Geochemistry of natural gases from mud volcanoes and surface gas seeps in NW-Columbia

Conference · Fri Mar 01 00:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5867068

Beeunas, M A ^[1]; Schoell, M ^[2]; Beroiz, C ^[3]

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1. Chevron U.S.A., New Orleans, LA (United States)
2. Chevron Oil Field Research Co., La Habra, CA (United States)
3. Chevron Overseas Petroleum Inc., San Ramon, CA (United States)

Mud volcanoes and natural gas seeps are common in the southwest-northeast-trending Sinu Atlantico basin (SAB) and San Jacinto Fold Belt (SJFB) of NW-Colombia. The structural subunits are part of a highly complex active continental margin where the sediments become increasingly younger to the west from Late Cretaceous to Early Tertiary in the SJFB to Late Tertiary in the SAB. Some of the mud volcanoes are permanently active and form huge structures and are often aligned along major faults. Both seep and mud volcano gases are with low C{sub 2}-C{sub 4} and CO{sub 2} contents. Carbon and hydrogen isotope concentrations allow the subdivision into four groups of gas. These gases can be divided into four genetic based on their carbon and hydrocarbon isotope compositions. The isotopic variability of the different groups attests to the fact that very different gas-forming processes are or have been operating in the subsurface ranging from low-temperature thermogenesis. The various groups show, with few exceptions, a distinct regional distribution: Mud volcanoes and seeps with bacterial gases are restricted to the southern part of the SAB where the greatest thickness of young sediments is observed; gases of mixed thermogenic and bacterial origin are found in the coastal areas of the northern SAB; gases of thermogenic origin are predominantly observed in the SJFB; the thermogenic gases of Group 3 are restricted to two locations in the north of the SJFB. This regional association of genetic gas types with specific geotectonic units reflects different thermal histories of the respective tectonic areas and allowed the authors to delineate prospective areas for oil in NW-Colombia.

• OSTI ID: 5867068
• Report Number(s): CONF-910403-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 75:3; Conference: Annual meeting of the American Association of Petroleum Geologists (AAPG), Dallas, TX (United States), 7-10 Apr 1991; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
02 PETROLEUM
58 GEOSCIENCES
COLOMBIA
NATURAL GAS DEPOSITS
PETROLEUM DEPOSITS
NATURAL GAS
CHEMICAL COMPOSITION
GEOCHEMISTRY
EXPLORATION
CRETACEOUS PERIOD
GEOLOGIC HISTORY
ISOTOPE RATIO
METHANE
ORIGIN
RESOURCE POTENTIAL
SEDIMENTARY BASINS
TERTIARY PERIOD
ALKANES
CENOZOIC ERA
CHEMISTRY
DEVELOPING COUNTRIES
ENERGY SOURCES
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
HYDROCARBONS
LATIN AMERICA
MESOZOIC ERA
MINERAL RESOURCES
ORGANIC COMPOUNDS
RESOURCES
SOUTH AMERICA
033000* - Natural Gas- Properties & Composition
020200 - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences