E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Special Issue "Coastal Ocean Natural Gas Hydrate 2014"

Quicklinks

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (31 January 2015)

Special Issue Editor

Guest Editor
Prof. Richard B. Coffin (Website)

Department of Physical and Environmental Sciences, Texas A&M University - Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78421, USA
Interests: variation in methane hydrate abundance in world ocean coastal regions; shallow sediment methane cycling; methane flux to the atmosphere; elemental isotope analyses

Special Issue Information

Dear Colleagues,

Gas hydrates are recognized an opportunity for new energy, a contribution to climate change, a significant factor in coastal stability and a potential approach to reduce carbon dioxide emissions. State of the art field and laboratory research requires integration of geophysics, geology, biology and geochemistry in field and laboratory to assess sediment methane hydrate loadings, predict carbon dioxide and methane hydrate stability, understand the hydrate role in ocean cycles, global economy, and reducing greenhouse gas emissions. Over the past years publications in this special issue have presented science on key issues lead by world leaders in gas hydrate research.

Recent studies show a strong potential of future energy for many nations. Ongoing climate change studies in the Arctic are working for a better understanding of the relative methane contribution from permafrost and coastal regions to the atmosphere. Initial experiments show the potential to exchange hydrate methane with carbon dioxide to address the anthropogenic influence on climate change and lower the risk of coastal and platform stability that results from mining. This Special Issue invites papers on methane hydrate exploration and methane — carbon dioxide hydrate exchange related to alternate energy, carbon sequestration and climate change.

Dr. Richard B. Coffin
Guest Editor

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs).


Keywords

  • gas hydrates
  • coastal
  • formation
  • stability
  • mining
  • energy
  • climate change

Published Papers (10 papers)

