Cost Efficient Seismic Acquisition - Portable Seismic Source Systems

Exploiting wind-turbine noise for seismic imaging and monitoring

10.5194/egusphere-egu2020-11208 ◽

2020 ◽

Author(s):

Elmer Ruigrok ◽

Lisanne Jagt ◽

Britt van der Vleut

Keyword(s):

Wind Turbine ◽

Seismic Noise ◽

Seismic Source ◽

Seismic Network ◽

Seismic Sources ◽

The Novel ◽

Wind Turbine Noise ◽

Cost Reductions ◽

Cost Efficient ◽

Subsurface Monitoring

<p>Wind turbines (WTs) have proven to be an increasingly cost-efficient source of sustainable energy. With further cost reductions and growth of environmental awareness, the amount and size of WTs will further expand. In the seismic literature, WTs have mainly been considered a threat rather than an opportunity. WTs act as infrasound and seismic sources, whose wavefield might overwhelm signal from earthquakes. Rather than focusing on the detrimental effects, we embrace the WT revolution and focus on the novel possibilities of the WT seismic source. We show detailed characteristics of this source using recordings over the Groningen seismic network. We further show examples of using the WT seismic noise for extracting medium parameters. Moreover, we exploit the repeatable nature of the source for subsurface monitoring.</p>

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Wavefield decomposition based on acoustic reciprocity: Theory and applications to marine acquisition

Geophysics ◽

10.1190/geo2012-0332.1 ◽

2013 ◽

Vol 78 (2) ◽

pp. WA41-WA54 ◽

Cited By ~ 12

Author(s):

Roald Gunnar van Borselen ◽

Jacob Fokkema ◽

Peter van den Berg

Keyword(s):

Free Surface ◽

Seismic Source ◽

Sensor Data ◽

Constant Depth ◽

Seismic Acquisition ◽

Single Sensor ◽

Recorded Data ◽

Marine Seismic ◽

Wavefield Decomposition ◽

Multisensor Data

In marine seismic acquisition, the free surface generates seismic events in our recorded data that are often categorized as noise because these events do not contain independent information about the subsurface geology. Ghost events are considered as such noise because these events are generated when the energy generated by the seismic source, as well as any upgoing wavefield propagating upward from the subsurface, is reflected downward by the free surface. As a result, complex interference patterns between up- and downgoing wavefields are present in the recorded data, affecting the spectral bandwidth of the recorded data negatively. The interpretability of the data is then compromised, and hence it is desirable to remove the ghost events from the data. Rayleigh’s reciprocity theorem is used to derive the relevant equations for wavefield decomposition for multisensor and single-sensor data, for depth-varying and depth-independent recordings from marine seismic experiments using a single-source or dual-source configuration. A comparison is made between the results obtained for a 2D synthetic example designed to highlight the strengths and weaknesses of the various acquisition configurations. It is demonstrated that, using the proposed wavefield decomposition method, multisensor data (measurements of pressure and particle velocity components, or multidepth pressure measurements) allow for optimal wavefield decomposition as independent measurements are used to eliminate the interference patterns caused by the free surface. Single-sensor data using constant-depth recordings are found to be incapable of producing satisfactory results in the presence of noise. Single-sensor data using a configuration with depth-varying measurements are able to deliver better results than when constant-depth recordings are used, but the results obtained are not of the same quality when multisensor data are used.

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On low frequencies emitted by air guns at very shallow depths — An experimental study

Geophysics ◽

10.1190/geo2018-0687.1 ◽

2019 ◽

Vol 84 (5) ◽

pp. P61-P71 ◽

Cited By ~ 1

Author(s):

Daniel Wehner ◽

Martin Landrø ◽

Lasse Amundsen

Keyword(s):

