Repeatability study of seismic source signatures

Geophysics ◽  
2001 ◽  
Vol 66 (6) ◽  
pp. 1811-1817 ◽  
Author(s):  
Bibi C. Aritman
Keyword(s):  
Phase Difference ◽  
Seismic Source ◽  
Seismic Survey ◽  
Surface Source ◽  
Near Surface ◽  
Seismic Surveys ◽  
Instantaneous Phase ◽  
Reservoir Monitoring ◽  
The Difference

This study discusses the repeatability of source signature using the instantaneous phase, as derived from the complex trace attributes. The study is part of a very large 2‐D seismic survey using sources of vibroseis and surface dynamite. The field procedure consisted of recording the production record, retaining the positions, then repeat‐recording the same shake or shot. The instantaneous phase was found to be the best measure for the difference between the first and the repeat records. In addition to the instantaneous phase, other analyses were used to evaluate changes in source signature. Results were tabulated for statistical comparisons and graded for quality. Excluding erroneous cases, the remainder of poor repeatabilities were studied. The analyses of near‐offset data seem to indicate that nonrepeatability of source signature relates mostly to changes in absorption and cohesion induced by elastic saturation at the near surface. In general, by time shifting and phase rotating the repeat record, the difference in instantaneous phase tends to diminish. The new idea of using instantaneous phase difference plots to evaluate repeatability offers improved evaluation of source signatures and can also be used to detect time‐lapsed changes in reservoir monitoring. By evaluating repeatability and avoiding elastic saturation near the surface, source signatures can be made more consistent, thus increasing the resolution of stacked data for 2‐D, 3‐D, and 4‐D seismic surveys.

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

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

<p>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 in<sup>3</sup> 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.</p>

Unlocking ultra-high-density seismic for CCUS applications by combining nimble nodes and agile source technologies

2022 ◽  
Vol 41 (1) ◽  
pp. 27-33
Author(s):  
Amine Ourabah ◽  
Allan Chatenay
Keyword(s):  
Carbon Capture ◽  
Oil And Gas ◽  
Test Site ◽  
High Density ◽  
Seismic Survey ◽  
Surface Model ◽  
Near Surface ◽  
Seismic Surveys ◽  
Time Migration ◽  
Trace Density

In the quest for denser, nimbler, and lower-cost seismic surveys, the industry is seeing a revolution in the miniaturization of seismic equipment, with autonomous nodes approaching the size of a geophone and sources becoming portable by crews on foot. This has created a paradigm shift in the way seismic is acquired in difficult terrains, making zero-environmental-footprint surveys a reality while reducing cost and health, safety, and environmental risk. The simplification of survey operation and the new entry price of seismic surveys unlocked by these technologies are already benefiting industries beyond oil and gas exploration. High trace density seismic has become accessible to industries playing a key role in the net-zero era, such as geothermal and carbon capture, utilization, and storage (CCUS), to which a good understanding of the subsurface geology is crucial to their success. We describe these benefits as observed during an ultra-high-density seismic survey acquired in June 2020 through a partnership between STRYDE, Explor, and Carbon Management Canada over the Containment and Monitoring Institute site. The smallest and lightest source and receiver equipment in the industry were used to achieve a trace density of 257 million traces/km2 over this test site dedicated to CCUS studies. We discuss the operational efficiency of the seismic acquisition, innovative techniques for data transfer and surveying, and preliminary results of the seismic data processing with a focus on the near-surface model and fast-track time migration.

An in‐hole shotgun source for engineering seismic surveys

Geophysics ◽  
1987 ◽  
Vol 52 (7) ◽  
pp. 985-996 ◽  
Author(s):  
S. E. Pullan ◽  
H. A. MacAulay
Keyword(s):  
Ground Surface ◽  
Seismic Source ◽  
Coarse Grained ◽  
Near Surface ◽  
Seismic Surveys ◽  
Fine Grained ◽  
Reflection Seismic ◽  
Weight Drop ◽  
Water Saturated ◽  
Excellent Source

We have conducted several source comparisons involving 12‐gauge and 8‐gauge Buffalo guns, a 7.3 kg sledgehammer, and a 75 kg weight drop. The results are strongly site‐dependent. We found that, when the near‐surface consisted of fine‐grained, water‐saturated sediments, the 12‐gauge Buffalo gun produced up to two orders of magnitude more energy than the conventional hammer across a broad frequency range. Under such conditions the gun produced the greatest improvement in energy between 200 and 400 Hz, where it yielded up to ten times more energy than the 75 kg weight drop. This indicates that the Buffalo gun may be particularly useful as a shallow reflection seismic source. However, at sites where the near‐surface materials were coarse‐grained and the water table was well below the ground surface, the advantages of using an in‐hole shotgun source as opposed to a hammer or weight drop were minimal. Nevertheless, in many areas we believe that the Buffalo gun is an excellent source for engineering seismic surveys. It is lightweight and portable (<5 kg), inexpensive to build (<$100 US), simple to use and maintain, and a good source of high‐frequency energy.