View options order results:
result details:
Displaying articles 1-10
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle Stability Analysis of Methane Hydrate-Bearing Soils Considering Dissociation
Energies 2015, 8(6), 5381-5412; doi:10.3390/en8065381
Received: 11 February 2015 / Revised: 26 May 2015 / Accepted: 29 May 2015 / Published: 5 June 2015
Cited by 1 | PDF Full-text (644 KB) | HTML Full-text | XML Full-text
Abstract
It is well known that the methane hydrate dissociation process may lead to unstable behavior such as large ground deformations, uncontrollable gas production, etc. A linear instability analysis was performed in order to investigate which variables have a significant effect on the [...] Read more.
It is well known that the methane hydrate dissociation process may lead to unstable behavior such as large ground deformations, uncontrollable gas production, etc. A linear instability analysis was performed in order to investigate which variables have a significant effect on the onset of the instability behavior of methane hydrate-bearing soils subjected to dissociation. In the analysis a simplified viscoplastic constitutive equation is used for the soil sediment. The stability analysis shows that the onset of instability of the material system mainly depends on the strain hardening-softening parameter, the degree of strain, and the permeability for water and gas. Then, we conducted a numerical analysis of gas hydrate-bearing soil considering hydrate dissociation in order to investigate the effect of the parameters on the system. The simulation method used in the present study can describe the chemo-thermo-mechanically coupled behaviors such as phase changes from hydrates to water and gas, temperature changes and ground deformation. From the numerical results, we found that basically the larger the permeability for water and gas is, the more stable the simulation results are. These results are consistent with those obtained from the linear stability analysis. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessFeature PaperArticle Molecular and Isotopic Composition of Volatiles in Gas Hydrates and in Sediment from the Joetsu Basin, Eastern Margin of the Japan Sea
Energies 2015, 8(6), 4647-4666; doi:10.3390/en8064647
Received: 31 January 2015 / Accepted: 12 May 2015 / Published: 25 May 2015
Cited by 2 | PDF Full-text (2603 KB) | HTML Full-text | XML Full-text
Abstract
Hydrate-bearing sediment cores were retrieved from the Joetsu Basin (off Joetsu city, Niigata Prefecture) at the eastern margin of the Japan Sea during the MD179 gas hydrates cruise onboard R/V Marion Dufresne in June 2010. We measured molecular and stable isotope compositions [...] Read more.
Hydrate-bearing sediment cores were retrieved from the Joetsu Basin (off Joetsu city, Niigata Prefecture) at the eastern margin of the Japan Sea during the MD179 gas hydrates cruise onboard R/V Marion Dufresne in June 2010. We measured molecular and stable isotope compositions of volatiles bound in the gas hydrates and headspace gases obtained from sediments to clarify how the minor components of hydrocarbons affects to gas hydrate crystals. The hydrate-bound hydrocarbons at Umitaka Spur (southwestern Joetsu Basin) primarily consisted of thermogenic methane, whereas those at Joetsu Knoll (northwestern Joetsu Basin, about 15 km from Umitaka Spur) contained both thermogenic methane and a mixture of thermogenic and microbial methane. The depth concentration profiles of methane, ethane, propane, CO2, and H2S in the sediments from the Joetsu Basin area showed shallow sulfate–methane interface (SMI) and high microbial methane production beneath the SMI depth. Relatively high concentrations of propane and neopentane (2,2-dimethylpropane) were detected in the headspace gases of the hydrate-bearing sediment cores obtained at Umitaka Spur and Joetsu Knoll. Propane and neopentane cannot be encaged in the structure I hydrate; therefore, they were probably excluded from the hydrate crystals during the structure I formation process and thus remained in the sediment and/or released from the small amounts of structure II hydrate that can host such large gas molecules. The lower concentrations of ethane and propane in the sediment, high δ13C of propane and isobutane, and below-detection normal butane and normal pentane at Umitaka Spur and Joetsu Knoll suggest biodegradation in the sediment layers. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessArticle Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone
Energies 2015, 8(5), 4073-4095; doi:10.3390/en8054073
Received: 18 January 2015 / Revised: 12 April 2015 / Accepted: 23 April 2015 / Published: 8 May 2015
Cited by 1 | PDF Full-text (2020 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
CO2 injection in hydrate-bearing sediments induces methane (CH4) production while benefitting from CO2 storage, as demonstrated in both core and field scale studies. CH4 hydrates have been formed repeatedly in partially water saturated Bentheim sandstones. Magnetic Resonance [...] Read more.
CO2 injection in hydrate-bearing sediments induces methane (CH4) production while benefitting from CO2 storage, as demonstrated in both core and field scale studies. CH4 hydrates have been formed repeatedly in partially water saturated Bentheim sandstones. Magnetic Resonance Imaging (MRI) and CH4 consumption from pump logs have been used to verify final CH4 hydrate saturation. Gas Chromatography (GC) in combination with a Mass Flow Meter was used to quantify CH4 recovery during CO2 injection. The overall aim has been to study the impact of CO2 in fractured and non-fractured samples to determine the performance of CO2-induced CH4 hydrate production. Previous efforts focused on diffusion-driven exchange from a fracture volume. This approach was limited by gas dilution, where free and produced CH4 reduced the CO2 concentration and subsequent driving force for both diffusion and exchange. This limitation was targeted by performing experiments where CO2 was injected continuously into the spacer volume to maintain a high driving force. To evaluate the effect of diffusion length multi-fractured core samples were used, which demonstrated that length was not the dominating effect on core scale. An additional set of experiments is presented on non-fractured samples, where diffusion-limited transportation was assisted by continuous CO2 injection and CH4 displacement. Loss of permeability was addressed through binary gas (N2/CO2) injection, which regained injectivity and sustained CO2-CH4 exchange. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessArticle Deep Sediment-Sourced Methane Contribution to Shallow Sediment Organic Carbon: Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico
Energies 2015, 8(3), 1561-1583; doi:10.3390/en8031561
Received: 23 August 2014 / Accepted: 11 February 2015 / Published: 18 February 2015
Cited by 2 | PDF Full-text (2484 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Coastal methane hydrate deposits are globally abundant. There is a need to understand the deep sediment sourced methane energy contribution to shallow sediment carbon relative to terrestrial sources and phytoplankton. Shallow sediment and porewater samples were collected from Atwater Valley, Texas-Louisiana Shelf, [...] Read more.
Coastal methane hydrate deposits are globally abundant. There is a need to understand the deep sediment sourced methane energy contribution to shallow sediment carbon relative to terrestrial sources and phytoplankton. Shallow sediment and porewater samples were collected from Atwater Valley, Texas-Louisiana Shelf, Gulf of Mexico near a seafloor mound feature identified in geophysical surveys as an elevated bottom seismic reflection. Geochemical data revealed off-mound methane diffusion and active fluid advection on-mound. Gas composition (average methane/ethane ratio ~11,000) and isotope ratios of methane on the mound (average δ13CCH4(g) = −71.2‰; D14CCH4(g) = −961‰) indicate a deep sediment, microbial source. Depleted sediment organic carbon values on mound (δ13CSOC = −25.8‰; D14CSOC = −930‰) relative to off-mound (δ13CSOC = −22.5‰; D14CSOC = −629‰) suggest deep sourced ancient carbon is incorporated into shallow sediment organic matter. Porewater and sediment data indicate inorganic carbon fixed during anaerobic oxidation of methane is a dominant contributor to on-mound shallow sediment organic carbon cycling. A simple stable carbon isotope mass balance suggests carbon fixation of dissolved inorganic carbon (DIC) associated with anaerobic oxidation of hydrate-sourced CH4 contributes up to 85% of shallow sediment organic carbon. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Figures

