Strontium isotopic study of subsurface brines from Illinois basin
The abundance of the radiogenic isotope /sup 87/Sr in a subsurface brine can be used as a tracer of brine origin, evolution, and diagenetic effects. The authors have determined the /sup 87/Sr//sup 86/Sr ratios of over 60 oil-field waters from the Illinois basin, where brine origin is perplexing because of the absence of any significant evaporite strata. Initially, they analyzed brines from 15 petroleum-producing sandstone and carbonate units; waters from Ordovician, Silurian, Devonian, and Mississippian strata have /sup 87/Sr//sup 86/Sr ratios in the range 0.7079-0.7108. All but those from the Ste. Genevieve Limestone (middle Mississippian) are more radiogenic in /sup 87/Sr//sup 86/Sr than seawater values for this interval of geologic time. The detrital source of the more radiogenic /sup 87/Sr may be the New Albany Shale group, considered to be a major petroleum source rock in the basin. The /sup 87/Sr//sup 86/Sr ratios of Ste. Genevieve brines apparently evolved without a contribution from fluid-shale interaction.
- Research Organization:
- Mobil Research and Development Corp., Farmers Branch, TX
- OSTI ID:
- 5201145
- Report Number(s):
- CONF-860624-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Vol. 70:5; ISSN AAPGB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
ALKALINE EARTH ISOTOPES
BRINES
CARBONATE ROCKS
DEVONIAN PERIOD
DIAGENESIS
FEDERAL REGION V
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
ILLINOIS
ISOTOPE RATIO
ISOTOPES
MINERAL RESOURCES
MISSISSIPPIAN PERIOD
NORTH AMERICA
ORDOVICIAN PERIOD
ORIGIN
PALEOZOIC ERA
PETROLEUM DEPOSITS
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY BASINS
SEDIMENTARY ROCKS
SHALES
SILURIAN PERIOD
SOURCE ROCKS
STRONTIUM ISOTOPES
USA