Seismic reflection imaging of a geothermal aquifer in an urban setting

A seismic reflection survey that was conducted in downtown Boise, Idaho, to help city planners site a new well for injection of spent geothermal water illustrates some methods to safely and successfully employ a seismic reflection survey in an urban setting. The objective of the seismic survey was to estimate the depth and continuity of a basalt and rhyolite volcanic sequence. Well siting was based on geothermal aquifer depth, location of interpreted faults, projected thermal impact of injection on existing wells, surface pipe extension costs, and public land availability. Seismic acquisition tests and careful processing were used to ensure high‐quality data while minimizing the potential for damage along city streets. A video camera placed in a sewer and a blast vibration monitor were used to confirm that energy from the seismic source (a 75-in3 land air gun) did not damage nearby buildings, street surfaces, or buried utilities along the survey lines. Walkaway seismic tests were also used to compare signal quality of the air‐gun source to an explosive source for imaging targets up to 800 m depth. These tests show less signal bandwidth from the air‐gun source compared to the buried explosive source, but the air‐gun signal quality was adequate to meet imaging objectives. Seismic reflection results show that the top of this rhyolite/basalt sequence dips (∼8–11°) southwest away from the Boise foothills at depths of 200 to 800 m. Seismic methods enabled interpretation of aquifer depths along the profiles and located fault zones where injected water may encounter fracture permeability and optimally benefit the existing producing system. The acquisition and processing techniques used to locate the Boise injection well may succeed for other hydrogeologic and environmental studies in urban settings.

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MARINE SEISMIC SURVEYS— A STUDY OF ENVIRONMENTAL IMPLICATIONS

The APPEA Journal ◽

10.1071/aj99048 ◽

2000 ◽

Vol 40 (1) ◽

pp. 692 ◽

Cited By ~ 79

Author(s):

R.D. McCauley ◽

J. Fewtrell ◽

A.J. Duncan ◽

C. Jenner ◽

M-N. Jenner ◽

...

Keyword(s):

Sea Turtles ◽

Seismic Source ◽

Signal Propagation ◽

Seismic Survey ◽

Humpback Whales ◽

Experimental Program ◽

3D Seismic ◽

Environmental Implications ◽

Alarm Response ◽

Air Gun

An experimental program was run by the Centre for Marine Science and Technology of Curtin University between March 1996 and October 1999 to study the environmental implications of offshore seismic survey noise. This work was initiated and sponsored by the Australian Petroleum Production and Exploration Association. The program:characterised air gun signal measurements; modelled air gun array sources and horizontal air gun signal propagation;developed an 'exposure model' to predict the scale of potential biological effects for a given seismic survey over its duration;made observations of humpback whales traversing a 3D seismic survey;carried out experiments of approaching humpback whales with a single operating air gun;carried out trials with an air gun approaching a cage containing sea turtles, fishes or squid; andmodelled the response of fish hearing systems to airgun signals.The generalised response of migrating humpback whales to a 3D seismic vessel was to take some avoidance manoeuvre at >4 km then to allow the seismic vessel to pass no closer than 3 km. Humpback pods containing cows which were involved in resting behaviour in key habitat types, as opposed to migrating animals, were more sensitive and showed an avoidance response estimated at 7−12 km from a large seismic source. Male humpbacks were attracted to a single operating air gun due to what was believed the similarity of an air gun signal and a whale breaching event (leaping clear of the water and slamming back in). Based on the response of captive animals to an approaching single air gun and scaling these results, indicated sea turtles displayed a general 'alarm' response at an estimated 2 km range from an operating seismic vessel and behaviour indicative of avoidance estimated at 1 km. Similar trials with captive fishes showed a generic fish 'alarm' response of swimming faster, swimming to the bottom, tightening school structure, or all three, at an estimated 2−5 km from a seismic source. Modelling the fish ear predicted that at ranges

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A comparative study of multi-scaled high-resolution seismic surveys in shallow marine environments: examples from three sites, offshore Korea