scholarly journals Acoustic Pressure, Particle Motion, and Induced Ground Motion Signals from a Commercial Seismic Survey Array and Potential Implications for Environmental Monitoring

2021 ◽  
Vol 9 (6) ◽  
pp. 571
Author(s):  
Robert D. McCauley ◽  
Mark G. Meekan ◽  
Miles J. G. Parsons
Keyword(s):  
Ground Motion ◽  
Particle Motion ◽  
Seismic Source ◽  
Propagation Loss ◽  
Seismic Survey ◽  
Ground Acceleration ◽  
Near Surface ◽  
North West ◽  
Northern Site ◽  
Southern Site

An experimental marine seismic source survey off the northwest Australian coast operated a 2600 cubic inch (41.6 l) airgun array, every 5.88 s, along six lines at a northern site and eight lines at a southern site. The airgun array was discharged 27,770 times with 128,313 pressure signals, 38,907 three-axis particle motion signals, and 17,832 ground motion signals recorded. Pressure and ground motion were accurately measured at horizontal ranges from 12 m. Particle motion signals saturated out to 1500 m horizontal range (50% of signals saturated at 230 and 590 m at the northern and southern sites, respectively). For unsaturated signals, sound exposure levels (SEL) correlated with measures of sound pressure level and water particle acceleration (r2= 0.88 to 0.95 at northern site and 0.97 at southern) and ground acceleration (r2= 0.60 and 0.87, northern and southern sites, respectively). The effective array source level was modelled at 247 dB re 1µPa m peak-to-peak, 231 dB re 1 µPa2 m mean-square, and 228 dB re 1 µPa2∙m2 s SEL at 15° below the horizontal. Propagation loss ranged from −29 to −30log10 (range) at the northern site and −29 to −38log10(range) at the southern site, for pressure measures. These high propagation losses are due to near-surface limestone in the seabed of the North West Shelf.

Structural interpretation using refraction velocities from marine seismic surveys

Geophysics ◽  
1986 ◽  
Vol 51 (1) ◽  
pp. 12-19 ◽  
Author(s):  
James F. Mitchell ◽  
Richard J. Bolander
Keyword(s):  
Sedimentary Rock ◽  
Seismic Energy ◽  
Seismic Survey ◽  
Subsurface Structure ◽  
Seismic Reflection Data ◽  
Near Surface ◽  
Reflection Data ◽  
Wide Range ◽  
Streamer Length ◽  
Set Up

Subsurface structure can be mapped using refraction information from marine multichannel seismic data. The method uses velocities and thicknesses of shallow sedimentary rock layers computed from refraction first arrivals recorded along the streamer. A two‐step exploration scheme is described which can be set up on a personal computer and used routinely in any office. It is straightforward and requires only a basic understanding of refraction principles. Two case histories from offshore Peru exploration demonstrate the scheme. The basic scheme is: step (1) shallow sedimentary rock velocities are computed and mapped over an area. Step (2) structure is interpreted from the contoured velocity patterns. Structural highs, for instance, exhibit relatively high velocities, “retained” by buried, compacted, sedimentary rocks that are uplifted to the near‐surface. This method requires that subsurface structure be relatively shallow because the refracted waves probe to depths of one hundred to over one thousand meters, depending upon the seismic energy source, streamer length, and the subsurface velocity distribution. With this one requirement met, we used the refraction method over a wide range of sedimentary rock velocities, water depths, and seismic survey types. The method is particularly valuable because it works well in areas with poor seismic reflection data.

Periodically poled KTA crystal investigated using coherent X-ray beams

2000 ◽  
Vol 33 (4) ◽  
pp. 1149-1153 ◽  
Author(s):  
P. Pernot-Rejmánková ◽  
P. A. Thomas ◽  
P. Cloetens ◽  
F. Lorut ◽  
J. Baruchel ◽  
...  
Keyword(s):  
Phase Difference ◽  
Domain Walls ◽  
Structural Information ◽  
Periodically Poled ◽  
Synchrotron Source ◽  
X Ray ◽  
Diffracted Waves ◽  
Coherent Beams ◽  
Diffraction Imaging ◽  
The Difference

The distribution of inverted ferroelectric domains on the surface and within the bulk of a periodically poled KTA (KTiOAsO4) single crystal has been observed using a simple X-ray diffraction imaging setup which takes advantage of the highly coherent beams available at a third-generation synchrotron source, such as the ESRF. This technique allows one to reveal the phase difference between the waves that are Bragg diffracted from adjacent domainsviafree-space propagation (Fresnel diffraction). The phase difference of the diffracted waves is mainly produced by the difference in phases of the structure factors involved, and contains precise structural information about the nature of the domain walls.

