Gas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile)
Fuente:
Redalyc
Saved in:
| Main Author: | |
|---|---|
| Format: | Artículo científico |
| Language: | en |
| Published: |
Servicio Nacional de Geología y Minería
2016
|
| Subjects: | |
| Online Access: | |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1876437711312650240 |
|---|---|
| author | Iván de la Cruz Vargas-Cordero |
| author_facet | Iván de la Cruz Vargas-Cordero |
| contents | Gas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile) Iván de la Cruz Vargas-Cordero Umberta Tinivella Lucía Villar-Muñoz Michela Giustiniani Ciencias de la Tierra AVO BSR BGR Pre Free gas In this study one seismic section offshore Chiloé Island was analyzed to better define the seismic character of the hydrate-bearing sediments. The velocity analysis was used to estimate the gas-phase concentration and relate it to the geological features. The velocity model allowed us to recognize two important layers that characterize hydrate- and free gas-bearing sediments above and below the BSR respectively: one located above the BSR, characterized by high velocity (1,800-2,200 m/s) and a second one, below the BSR, characterized by low velocity (1,600-1,700 m/s). A weak reflector at about 100 m below the BSR marks the base of the second layer. AVO analysis and offset stack sections confirming that the reflector interpreted as BGR is related to free gas presence in the pore space. The velocity field is affected by lateral variation, showing maximum (above the BSR) and minimum (below the BSR) values in the sector. Here, the highest gas hydrate and free gas concentrations were calculated, obtaining 9.5% and 0.5% of total volume respectively. A variable BSR depth (from 300 to 600 mbsf) can be justified supposing a variable geothermal gradient (from 25 to 45 °C/km). 2016 artículo científico 0718-7092 https://www.redalyc.org/articulo.oa?id=173947692002 https://www.redalyc.org/journal/1739/173947692002/ https://www.redalyc.org/journal/1739/173947692002/html/ https://www.redalyc.org/journal/1739/173947692002/173947692002.epub https://www.redalyc.org/journal/1739/173947692002/movil en http://www.redalyc.org/revista.oa?id=1739 Andean Geology application/pdf Servicio Nacional de Geología y Minería Andean Geology (Chile) Num.3 Vol.43 |
| format | Artículo científico |
| id | redalyc_173947692002 |
| institution | Redalyc |
| language | en |
| publishDate | 2016 |
| publisher | Servicio Nacional de Geología y Minería |
| spellingShingle | Gas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile) Iván de la Cruz Vargas-Cordero Ciencias de la Tierra AVO BSR BGR Pre Free gas Gas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile) Iván de la Cruz Vargas-Cordero Umberta Tinivella Lucía Villar-Muñoz Michela Giustiniani Ciencias de la Tierra AVO BSR BGR Pre Free gas In this study one seismic section offshore Chiloé Island was analyzed to better define the seismic character of the hydrate-bearing sediments. The velocity analysis was used to estimate the gas-phase concentration and relate it to the geological features. The velocity model allowed us to recognize two important layers that characterize hydrate- and free gas-bearing sediments above and below the BSR respectively: one located above the BSR, characterized by high velocity (1,800-2,200 m/s) and a second one, below the BSR, characterized by low velocity (1,600-1,700 m/s). A weak reflector at about 100 m below the BSR marks the base of the second layer. AVO analysis and offset stack sections confirming that the reflector interpreted as BGR is related to free gas presence in the pore space. The velocity field is affected by lateral variation, showing maximum (above the BSR) and minimum (below the BSR) values in the sector. Here, the highest gas hydrate and free gas concentrations were calculated, obtaining 9.5% and 0.5% of total volume respectively. A variable BSR depth (from 300 to 600 mbsf) can be justified supposing a variable geothermal gradient (from 25 to 45 °C/km). 2016 artículo científico 0718-7092 https://www.redalyc.org/articulo.oa?id=173947692002 https://www.redalyc.org/journal/1739/173947692002/ https://www.redalyc.org/journal/1739/173947692002/html/ https://www.redalyc.org/journal/1739/173947692002/173947692002.epub https://www.redalyc.org/journal/1739/173947692002/movil en http://www.redalyc.org/revista.oa?id=1739 Andean Geology application/pdf Servicio Nacional de Geología y Minería Andean Geology (Chile) Num.3 Vol.43 |
| title | Gas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile) |
| topic | Ciencias de la Tierra AVO BSR BGR Pre Free gas |
| url | https://www.redalyc.org/articulo.oa?id=173947692002 https://www.redalyc.org/journal/1739/173947692002/ https://www.redalyc.org/journal/1739/173947692002/html/ https://www.redalyc.org/journal/1739/173947692002/173947692002.epub https://www.redalyc.org/journal/1739/173947692002/movil |