scholarly journals Gas hydrate dissociation in sediments: Pressure-temperature evolution

2008 ◽  
Vol 9 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Tae-Hyuk Kwon ◽  
Gye-Chun Cho ◽  
J. Carlos Santamarina
Keyword(s):  
Gas Hydrate ◽  
Temperature Evolution ◽  
Hydrate Dissociation

Review of natural gas hydrate dissociation effects on seabed stability

2021 ◽  
Author(s):  
Min Zhang ◽  
Ming Niu ◽  
Shiwei Shen ◽  
Shulin Dai ◽  
Yan Xu
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Natural Gas Hydrate ◽  
Hydrate Dissociation

Improving the Accuracy of Gas Hydrate Dissociation Point Measurements

2006 ◽  
Vol 912 (1) ◽  
pp. 924-931 ◽  
Author(s):  
B. TOHIDI ◽  
R. W. BURGASS ◽  
A. DANESH ◽  
K. K. ØSTERGAARD ◽  
A. C. TODD
Keyword(s):  
Gas Hydrate ◽  
Hydrate Dissociation

Simulation of Arctic Gas Hydrate Dissociation in Response to Climate Change: Basin-Scale Assessment

2011 ◽  
Author(s):  
Matthew T. Reagan ◽  
George J. Moridis ◽  
Scott M. Elliott ◽  
Mathew Maltrud
Keyword(s):  
Climate Change ◽  
Gas Hydrate ◽  
Hydrate Dissociation ◽  
Scale Assessment ◽  
Basin Scale

Modeling Heating Curve for Gas Hydrate Dissociation in Porous Media

2005 ◽  
Vol 109 (36) ◽  
pp. 17205-17211 ◽  
Author(s):  
Christophe Dicharry ◽  
Pascal Gayet ◽  
Gérard Marion ◽  
Alain Graciaa ◽  
Anatoliy N. Nesterov
Keyword(s):  
Porous Media ◽  
Gas Hydrate ◽  
Hydrate Dissociation ◽  
Heating Curve

scholarly journals Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Jens Karstens ◽  
Haflidi Haflidason ◽  
Lukas W. M. Becker ◽  
Christian Berndt ◽  
Lars Rüpke ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Hydrate Dissociation

Assessing the Impact of Shallow Gas Hydrate Dissociation on Structural Integrity in Deepwater Wells

2021 ◽  
Author(s):  
P. V. Suryanarayana ◽  
Miodrag Bogdanovic ◽  
Kuhanesapathy Thavaras Pathy ◽  
M. Razali Paimin
Keyword(s):  
Gas Hydrate ◽  
Structural Integrity ◽  
Mechanical Response ◽  
Preliminary Assessment ◽  
Shallow Gas ◽  
Hydrate Dissociation ◽  
Integrity Assessment ◽  
Well Integrity ◽  
Transient Thermal ◽  
The Impact

Abstract Shallow gas hydrate zones are present in some deepwater fields. During production, the shallow hydrates may dissociate due to heat-up of the near wellbore formation, which can extend radially to several meters from the wellbore. This can compromise structural integrity of the well (particularly structural strings), cause subsidence, and impact subsea equipment installations. This problem is well known, and has been addressed in the literature. An enthalpy-based transient thermal simulation is required to determine the dissociation front. Further, post-dissociation formation mechanics and well integrity assessment are complex, requiring numerical approaches such as Finite Element Analyses. In this paper, we present an approach that allows a preliminary assessment of the severity of the impact of dissociation on well integrity, so that a more complex assessment may be undertaken only for severe situations. The main objectives of the preliminary assessment are: to model hydrate dissociation front and the radial extent of dissociation as a function of depth; evaluate response of formation to this dissociation; analyze mechanical response of the well to the modified mechanical properties within dissociated zone; and confirm well integrity. The paper describes the approach, and introduces two thermal metrics to assess the likely severity of the integrity impact of hydrate dissociation. Using these metrics, the need for a more detailed analysis can be determined. Further, load analysis and integrity checks of the structural strings and the wellhead that can be performed as part of the preliminary assessment are discussed. An illustrative example is used to demonstrate the approach.

