Tectonic control in source rock maturation and oil migration in Trinidad

Conference · Mon Feb 01 00:00:00 EST 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5941482

Persad, K M; Talukdar, S C; Dow, W G ^[1]

---

1. DGSI, The Woodlands, TX (United States)

Oil accumulation in Trinidad were sourced by the Upper Cretaceous calcareous shales deposited along the Cretaceous passive margin of northern South America. Maturation of these source rocks, oil generation, migration and re-migration occurred in a foreland basin setting that resulted from interaction between Caribbean and South American plates during Late Oligocene to recent times. During Middle Miocene-Recent times, the foreland basin experienced strong compressional events, which controlled generation, migration, and accumulation of oil in Trinidad. A series of mature source rock kitchens formed in Late Miocene-Recent times in the Southern and Colombus Basins to the east-southeast of the Central Range Thrust. This thrust and associated fratured developed around 12 m.y.b.p. and served as vertical migration paths for the oil generated in Late Miocene time. This oil migrated into submarine fans deposited in the foreland basin axis and older reservoirs deformed into structural traps. Further generation and migration of oil, and re-migration of earlier oil took place during Pliocene-Holocene times, when later thrusting and wrench faulting served as vertical migration paths. Extremely high sedimentation rates in Pliocene-Pleistocene time, concurrent with active faulting, was responsible for very rapid generation of oil and gas. Vertically migrating gas often mixed with earlier migrated oil in overlying reservoirs. This caused depletion of oil in light hydrocarbons with accompanied fractionation among hydrocarbon types resulting in heavier oil in lower reservoirs, enrichment of light hydrocarbons and accumulation of gas-condensates in upper reservoirs. This process led to an oil-gravity stratification within about 10,000 ft of section.

• OSTI ID: 5941482
• Report Number(s): CONF-930306-; CODEN: AABUD2
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (United States), Vol. 77:2; Conference: International congress of the American Association of Petroleum Geologists (AAPG), Caracas (Venezuela), 14-17 Mar 1993; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
GEOLOGIC FAULTS
TECTONICS
PETROLEUM
MIGRATION
SOURCE ROCKS
MATURATION
TRINIDAD AND TOBAGO
SEDIMENTARY BASINS
CRETACEOUS PERIOD
GEOLOGIC TRAPS
HYDROCARBONS
MIOCENE EPOCH
PETROLEUM DEPOSITS
PLATE TECTONICS
SEDIMENTATION
SHALES
STRATIFICATION
CENOZOIC ERA
ENERGY SOURCES
FOSSIL FUELS
FUELS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
ISLANDS
LESSER ANTILLES
MESOZOIC ERA
MINERAL RESOURCES
ORGANIC COMPOUNDS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
TERTIARY PERIOD
WEST INDIES
020200* - Petroleum- Reserves
Geology
& Exploration