Near Surface Research and Excitation Horizon Prediction Based on Old River Course of Xiaoqing River in Shan Dong

2013 ◽  
Vol 664 ◽  
pp. 94-98
Author(s):  
Guang De Zhang
Keyword(s):  
Seismic Data ◽  
Practical Significance ◽  
Cone Penetration ◽  
Surface Deposition ◽  
Near Surface ◽  
Sedimentary Characteristics ◽  
The Difference ◽  
Exploration Area ◽  
Data Requirements ◽  
Static Cone Penetration Test

Following deepened exploration and development in Shengli exploration area, seismic data requirements are also getting higher and higher. However, in recent years the difference of Xiaoqing river on both sides have made us know that the importance of this problem. In view of the above, this task is aimed at quaternary shallow of old river course within Xiaoqing River. Our analysis of lithology and sedimentary characteristics are using static cone penetration test and rock core exploration method, and we want to reappear near surface deposition of old river course within Xiaoqing River. The research is close combined with the exploration demand and theoretical study, so it has important theoretical and practical significance.

45° REFLECTOMETRY OF SEMICONDUCTOR QUANTUM WELLS

2001 ◽  
Vol 15 (17n19) ◽  
pp. 683-687
Author(s):  
A. SILVA-CASTILLO ◽  
F. PEREZ-RODRIGUEZ
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Growth Direction ◽  
Angle Of Incidence ◽  
Near Surface ◽  
New Information ◽  
Difference Formula ◽  
Exciton Polaritons ◽  
The Difference ◽  
First Time

We have applied the 45° reflectometry for the first time to study exciton-polaritons in quantum wells. The 45° reflectometry is a new polarization-modulation technique, which is based on the measurement of the difference [Formula: see text] between the p-polarization reflectivity (Rp) and the squared s-polarization reflectivity [Formula: see text] at an angle of incidence of 45°. We show that [Formula: see text] spectra may provide qualitatively new information on the exciton-polariton modes in a quantum well. These optical spectra turn out to be very sensitive to the zeros of the dielectric function along the quantum-well growth direction and, therefore, allow to identify the resonances associated with the Z exciton-polariton mode. We demonstrate that 45° reflectometry could be a powerful tool for studying Z exciton-polariton modes in near-surface quantum wells, which are difficult to observe in simple spectra of reflectivity Rp

Memoirs: On a New Genus of Synascidians from Japan

1892 ◽  
Vol s2-33 (130) ◽  
pp. 313-324
Author(s):  
ASAJIRO OKA ◽  
ARTHUR WILLEY
Keyword(s):  
Thin Layer ◽  
New Genus ◽  
Postembryonic Development ◽  
Point Of View ◽  
Canal System ◽  
Near Surface ◽  
New Form ◽  
The Difference ◽  
Bladder Cells ◽  
First Time

Sarcodidemnoides misakiense, Oka and Willey. Generic Characters.--Colony (or cormus) forming very thick lobose masses, laterally compressed; sessile, but not encrusting. Excurrent orifices placed on the tips of the knoll-like prominences. Ascidiozooids very numerous, not arranged in systems; branchial sac with four rows of stigmata; canal system complicated, differentiated into peripheral and central portions. Specific Characters.--Atrial apertures of Ascidiozooids simple pores without teeth or languet; spicules fairly abundant, extremely delicate, confined to a thin layer near surface of test. Test gelatinous, containing numerous bladder-cells, crystals, fusiform cells, and pigment concretions. Stomach of Ascidiozooids vertically placed; surface of attachment of colony narrower than the free portion. Colour, brilliant red. Habitat.--Moroiso, Japan, between the tide-marks. N.B.--Since the above was written I have seen for the first time the exhaustive work of Fernand Lahille, entitled ‘Recherches sur les Tuniciers des côtes de France,' Toulouse, 1890. Lahille devotes considerable attention to what have been spoken of above as tentacle-like processes of the larva, figures them in many larvæ, and gives an excellent figure of the metamorphosing larva of Styela glomerata. He gives an opinion as to their significance which I cannot entirely endorse in the light of my own researches on the "Postembryonic development of Styela," commenced last August at Plymouth. However, I hope to return to this question on a future occasion. Lahille raises an objection to von Drasche's genus Didemnoides on the ground that the thickness of the cormus is not an anatomical character, and that the distinction between thick and thin colonies is a purely subjective one. There is no doubt some truth in this; but the difference between a compound Ascidian which possesses, say, a very few spicules, and one which possesses none at all, would appear to be no more fundamental than that between a colony whose mode of growth resulted in the production of a fleshy mass and one which grew in the form of a thin leathery crust. As stated above, von Drasche intends by Didemnoides a fleshy form of Leptoclinum, the test containing spicules, and the Ascidiozooids having four rows of stigmata in the branchial sac. Lahille, on the contrary,applies the name Didemnoides to those Didemnidse which are characterised by the absence of spicules, and the possession of three rows of stigmata in the branchial sac. The compound Ascidian which we have described above has spicules in the test, and four rows of stigmata in the branchial sac. But as it would be too absurd to call the new form "Sarcoleptoclinum," we shall persist in regarding the genus Didemnoides from the point of view of von Drasche.--A. W.

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