10.5194/egusphere-egu2020-12869 ◽

2020 ◽

Author(s):

Young Jun Kim ◽

Snons Cheong ◽

Deniz Cukur ◽

Dong-Geun Yoo

Keyword(s):

High Resolution ◽

Data Processing ◽

Seismic Data ◽

Single Channel ◽

Seismic Source ◽

Seismic Survey ◽

Minimum Length ◽

Seismic Surveys ◽

Air Gun ◽

Target Depth

In marine seismic surveys, various acquisition systems are used depending on the survey purpose, target depth, survey environment, and conditions. A 3D survey of oil and/or gas exploration, for instance, require large-capacity air-gun arrays and six or more streamers with a minimum length of 6 km. In contrast, a high-resolution seismic survey for the shallow-water geological research and engineering needs a small capacity source such as air-gun, sparker, and boomer, deployed with a single-channel or multi-channel (24-channel) streamers. The main purpose of our seismic survey was to investigate the Quaternary geology and stratigraphy of offshore, Korea. Because the Quaternary is the most recent geological period, our target depth was very shallow at about 50 m below the sea-bottom. We used a high-frequency seismic source including a sparker of 2,000 J capacity or a 60 in3 mini GI-gun and an eight-channel streamer with a 3.125 m group interval or a single-channel streamer that included 96 elements. To compare the resolution of seismic data according to the seismic source, a boomer or sparker systems were used with the single-channel streamer on a small survey ship. The seismic data processing was performed at the Korea Institute of Geoscience and Mineral Resources (KIGAM) with ProMAX, and the data processing and resolution of each survey were compared based on their acquisition systems.

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Locating faults in underground coal mines using high‐resolution seismic reflection techniques

Geophysics ◽

10.1190/1.1442619 ◽

1989 ◽

Vol 54 (12) ◽

pp. 1521-1527 ◽

Cited By ~ 15

Author(s):

Lawrence M. Gochioco ◽

Steven A. Cotten

Keyword(s):

High Resolution ◽

Seismic Data ◽

Seismic Reflection ◽

Coal Mines ◽

Seismic Source ◽

Seismic Survey ◽

Underground Coal Mines ◽

Vertical Displacements ◽

Seismic Sections ◽

Mine Development

A high‐resolution seismic reflection technique was used to locate faults in coal seams that were not visible on the surface and could only be observed in underground coal mines. An 8‐gauge buffalo gun, built by the research and development department of Consolidation Coal Company, was used as the seismic source. The coal seam at a depth of 700 ft produces a reflection with a predominant frequency of about 125 Hz. The high‐resolution seismic data permitted faults with vertical displacements of the same magnitude as the seam thickness to be detected at depths of several hundred feet beneath the surface. Several faults were detected and interpreted from the seismic sections, and the magnitudes of their displacement were estimated by matching the recorded seismic data to synthetic seismic data. Subsequent underground mine development in the study area confirmed two interpreted faults and their estimated displacements. Mining engineers were able to use the information provided by the seismic survey to plan an entry system through the fault zone so that less rock needed to be mined, resulting in a safer and more productive mine.

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The shape of things to come — Development and testing of a new marine vibrator source

The Leading Edge ◽

10.1190/tle38090680.1 ◽

2019 ◽

Vol 38 (9) ◽

pp. 680-690 ◽

Cited By ~ 1

Author(s):

Benoît Teyssandier ◽

John J. Sallas

Keyword(s):

