Geochemical Analysis as a Complementary Tool to Estimate the Uplift of Sediments Caused by Shallow Gas Hydrates in Mounds at the Seafloor of Joetsu Basin, Eastern Margin of the Japan Sea

Freire, Antônio Fernando Menezes; Matsumoto, Ryo; Akiba, Fumio

doi:10.1155/2012/839840

Cited by 8 publications

(7 citation statements)

References 16 publications

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“…Overall, one can clearly see that the shallowest SMTZ depths are encountered at sites characterized by positive reliefs and where the GHOZ is shallow (Figures to ). In addition, the fact that shallow hydrates were recovered at the bulges suggests that the hydrate formation induced an uplift of the superficial sediment as observed on the Eastern Margin of the Japan sea [ Freire et al ., ]. These observations combined with the high contrast in shape of the sulfate profiles for cores GMCS‐14 and GMCS‐15, two cores located close to each other with the former being within Pockmark‐C2 and the latter outside, strongly highlight the links between fluid flow, gas hydrate occurrence and pockmark perimeter and morphology at the investigated area.…”

Section: Discussionmentioning

confidence: 78%

Focused hydrocarbon‐migration in shallow sediments of a pockmark cluster in the Niger Delta (Off Nigeria)

Prunelé

Ruffine

Riboulot

et al. 2017

Geochem Geophys Geosyst

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The Niger Delta is one of the largest hydrocarbon basin offshore Africa and it is well known for the presence of active pockmarks on the seabed. During the Guineco-MeBo cruise in 2011, long cores were taken from a pockmark cluster in order to investigate the state of its current activity. Gas hydrates, oil, and pore-water were sampled for geochemical studies. The resulting dataset combined with seismic data reveal that shallow hydrocarbon migration in the upper sedimentary section was focused exclusively within the pockmarks. There is a clear tendency for gas migration within the hydrate-bearing pockmarks, and oil migration within the carbonate-rich one. This trend is interpreted as a consequence of hydrate dissolution followed by carbonate precipitation in the course of the evolution of these pockmarks. We also demonstrate that Anaerobic Oxidation of Methane (AOM) is the main process responsible for the depletion of pore-water sulfate, with depths of the Sulfate-Methane Transition Zone (SMTZ) ranging between 1.8 and 33.4 m. In addition, a numerical transport-reaction model was used to estimate the age of hydrate-layer formation from the present-day sulfate profiles. The results show that the sampled hydrate-layers were formed between 21 and 3750 years before present. Overall, this work shows the importance of fluid flow on the dynamics of pockmarks, and the investigated cluster offers new opportunities for future cross-site comparison studies. Our results imply that sudden discharges of gas can create hydrate layers within the upper sedimentary column which can affect the seafloor morphology over few decades. Key Points:Seismic surveys and geochemical analyses were combined to study a cluster of hydrate-bearing pockmarks The pockmark dynamics is governed by fluid flow Sulfate-profile simulation allowed estimating the formation age of four selected hydrate layers Supporting Information:Supporting Information S1Correspondence to: L. Ruffine, livio.ruffine@ifremer.fr Citation:de Prunel e, A., et al. (2017), Focused hydrocarbon-migration in shallow sediments of a pockmark cluster in the

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Section: Discussionmentioning

confidence: 78%

Focused hydrocarbon‐migration in shallow sediments of a pockmark cluster in the Niger Delta (Off Nigeria)

Prunelé

Ruffine

Riboulot

et al. 2017

Geochem Geophys Geosyst

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“…The occurrence of seeps and plumes escaping from the seafloor indicates the lack of trapped gas (Matsumoto, 2005;Matsumoto, 2009 in Freire et al, 2011). Although the weak efficiency of both seal and trap for conventional oil and gas production, this scenario is perfect for gas hydrates reservoirs due to the gas supply (Freire, 2010). (Freire, 2010).…”

Section: Geologic Settingmentioning

confidence: 99%

Analysis of seismic attributes to enhance a Bottom Simulating Reflector (BSR) in the gas hydrate area of Umitaka Spur, eastern margin of Japan Sea

et al. 2022

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This work aims to evaluate the best seismic attributes to use to identify the Bottom Simulating Reflector (BSR) of Umitaka Spur, a well-known gas hydrate area in Joetsu Basin, Japan. For this purpose, it uses 2D single-channel seismic data from cruises NT07-20 and NT08-09 provided by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). The methodology used for the qualitative analysis of six seismic attributes to highlight the BSR was done using Schlumberger’s Petrel software. These attributes were Envelope, RMS Amplitude, Amplitude Volume Technique (tecVA), Relative Acoustic Impedance, Spectral Decomposition and Instantaneous Frequency. Thus, this study was fundamental to investigate gas hydrates occurrence through the seismic assessment of some geophysical property (amplitude and frequency) and the geological attributes that highlighted the faults of the complex local geology. The application of these attributes can be used in other areas providing an effective tool to enhance the recognition of BSR all over the world.

