Temperature field of the Mallik gas hydrate occurrence - implications on phase changes and thermal properties

Henninges, Jan; Schrötter, Jörg; Erbaş, Kadir Can; Huenges, Ernst

doi:10.4095/220890

Cited by 29 publications

(37 citation statements)

References 17 publications

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“…a stable ground-temperature profile and a constant geothermal-heat flux). Henninges et al (2005) demonstrated that, at the time of these temperature measurements, the short-term thermal effects of drilling had largely dissipated. On the other hand, the Mallik site is known to have experienced significant changes in surface temperature during the Holocene and earlier times.…”

Section: Bulk Thermal Conductivity Of Mallik Sedimentary Units As Calmentioning

confidence: 99%

Thermal conductivity of sediments within the gas-hydrate-bearing interval at the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well

Wright¹,

Nixon²,

Dallimore

et al. 2005

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Three separate techniques were employed to investigate the thermal conductivity of unconsolidated sediments within the gas-hydrate-bearing reservoir at the Mallik gas hydrate production research site. A miniature needle probe was used to obtain thermal-conductivity measurements of quartz sand and a core specimen recovered from the Mallik reservoir. Measurements were obtained for various pore-water phases relevant to the Mallik geological setting, including pore occupancy by liquid water, gas hydrate, and ice. Measured thermal conductivities were compared to the predictions of an empirical model, which generates estimates of thermal conductivity based on the prescribed physical properties of sediments. Finally, calculations based on ground-temperature data and an estimate of the local geothermal heat flux identified distinct zonal variations in thermal conductivity within the broader gas-hydrate-bearing interval in the Mallik reservoir. These zonal variations are clearly related to variations in sediment character, rather than to the presence or absence of gas hydrate. Résumé : Nous avons employé trois méthodes différentes pour déterminer la conductivité thermique des sédiments non consolidés du réservoir d'hydrates de gaz qui a été mis à l'étude au site Mallik de recherche sur la production d'hydrates de gaz. Une sonde aiguille miniature a servi à effectuer des mesures de conductivité thermique sur du sable de quartz pur et sur un échantillon de carotte prélevé dans le réservoir Mallik. Ces mesures ont été obtenues pour diverses phases interstitielles pertinentes au cadre géologique du réservoir, dont l'eau liquide, les hydrates de gaz et la glace. Les conductivités thermiques mesurées ont été comparées à des prévisions obtenues au moyen d'un modèle empirique qui génère des estimations de la conductivité thermique à partir de spécifications des propriétés physiques des sédiments. Enfin, des calculs basés sur des données de température du sol et sur une estimation du flux géothermique local ont permis d'identifier des variations zonales distinctes de la conductivité thermique dans l'ensemble de l'intervalle renfermant des hydrates de gaz dans le réservoir Mallik. Il est clair que ces variations zonales sont reliées à des variations de la nature des sédiments plutôt qu'à la présence ou à l'absence d'hydrates de gaz.

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Section: Bulk Thermal Conductivity Of Mallik Sedimentary Units As Calmentioning

confidence: 99%

Thermal conductivity of sediments within the gas-hydrate-bearing interval at the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well

Wright¹,

Nixon²,

Dallimore

et al. 2005

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“…The Mallik well sites in the Mackenzie Delta provide an excellent example where the position of the IBP and GHs contacts are well described and can be used to evaluate model results. At the same location the geothermal environment and GH stability conditions are well described Benton and Twitchett, 2003;Henninges et al, 2005a), both onshore and offshore (Fig. 1).…”

Section: Geological Setting Of Bmb Ice Bearing Permafrost and Gas Hydmentioning

confidence: 81%

“…During that interval large-scale ice sheets were absent and forests extended to polar latitudes. Temperature also peaked 52-50 Myr ago, when atmospheric CO 2 concentrations were 1125-3000 parts per million, but by 20 Myr ago, atmospheric CO 2 concentration dropped to about 400 ppm (Polsson, 2007;Henninges et al, 2005a;Rath and Henninges, 2008). Following the Paleocene-early Eocene the climate cooled variably towards the Pleistocene glacial environment (Judge and Majorowicz, 1992;Henninges et al, 2005;Rath and Henninges, 2008).…”

Section: Ground Surface Temperature Historymentioning

confidence: 99%

“…We employ a GST history based on several sources (Peltier and Andrews, 1976;Osadetz and Chen, 2010;Lorenson et al, 2005;Collett, 1997;Majorowicz et al, 2008;Dallimore and Collett, 2005;Judge and Majorowicz, 1992;Henninges et al, 2005a;Rath and Henninges, 2008) adapted to our model study location. Our evidence for past temperatures comes mainly from global temperature reconstructions based on isotopic data, especially δ 18 O, which provide a consistent and continuous temperature record of the last few tens of millions years (Myr).…”

Section: Ground Surface Temperature Historymentioning

confidence: 99%

“…Aspects of the current and more recent BMB GST forcing environment and history can be obtained from shallow temperature profiles (Henninges et al, 2005a;Rath and Henninges, 2008). However, a complete and continuous glacial-interglacial GST forcing history must be derived from sources distant from the BMB study area.…”