Susceptibility assessment of gas hydrate dissociation occurrence along European continental margins and adjacent areas. GARAH project (GeoERA)

2021 ◽  
Author(s):  
Ricardo León ◽  
Christopher Rochelle ◽  
André Burnol ◽  
Carmen Julia Giménez- Moreno ◽  
Tove Nielsen ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Gas Hydrate ◽  
Control Factor ◽  
Continental Margins ◽  
Baseline Scenario ◽  
Submarine Landslides ◽  
Susceptibility Assessment ◽  
Map Algebra ◽  
Hydrate Dissociation ◽  
Density Map

<p>The Pan-European gas-hydrate relate GIS database of GARAH project has allowed assessing the susceptibility of seafloor areas affected by hydrate dissociation. This study has been applied as a first step for the hydrate related risk assessment along the European continental margins. Several factors and variables have been taken into account. They have been defined by their relationship with the presence of hydrates below seafloor and weighted depending on the confidence of finding hydrates in this site. The maximum weight (or confidence) has been given to the recovered samples of gas hydrates or hydrate-dissociation evidences such as degassing or liquation structures observed in gravity cores. Seismic indicators of the presence of gas hydrate or hydrocarbon seabed fluid flow such as BSR, blanking acoustic, amplitude anomalies or the presence of geological structures of seabed fluid flow in the neighbouring of the GHSZ have been weighted with a lower value. The theoretical gas hydrate stability zone (GHSZ) for a standard composition for biogenic gas has been taken into account as another control factor and constrain feature. Seafloor areas out of the theoretical GSHZ have been excluded as potential likelihood to be affected by hydrate dissociation processes. The base of GHSZ has been classified as a critical area for these dissociation processes.</p><p>The proposed methodology analyses the geological hazard by means of the susceptibility assessment, defined by the likelihood of occurrence of hydrate dissociation, collapses, crater-like depressions or submarine landslides over seafloor. The baseline scenario is that gas hydrate occurrence is only possible in seafloor areas where pressure (bathymetry) and seafloor temperature conditions are inside the theoretical GHSZ. Inside GHSZ, the occurrence of gas hydrate is directly related to the presence of its evidences (direct samples of hydrates) or indicators (eg. pore water and velocity anomalies, BSR, gas chimneys, among others), as well as the occurrence of hydrocarbon fluid flow structures inside GHSZ. Finally, the likelihood of the seafloor to be affect gas hydrate dissociation processes will be major at the base of the GHSZ and in the neighbouring of the gas hydrate evidences and indicators. In order to proof this initial hypothesis, a susceptibility assessment has been carried out throughout map algebra in a GIS environment from a density map of evidences and indicators and the Pan-European map of the GHSZ over seafloor. Specifically, it has been conceived as a segmentation in three levels by quantiles resulting of the addition of the density map of evidences and indicators and the weighted map of the GHSZ over seafloor.</p><p> </p><p><strong>Acknowledgment</strong></p><p>GARAH project. GeoERA - GeoE.171.002</p>

Submarine slope failure due to gas hydrate dissociation: a preliminary quantification

2007 ◽  
Vol 44 (3) ◽  
pp. 314-325 ◽  
Author(s):  
M F Nixon ◽  
J LH Grozic
Keyword(s):  
Slope Stability ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Numerical Study ◽  
Fluid Pressure ◽  
Slope Failures ◽  
Case Histories ◽  
Hydrate Dissociation ◽  
Methane Gas ◽  
Submarine Slope

Gas hydrates are icelike compounds composed of water and methane gas in very compact form. There is substantial evidence from case histories that links gas hydrate dissociation to submarine slope failures and other geohazards. Theoretical analyses have also shown that upon dissociation gas hydrates will cause an increase in fluid pressure and a reduction in effective stress and thus result in loss of the soil strength. This paper presents a preliminary quantification of the effects of gas hydrate dissociation through development of a pore-pressure model that was incorporated into one- and two-dimensional slope stability analyses. The ensuing numerical study investigated submarine slope stability through parametric studies and application to two important case histories and found that dissociation of even small amounts of hydrate can have a significant destabilizing effect. Yet whether gas hydrate dissociation can alone cause large-scale slope failures has still to be demonstrated as there are often many destabilizing processes; however, this research highlights the importance of assessing the effects of gas hydrate dissociation on the behaviour of submarine slopes.Key words: gas hydrates, slope stability, marine, offshore, methane gas, instability.

Possible Effect of Main Roof Settlement on Outburst Hazard in Case of Gas Hydrate Dissociation during Coal Mining

2017 ◽  
Vol 53 (5) ◽  
pp. 801-810 ◽  
Author(s):  
V. V. Dyrdin ◽  
V. N. Oparin ◽  
A. A. Fofanov ◽  
V. G. Smirnov ◽  
T. L. Kim
Keyword(s):  
Coal Mining ◽  
Gas Hydrate ◽  
Main Roof ◽  
Hydrate Dissociation ◽  
Roof Settlement ◽  
Outburst Hazard
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