Seismic Source ◽

Test Facility ◽

Data Sets ◽

Far Field ◽

Ocean Bottom ◽

Air Gun ◽

Seismic Image ◽

Field Radiation ◽

Technical Issues ◽

To Come

Ten years ago, CGG launched a project to develop a new concept of marine vibrator (MV) technology. We present our work, concluding with the successful acquisition of a seismic image using an ocean-bottom-node 2D survey. The expectation for MV technology is that it could reduce ocean exposure to seismic source sound, enable new acquisition solutions, and improve seismic data quality. After consideration of our objectives in terms of imaging, productivity, acoustic efficiency, and operational risk, we developed two spectrally complementary prototypes to cover the seismic bandwidth. In practice, an array composed of several MV units is needed for images of comparable quality to those produced from air-gun data sets. Because coupling to the water is invariant, MV signals tend to be repeatable. Since far-field pressure is directly proportional to piston volumetric acceleration, the far-field radiation can be well controlled through accurate piston motion control. These features allow us to shape signals to match precisely a desired spectrum while observing equipment constraints. Over the last few years, an intensive validation process was conducted at our dedicated test facility. The MV units were exposed to 2000 hours of in-sea testing with only minor technical issues.

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An experimental study of source motion synthesis from first arrivals

Bulletin of the Seismological Society of America ◽

10.1785/bssa0530050955 ◽

1963 ◽

Vol 53 (5) ◽

pp. 955-963

Author(s):

Henry N. Pollack

Keyword(s):

Experimental Study ◽

Source Function ◽

Seismic Source ◽

The Body ◽

Body Waves ◽

Fixed Position ◽

Explosive Source ◽

Simple Medium ◽

Surface Ice ◽

Source Motion

Abstract The motion near a seismic source is synthesized from experimentally obtained seismograms of non-dispersed body waves. The body waves were emitted from an explosive source submerged in a lake with a frozen surface. The seismograms were recorded at several distances by moving the source to a greater depth for each record, while the seismometer remained in a fixed position on the surface ice sheet. All syntheses of the waveform one meter from the source yield the impulsive nature of the source. Deviations between the synthesized one-meter record and the observed one-meter motion are thought to reflect primarily the changing character of the shot medium with depth from the ice. These results indicate that over the short propagation distances (about three wavelengths for the higher frequencies recorded) through the simple medium of this experiment, the observed waveforms and their associated spectra retain characteristics of the source function. The records also yield some information regarding the nature and structure of the elastic medium about the source.

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Some notes on air-gun development as a marine seismic source

The Leading Edge ◽

10.1190/1.3259610 ◽

2009 ◽

Vol 28 (11) ◽

pp. 1334-1335 ◽

Cited By ~ 1

Author(s):

Ben F. Giles

Keyword(s):

Seismic Source ◽

Air Gun ◽

Marine Seismic

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Near-surface glaciotectonic structures in the sediments of an overdeepened glacial valley revealed by a shallow 3D seismic survey

10.5194/egusphere-egu21-8195 ◽

2021 ◽

Author(s):

David Tanner ◽

Hermann Buness ◽

Thomas Burschil

Keyword(s):

Seismic Reflection ◽

P Wave ◽

Seismic Survey ◽

Small Scale ◽

Academic Press ◽

Near Surface ◽

Glacial Sediments ◽

Area Source ◽

Terminal Moraine ◽

Rhine Valley

Glaciotectonic structures commonly include thrusting and folding, often as multiphase deformation. Here we present the results of a small-scale 3-D P-wave seismic reflection survey of glacial sediments within an overdeepened glacial valley in which we recognise unusual folding structures in front of push-moraine. The study area is in the Tannwald Basin, in southern Germany, about 50 km north of Lake Constance, where the basin is part of the glacial overdeepened Rhine Valley. The basin was excavated out of Tertiary Molasse sediments during the Hosskirchian stage, and infilled by 200 m of Hosskirchian and Rissian glacioclastics (Dietmanns Fm.). After an unconformity in the Rissian, a ca. 7 m-thick till (matrix-supported diamicton) was deposited, followed by up to 30 m of Rissian/W&#252;rmian coarse gravels and minor diamictons (Illmensee Fm.). The terminal moraine of the last W&#252;rmian glaciation overlies these deposits to the SW, not 200 m away.We conducted a 3-D, 120 x 120 m&#178;, P-wave seismic reflection survey around a prospective borehole site in the study area. Source/receiver points and lines were spaced at 3 m and 9 m, respectively. A 10 s sweep of 20-200 Hz was excited by a small electrodynamic, wheelbarrow-borne vibrator twice at every of the 1004 realized shot positions. We recognised that the top layer of coarse gravel above the till is folded, but not in the conventional buckling sense, rather as cuspate-lobate folding. The fold axes are parallel to the terminal moraine front. The wavelength of the folding varies between 40 and 80 m, and the thickness of the folded layer is on average about 20 m. Cuspate-lobate folding is typical for deformation of layers of differing mechanical competence (after Ramsay and Huber 1987; &#181;1/&#181;2 less than 10), so this tell us something about the relative competence (or stiffness) of the till layer compared to the coarse clastics above. We also detected small thrust faults that are also parallel to the push-moraine, but these have very little offset and most of the deformation was achieved by folding.Ramsay, J.G. and Huber, M. I. (1987): The techniques of modern structural geology, vol. 2: Folds and fractures: Academic Press, London, 700 pp.