Section: Thermal Environment and History Reconstructionmentioning

confidence: 99%

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Inferred gas hydrate and permafrost stability history models linked to climate change in the Beaufort-Mackenzie Basin, Arctic Canada

2012

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Abstract. Atmospheric methane from episodic gas hydrate (GH) destabilization, the "clathrate gun" hypothesis, is proposed to affect past climates, possibly since the Phanerozoic began or earlier. In the terrestrial Beaufort-Mackenzie Basin (BMB), GHs occur commonly below thick ice-bearing permafrost (IBP), but they are rare within it. Two end-member GH models, where gas is either trapped conventionally (Case 1) or where it is trapped dynamically by GH formation (Case 2), were simulated using profile (1-D) models and a 14 Myr ground surface temperature (GST) history based on marine isotopic data, adjusted to the study setting, constrained by deep heat flow, sedimentary succession conductivity, and observed IBP and Type I GH contacts in Mallik wells. Models consider latent heat effects throughout the IBP and GH intervals. Case 1 GHs formed at ∼0.9 km depth only ∼1 Myr ago by in situ transformation of conventionally trapped natural gas. Case 2 GHs begin to form at ∼290-300 m ∼6 Myr ago in the absence of lithological migration barriers. During glacial intervals Case 2 GH layers expand both downward and upward as the permafrost grows downward through and intercalated with GHs. The distinctive model results suggest that most BMB GHs resemble Case 1 models, based on the observed distinct and separate occurrences of GHs and IBP and the lack of observed GH intercalations in IBP. Case 2 GHs formed >255 m, below a persistent ice-filled permafrost layer that is as effective a seal to upward methane migration as are Case 1 lithological seals. All models respond to GST variations, but in a delayed and muted manner such that GH layers continue to grow even as the GST begins to increase. The models show that the GH stability zone history is buffered strongly by IBP during the interglacials. Thick IBP and GHs could have persisted since ∼1.0 Myr ago and ∼4.0 Myr ago for Cases 1 and 2, respectively. Offshore BMB IBP and GHs formed terrestrially during Pleistocene sea level low stands. Where IBP is sufficiently thick, both IBP and GHs persist even where inundated by a Holocene sea level rise and both are also expected to persist into the next glacial even if atmospheric CO 2 doubles. We do not address the "clathrate gun" hypothesis directly, but our models show that sub-IBP GHs respond to, rather than cause GST changes, due to both how GST changes propagates with depth and latent heat effects. Models show that many thick GH accumulations are prevented from contributing methane to the atmosphere, because they are almost certainly trapped below either ice-filled IBP or lithological barriers. Where permafrost is sufficiently thick, combinations of geological structure, thermal processes and material properties make sub-IBP GHs unlikely sources for significant atmospheric methane fluxes. Our sub-IBP GH model histories suggest that similar models applied to other GH settings could improve the understanding of GHs and their potential to affect climate.

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Numerical model of the geothermal regime on the Beaufort Shelf, arctic Canada since the Last Interglacial

Taylor

Dallimore

Hill

et al. 2013

J. Geophys. Res. Earth Surf.

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[1] A finite element geothermal model is developed for the outer Mackenzie Delta-Beaufort Sea shelf to predict permafrost evolution since the Last Interglacial~130-116 kaBP(cal). The purpose is to reconcile sparse observations of the depth and extent of ice-bonded permafrost with sediment properties and the paleoenvironment. Sea level curves determine, as a function of time, areas of the shelf that were subaerially exposed, promoting permafrost aggradation, and areas that were submerged, promoting permafrost degradation. Assuming as a model starting point that a paleoclimate similar to today persisted through the Last Interglacial, permafrost subsequently aggrades in depth and advances seaward from the present shoreline to the shelf/slope bathymetric break by the Last Glacial Maximum (LGM)~26 kaBP(cal). Modeled permafrost exhibits reduced growth in depth and seaward progression that correlate with early and middle Wisconsin stillstands in sea level. Following the LGM and rise in sea level, offshore permafrost degrades and permafrost base rises~100 m to its present depth of 600 m. The offshore limit of modeled ice-bonded permafrost lies at the~95 m isobath, within 1 km of the bathymetric shelf/slope break. The model replicates features of offshore permafrost body observed seismically and demonstrates that warm outflow from the Mackenzie River depresses the upper surface of offshore permafrost by tens of meters to the 20 m isobath. Although Pleistocene permafrost predated the Wisconsinan, the model demonstrates that the paleoenvironment of the last 125,000 years is sufficient to develop the depth, seaward extent, and principal features of the permafrost body.

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Temperature field of the Mallik gas hydrate occurrence - implications on phase changes and thermal properties

Cited by 29 publications

References 17 publications

Thermal conductivity of sediments within the gas-hydrate-bearing interval at the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well

Thermal conductivity of sediments within the gas-hydrate-bearing interval at the JAPEX/JNOC/GSC et al. Mallik 5L-38 gas hydrate production research well

Inferred gas hydrate and permafrost stability history models linked to climate change in the Beaufort-Mackenzie Basin, Arctic Canada

Numerical model of the geothermal regime on the Beaufort Shelf, arctic Canada since the Last Interglacial

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