing ◽  
Rapid Processing

Distributed Acoustic Sensing (DAS) is a novel technique with low cost, no production deferment, complete coverage and repeatability for seismic data acquisition in vertical seismic profile (VSP), hydraulic fracturing monitoring, well and reservoir surveillance and micro-seismic detection. In this paper, we give a review on the field applications of DAS and the corresponding pre-processing methods as well as the limitations that hinder its further applications in exploration and production. Finally, future developments for DAS are discussed, including the enhancement of S/N ratio, precise determination of receiver channels in depth, rapid processing of massive data and integrated interpretation of multi-mode optical fiber.

Luminescence Properties of Europium-Doped Yttrium Oxides Derived from Their Dodecylsulfate-Templated Mesostructure and Nanotube Forms

2003 ◽  
Vol 775 ◽  
Author(s):  
Tsuyoshi Kijima ◽  
Kenichi Iwanaga ◽  
Tomomi Hamasuna ◽  
Shinji Mohri ◽  
Mitsunori Yada ◽  
...  
Keyword(s):  
Room Temperature ◽  
Broad Band ◽  
Concentration Quenching ◽  
Precipitation Method ◽  
Homogeneous Precipitation ◽  
Bulk Materials ◽  
Main Band ◽  
Homogeneous Precipitation Method ◽  
Order Of Magnitude ◽  
Weak Luminescence

AbstractEuropium-doped hexagonal-mesostructured and nanotubular yttrium oxides templated by dodecylsulfate species as well as surfactant free bulk oxides were synthesized by the homogeneous precipitation method. All the as grown nanostructured or bulk materials with amorphous or poorly crystalline frameworks showed weak luminescence bands at room temperature. On calcination at 1000°C these materials were converted into highly crystalline yttrium oxides, resulting in a total increase in intensity of all the bands by one order of magnitude. In the hexagonal-mesostructured system, the main band due to the 5D0-7F2 transition for the calcined phases showed a sharp but asymmetrical multiplet splitting indicating multiple Eu sites. Concentration quenching was found at a Eu content of 3 mol% or above for these phases. In contrast, the main emission for the calcined solids in the nanotubular system occurred as poorly resolved broad band and the intensity of the main band at higher Eu content was significantly enhanced compared with those for the other two systems.

scholarly journals CrossGR

2021 ◽  
Vol 5 (1) ◽  
pp. 1-23
Author(s):  
Xinyi Li ◽  
Liqiong Chang ◽  
Fangfang Song ◽  
Ju Wang ◽  
Xiaojiang Chen ◽  
...  
Keyword(s):  
Gesture Recognition ◽  
Low Cost ◽  
User Involvement ◽  
Recognition System ◽  
Training Data ◽  
Generative Adversarial Network ◽  
Adversarial Network ◽  
Target User ◽  
Order Of Magnitude ◽  
Training Examples

This paper focuses on a fundamental question in Wi-Fi-based gesture recognition: "Can we use the knowledge learned from some users to perform gesture recognition for others?". This problem is also known as cross-target recognition. It arises in many practical deployments of Wi-Fi-based gesture recognition where it is prohibitively expensive to collect training data from every single user. We present CrossGR, a low-cost cross-target gesture recognition system. As a departure from existing approaches, CrossGR does not require prior knowledge (such as who is currently performing a gesture) of the target user. Instead, CrossGR employs a deep neural network to extract user-agnostic but gesture-related Wi-Fi signal characteristics to perform gesture recognition. To provide sufficient training data to build an effective deep learning model, CrossGR employs a generative adversarial network to automatically generate many synthetic training data from a small set of real-world examples collected from a small number of users. Such a strategy allows CrossGR to minimize the user involvement and the associated cost in collecting training examples for building an accurate gesture recognition system. We evaluate CrossGR by applying it to perform gesture recognition across 10 users and 15 gestures. Experimental results show that CrossGR achieves an accuracy of over 82.6% (up to 99.75%). We demonstrate that CrossGR delivers comparable recognition accuracy, but uses an order of magnitude less training samples collected from the end-users when compared to state-of-the-art recognition systems.

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