Active processes on a mixed clastic carbonate Brazilian shelf margin: Importance for hydrocarbon exploration in turbidites

Conference · Fri Mar 01 04:00:00 EST 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5875434

Cainelli, C ^[1]

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1. Petrobras, Rio de Janeiro (Brazil)

The search for subtle hydrocarbon accumulations in turbidite systems requires additional approaches for more successful exploration, particularly when direct recognition on seismic lines is difficult. This includes the determination and understanding of processes controlling sand distribution on the shelf and the mapping of sand pathways from the shelf to the slop/basin that can guide efforts to look for more favorable sites for turbidite sandstone deposition. The approach can be exemplified in the Sergipe-Alagoas basin, on the Brazillian Atlantic passive margin. The section analyzed is the Piacabucu Formation, a thick seaward prograding wedge composed of coastal sandstones and shelf edge carbonates on a narrow shelf and slope-basin shales with turbidite lenses. Waves and currents control the redistribution of sediments transported to the shelf by rivers. More wave energy is expended in ten hours in the San Francisco delta than in an entire year in the Mississippi delta. Such environment precludes deposition of mud on the shelf, but it stimulates the development of shelf edge carbonates. Rimed carbonates along the shelf break serve as a barrier for downslope movements of coarse-grained sediment, where turbidites are oil targets. The search for gaps in the carbonate barrier which can tap the behind-barrier sands is critical for sand-rich turbidite development. It is believed that canyons create these gaps and act as active turbidity current routes.

• OSTI ID: 5875434
• Report Number(s): CONF-910403--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
03 NATURAL GAS
030200 -- Natural Gas-- Reserves
Geology
& Exploration
BRAZIL
CONTINENTAL MARGIN
CURRENTS
DEPOSITION
DEVELOPING COUNTRIES
EXPLORATION
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
LATIN AMERICA
MINERAL RESOURCES
NATURAL GAS DEPOSITS
OFFSHORE SITES
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
RESERVOIR ROCK
RESOURCES
ROCKS
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SOURCE ROCKS
SOUTH AMERICA
STRATIGRAPHY
SUBMARINE CANYONS
WATER CURRENTS