Large Volume ◽

Field Experiments ◽

Field Measurements ◽

Seismic Source ◽

Sea Surface ◽

Frequency Signal ◽

Low Frequencies ◽

Air Gun ◽

Seismic Acquisition ◽

Marine Seismic

In marine seismic acquisition, the enhancement of frequency amplitudes below 5 Hz is of special interest because it improves imaging of the subsurface. The frequency content of the air gun, the most commonly used marine seismic source, is mainly controlled by its depth and the volume. Although the depth dependency on frequencies greater than 5 Hz has been thoroughly investigated, for frequencies less than 5 Hz it is less understood. However, recent results suggest that sources fired very close to the sea surface might enhance these very low frequencies. Therefore, we conduct dedicated tank experiments to investigate the changes of the source signal for very shallow sources in more detail. A small-volume air gun is fired at different distances from the water-air interface, including depths for which the air bubble bursts directly into the surrounding air. The variations of the oscillating bubble and surface disturbances, which can cause changes of the reflected signal from the sea surface, are explored to determine whether an increased frequency signal below 5 Hz can be achieved from very shallow air guns. The results are compared with field measurements of a large-volume air gun fired close to the sea surface. The results reveal an increased signal for frequencies below 5 Hz of up to 10 and 20 dB for the tank and field experiments, respectively, for the source depth at which the air gun bubble bursts directly into the surrounding air. For large-volume air guns, an increased low-frequency signal might also be achieved for sources that are slightly deeper than this bursting depth. From these observations, new design considerations in the geometry of air-gun arrays in marine seismic acquisition are suggested.

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Innovative seismic imaging of VMS deposits, Neves-Corvo, Portugal: Part I - In-mine array

Geophysics ◽

10.1190/geo2020-0565.1 ◽

2021 ◽

pp. 1-76

Author(s):

Bojan Brodic ◽

Alireza Malehmir ◽

Nelson Bruno Monteiro Pacheco ◽

Christopher Juhlin ◽

Joao Carvalho ◽

...

Keyword(s):

Seismic Imaging ◽

Ground Surface ◽

Seismic Source ◽

Massive Sulfide ◽

Seismic Profiles ◽

Time Migration ◽

Active Source ◽

Seismic Experiment ◽

Rock Mining ◽

Seismic Acquisition

To evaluate and upscale the feasibility of utilizing exploration tunnels in an operating mine for active-source seismic imaging, a seismic experiment was conducted at the Neves-Corvo mine, in southern Portugal. Four seismic profiles were deployed in exploration drifts ca. 650 m beneath the ground surface, above the world-class Lombador volcanogenic massive sulfide (VMS) deposit. In addition to the tunnel profiles, two perpendicular surface seismic profiles were deployed above the exploration tunnels. The survey was possible due to a newly developed prototype GPS-time transmitter enabling accurate GPS synchronization of cabled and nodal seismic recorders, both below and on the surface. Another innovative acquisition aspect was a 1.65 t broadband, linear synchronous motor (LSM) driven - electric seismic vibrator (e-vib) used as the seismic source along two of the exploration tunnels. Challenges and innovations necessary for active-source tunnel seismic acquisition, characterized by high levels of vibrational noise from the mining activities, are discussed. Additionally, the LSM vibrator’s signal and overall seismic data quality in this hard rock mining environment are evaluated. Processing results from the tunnel data and 3D reflection imaging of the Lombador deposit below the exploration tunnels are shown and the results checked for consistency through constant-velocity 3D ray-tracing traveltime forward modeling. For imaging purposes, 3D Kirchhoff pre-stack depth and post-stack time migration algorithms were used, with both successfully imaging the targeted deposit. The results obtained show that active-source seismic imaging using subsurface mining infrastructure of operational mines is possible. However, it requires innovative exploration strategies, a broadband seismic source, an accurate GPS-time system capable of transmitting GPS-time hundreds of meters below the surface and careful processing. The results obtained open up possibilities for similar studies in different mining or tunneling projects.

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Shallow Imaging of Gas and Hydrate Using the Deep-towed ACS Data in Joetsu Basin, Niigata, Japan

10.5194/egusphere-egu21-14384 ◽

2021 ◽

Author(s):

Fernando Hutapea ◽

Takeshi Tsuji ◽

Masafumi Katou ◽

Eiichi Asakawa

Keyword(s):

