Estimación de hidratos de metano y gas libre mediante análisis sísmico frente a Chiloé (Chile)

Translated title of the contribution: 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

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

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).

Translated title of the contributionGas hydrate and free gas estimation from seismic analysis offshore Chiloé island (Chile)
Original languageSpanish
Pages (from-to)263-274
Number of pages12
JournalAndean Geology
Volume43
Issue number3
DOIs
Publication statusPublished - Sep 2016

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology
  • Stratigraphy
  • Palaeontology

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