El Furrial oil field, a new giant in an old basin

Conference · Sat Sep 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5990803

Prieto, R; Valdes, G ^[1]

---

1. Lagoven, S.A., Caracas (Venezuela)

In 1978, Lagoven S.A., affiliate of Petroleos de Venezuela S.A., started an exploration program for deeper tracts in the northern flank of the Eastern Venezuelan basin, where the shallow upper Tertiary section had been explored for more than eight decades. The quality of the seismic data collected was sufficient to indicate thrust faults with associated structures. From 1978 to 1985, surface geology surveying, structural modeling, and interpretation of seismic data were combined to define the first prospect, 1 El Furrial. The discovery well, 1 FUL, penetrated 276 m (905 ft) of net oil sand in an 80-km{sup 2} (31-mi{sup 2}) structure with a closure of 915 m (3,000 ft). 1 FUL tested up to 12,500 bbl/day of 29{degree} API oil. This is one of the largest single discoveries of medium-gravity oil in the last 25 yr in South America. Folding and thrusting of the northern flank of the Eastern Venezuela basin occurred during the collision of the Caribbean and the South American plates. The evolution began at least by the early Paleocene. Folds associated with thrusts tend to be cylindrical and are aligned in series up to 70 km (43 mi) long. There are three tectonic domains within the foreland basin: the northern edge, constituted by the Pirital allochthonous block; the thrusted and folded middle area where the field is located; and the extensional province toward the south. The reservoir rock is a shallow-marine sandstone deposited during the late Oligocene. Gross thickness ranges from 457 to 518 m (1,500 to 1,700 ft) and porosities range from 11 to 16%; the oil is considered of marine origin, mature, and from a Cretaceous source (Cenomanian-Turonian). The El Furrial discovery represents an excellent example of the prospectivity of a foreland overthrust area and an example of continued successful exploration in an area already considered mature in the pursuit of deeper objectives.

• OSTI ID: 5990803
• Report Number(s): CONF-9010204--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
ANTICLINES
CENOZOIC ERA
CRETACEOUS PERIOD
DEPOSITION
DEVELOPING COUNTRIES
EXPLORATION
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GEOPHYSICAL SURVEYS
LATIN AMERICA
MATURATION
MESOZOIC ERA
MINERAL RESOURCES
OIL FIELDS
ORIGIN
PETROLEUM DEPOSITS
POROSITY
RESERVOIR ROCK
RESOURCES
ROCKS
SAND
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEISMIC SURVEYS
SOUTH AMERICA
SURVEYS
TECTONICS
TERTIARY PERIOD
VENEZUELA