A first estimation of gas hydrates offshore Patagonia (Chile)

Lucía Villar-Muñoz, Joaquim P. Bento, Dirk Klaeschen, Umberta Tinivella, Iván de la Cruz Vargas-Cordero, Jan H. Behrmann

Resultado de la investigación: Article

Resumen

In many places along the central and southern Chilean active continental margin sedimentary successions covering the forearc contain methane hydrate, resulting from a mixture of biogenic and thermogenic processes. Here, we report the spatial distribution of gas hydrate in the accretionary prism and forearc sediments offshore western Patagonia (50°S and 57°S), landward of the Antarctica-South America plate boundary. Knowledge of the forearc structure here is limited, owing to the small number of reflection seismic profiles available, lack of high-resolution bathymetry data and the absence of scientific drillholes. However bottom-simulating reflectors (BSR) indicative of gas hydrate occur regionally extensive below about one third of the forearc slope, between about 280 and 630 m below sea floor. BSR-derived heat flow was calculated at about 30 and 70 mWm−2. These are typical values above subduction zones of oceanic crust older than 10 Ma, where vigorous fluid flow above young and hot subducting oceanic crust has leveled off. To move towards an estimate of gas hydrate present in the sediments, the velocity model was converted into a gas-phase concentration model using data from one of the seismic sections. Average thickness of gas hydrate is about 290 m, and average concentrations estimated are in a range of 3.4%–10%. If we use the minimum value of 3.4%, the amount of methane present in the region is about 3.0 × 1013 m3 at standard pressure-temperature conditions. We conclude that the Pacific forearc of Patagonia area is an important reservoir of methane hydrates and we propose this area be considered as a potential methane hydrate concentrated zone and a key area to be investigated in the future.

IdiomaEnglish
Páginas232-239
Número de páginas8
PublicaciónMarine and Petroleum Geology
Volumen96
DOI
EstadoPublished - 1 sep 2018

Huella dactilar

Chile
gas hydrate
hydrates
methane
gases
oceanic crust
accretionary prism
reflectors
plate boundary
bathymetry
crusts
heat flow
sediments
sediment
seismic reflection
subduction zone
fluid flow
continental margin
seafloor
spatial distribution

Keywords

    ASJC Scopus subject areas

    • Oceanography
    • Geophysics
    • Geology
    • Economic Geology
    • Stratigraphy

    Citar esto

    Villar-Muñoz, Lucía ; Bento, Joaquim P. ; Klaeschen, Dirk ; Tinivella, Umberta ; Vargas-Cordero, Iván de la Cruz ; Behrmann, Jan H. / A first estimation of gas hydrates offshore Patagonia (Chile). En: Marine and Petroleum Geology. 2018 ; Vol. 96. pp. 232-239.
    @article{974c668fb4d644c087dc25ffa8aaec92,
    title = "A first estimation of gas hydrates offshore Patagonia (Chile)",
    abstract = "In many places along the central and southern Chilean active continental margin sedimentary successions covering the forearc contain methane hydrate, resulting from a mixture of biogenic and thermogenic processes. Here, we report the spatial distribution of gas hydrate in the accretionary prism and forearc sediments offshore western Patagonia (50°S and 57°S), landward of the Antarctica-South America plate boundary. Knowledge of the forearc structure here is limited, owing to the small number of reflection seismic profiles available, lack of high-resolution bathymetry data and the absence of scientific drillholes. However bottom-simulating reflectors (BSR) indicative of gas hydrate occur regionally extensive below about one third of the forearc slope, between about 280 and 630 m below sea floor. BSR-derived heat flow was calculated at about 30 and 70 mWm−2. These are typical values above subduction zones of oceanic crust older than 10 Ma, where vigorous fluid flow above young and hot subducting oceanic crust has leveled off. To move towards an estimate of gas hydrate present in the sediments, the velocity model was converted into a gas-phase concentration model using data from one of the seismic sections. Average thickness of gas hydrate is about 290 m, and average concentrations estimated are in a range of 3.4{\%}–10{\%}. If we use the minimum value of 3.4{\%}, the amount of methane present in the region is about 3.0 × 1013 m3 at standard pressure-temperature conditions. We conclude that the Pacific forearc of Patagonia area is an important reservoir of methane hydrates and we propose this area be considered as a potential methane hydrate concentrated zone and a key area to be investigated in the future.",
    keywords = "BSR, Chile, Forearc, Gas hydrate, Heat flow, Patagonia",
    author = "Luc{\'i}a Villar-Mu{\~n}oz and Bento, {Joaquim P.} and Dirk Klaeschen and Umberta Tinivella and Vargas-Cordero, {Iv{\'a}n de la Cruz} and Behrmann, {Jan H.}",
    year = "2018",
    month = "9",
    day = "1",
    doi = "10.1016/j.marpetgeo.2018.06.002",
    language = "English",
    volume = "96",
    pages = "232--239",
    journal = "Marine and Petroleum Geology",
    issn = "0264-8172",
    publisher = "Elsevier BV",

    }

    A first estimation of gas hydrates offshore Patagonia (Chile). / Villar-Muñoz, Lucía; Bento, Joaquim P.; Klaeschen, Dirk; Tinivella, Umberta; Vargas-Cordero, Iván de la Cruz; Behrmann, Jan H.

