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| Gay, Aurelien; Lopez, M; Cochonat, Pierre; Seranne, M; Levache, D; Sermondadaz, G. |
| Based on high-resolution 3D seismic data sets, we document the subsurface reservoir architecture and organization of a portion of the Oligocene-Miocene stratigraphy within the Congo Basin, offshore southwestern Africa. Within the 3D seismic volume, we have identified four levels of turbiditic palaeochannels, which are separated by low-amplitude continuous reflectors interpreted as hemipelagic sediments. Geochemical analyses on sediment samples taken within overlying seafloor pockmarks reveal the presence of thermogenic gases and oils, suggesting that deep-seated fluids have migrated through both the channel deposits and the impermeable layers between them, forming a conduit to the surface. Deep thermogenic fluids produced within Cretaceous source rocks are... |
| Tipo: Text |
Palavras-chave: Polygonal faults; BSR; Fluid chimneys; Pipes; Hydrates; Turbiditic palaeochannels; Pockmarks; Fluid migration. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1111.pdf |
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| Nouze, Herve; Cosquer, Emmanuel; Collot, Julien; Foucher, Jean-paul; Klingelhoefer, Frauke; Lafoy, Yves; Geli, Louis. |
| High-resolution reflection and refraction seismic data were collected in 2004 to investigate, in further detail than allowed by pre-existing low resolution seismic data, the nature of a Bottom Simulating Reflector (BSR) that extends over a broad area of the Fairway Basin, a rifted, continental structure located on the eastern flank of the Lord Howe Rise, to the southwest of New Caledonia. Two main reflectors are documented: the shallower (RN) mimics the seafloor and has a negative polarity while the deeper (RP) does not always mimic the seafloor and has a positive polarity. Using the existing regional seismic lines, we can show that reflector RN can be continuously followed up to DSDP 208 drill hole site. Reflector RP is discontinuous and cannot be traced... |
| Tipo: Text |
Palavras-chave: Stratigraphy; Gas hydrates; Geophysics; Southwest Pacific; Fairway Basin; BSR. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-7321.pdf |
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| Ker, Stephan; Thomas, Yannick; Riboulot, Vincent; Sultan, Nabil; Bernard, Céline; Scalabrin, Carla; Ion, G; Marsset, Bruno. |
| A comprehensive characterization of the gas hydrate system offshore the western Black Sea was performed through an integrated analysis of geophysical data. We detected the Bottom Simulating Reflector (BSR), which marks, in this area, the base of gas hydrate stability. The observed BSR depth does not fit the theoretical steady-state base of gas hydrate stability zone (BGHSZ). We show that the disparity between the BSR and predicted BGHSZ is the result of a transient state of the hydrate system due to the ongoing re-equilibrium since the Last Glacial Maximum. When gas hydrates are brought outside the stability zone due to changes in temperature and sea level, their dissociation generates an increase in interstitial pore pressure. This process is favorable to... |
| Tipo: Text |
Palavras-chave: Gas hydrate; BSR; Excess pore pressure; Black Sea. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00474/58531/61081.pdf |
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| Riboulot, Vincent; Cattaneo, Antonio; Scalabrin, Carla; Gaillot, Arnaud; Jouet, Gwenael; Ballas, Gregory; Marsset, Tania; Garziglia, Sebastien; Ker, Stephan. |
| The Romanian sector of the Black Sea deserves attention because the Danube deep-sea fan is one of the largest sediment depositional systems worldwide and is considered the world's most isolated sea, the largest anoxic water body on the planet and a unique energy-rich sea. Due to the high sediment accumulation rate, presence of organic matter and anoxic conditions, the Black sea sediments offshore the Danube delta is rich in gas and thus shows Bottom Simulating Reflectors (BSR). The cartography of the BSR over the last 20 years, exhibits its widespread occurrence, indicative of extensive development of hydrate accumulations and a huge gas hydrate potential. By combining old and new datasets acquired in 2015 during the GHASS expedition, we performed a... |
| Tipo: Text |
Palavras-chave: Hydrates de gaz; Gaz libre; Panaches de gaz; BSR; Mer Noire; Géomorphologie; Gas hydrates; Free gas; Gas flares; BSR; Black Sea; Geomorphology. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00407/51860/53914.pdf |
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| Villar-muñoz, Lucía; Vargas-cordero, Iván; Bento, Joaquim; Tinivella, Umberta; Fernandoy, Francisco; Giustiniani, Michela; Behrmann, Jan; Calderón-díaz, Sergio. |
| Large amounts of gas hydrate are present in marine sediments offshore Taitao Peninsula, near the Chile Triple Junction. Here, marine sediments on the forearc contain carbon that is converted to methane in a regime of very high heat flow and intense rock deformation above the downgoing oceanic spreading ridge separating the Nazca and Antarctic plates. This regime enables vigorous fluid migration. Here, we present an analysis of the spatial distribution, concentration, estimate of gas-phases (gas hydrate and free gas) and geothermal gradients in the accretionary prism, and forearc sediments offshore Taitao (45.5°–47° S). Velocity analysis of Seismic Profile RC2901-751 indicates gas hydrate concentration values <10% of the total rock volume and extremely... |
| Tipo: Text |
Palavras-chave: BSR; Gas hydrate; Methane; Seepage; Active margin; Chile Triple Junction. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00475/58678/61173.pdf |
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