Structurally Controlled Diagenesis in Upper Devonian Dolomite: North-Central Montana and Southern Alberta
Department of Earth Sciences, Montana State University, Bozeman, MT, USA
The major objective of this work is to characterize brittle structural features such as fractures and faults in Upper Devonian (Frasnian Stage) dolomite outcrops across north-central Montana and the Alberta Rocky Mountains in effort to understand the extent of structurally controlled diagenesis in different facies. These dolomite outcrops will be used as analogs to the age- and lithologic-equivalent subsurface Duperow Formation at Kevin Dome (Toole County, Montana), a carbon dioxide reservoir and injection site of the Big Sky Carbon Sequestration Partnership. Primary methods applied to outcrops include field and laboratory based fracture analysis, triaxial stress tests to determine the strength of rock units, detailed petrographic analyses of diagenetic features proximal and distal to fractures and faults, and analysis of fluid inclusions within veins to determine the approximate temperature of dolomitizing fluids. This work takes a regional approach to understanding how fractures and faults as conduits may control the fluid alteration of rock units over time, and will provide new information on stages of carbonate diagenesis specific to fractures and dolomitization. This information will be applied to the Duperow Formation at Kevin Dome in order to predict how injected carbon dioxide may be distributed throughout the fractured reservoir unit as well as diagenetically alter the existing lithology.
AAPG Search and Discovery Article #90199 © 2014 AAPG Foundation 2014 Grants-in-Aid Projects