The fractured Green River and Wasatch Formations of the Uinta Basins, Utah: Ideal targets for horizontal drilling

Conference · Sat Jun 01 04:00:00 EDT 1991 · AAPG Bulletin (American Association of Petroleum Geologists); (United States)

OSTI ID:5982515

Chidsey, T C; Morgan, C D ^[1]; Laine, M D ^[2]

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1. Utah Geological and Mineral Survey, Salt Lake City (United States)
2. Utah Division of Oil, Gas and Mining, Salt Lake City (United States)

The fractured Tertiary (Eocene) Green River and Wasatch Formations of the Uinta basin represent ideal targets for exploration and development using horizontal drilling techniques. These formations have the following characteristics favorable for horizontal drilling: (1) predictable orientations of natural fractures which control production; (2) multiple, low-permeability sandstone and siltstone reservoirs; (3) overpressured zones; and (4) thick, heterogeneous oil-bearing and oil-generating sequences. The Green River and Wasatch formations have produced over 200 million bbl of oil in the Uinta basin from conventional vertical wells. In the Greater Altamont-Bluebell field, the Wasatch and Green River formations represent an 8,000-ft-thick oil-bearing section, of which 2,500 ft is overpressured. Production occurs in multiple, low-matrix porosity, thin-bedded sandstones and siltstones which are widely distributed in the vertical sequence. Permeability is enhanced by vertical fractures exhibiting a single dominant north-northwest trend. These zones are excellent targets for horizontal (or high-angle) drilling perpendicular to the fractures. To the south, several fields occur along the east-west-trending Duchesne fracture zone with production from subtle, fractured structural noses such as the Duchesne field. One of the Duchesne field's 27 wells, the Ute Tribal 1, penetrated a greater fracture density in the Wasatch Formation than other wells in the field and accounts for nearly one-third of the total production. Similar results may be achieved with horizontal drilling techniques in existing fields and future discoveries in the Uinta basin.

• OSTI ID: 5982515
• Report Number(s): CONF-9107109--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (United States) Journal Volume: 75:6
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
020300 -- Petroleum-- Drilling & Production
CENOZOIC ERA
DEVELOPED COUNTRIES
DIRECTIONAL DRILLING
DRILLING
ENHANCED RECOVERY
EOCENE EPOCH
EXPLORATION
FEDERAL REGION VIII
FRACTURED RESERVOIRS
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPRESSURED SYSTEMS
GREEN RIVER FORMATION
MINERAL RESOURCES
NORTH AMERICA
OIL FIELDS
OIL WELLS
PETROLEUM DEPOSITS
PRODUCTION
PRODUCTIVITY
RECOVERY
RESERVOIR ROCK
RESOURCES
TERTIARY PERIOD
UINTA BASIN
USA
UTAH
WASATCH FORMATION
WELLS