Occurrence and seismic characteristics of gas hydrate in the Ulleung Basin, East Sea

Yoo, Dong Geun; Kang, Nyeon‐Keon; Yi, Bo‐Yeon; Kim, Gil Y.; Ryu, Byong Jae; Lee, Keumsuk; Lee, Gwang H.; Riedel, Michael

doi:10.1016/j.marpetgeo.2013.07.001

Cited by 81 publications

(39 citation statements)

References 47 publications

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“…The presence of gas hydrates in sediments has a pronounced effect on the amplitude and frequency characteristics of a seismic signal also (Guerin and Goldberg, 2002;Pratt et al, 2003;Chand and Minshull, 2004). Hydrates in sediments show contradicting amplitude characteristics in seismic sections such as amplitude blanking (Korenaga et al, 1997) and amplitude enhancements (Nouzé et al, 2004;Riedel et al, 2010;Yoo et al, 2013) at different geologic settings.…”

Section: Introductionmentioning

confidence: 99%

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

et al. 2016

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We have estimated the seismic attenuation in gas hydrate and free-gas-bearing sediments from high-resolution P-cable 3D seismic data from the Vestnesa Ridge on the Arctic continental margin of Svalbard. P-cable data have a broad bandwidth (20-300 Hz), which is extremely advantageous in estimating seismic attenuation in a medium. The seismic quality factor (Q), the inverse of seismic attenuation, is estimated from the seismic data set using the centroid frequency shift and spectral ratio (SR) methods. The centroid frequency shift method establishes a relationship between the change in the centroid frequency of an amplitude spectrum and the Q value of a medium. The SR method estimates the Q value of a medium by studying the differential decay of different frequencies. The broad bandwidth and short offset characteristics of the P-cable data set are useful to continuously map the Q for different layers throughout the 3D seismic volume. The centroid frequency shift method is found to be relatively more stable than the SR method. Q values estimated using these two methods are in concordance with each other. The Q data document attenuation anomalies in the layers in the gas hydrate stability zone above the bottom-simulating reflection (BSR) and in the free gas zone below. Changes in the attenuation anomalies correlate with small-scale fault systems in the Vestnesa Ridge suggesting a strong structural control on the distribution of free gas and gas hydrates in the region. We argued that high and spatially limited Q anomalies in the layer above the BSR indicate the presence of gas hydrates in marine sediments in this setting. Hence, our workflow to analyze Q using high-resolution P-cable 3D seismic data with a large bandwidth could be a potential technique to detect and directly map the distribution of gas hydrates in marine sediments.

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Section: Introductionmentioning

confidence: 99%

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

et al. 2016

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“…However, it appears that in regions of dense occurrence of blank zones (chimneys), no clear BSR is developed. BSR-distribution maps for smaller sub-sets of seismic data across the Ulleung Basin were previously published by Horozal et al (2009) and Yoo et al (2013). Our regional coverage (Fig.…”

Section: Seismic Velocity Structure and Bsrsmentioning

confidence: 96%

“…Seismic data were mainly processed to define the regional distribution of BSRs and seismic blank zones (e.g., Ryu et al 2004Ryu et al , 2009Lee et al 2005;Yoo et al 2008Yoo et al , 2013Horozal et al 2009) as primary indicators for gas hydrates. The vertical extent of the GHSZ across the basin was defined either by using the BSRs or thermal modeling.…”

Section: Geophysical Data Acquisition and Processingmentioning

confidence: 99%

“…Additional seismic facies classifications were carried out by Riedel et al (2013a, b) for a sub-set of the seismic data and well sites with an aim to improve seismic-based estimation of hydrate concentrations. Yoo et al (2013) also used seismic facies classifications for resource estimation, and classified the seismic facies into five facies using reflection pattern such as stratified and chaotic, and strength of amplitude.…”

Section: Seismic-and Echofacies Of the Sedimentary Stratamentioning

confidence: 99%

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Gas hydrates in the Ulleung Basin, East Sea of Korea

Ryu¹,

Riedel²

2017

Terr. Atmos. Ocean. Sci.

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To develop gas hydrates as a potential energy source, geophysical surveys and geological studies of gas hydrates in the Ulleung Basin, East Sea off the east coast of Korea have been carried out since 1997. Bottom-simulating reflector (BSR), initially used indicator for the potential presence of gas hydrates was first identified on seismic data acquired in 1998. Based on the early results of preliminary R&D project, 12367 km of 2D multichannel reflection seismic lines, 38 piston cores, and multi-beam echo-sounder data were collected from 2000 to 2004. The cores showed high amounts of total organic carbon and high residual hydrocarbon gas levels. Gas composition and isotope ratios define it as of primarily biogenic origin. In addition to the BSRs that are widespread across the basin, numerous chimney structures were found in seismic data. These features indicate a high potential of the Ulleung Basin to host significant amounts of gas hydrate. Dedicated geophysical surveys, geological and experimental studies were carried out culminating in two deep drilling expeditions, completed in 2007 and 2010. Sediment coring (including pressure coring), and a comprehensive well log program complements the regional studies and were used for a resource assessment. Two targets for a future test-production are currently proposed: pore-filling gas hydrate in sand-dominated sediments and massive occurrences of gas hydrate within chimney-like structures. An environmental impact study has been launched to evaluate any potential risks to production.

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“…In particular, accurate analysis of reflector polarity (Yoo et al, 2013) may not be possible when data is converted from a paper record. However, this does not mean that data acquired in the past is not useful.…”

Section: Introductionmentioning

confidence: 99%

Review: Marine Seismic And Side-Scan Sonar Investigations For Seabed Identification With Sonar System

Lubis

Anggraini

Kausarian

et al. 2017

J. Geoscience Eng. Environ. Technol.

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Marine seismic reflection data have been collected for decades and since the mid-to late-1980s much of this data is positioned relatively accurately. Marine geophysical acquisition of data is a very expensive process with the rates regularly ship through dozens of thousands of euros per day. Acquisition of seismic profiles has the position is determined by a DGPS system and navigation is performed by Hypack and Maxview software that also gives all the offsets for the equipment employed in the survey. Examples of some projects will be described in terms of the project goals and the geophysical equipment selected for each survey and specific geophysical systems according to with the scope of work. For amplitude side scan sonar image, and in the multi-frequency system, color, becoming a significant properties of the sea floor, the effect of which is a bully needs to be fixed. The main confounding effect is due to absorption of water; geometric spread; shape beam sonar function (combined transmit-receive sonar beam intensity as a function of tilt angle obtained in this sonar reference frame); sonar vehicle roll; form and function of the seabed backscatter (proportion incident on the seabed backscattered signal to sonar as a function of the angle of incidence relative to the sea floor); and the slope of the seabed. The different angles of view are generated by the translation of the sonar, because of the discrete steps involved by the sequential pings, the angular sampling of the bottom.

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Occurrence and seismic characteristics of gas hydrate in the Ulleung Basin, East Sea

Cited by 81 publications

References 47 publications

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

Gas hydrate and free gas detection using seismic quality factor estimates from high-resolution P-cable 3D seismic data

Gas hydrates in the Ulleung Basin, East Sea of Korea

Review: Marine Seismic And Side-Scan Sonar Investigations For Seabed Identification With Sonar System

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