Open AccessArticle Experimental Investigation into the Combustion Characteristics of Propane Hydrates in Porous Media
Energies 2015, 8(2), 1242-1255; doi:10.3390/en8021242
Received: 11 November 2014 / Revised: 26 December 2014 / Accepted: 26 January 2015 / Published: 5 February 2015
Cited by 4 | PDF Full-text (1233 KB) | HTML Full-text | XML Full-text
Abstract
The combustion characteristics of both pure propane hydrates and the mixtures of hydrates and quartz sands were investigated by combustion experiments. The flame propagation, flame appearance, burning time and temperature in different hydrate layers were studied. For pure propane hydrate combustion, the [...] Read more.
The combustion characteristics of both pure propane hydrates and the mixtures of hydrates and quartz sands were investigated by combustion experiments. The flame propagation, flame appearance, burning time and temperature in different hydrate layers were studied. For pure propane hydrate combustion, the initial flame falls in the “premixed” category. The flame propagates very rapidly, mainly as a result of burnt gas expansion. The flame finally self-extinguishes with some proportion of hydrates remaining unburned. For the hydrate-sand mixture combustion, the flame takes the form of many tiny discontinuous flames appearing and disappearing at different locations. The burn lasts for a much shorter amount of time than pure hydrate combustion. High porosity and high hydrate saturation is beneficial to the combustion. The hydrate combustion is the combustion of propane gas resulting from the dissociation of the hydrates. In both combustion test scenarios, the hydrate-dissociated water plays a key role in the fire extinction, because it is the main resistance that restrains the heat transfer from the flame to the hydrates and that prevents the hydrate-dissociated gas from releasing into the combustion zone. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessArticle Methane Flux and Authigenic Carbonate in Shallow Sediments Overlying Methane Hydrate Bearing Strata in Alaminos Canyon, Gulf of Mexico
Energies 2014, 7(9), 6118-6141; doi:10.3390/en7096118
Received: 11 August 2014 / Revised: 4 September 2014 / Accepted: 9 September 2014 / Published: 23 September 2014
Cited by 1 | PDF Full-text (4789 KB) | HTML Full-text | XML Full-text
Abstract
In June 2007 sediment cores were collected in Alaminos Canyon, Gulf of Mexico across a series of seismic data profiles indicating rapid transitions between the presence of methane hydrates and vertical gas flux. Vertical profiles of dissolved sulfate, chloride, calcium, magnesium, and [...] Read more.
In June 2007 sediment cores were collected in Alaminos Canyon, Gulf of Mexico across a series of seismic data profiles indicating rapid transitions between the presence of methane hydrates and vertical gas flux. Vertical profiles of dissolved sulfate, chloride, calcium, magnesium, and dissolved inorganic carbon (DIC) concentrations in porewaters, headspace methane, and solid phase carbonate concentrations were measured at each core location to investigate the cycling of methane-derived carbon in shallow sediments overlying the hydrate bearing strata. When integrated with stable carbon isotope ratios of DIC, geochemical results suggest a significant fraction of the methane flux at this site is cycled into the inorganic carbon pool. The incorporation of methane-derived carbon into dissolved and solid inorganic carbon phases represents a significant sink in local carbon cycling and plays a role in regulating the flux of methane to the overlying water column at Alaminos Canyon. Targeted, high-resolution geochemical characterization of the biogeochemical cycling of methane-derived carbon in shallow sediments overlying hydrate bearing strata like those in Alaminos Canyon is critical to quantifying methane flux and estimating methane hydrate distributions in gas hydrate bearing marine sediments. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessArticle Contribution of Vertical Methane Flux to Shallow Sediment Carbon Pools across Porangahau Ridge, New Zealand
Energies 2014, 7(8), 5332-5356; doi:10.3390/en7085332
Received: 12 June 2014 / Revised: 4 August 2014 / Accepted: 11 August 2014 / Published: 18 August 2014
Cited by 6 | PDF Full-text (1493 KB) | HTML Full-text | XML Full-text
Abstract
Moderate elevated vertical methane (CH4) flux is associated with sediment accretion and raised fluid expulsion at the Hikurangi subduction margin, located along the northeast coast of New Zealand. This focused CH4 flux contributes to the cycling of inorganic and [...] Read more.
