| Titre | Occurrence of high salinity fluids associated with massive near-seafloor gas hydrate deposits |
| Auteur | Torres, M E; Kim, J H; Choi, J Y; Ryu, B J; Bahk, J J; Riedel, M; Collett, T S; Hong, W L; Kastner, M |
| Source | Proceedings of the 7th International Conference on Gas Hydrates (ICGH 2011); 2011 p. 1-19 |
| Année | 2011 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20110048 |
| Réunion | 7th International Conference on Gas Hydrates (ICGH 2011); Edinburgh; GB; juillet 17-21, 2011 |
| Document | livre |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Région extracotière de l'ouest |
| SNRC | 92D |
| Lat/Long OENS | -128.0000 -124.0000 49.0000 44.0000 |
| Lat/Long OENS | 80.0000 86.0000 20.0000 15.0000 |
| Lat/Long OENS | 130.0000 131.0000 37.0000 35.5000 |
| Sujets | hydrate; milieu sédimentaire; chlorure; salinité; saumure; interpretations sismiques; résistivité électrique; fluides des pores; hydrates de gaz; géologie marine; géophysique; sédimentologie; combustibles
fossiles |
| Programme | Hydrates de gaz, Caractérisation des Hydrates de gaz |
| Résumé | (disponible en anglais seulement)
Since the report of the presence of brines associated with massive gas hydrate deposits on Hydrate Ridge (Oregon), there have been additional observations of
pore fluids highly enriched in dissolved chloride at sites of massive gas hydrate occurrence in northern Cascadia accretionary margin (Canada), the Krishna-Godavari Basin (India) and the Ulleung Basin (Korea). Dissolved chloride (up to 1440 mM in the
Ulleung Basin) generally extends from near-seafloor (~1 mbsf) to depths of ~100 mbsf. Below the depth of chloride maxima, chloride values approach concentrations that are lower or equal to seawater values, with minor negative chloride anomalies
superimposed on baseline that reflect discrete gas hydrate bearing horizons. The Ulleung Basin and northern Cascadia sites were all drilled on seismic acoustic chimneys, indicative of methane transport in the gas phase. None of these sites, however,
show any evidence for the formation of a salinity front that can shift the thermodynamic equilibrium and sustain gas transport through the gas hydrate stability front, as postulated by current models. More likely, hydrofracturing and critical gas
pressures below the GHSZ support the gas transport. The composition of gases sampled after gas hydrate dissociation from massive shallow deposits is similar to those of disseminated hydrate within the sediment column, indicating that the gas source
for the massive hydrate is not different than that for other gas hydrate deposits. |
| GEOSCAN ID | 288661 |
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