Source rock potential of an Eocene carbonate slope: The Armancies Formation of the south-Pyrenean basin, northeast Spain
- Universitat de Barcelona (Spain)
The Armancies Formation is an Eocene carbonate slope succession in the Catalonian South Pyrenean basin. It ranges from 500 to 700 m in thickness. The first 200 m are made of a thin-bedded facies of wackestones alternating with dark pelagic fauna of miliolid, ostracods, bryozoans, and planktonic foraminifers and show significant bioturbation. They also show a low organic content (< 0.5% TOC). The lime-mudstone beds show a massive structure or planar millimeter laminations. They may contain sparse pelagic fossils of planktonic foraminifers, ostracods, and dinoflagellates; they do not show any bioturbation, and have high TOC values, which can reach individual scores of about 14%. They qualify, therefore, as a typical oil shale. Rock-Eval Pyrolysis analysis affords a mean S{sub 2} value of 25 mg HC/g. Mean S{sub 1} value is around 1.0 mg HC/g. As is typical of an initial oil window, T{sub max} maturity parameter ranges from 432 to 440{degree}C (mean = 434{degree}C). This degree of evolution is in accordance with the very low value of carbonyl and carboxyl groups, as determined by IR spectrometry and NMR on Fischer assay extract. The proton NMR shows an aromatic/aliphatic hydrocarbon ratio of 1:4, as expected in earlier stages of catagenesis. N-alkane gas chromatography profiles show n-C{sub 15} to n-C{sub 19} prevalence and that neither even nor odd carbon numbers prevail. This distribution perfectly matches that of typical sediments of marine origin and also agrees with obtained hydrogen index values (mean HI = 500 mg HC/g TOC). Sedimentological and geochemical results indicate an autochthonous marine organic matter and the potential of these slope shales is good oil-prone source beds.
- OSTI ID:
- 5537465
- Report Number(s):
- CONF-8809346--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 72:8; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
ANIMALS
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CARBONATE ROCKS
CENOZOIC ERA
CHEMICAL REACTIONS
CHROMATOGRAPHY
DECOMPOSITION
DEVELOPING COUNTRIES
ENERGY SOURCES
EUROPE
FORAMINIFERA
FOSSIL FUELS
FOSSILS
FUELS
GAS CHROMATOGRAPHY
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
INVERTEBRATES
MATERIALS
MATURATION
MICROORGANISMS
MINERAL RESOURCES
OIL SHALES
PETROLEUM DEPOSITS
PROTOZOA
PYROLYSIS
RESOURCES
ROCKS
SARCODINA
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEPARATION PROCESSES
SOURCE ROCKS
SPAIN
TERTIARY PERIOD
THERMOCHEMICAL PROCESSES
WESTERN EUROPE