Moderate elevated vertical methane (CH4) flux is associated with sediment accretion and raised fluid expulsion at the Hikurangi subduction margin, located along the northeast coast of New Zealand. This focused CH4 flux contributes to the cycling of inorganic and organic carbon in solid phase sediment and pore water. Along a 7 km offshore transect across the Porangahau Ridge, vertical CH4 flux rates range from 11.4 mmol·m−2·a−1 off the ridge to 82.6 mmol·m−2·a−1 at the ridge base. Stable carbon isotope ratios (δ13C) in pore water and sediment were variable across the ridge suggesting close proximity of heterogeneous carbon sources. Methane stable carbon isotope ratios ranging from −107.9‰ to −60.5‰ and a C1:C2 of 3000 indicate a microbial, or biogenic, source. Near ridge, average δ13C for pore water and sediment inorganic carbon were 13C-depleted (−28.7‰ and −7.9‰, respectively) relative to all core subsamples (−19.9‰ and −2.4‰, respectively) suggesting localized anaerobic CH4 oxidation and precipitation of authigenic carbonates. Through the transect there was low contribution from anaerobic oxidation of CH4 to organic carbon pools; for all cores δ13C values of pore water dissolved organic carbon and sediment organic carbon averaged −24.4‰ and −22.1‰, respectively. Anaerobic oxidation of CH4 contributed to pore water and sediment organic carbon near the ridge as evidenced by carbon isotope values as low as to −42.8‰ and −24.7‰, respectively. Carbon concentration and isotope analyses distinguished contributions from CH4 and phytodetrital carbon sources across the ridge and show a low methane contribution to organic carbon. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessArticle Numerical Investigation of Hydrate Dissociation Performance in the South China Sea with Different Horizontal Well Configurations
Energies 2014, 7(8), 4813-4834; doi:10.3390/en7084813
Received: 4 April 2014 / Revised: 3 July 2014 / Accepted: 16 July 2014 / Published: 28 July 2014
Cited by 10 | PDF Full-text (2515 KB) | HTML Full-text | XML Full-text
Abstract
Based on the available measurement data and literature on the hydrate deposits of the South China Sea, a numerical simulation with a new dual horizontal well system has been carried out. Warm brine stimulation combined with depressurization is employed as the production [...] Read more.
Based on the available measurement data and literature on the hydrate deposits of the South China Sea, a numerical simulation with a new dual horizontal well system has been carried out. Warm brine stimulation combined with depressurization is employed as the production method. Two horizontal wells were situated in the same horizontal plane and they were placed in the middle of the Hydrate-Bearing Layer (HBL). The warm brine is injected from the left well (LW) into the reservoir, and the right well (RW) acted as the producer under constant pressure. The simulation results show that the effects of hydrate dissociation rate, gas to water ratio, and energy ratio are all better than the previous work in which the dual horizontal wells are placed in the same vertical plane. In addition, the sensitivity analysis indicates that a higher injection rate can enhance the hydrate dissociation rate and gas production rate, while a lower injection rate gives a more favorable gas to water ratio and energy ratio. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
Open AccessArticle Gas Hydrate Occurrence Inferred from Dissolved Cl Concentrations and δ18O Values of Pore Water and Dissolved Sulfate in the Shallow Sediments of the Pockmark Field in Southwestern Xisha Uplift, Northern South China Sea
Energies 2014, 7(6), 3886-3899; doi:10.3390/en7063886
Received: 19 February 2014 / Revised: 26 May 2014 / Accepted: 3 June 2014 / Published: 20 June 2014
Cited by 1 | PDF Full-text (832 KB) | HTML Full-text | XML Full-text
Abstract
Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in [...] Read more.
Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in the southwestern Xisha Uplift, northern South China Sea (SCS). Pore water collected from a gravity-core inside of a mega-pockmark exhibits a downward Cl concentration decrease concomitant with an increase in δ18O value at the interval of 5.7–6.7 mbsf. Concentrations of Cl, Na+, and K+ mainly cluster along the seawater freshening line without distinct Na+ enrichment and K+ depletion. Thus, we infer that the pore water anomalies of Cl concentrations and δ18O values are attributed to gas hydrate dissociation instead of clay mineral dehydration. Moreover, the lower δ18O values of sulfate in the target core (C14) than those in the reference core (C9) may be associated with the equilibrium oxygen fractionation during sulfate reduction between sulfate and the relatively 18O-depleted ambient water resulting from gas hydrate formation. The gas hydrate contents are estimated to be 6%–10% and 7%–15%, respectively, according to the offset of Cl concentrations and δ18O values from the baselines. This pockmark field in southwestern Xisha Uplift is likely to be a good prospective area for the occurrence of gas hydrate in shallow sediments. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)

