A5025759293- Seismic Imaging and Inversion Techniques
- Seismic Waves and Analysis
- Seismology and Earthquake Studies
- Hydraulic Fracturing and Reservoir Analysis
- earthquake and tectonic studies
- Drilling and Well Engineering
- Geophysics and Sensor Technology
- Reservoir Engineering and Simulation Methods
- Hearing Loss and Rehabilitation
- Noise Effects and Management
- Geological Formations and Processes Exploration
- Advanced Fiber Optic Sensors
- Neuroscience and Music Perception
- Geophysical Methods and Applications
- Visual perception and processing mechanisms
- Cryospheric studies and observations
- Climate change and permafrost
- Rock Mechanics and Modeling
- Geological and Geochemical Analysis
- Landslides and related hazards
- Methane Hydrates and Related Phenomena
- Visual Attention and Saliency Detection
- High-pressure geophysics and materials
- Fault Detection and Control Systems
- Underwater Vehicles and Communication Systems
Norsar
2013-2024
Lund University
2023
Norwegian University of Science and Technology
2023
Institut des Sciences de la Terre
2019
University of Bristol
2010-2014
Los Alamos National Laboratory
2011
University of California, Riverside
1992-2000
Abstract During the past few years, distributed acoustic sensing (DAS) has become an invaluable tool for recording high-fidelity seismic wavefields with great spatiotemporal resolutions. However, considerable amount of data generated during DAS experiments limits their distribution broader scientific community. Such a bottleneck inherently slows down pursuit new discoveries in geosciences. Here, we introduce PubDAS—the first large-scale open-source repository where several datasets from...
ABSTRACT Monitoring of induced seismicity is gaining importance in a broad range industrial operations from hydrocarbon reservoirs to mining geothermal fields. Such passive seismic monitoring mainly aims at identifying fractures, which special interest for safety and productivity reasons. By analysing shear‐wave splitting it possible determine the anisotropy rock, may be caused by sedimentary layering and/or aligned turn offers insight into state stress reservoir. We present workflow...
Abstract Distributed Acoustic Sensing (DAS) involves the transmission of laser pulses along a fiber‐optic cable. These are backscattered at fiber inhomogeneities and again detected by same interrogator unit that emits pulses. Elastic deformation causes phase shifts in which converted to spatially averaged strain measurements, typically regular intervals. DAS systems provide potential employ array processing algorithms. However, there certain differences between conventional sensors. While...
Climate change is impacting the Arctic faster than anywhere else in world. As a response, ecosystems are rapidly changing. result, we can expect rapid shifts whale migration and habitat use concurrent with changes human patterns. In this context, responsible management conservation requires improved monitoring of presence movement over large ranges, at fine scales near-real-time compared to legacy tools. We demonstrate that could be enabled by Distributed Acoustic Sensing (DAS). DAS converts...
Snow avalanches pose a significant hazard in mountainous areas, especially when snowpacks block roads, either burying vehicles directly or exposing traffic to subsequent during active cycles.We have been monitoring avalanche activity along road stretches Northern Norway since 2022 using Distributed Acoustic Sensing (DAS),  a technology capable of theoretically covering spans up 170 km. Traditional detection methods often focus on only limited section stretch, making effective risk...
Several studies in the auditory-perception literature hint that listeners may be able to anticipate time of arrival an approaching sound source. Two experiments are reported which judged car on basis various portions its auditory signal. Subjects pressed a computer key indicate when would have just passed them, assuming maintained constant approach velocity. A number variables were tested including (a) between offset signal and virtual passage, (b) duration signal, (c) feedback concerning...
Hydraulic overpressure can induce fractures and increase permeability in a range of geological settings, including volcanological, glacial petroleum reservoirs. Here we consider an example induced hydraulic fracture stimulation tight-gas sandstone. Successful exploitation reservoirs requires networks, either naturally occurring, or generated through stimulation. The study seismic anisotropy provides means to infer properties such as the dominant orientation sets compliances. Shear wave...
Abstract During February 2023, a total of 32 individual distributed acoustic sensing (DAS) systems acted jointly as global seismic monitoring network. The aim this Global DAS Month campaign was to coordinate diverse network organizations, instruments, and file formats gain knowledge move toward the next generation earthquake networks. campaign, 156 earthquakes magnitude 5 or larger were reported by U.S. Geological Survey contributors shared data for 60 min after each event’s origin time....
A priori assessment of the expected location accuracy a sensor network is typically done through inversion traveltime spatial gradients. This approach assumes that applied algorithm successfully recovers global minimum objective function. However, even for accurate and precise phase picks, complexity in velocity model limitations layout may inhibit finding minimum. The algorithms end up local instead. We compare performance various functions minimization approaches. Although most analyzed...
Abstract From June to August 2021, we deployed a dense seismic nodal network across the Hengill geothermal area in southwest Iceland image and characterize faults high-temperature zones at high resolution. The comprised 498 geophone nodes spread northern Nesjavellir southern Hverahlíð fields was complemented by an existing permanent temporary backbone of total 44 short-period broadband stations. In addition, recorded distributed acoustic sensing data along two fiber optic telecommunication...