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Far-offset detection of normal modes and diving waves: a case study in Valhall, southern North Sea

Geophysics ◽

10.1190/geo2021-0267.1 ◽

2021 ◽

pp. 1-50

Author(s):

Filipe Borges ◽

Martin Landrø

Keyword(s):

Normal Modes ◽

Seismic Source ◽

Velocity Model ◽

Seismic Survey ◽

The Past ◽

Lack Of Control ◽

Record Data ◽

Refracted Waves ◽

1D Velocity Model

The use of permanent arrays for continuous reservoir monitoring has become a reality in the past decades, with Ekofisk and Valhall being its flagships. One of the possibilities when such solution is available is to passively record data while acquisitions with an active source are ongoing in nearby areas. These recordings might contain ultrafar-offset data (over 30 km), which are hardly used in standard reservoir exploration and monitoring, as they are mostly a combination of normal modes, deep reflections and diving waves. We present here data from the Valhall Life of Field Seismic array, recorded while an active seismic survey was being acquired in Ekofisk, in April 2014. Despite the lack of control on source firing time and position, analysis of the data shows that the normal modes are remarkably clear, overcoming the ambient noise in the field. The normal modes can be well explained by a two-layer acoustic model, while a combination of diving waves and refracted waves can be fairly well reproduced with a regional 1D velocity model. We suggest a method to use the far-offset recordings to monitor changes in the shallow sediments between source and receivers, both with and without a coherent seismic source in the area.

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Design of Near-orthogonal Air-gun Sequences for Marine Seismic Source Encoding

78th EAGE Conference and Exhibition 2016 ◽

10.3997/2214-4609.201600948 ◽

2016 ◽

Author(s):

M.B. Mueller ◽

D.F. Halliday ◽

D.J. van Manen ◽

J.O.A. Robertsson

Keyword(s):

Seismic Source ◽

Air Gun ◽

Marine Seismic ◽

Source Encoding

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Introduction to this special section: Acquisition and sensing

The Leading Edge ◽

10.1190/tle38090670.1 ◽

2019 ◽

Vol 38 (9) ◽

pp. 670-670

Author(s):

Margarita Corzo ◽

Tim Brice ◽

Ray Abma

Keyword(s):

Special Section ◽

Seismic Survey ◽

Ocean Bottom ◽

Total Cost ◽

Small Boat ◽

Air Gun ◽

Seismic Acquisition ◽

The Cost ◽

Seismic Images

Seismic acquisition has undergone a revolution over the last few decades. The volume of data acquired has increased exponentially, and the quality of seismic images obtained has improved tremendously. While the total cost of acquiring a seismic survey has increased, the cost per trace has dropped precipitously. Land surveys have evolved from sparse 2D lines acquired with a few dozen receivers to densely sampled 3D multiazimuth surveys. Marine surveys that once may have consisted of a small boat pulling a single cable have evolved to large streamer vessels pulling multiple cables and air-gun arrays and to ocean-bottom detectors that require significant fleets to place the detectors, shoot the sources, and provide support. These surveys collect data that are wide azimuth and typically fairly well sampled.

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