The 1-AB block fields-a giant oil accumulation in Eastern Peru

Conference · Mon Feb 01 04:00:00 EST 1993 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:6105024

Jarvis, H A; Lay, V ^[1]; Orosco, C ^[2]

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1. Occidental International Exploration and Production Company, Lima (Peru)
2. Occidental Petroleum Corporation, Lima (Peru)

The 1-Ab block fields are located in the northeastern part of Peru. Geologically, the area is the sub-Andean Maranon Basin, a continuation of the Napo Basin from eastern Ecuador. During the 20 years that Occidental has operated Block 1-AB, approximately 11,500 km of seismic data has been recorded and 34 exploratory wells have been drilled, resulting in the discovery of 18 fields, or 53% exploration success. The 1-AB oil accumulation discovered in 1972 is a group of medium to small asymmetric anticlines distributed along six northwest-southeast trending structural alignments: North Capahuari-South Capahuari-Tambo, Carmen-North San Jaacinto and Bartra. This concentration of productive structures in a relative small area is unique within the Maranon basin. The controlling factors include exceptional pre-Cretaceous uplifting and the presence of very good to excellent Cretaceous sandstones reservoirs. The two major Cretaceous producing zones, the Chonta and Vivian sandstones, have been defined within the Coniacian and Campanian ages respectively. The Chonta sands are related to shelfal deposition across Block 1-AB, represented by strand plain and barrier island sediments. The Vivian formation is a massive fluvial sandstone covering all of the Maranon basin and ranging in thickness between 40 and 200 feet. After oil was accumulated, fresh water influxes into the reservoirs of the northern and eastern fields caused oil biodegradation and salinity variation of the reservoir waters, depending upon the intensity of biodegradation. Oil remigration also has been documented for the South Huayari field.

• OSTI ID: 6105024
• Report Number(s): CONF-930306--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 77:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
ANTICLINES
BIODEGRADATION
CHEMICAL REACTIONS
DECOMPOSITION
DEPOSITION
DEVELOPING COUNTRIES
DIMENSIONS
ENERGY SOURCES
EXPLORATORY WELLS
FOSSIL FUELS
FUELS
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
LATIN AMERICA
MINERAL RESOURCES
OIL FIELDS
PERU
PETROLEUM
PETROLEUM DEPOSITS
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SEDIMENTS
SOUTH AMERICA
THICKNESS
WATER INFLUX
WELLS