The Boscan Field-Venezuela's giant stratigraphic trap with a complex history
- Swanson Consulting Services, Houston, TX (United States)
- Corpoven S.A., Caracas (Venezuela)
The Boscan Field lies in the northwest quadrant of the Maracaibo Basin, Venezuela. It is a large stratigraphic trap that has produced more than 800 million barrels of heavy oil since 1946, principally from Eocene fluvial-deltaic clastic reservoirs. These are faulted, folded, and are truncated by a pre-Oligocene unconformity. The geochronology of the Boscan Field has been interpreted as follows: (1) Eocene fluvial-deltaic deposits prograded east and southeast across the Boscan Field Area. A subsiding area northeast towards the State of Falcon received tremendous quantities of Eocene fine grained organic-rich deposits in pro-delta and deep water environments. (2) The Eocene shales in the deep basin began to generate hydrocarbons which migrated towards the west and southwest. (3) In the Boscan Area, Eocene deposits were folded, faulted, and tilted towards the east and southeast and an active fluvial flood-plain truncated the deposits resulting in subcrop bands that form the pre-Oligocene unconformity topographic surface. (4) Hydrocarbon generation and migration continues in the deep basin. (5) Oligocene fluvial sandstones deposited on the underlying unconformity often cut into and are in direct contact with truncated Eocene sandstones. This allowed some oil to leak up into the Oligocene deposits. (6) By the end of the Oligocene, migration of oil into the gross Boscan trap was well underway. The east-west and northwest southeast trending fluvial conduits carried the oil out of the Eocene basin northwestward until it was blocked by reservoir truncation on the west and northwest sides of the Boscan Field. (7) Regional subsidence of the Maracaibo Basin has caused the Boscan reservoirs to dip towards the southwest resulting in realignment of fluids. The present-day Boscan Field is a composite of stacked, linear, faulted, and truncated reservoir segments. They may be isolated or interactive with other segments and form a complex [open quotes]plumbing[close quotes] tangle.
- OSTI ID:
- 5939097
- Report Number(s):
- CONF-930306--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (United States), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Vol. 77:2; ISSN 0149-1423; ISSN AABUD2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Control of facies, burial history, and oil migration on diagenesis and reservoir quality: Maracaribo basin, Venezuela
Reservoir quality in relation to facies, burial history, and oil migration: A review
Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
CENOZOIC ERA
COASTAL REGIONS
DEVELOPING COUNTRIES
EOCENE EPOCH
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRUCTURES
GEOLOGIC TRAPS
GEOLOGY
HYDROCARBONS
LATIN AMERICA
MIGRATION
MINERAL RESOURCES
OIL FIELDS
ORGANIC COMPOUNDS
ORIENTATION
ORIGIN
PETROLEUM DEPOSITS
PETROLEUM GEOLOGY
RESERVOIR ROCK
RESOURCES
RIVER DELTAS
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
SHALES
SOURCE ROCKS
SOUTH AMERICA
STRATIGRAPHY
TERTIARY PERIOD
VENEZUELA