Seismic Source ◽

Frequency Component ◽

Depth Information ◽

Seismic Attribute ◽

Processing Scheme ◽

Free Gas ◽

Reflection Amplitude ◽

Hyperbolic Curve ◽

Seismic Acquisition ◽

Gas Chimneys

<p>The deep-towed Autonomous Continuous Seismic (ACS) is a deep-towed marine seismic acquisition method. The ACS utilizes high frequency seismic source (ranging from 700 Hz to 2300 Hz) and multi-channel receivers that both source and receivers can be located close the seafloor. Moreover, the ACS is suitable to obtain high-resolution image of shallow geological structures. Since ACS data acquisition can be operated near the seafloor, the ocean (strong) current makes the position of both receivers and sources irregular (unstable) and it is hard to measure the absolute depth of both receivers and sources. During data processing, the unstable depth of both sources and receivers not only make the recorded seismic reflection curve (hyperbolic curve) rugged, but also makes the velocity analysis process more difficult because the velocity semblance is not clear. In this study, we propose a processing scheme to solve the unstable source&#8211;receiver position problem and thus to construct an accurate final stack profile (Hutapea et al., 2020 doi:10.1016/j.jngse.2020.103573). We used deep-towed ACS data acquired in the Joetsu Basin in Niigata, Japan, where hydrocarbon features in the form of gas chimneys, gas hydrate, and free gas have been observed. Furthermore, sidelobes in the ACS source signature defocus the source wavelet and decrease the bandwidth frequency content. We designed a filter to focus the source signature. Our proposed approach considerably improved the quality of bandwidth frequency of the source signature and the final stacked profile. Even though depth information was not available for all receivers, the velocity semblance was well focused. Our seismic attribute analyses for the final stack section shows that free gas accumulations are characterized by low reflection amplitude and an unstable frequency component, and that hydrate close to the seafloor can be identified by its high reflection amplitude.</p>

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Correction to "Ascending seismic source during an explosive eruption at Tungurahua volcano, Ecuador”

Geophysical Research Letters ◽

10.1029/2011gl048236 ◽

2011 ◽

Author(s):

Hiroyuki Kumagai ◽

Pablo Placios ◽

Mario Ruiz ◽

Hugo Yepes ◽

Tomofumi Kozono

Keyword(s):

Explosive Eruption ◽

Seismic Source ◽

Tungurahua Volcano

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Modern university as an economic growth driver: Models & missions

Voprosy Ekonomiki ◽

10.32609/0042-8736-2017-3-58-76 ◽

2017 ◽

pp. 58-76 ◽

Cited By ~ 4

Author(s):

A. Karpov

Keyword(s):

Economic Growth ◽

Education Research ◽

Advanced Technology ◽

Global Competitiveness ◽

Technology Markets ◽

Fast Growing ◽

Business Ecosystem ◽

Cost Efficient ◽

National Economies ◽

The University

The paper considers the modern university as an economic growth driver within the University 3.0 concept (education, research, and commercialization of knowledge). It demonstrates how the University 3.0 is becoming the basis for global competitiveness of national economies and international alliances, and how its business ecosystem generates new fast-growing industries, advanced technology markets and cost-efficient administrative territories.

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Unravelling a microbial synergy to boost caproate production via carboxylates chain elongation with ethanol

HKIE Transactions ◽

10.33430/v26n2thie-2018-0041 ◽

2019 ◽

Vol 26 (2) ◽

pp. 63-71

Author(s):

Ling Leng ◽

Ying Wang ◽

Peixian Yang ◽

Takashi Narihiro ◽

Masaru Konishi Nobu ◽

...

Keyword(s):

Fatty Acids ◽

Volatile Fatty Acids ◽

Microbial Consortia ◽

Chain Elongation ◽

Desulfovibrio Vulgaris ◽

Rrna Gene ◽

Selective Enrichment ◽

Microbial Network ◽

Cost Efficient ◽

Rrna Gene Sequencing

Chain elongation of volatile fatty acids for medium chain fatty acids production (e.g. caproate) is an attractive approach to treat wastewater anaerobically and recover resource simultaneously. Undefined microbial consortia can be tailored to achieve chain elongation process with selective enrichment from anaerobic digestion sludge, which has advantages over pure culture approach for cost-efficient application. Whilst the metabolic pathway of the dominant caproate producer, Clostridium kluyveri, has been annotated, the role of other coexisting abundant microbiomes remained unclear. To this end, an ethanol-acetate fermentation inoculated with fresh digestion sludge at optimal conditions was conducted. Also, physiological study, thermodynamics and 16 S rRNA gene sequencing to elucidate the biological process by linking the system performance and dominant microbiomes were integrated. Results revealed a possible synergistic network in which C. kluyveri and three co-dominant species, Desulfovibrio vulgaris, Fusobacterium varium and Acetoanaerobium sticklandii coexisted. D. vulgaris and A. sticklandii (F. varium) were likely to boost the carboxylates chain elongation by stimulating ethanol oxidation and butyrate production through a syntrophic partnership with hydrogen (H2) serving as an electron messenger. This study unveils a synergistic microbial network to boost caproate production in mixed culture carboxylates chain elongation.

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