Review

Jump to: Research

Open AccessReview Is the Surface of Gas Hydrates Dry?
Energies 2015, 8(6), 5361-5369; doi:10.3390/en8065361
Received: 27 January 2015 / Revised: 25 May 2015 / Accepted: 28 May 2015 / Published: 4 June 2015
PDF Full-text (351 KB) | HTML Full-text | XML Full-text
Abstract
Adhesion (cohesion) and agglomeration properties of gas hydrate particles have been a key to hydrate management in flow assurance in natural gas pipelines. Despite its importance, the relevant data in the area, such as the surface energy and the interfacial energy of [...] Read more.
Adhesion (cohesion) and agglomeration properties of gas hydrate particles have been a key to hydrate management in flow assurance in natural gas pipelines. Despite its importance, the relevant data in the area, such as the surface energy and the interfacial energy of gas hydrates with gas and/or water, are scarce; presumably due to the experimental difficulties involved in the measurements. Here we review what is known about the surface energy and the interfacial energy of gas hydrates to date. In particular, we ask a question as to whether pre-melting can occur on the surface of gas hydrates. Surface thermodynamic analyses show that pre-melting is favoured to occur on the surface of gas hydrates, however, not sufficient data are available to assess its thickness. The effects of the existence of pre-melting layers on the cohesion and friction forces between gas hydrate particles are also discussed. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)

Journal Contact

MDPI AG
Energies Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
energies@mdpi.com
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Energies
Back to Top