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“…Thousands of chimney structures and plumes have been observed on the seafloor in Japan's Joetsu Basin, where plumes could rise hundreds of meters above the seafloor into the water column (Matsumoto, 2009). Chimney structure diameters range 200-900 m. In this area, hydrates often grow in conduits or seafloor outcrops (Freire et al, 2012). Ultra-high resolution three-dimensional seismic data has enabled a better understanding of submarine plumbing systems and their relationships with shallow gas hydrate occurrences (Gay et al, 2009;Andresen et al, 2011).…”

Section: Shallow Hydrate Mounds: More Promising Deposits For Productionmentioning

confidence: 99%

Progress in Global Gas Hydrate Development and Production as a New Energy Resource

Liu

Sun

Zhang

et al. 2019

Acta Geologica Sinica (Eng)

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Natural gas hydrates have been hailed as a new and promising unconventional alternative energy, especially as fossil fuels approach depletion, energy consumption soars, and fossil fuel prices rise, owing to their extensive distribution, abundance, and high fuel efficiency. Gas hydrate reservoirs are similar to a storage cupboard in the global carbon cycle, containing most of the world's methane and accounting for a third of Earth's mobile organic carbon. We investigated gas hydrate stability zone burial depths from the viewpoint of conditions associated with stable existence of gas hydrates, such as temperature, pressure, and heat flow, based on related data collected by the global drilling programs. Hydrate-related areas are estimated using various biological, geochemical and geophysical tools. Based on a series of previous investigations, we cover the history and status of gas hydrate exploration in the USA, Japan, South Korea, India, Germany, the polar areas, and China. Then, we review the current techniques for hydrate exploration in a global scale. Additionally, we briefly review existing techniques for recovering methane from gas hydrates, including thermal stimulation, depressurization, chemical injection, and CH 4 -CO 2 exchange, as well as corresponding global field trials in Russia, Japan, United States, Canada and China. In particular, unlike diagenetic gas hydrates in coarse sandy sediments in Japan and gravel sediments in the United States and Canada, most gas hydrates in the northern South China Sea are non-diagenetic and exist in fine-grained sediments with a vein-like morphology. Therefore, especially in terms of the offshore production test in gas hydrate reservoirs in the Shenhu area in the north slope of the South China Sea, Chinese scientists have proposed two unprecedented techniques that have been verified during the field trials: solid fluidization and formation fluid extraction. Herein, we introduce the two production techniques, as well as the so-called "four-in-one" environmental monitoring system employed during the Shenhu production test. Methane is not currently commercially produced from gas hydrates anywhere in the world; therefore, the objective of field trials is to prove whether existing techniques could be applied as feasible and economic production methods for gas hydrates in deep-water sediments and permafrost zones. Before achieving commercial methane recovery from gas hydrates, it should be necessary to measure the geologic properties of gas hydrate reservoirs to optimize and improve existing production techniques. Herein, we propose horizontal wells, multilateral wells, and cluster wells improved by the vertical and individual wells applied during existing field trials. It is noteworthy that relatively pure gas hydrates occur in seafloor mounds, within near-surface sediments, and in gas migration conduits. Their extensive distribution, high saturation, and easy access mean that these types of gas hydrate may attract considerable attention from academia and industry in the f...

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Geochemical Analysis as a Complementary Tool to Estimate the Uplift of Sediments Caused by Shallow Gas Hydrates in Mounds at the Seafloor of Joetsu Basin, Eastern Margin of the Japan Sea

Cited by 8 publications

References 16 publications

Focused hydrocarbon‐migration in shallow sediments of a pockmark cluster in the Niger Delta (Off Nigeria)

Focused hydrocarbon‐migration in shallow sediments of a pockmark cluster in the Niger Delta (Off Nigeria)

Analysis of seismic attributes to enhance a Bottom Simulating Reflector (BSR) in the gas hydrate area of Umitaka Spur, eastern margin of Japan Sea

Progress in Global Gas Hydrate Development and Production as a New Energy Resource

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