Abstract The literature on perception of sound source distance reveals a wide range listener accuracy. Most experiments have listeners perform unintuitive tasks, using unnatural sounds presented in impoverished acoustic environments. present implement an affordance paradigm for which judge the reachability natural, live familiar environment. Results reveal that are quite accurate judging whether is reachable and sensitive to advantage afforded by two vs. one degree freedom reaches. Further...
Changing stress conditions are well known to cause rupturing of rock. This is constrained on a small scale from laboratory experiments and inferred much larger tectonic earthquakes. Here, we present study rock fracturing induced by changes in state during block-caving operations an Australian mine. intermediate-scale provides further evidence the scalability processes involved thus helps link seismological observations. We analyse temporal evolution production cycle using analysis...
We have derived analytical formulations for the strain field produced by a moment tensor source in homogeneous isotropic media. Such are important microseismic projects that increasingly monitored with fiber-optic distributed acoustic sensing (DAS) systems. find spatial derivative of displacement produces new terms proportional to [Formula: see text] text]. In viscoelastic media, also an additional far-field term is scaled frequency-dependent factor. When comparing full wavefield synthetic...
We have analyzed seismic anisotropy using shear-wave-splitting measurements made on microseismic events recorded during a hydraulic fracture experiment in tight gas reservoir Carthage, east Texas. Microseismic were two downhole arrays of three-component sensors, the geometry which provided good ray coverage for analysis. A total 16,633 seismograms from 888 located yielded 1545 well-constrained measurements. Manual analysis splitting subset this data set reveals temporal changes fracturing....
The success of a distributed acoustic sensing (DAS) survey depends on strain energy impeding at favorable angles most sections the fiber. Although constrained to path wellbore, there are various design parameters that can influence recorded DAS amplitude. We present here method model performance installations. use precise raypath modeling in complex velocity models determine ray incidence and show variations between different wrapping detection thresholds. then propose way evaluate...
An automatic analysis code, Anisomat+, was developed, tested and improved to calculate anisotropic parameters: fast polarization direction delay time. Anisomat+ applied on data coming from three zones of the Apennines in Italy. For each area, parameters have been interpreted determine fracture stress field taking into account geological structural settings. It recognized that averages directions are NW-SE–oriented at all sites, agreement with orientation maximum horizontal as well strike...
ABSTRACT Downhole monitoring with fibre‐optic Distributed Acoustic Sensing (DAS) systems offers unprecedented spatial resolution. At the same time, costs are reduced since repeated wireline surveys can be replaced by permanent installation of comparatively cheap fibre cables. However, single component nature data requires novel approaches when designing a project such as cross‐well seismics. example shallow CO 2 injection test site in Svelvik, Norway, we model evolution velocity changes...
ABSTRACT Fractures and faults within a reservoir can provide important pathways for the movement of fluids. Understanding character properties these features on range length scales be vital efficient exploitation natural resources, whether it enhanced oil gas recovery, safe storage CO 2 , or better geothermal heat. The monitoring microseismicity illuminates active faults, but events also used to characterize fracture networks through measurements seismic anisotropy. In this study we use...
Abstract Over the past decade, microsesimic monitoring has become approach most often used to gain an in-situ understanding of rock's response during hydraulic fracture stimulations. From initial performed in Barnett Shale currently being carried out for example Horn River and Marcellus formations, we review evolution microseismic from data collection (single versus multi-well array configurations, utilization long lateral stimulation wells), analysis incorporation parameters constrain...
Abstract A common challenge in acoustic meteoroid signal analyses is to discriminate whether the observed wavefield can be better described by line-source or point-source models. This typically arises from a sparse availability of observations. In this work, we present an outstanding record ground-coupled waves local large-N seismic and distributed sensing (DAS) observations Iceland. Our complete data set includes additional regional stations located within 300 km meteoroid’s trajectory. The...
To achieve high recovery rates, modern-day production management can benefit from not only snapshot images of the state reservoir at regular time intervals, but also continuous monitoring dynamic processes induced by pressure changes and fluid movement during production. Production using time-lapse 4D snapshots is reactive, i.e., adjustments addressing sweep efficiency or integrity be instigated once next image available after acquisition, processing interpretation, often years later. For a...
Determining accurate microseismic event locations at the Groningen gas field in Netherlands has important implications for understanding ongoing induced seismicity and its associated seismic hazard. To improve depth constraint of microseismicity, downhole monitoring arrays have been deployed central region field. The observed these receivers is characterized by significant complexity waveforms, due to high velocity contrasts that exist acquisition geometry. Reliably identifying picking...
This research examined accuracy in an auditory time-to-arrival task when performance feedback was first provided to listeners and subsequently withdrawn. Listeners made judgments about the time arrival of approaching car based on various portions event. participated 3 experimental sessions consecutive days. The group received no during session, second final session. When withdrawn, higher level attained training retained. We discuss results terms theories perception importance stimulus naturalness.