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Title: Petroleum migration in Denver basin inferred from thermal maturity and hydrologic data

Abstract

Cretaceous petroleum accumulations in the Denver basin of eastern Colorado and southwestern Nebraska occur in a productive fairway where potential source rocks are thermally immature for oil generation. Reconstructed potentiometric surfaces, vitrinite reflectance (R/sub 0/), and other thermal maturity data suggest that fluids within the basin have migrated hundreds of kilometers from western thermally mature areas (> 0.65% R/sub 0/) updip to eastern thermally immature areas (< 0.50% R/sub 0/). Oil fields such as Adena and Little Beaver with cumulative production of tens of millions of bbl of oil occur where R/sub 0/ is below the threshold 0.60% value, the commonly accepted value that indicates the beginning of thermogenic petroleum generation. Variations in cementation, evidenced in the Denver basin by present east-to-west reductions in porosity and permeability, may have affected secondary migration. Ground-water potentials for the Lower Cretaceous J sandstone, calculated from drill-stem test data, decrease from west to east across the basin with a gradient of about 3 m/km. Local potential minima in Morgan and Logan Counties, as well as an increase information water salinity from 1000 ppm to 12,000 ppm toward the basin center, suggest the concentration of formation fluids in those areas. About 65 Ma, when Cretaceousmore » shales first became mature enough to expel hydrocarbons, the initial uplift of the Rocky Mountains created a fluid potential field similar to the present one but of greater magnitude. This ancestral potential caused the generated hydrocarbons to migrate eastward; oil pools then concentrated at paleopotential minima. The analysis of fluid potential gradients makes it possible to determine the dynamics of forces that redistribute fluids in a basin.« less

Authors:
; ;
Publication Date:
Research Org.:
Harvard Univ., Cambridge, MA
OSTI Identifier:
5993217
Report Number(s):
CONF-870606-
Journal ID: CODEN: AABUD
Resource Type:
Conference
Journal Name:
AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)
Additional Journal Information:
Journal Volume: 71:5; Conference: American Association of Petroleum Geologists annual meeting, Los Angeles, CA, USA, 7 Jun 1987
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; COLORADO; PETROLEUM DEPOSITS; SEDIMENTARY BASINS; NEBRASKA; ORIGIN; SOURCE ROCKS; MATURATION; CRETACEOUS PERIOD; MACERALS; OPTICAL PROPERTIES; PERMEABILITY; POROSITY; RESERVOIR ROCK; SANDSTONES; FEDERAL REGION VII; FEDERAL REGION VIII; GEOLOGIC AGES; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; MESOZOIC ERA; MINERAL RESOURCES; NORTH AMERICA; PHYSICAL PROPERTIES; RESOURCES; ROCKS; SEDIMENTARY ROCKS; USA; 020200* - Petroleum- Reserves, Geology, & Exploration

Citation Formats

Jones, Jr, E A, Gautier, D L, and Siever, R. Petroleum migration in Denver basin inferred from thermal maturity and hydrologic data. United States: N. p., 1987. Web.
Jones, Jr, E A, Gautier, D L, & Siever, R. Petroleum migration in Denver basin inferred from thermal maturity and hydrologic data. United States.
Jones, Jr, E A, Gautier, D L, and Siever, R. Fri . "Petroleum migration in Denver basin inferred from thermal maturity and hydrologic data". United States.
@article{osti_5993217,
title = {Petroleum migration in Denver basin inferred from thermal maturity and hydrologic data},
author = {Jones, Jr, E A and Gautier, D L and Siever, R},
abstractNote = {Cretaceous petroleum accumulations in the Denver basin of eastern Colorado and southwestern Nebraska occur in a productive fairway where potential source rocks are thermally immature for oil generation. Reconstructed potentiometric surfaces, vitrinite reflectance (R/sub 0/), and other thermal maturity data suggest that fluids within the basin have migrated hundreds of kilometers from western thermally mature areas (> 0.65% R/sub 0/) updip to eastern thermally immature areas (< 0.50% R/sub 0/). Oil fields such as Adena and Little Beaver with cumulative production of tens of millions of bbl of oil occur where R/sub 0/ is below the threshold 0.60% value, the commonly accepted value that indicates the beginning of thermogenic petroleum generation. Variations in cementation, evidenced in the Denver basin by present east-to-west reductions in porosity and permeability, may have affected secondary migration. Ground-water potentials for the Lower Cretaceous J sandstone, calculated from drill-stem test data, decrease from west to east across the basin with a gradient of about 3 m/km. Local potential minima in Morgan and Logan Counties, as well as an increase information water salinity from 1000 ppm to 12,000 ppm toward the basin center, suggest the concentration of formation fluids in those areas. About 65 Ma, when Cretaceous shales first became mature enough to expel hydrocarbons, the initial uplift of the Rocky Mountains created a fluid potential field similar to the present one but of greater magnitude. This ancestral potential caused the generated hydrocarbons to migrate eastward; oil pools then concentrated at paleopotential minima. The analysis of fluid potential gradients makes it possible to determine the dynamics of forces that redistribute fluids in a basin.},
doi = {},
journal = {AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)},
number = ,
volume = 71:5,
place = {United States},
year = {1987},
month = {5}
}

Conference:
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