Detection of hydrocarbon microseepage in a rain forest environment (Jurua Gas field, northern Brazil) using Landsat MSS data

Conference · Tue May 01 00:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6673694

Miranda, F P; Cunha, F M.B. ^[1]

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1. Petrobras, New York, NY (USA)

The Jurua gas field is the first important hydrocarbon accumulation found in the jungle-covered Solimoes basin. The tectonic framework in this area is characterized by a right-lateral transpressional zone (Jurua structural trend). Hydrocarbon traps are anticlines developed along the upthrown block of a reverse fault. The prospective 2,200-m-thick Paleozoic section is unconformably covered by a 2,800-m-thick pile of Mesozoic and Cenozoic continental sediments. Anomalous concentrations of hydrocarbons (C{sub 2}-C{sub 4}) in soil samples are concordantly aligned with the trace of the reverse fault crossing the gas field, indicating that this feature acted as a conduit for hydrocarbon microseepage. Gas-producing wells are located over a tabular watershed which coincides with the northeast-southwest Jurua structural trend. An unsupervised classification of Landsat MSS data over the gas field area reveals that one spectral class of vegetation is aligned with the Jurua structural trend. Field checking shows that the vegetation near the gas-producing well 1-JR-1-AM is not as dense as the forest outside the limits of the Jurua gas field. Two geologic factors may account for the vegetation anomaly over the gas field. (1) The northeast-southwest tabular watershed corresponds to a Pleistocene erosional surface associated with weathering products such as bauxite and laterite. The resulting soil is impermeable and low in nutrients. (2) The spectral behavior of vegetation may represent the response of plants to long-term anaerobic soil conditions brought about by gas leakage from the Paleozoic reservoir.

• OSTI ID: 6673694
• Report Number(s): CONF-900605-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:5; Conference: Annual convention and exposition of the American Association of Petroleum Geologists, San Francisco, CA (USA), 3-6 Jun 1990; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
58 GEOSCIENCES
BRAZIL
NATURAL GAS DEPOSITS
EXPLORATION
ANTICLINES
GEOLOGIC TRAPS
PLANTS
QUATERNARY PERIOD
RESERVOIR ROCK
SEDIMENTARY BASINS
CENOZOIC ERA
DEVELOPING COUNTRIES
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
LATIN AMERICA
MINERAL RESOURCES
RESOURCES
SOUTH AMERICA
030200* - Natural Gas- Reserves
Geology
& Exploration
580000 - Geosciences