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Collaborating Authors
Results
Combined onshore and offshore wide scale seismic data acquisition and imaging for CCS exploration in Havns, Denmark
Zappal, Samuel (Uppsala University) | Malehmir, Alireza (Uppsala University) | Papadopoulou, Myrto (Uppsala University) | Gregersen, Ulrik (Geological Survey of Denmark and Greenland (GEUS)) | Funck, Thomas (Geological Survey of Denmark and Greenland (GEUS)) | Clausen, Ole R. (Aarhus University) | Nrmark, Egon (Aarhus University)
Strong global actions for climate change include carbon capture and storage (CCS) as a feasible solution to reach carbon neutrality and raise opportunities for detailed subsurface investigations. An acquisition set-up designed for onshore-offshore zones was maximized for a wide-scale high-resolution structural imaging and implemented to cover a domal structure of interest for CCS utilization close to the town of Havns�nmark). Challenges of a combined acquisition and processing of land and marine multi-sensor data along a 42 km seismic profile are analyzed, suggested solutions are applied and limitations discussed. On the onshore side, a nodal array and a seismic landstreamer system were simultaneously used while along the transition zone a marine seismic streamer and ocean bottom seismometers were added to record the seismic response generated by two seismic vibrator sources. The adopted sensing domains (velocity, acceleration, and pressure) were studied and different processing steps were evaluated to enable their processing and subsequent data set merging. Results suggest as a best approach, a separate prestack processing of the different data sets and the computation of new geometries and new surface-consistent residual static correction after their merging. The data acquired in the transition zone illuminate for the first time the subsurface geology of the region delineating an expected domal closure. The final seismic section shows high continuity of the reflections with good resolution along the entire profile, identifying the main reservoir structure and the surrounding areas, which are important to ensure the reservoir integrity and safe exploitation over longer time scales. Shallow and deep reflections are consistent with the stratigraphic column from a well-log near the profile. The presented study shows a comprehensive workflow for processing such a multi-sensor data set in onshore and transition zone settings.
- Europe > Denmark (1.00)
- North America > United States > Illinois > Madison County (0.24)
- Research Report > New Finding (0.66)
- Research Report > Experimental Study (0.48)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.46)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition > Marine Seismic Acquisition (1.00)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition > Land Seismic Acquisition (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
- Europe > Norway > North Sea > Central North Sea > Central Graben > PL 019 > Gassum Formation (0.99)
- Oceania > Australia > Victoria > Bass Strait > Gippsland Basin (0.89)
- North America > Canada > Alberta > Border Field > Anglo Pacific Et Al Czar 11-33-41-5 Well (0.89)
- (5 more...)
ABSTRACT Rockfalls pose a threat to human infrastructure below cliffs. Sensitive and reactive alarm systems are needed for rail traffic safety because small rockfalls () impacting the railroad may cause train derailment. We develop a seismic processing workflow for rockfall early warning, powered by dense arrays deployed along the track. The method is evaluated by dropping rocks from a controlled height and triggering rockfalls on a cliff. We indicate that seismic arrays are highly sensitive to small impacts and are able to detect them, locate them, and estimate their magnitude. The detection can be performed in near real-time with a simple algorithm because small-scale rockfalls produce impulsive waveforms near the impact. Precise localization with matched field processing is able to track the trajectory of a rockfall. Impacts against the steel rails may be recognized by their source signature. The seismic amplitudes are related to the rockfall volume by the Hertz law, which may be used to estimate their volume. These results indicate the potential of seismic-driven near real-time rockfall alarm systems.
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Passive Seismic Surveying (0.69)
Abstract We assembled a low-cost drone-based magnetic surveying system from a Scintrex ENVI PRO proton magnetometer and DJI Matrice 600 Pro drone. We used this system to locate an old exploration well in eastern Nebraska that is now out of sight in the middle of a cornfield. Because the well was drilled nearly five decades ago, before the advent of GPS, its coordinates are inaccurate. We used the magnetic signature of the well's casing to locate it. Our survey shows the pronounced magnetic anomaly approximately 35 m to the southwest of the well's database coordinates. The results of our survey show that our drone-based magnetic system provides a fast and efficient way to record magnetic data.
Abstract The U.S. Department of Energy's National Energy Technology Laboratory (NETL) conducted research to field test the ability of airborne methods to locate existing wells quickly and accurately with minimal landowner impact. Helicopter surveys with two boom-mounted atomic magnetometers were used to locate wells at two oil fields in Wyoming and at four large oil and gas producing areas in Pennsylvania. At the two Wyoming oil fields, the helicopter magnetic survey identified 91%–96% of the wells located by exhaustive ground search. A different validation was used for the thickly forested Pennsylvania flight areas where well picks from the helicopter magnetic survey were used to direct the ground search to potential well locations for verification. The number and location of verified well locations were then compared to well records in the state database. For the oldest wells (circa 1860–1880), the number of wells in the state database exceeded the number of wells identified by the helicopter magnetic survey because many early wells had wood casing (nonmagnetic). For wells drilled between 1880 and 1950, the helicopter surveys found two to five undocumented wells for each well in the state database. The best results were achieved at a gas storage field where wells were drilled after 1950. There, 98% of the wells located by the helicopter magnetic survey were documented. In 2017, NETL used an atomic magnetometer on a small uncrewed aircraft system (sUAS) to refly an area previously flown with a crewed helicopter. The magnetic map from the sUAS survey was equal to that obtained with a crewed helicopter. High-resolution topographic images developed from sUAS LiDAR surveys were found to be helpful in locating very early wells with wood casing. When the wood casing decayed, soil subsided into the well void, leaving a circular depression that is easily recognized in high-resolution LiDAR imagery.
- North America > United States > Pennsylvania (1.00)
- North America > United States > Oklahoma > Osage County (0.29)
- North America > United States > Wyoming > Natrona County (0.29)
- Overview (0.46)
- Questionnaire & Opinion Survey (0.34)
- Transportation > Air (1.00)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Wyoming > Powder River Basin > Salt Creek Field (0.99)
- North America > United States > Wyoming > Powder River Basin > NPR-3 > Teapot Dome Field > Wall Creek Formation (0.99)
- North America > United States > Wyoming > Powder River Basin > NPR-3 > Teapot Dome Field > Tensleep Formation (0.99)
- (11 more...)
ABSTRACT Distributed acoustic sensing (DAS) is an emerging technology gaining acceptance in a variety of seismological applications. We systematically analyze the adaptability and usefulness of horizontal DAS deployments for near-surface geophysical applications, such as surface wave inversion, diving wave tomography, and passive subsurface source location. We find that, in accordance with previous studies, DAS data are generally similar to traditional sensors and can be successfully used independently. Nonetheless, DAS data suffer from inherent limitations due to the design of the optical measurement system. Among others, we identify the gauge length, measurement directivity, and saturation at near offsets as the primary limiting factors. When operating in low-velocity environments and a standard 10 m gauge length, surface wave analysis may be constrained to the usage of low frequencies due to the wavenumber filtering effect of the gauge length. The measurement directivity generally prohibits applications that are based on upgoing P-wave energy, such as near-offset diving wave tomography. In addition, saturation at near offsets prevents reliable diving wave traveltime picking. As a consequence of these limitations, the ultrashallow resolution achievable with DAS data is poor. Source directivity also strongly limits passive source location resolution. Whereas some of the limitations can be alleviated through an optimal choice of optical parameters at the interrogator level, we mostly rely on adapted field acquisition and data processing workflows that use the undisturbed portion of the recorded signal. Eventually, the spatiotemporal resolution and relative ease of long-term deployments turn DAS into a worthwhile option for monitoring and time-lapse scenarios, or when operating in urban environments over existing infrastructure.
Rockfalls pose a threat to human infrastructure below cliffs. Sensitive and reactive alarm systems are needed for rail traffic safety, as small rockfalls ( 0.01 m) impacting the rail may cause train derailment. We propose to use seismic processing for rockfall early warning, powered by dense arrays deployed along the track. The method is evaluated by dropping rocks from a controlled height and triggering rockfalls on a cliff. We show that seismic arrays are highly sensitive to small impacts, and are able to detect them, locate them, and estimate their magnitude. The detection can be performed in near real-time with a simple algorithm, as small-scale rockfalls produce impulsive waveforms near the impact. Precise localization with Matched Field Processing is able to track the trajectory of a rockfall. Impacts against a rail might be recognized by their source signature. The seismic amplitudes are related to the rockfall volume by the Hertz law, which may be used to estimate their volume. These results show the potential of seismic-driven near real-time rockfall alarm systems.
- Research Report > Experimental Study (0.48)
- Research Report > New Finding (0.34)
Monitoring induced microseismicity in an urban context using very small seismic arrays: The case study of the Vendenheim EGS project
Fiori, Rémi (Strasbourg University/CNRS, Agence de l’environnement et de la Maîtrise de l’Energie) | Vergne, Jérôme (Strasbourg University/CNRS) | Schmittbuhl, Jean (Strasbourg University/CNRS) | Zigone, Dimitri (Strasbourg University/CNRS)
ABSTRACT Monitoring the seismicity induced by fluid injections in deep geothermal reservoirs is often limited by the significant anthropogenic ambient noise level inherent to most enhanced geothermal system (EGS) projects in urban contexts. We report on the performance of a monitoring network made of three small aperture (72 m) seismic arrays composed of 21 3D nodes. We test the setup for four months (from 12 December 2020 to 8 April 2021) of the Strasbourg sequence of induced earthquakes (2019–2022) related to the EGS Georhin project (Vendenheim, France). The deployment starts a few days after the MLv = 3.6 induced earthquake of 4 December 2020 and covers the early shut-in period of the wells. We use a beamforming technique to characterize the main noise sources, which consist of slow apparent velocities of surface waves emitted from mobile anthropogenic sources (motorway and railway traffic). We detect events with a phase-weighted stacking method, which is efficient when wavefronts illuminate the arrays with a high apparent velocity. Earthquakes associated with these detections are located using a matched field processing technique. The obtained catalog includes 216 seismic events, which represent four times more events than the reference catalog from Le Bureau Central Sismologique Français–Renass (the national academic agency in charge of seismicity monitoring in France), and a reduction of the completeness magnitude from 0.3 to −0.5. The clustering of the seismicity is analyzed using waveform correlation. The enriched catalog reveals intermittent seismic activity during the slow and continuous decrease in fluid pressure after shut-in.
