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Title: Faulted shoreline and tidal deposits in the Moenkopi Formation of the Grassy Trail Creek field, Utah

Abstract

The Grassy Trail Creek field produces 40{degrees} API oil and minor gas from shallow marine sandstones of the Triassic Moenkopi Formation on the north-plunging nose of the San Rafael swell in central Utah. Production is controlled by a combination of stratigraphic variations and minor north-south-trending faults. Although fracture permeability enhances production of the reservoir, some faults act as barriers to fluid migration, segmenting the area into productive and dry fault blocks. Horizontal drilling techniques developed in this field in the early 1980s resulted in significantly better production. Log analyses indicate the main reservoir is a complex stack of this thin tidal channel sandstones. Isochore maps of the A and B zones indicate thickened meanders that form localized reservoir pods that are vertically offset. The distribution of isochore thicks appears to represent deposition along a northwest-southeast-trending shoreline fed by sediments from the northeast. There is potential for field extensions in similar deposits along this paleoshoreline. The Moenkopi Formation, long thought to be self-sourcing, may contain oil generated in Precambrian sediments equivalent to the Late Proterozoic Chuar Group. Presence of this older oil would have required migration from Precambrian sedimentary rocks surrounding the San Rafael swell.

Authors:
 [1];  [2]
  1. Utah Geological and Mineral Survey, Salt Lake City (United States)
  2. Univ. of Utah Research Inst., Salt Lake City (United States)
Publication Date:
OSTI Identifier:
6093814
Report Number(s):
CONF-9107109-
Journal ID: ISSN 0149-1423; CODEN: AABUD
Resource Type:
Conference
Journal Name:
AAPG Bulletin (American Association of Petroleum Geologists); (United States)
Additional Journal Information:
Journal Volume: 75:6; Conference: American Association of Petroleum Geologists (AAPG) Rocky Mountain Section meeting, Billings, MT (United States), 28-31 Jul 1991; Journal ID: ISSN 0149-1423
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; GEOLOGIC TRAPS; PETROLEUM GEOLOGY; PETROLEUM DEPOSITS; STRATIGRAPHY; UTAH; DIRECTIONAL DRILLING; DOLOMITE; DRILL CORES; GEOLOGIC FAULTS; GEOLOGIC FORMATIONS; GEOLOGIC FRACTURES; GEOLOGIC HISTORY; OIL FIELDS; PERMEABILITY; PRODUCTION; RESERVOIR ROCK; SANDSTONES; TRIASSIC PERIOD; CARBONATE MINERALS; DEVELOPED COUNTRIES; DRILLING; FEDERAL REGION VIII; GEOLOGIC AGES; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; GEOLOGY; MESOZOIC ERA; MINERAL RESOURCES; MINERALS; NORTH AMERICA; RESOURCES; ROCKS; SEDIMENTARY ROCKS; USA; 020200* - Petroleum- Reserves, Geology, & Exploration

Citation Formats

Allison, M L, and Lutz, S J. Faulted shoreline and tidal deposits in the Moenkopi Formation of the Grassy Trail Creek field, Utah. United States: N. p., 1991. Web.
Allison, M L, & Lutz, S J. Faulted shoreline and tidal deposits in the Moenkopi Formation of the Grassy Trail Creek field, Utah. United States.
Allison, M L, and Lutz, S J. 1991. "Faulted shoreline and tidal deposits in the Moenkopi Formation of the Grassy Trail Creek field, Utah". United States.
@article{osti_6093814,
title = {Faulted shoreline and tidal deposits in the Moenkopi Formation of the Grassy Trail Creek field, Utah},
author = {Allison, M L and Lutz, S J},
abstractNote = {The Grassy Trail Creek field produces 40{degrees} API oil and minor gas from shallow marine sandstones of the Triassic Moenkopi Formation on the north-plunging nose of the San Rafael swell in central Utah. Production is controlled by a combination of stratigraphic variations and minor north-south-trending faults. Although fracture permeability enhances production of the reservoir, some faults act as barriers to fluid migration, segmenting the area into productive and dry fault blocks. Horizontal drilling techniques developed in this field in the early 1980s resulted in significantly better production. Log analyses indicate the main reservoir is a complex stack of this thin tidal channel sandstones. Isochore maps of the A and B zones indicate thickened meanders that form localized reservoir pods that are vertically offset. The distribution of isochore thicks appears to represent deposition along a northwest-southeast-trending shoreline fed by sediments from the northeast. There is potential for field extensions in similar deposits along this paleoshoreline. The Moenkopi Formation, long thought to be self-sourcing, may contain oil generated in Precambrian sediments equivalent to the Late Proterozoic Chuar Group. Presence of this older oil would have required migration from Precambrian sedimentary rocks surrounding the San Rafael swell.},
doi = {},
url = {https://www.osti.gov/biblio/6093814}, journal = {AAPG Bulletin (American Association of Petroleum Geologists); (United States)},
issn = {0149-1423},
number = ,
volume = 75:6,
place = {United States},
year = {Sat Jun 01 00:00:00 EDT 1991},
month = {Sat Jun 01 00:00:00 EDT 1991}
}

Conference:
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