    En: Marine and Petroleum Geology, Vol. 96, 01.09.2018, p. 232-239.

    Resultado de la investigación: Article

    TY - JOUR

    T1 - A first estimation of gas hydrates offshore Patagonia (Chile)

    AU - Villar-Muñoz, Lucía

    AU - Bento, Joaquim P.

    AU - Klaeschen, Dirk

    AU - Tinivella, Umberta

    AU - Vargas-Cordero, Iván de la Cruz

    AU - Behrmann, Jan H.

    PY - 2018/9/1

    Y1 - 2018/9/1

    N2 - In many places along the central and southern Chilean active continental margin sedimentary successions covering the forearc contain methane hydrate, resulting from a mixture of biogenic and thermogenic processes. Here, we report the spatial distribution of gas hydrate in the accretionary prism and forearc sediments offshore western Patagonia (50°S and 57°S), landward of the Antarctica-South America plate boundary. Knowledge of the forearc structure here is limited, owing to the small number of reflection seismic profiles available, lack of high-resolution bathymetry data and the absence of scientific drillholes. However bottom-simulating reflectors (BSR) indicative of gas hydrate occur regionally extensive below about one third of the forearc slope, between about 280 and 630 m below sea floor. BSR-derived heat flow was calculated at about 30 and 70 mWm−2. These are typical values above subduction zones of oceanic crust older than 10 Ma, where vigorous fluid flow above young and hot subducting oceanic crust has leveled off. To move towards an estimate of gas hydrate present in the sediments, the velocity model was converted into a gas-phase concentration model using data from one of the seismic sections. Average thickness of gas hydrate is about 290 m, and average concentrations estimated are in a range of 3.4%–10%. If we use the minimum value of 3.4%, the amount of methane present in the region is about 3.0 × 1013 m3 at standard pressure-temperature conditions. We conclude that the Pacific forearc of Patagonia area is an important reservoir of methane hydrates and we propose this area be considered as a potential methane hydrate concentrated zone and a key area to be investigated in the future.

    AB - In many places along the central and southern Chilean active continental margin sedimentary successions covering the forearc contain methane hydrate, resulting from a mixture of biogenic and thermogenic processes. Here, we report the spatial distribution of gas hydrate in the accretionary prism and forearc sediments offshore western Patagonia (50°S and 57°S), landward of the Antarctica-South America plate boundary. Knowledge of the forearc structure here is limited, owing to the small number of reflection seismic profiles available, lack of high-resolution bathymetry data and the absence of scientific drillholes. However bottom-simulating reflectors (BSR) indicative of gas hydrate occur regionally extensive below about one third of the forearc slope, between about 280 and 630 m below sea floor. BSR-derived heat flow was calculated at about 30 and 70 mWm−2. These are typical values above subduction zones of oceanic crust older than 10 Ma, where vigorous fluid flow above young and hot subducting oceanic crust has leveled off. To move towards an estimate of gas hydrate present in the sediments, the velocity model was converted into a gas-phase concentration model using data from one of the seismic sections. Average thickness of gas hydrate is about 290 m, and average concentrations estimated are in a range of 3.4%–10%. If we use the minimum value of 3.4%, the amount of methane present in the region is about 3.0 × 1013 m3 at standard pressure-temperature conditions. We conclude that the Pacific forearc of Patagonia area is an important reservoir of methane hydrates and we propose this area be considered as a potential methane hydrate concentrated zone and a key area to be investigated in the future.

    KW - BSR

    KW - Chile

    KW - Forearc

    KW - Gas hydrate

    KW - Heat flow

    KW - Patagonia

    UR - http://www.scopus.com/inward/record.url?scp=85048539171&partnerID=8YFLogxK

    U2 - 10.1016/j.marpetgeo.2018.06.002

    DO - 10.1016/j.marpetgeo.2018.06.002

    M3 - Article

    VL - 96

    SP - 232

    EP - 239

    JO - Marine and Petroleum Geology

    T2 - Marine and Petroleum Geology

    JF - Marine and Petroleum Geology

    SN - 0264-8172

    ER -