Abstract Landslides are a frequent natural hazard that affect millions of people globally and cause considerable damage and fatalities each year. Changing climate patterns and expanding urban areas are leading to an increased landslide risk. Thus, there is a need for novel methods to mitigate the hazard. Here, we provide an overview of recent work conducted within the densely populated San Francisco Bay Area, where geophysical characterization and monitoring are used to gain a predictive understanding of landslide processes. First, we show how geophysical and remote sensing can be used to map the landslide hazard, and then we show how geophysical data can be used to estimate the temporal variability of the hazard and possibly to provide landslide early warning. To estimate variations in soil properties and deformations across the site, we installed a wireless sensor network. We show how data from this network can be used to provide a predictive estimation of critical conditions. Eventually, the data presented here will be used by site management to address and mitigate the landslide hazard.
- Geology > Geological Subdiscipline > Geomechanics (0.90)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.46)
- Energy > Oil & Gas > Upstream (1.00)
- Government (0.93)
HDF5eis: A storage and input/output solution for big multidimensional time series data from environmental sensors
White, Malcolm C. A. (Massachusetts Institute of Technology) | Zhang, Zhendong (Massachusetts Institute of Technology) | Bai, Tong (Massachusetts Institute of Technology) | Qiu, Hongrui (Massachusetts Institute of Technology) | Chang, Hilary (Massachusetts Institute of Technology) | Nakata, Nori (Massachusetts Institute of Technology)
ABSTRACT Modern high-performance computing (HPC) tasks overwhelm conventional geophysical data formats. We describe a new data schema called HDF5eis (read H-D-F-size) for handling big multidimensional time series data from environmental sensors in HPC applications and implement a freely available Python application programming interface (API) for building and processing HDF5eis files. HDF5eis augments the popular Hierarchical Data Format 5 with a minimal set of additional conventions that facilitate fast and flexible data input and output protocols for regularly sampled (in time) data with any number of dimensions. HDF5eis supports arbitrary ancillary data (e.g., metadata) storage in columnar format or as UTF-8 encoded byte streams alongside time series data. Our HDF5eis API enables simple and efficient access to big data sets distributed across a potentially large number of small heterogeneous files through a single point of access. HDF5eis outperforms conventional seismic data formats by up to two orders of magnitude in terms of random read access times. We contribute HDF5eis as an operational tool and an experimental draft proposal that will help establish the next generation of data standards in the earth sciences.
- North America > United States > Massachusetts (0.28)
- North America > United States > California (0.28)
- Information Technology > Software (1.00)
- Information Technology > Data Science (0.94)
- Information Technology > Information Management (0.94)
- (3 more...)
ABSTRACT Processing seismic data from drillbit-generated vibrations requires a reliable source signature for correlation and deconvolution purposes. Recently, a land field trial has been conducted in a desert environment. A memory-based downhole vibration accelerometer has been used together with a more conventional top-drive sensor to continuously record the pilot signal from 590 to 8600 ft (180–2621 m). Past results indicate that seismic-while-drilling (SWD) data processed using the top-drive accelerometer exhibit good quality in the middle sections of the well but a reduced signal-to-noise ratio for shallow and deep sections. One of the main challenges in using the downhole pilot is a substantial drift of the downhole clock time. To resolve it, a novel automated time-alignment procedure using the GPS-synchronized signal of the top-drive sensor as a reference is applied. The downhole recording provides a source signature of better quality. In shallow sections of the well, it helps to overcome the intense surface-related vibrational noise, whereas, in deeper sections, it provides a cleaner extraction of weaker signals from the polycrystalline diamond compact bits. Processing with the downhole pilot results in better surface seismic data quality than with a conventional top-drive sensor. Therefore, enabling the use of the synchronized downhole pilot signal is of crucial importance for SWD applications. Modern cost-effective near-bit vibrational sensors widely used for different nonseismic applications could be an effective acquisition solution, as shown in this study.
- Asia > Middle East > Saudi Arabia (0.47)
- North America > Canada > Alberta > Woodlands County (0.40)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment > Eolian Environment (0.60)
- Geology > Rock Type (0.46)
- Geology > Geological Subdiscipline > Geomechanics (0.46)