Origin and Nature of Dolomitization of the St. George Group in Western Newfoundland, Canada: Implications for Porosity Controls

Lead Researcher and Department
Dr. Karem Azmy, Department of Earth Sciences, Memorial University

Funding Resources
Petroleum Research Atlantic Canada (PRAC)

Summary
Hydrothermal dolomites have progressively become a major target in the carbonate sequences of eastern North America where significant reservoirs are currently producing from the Appalachians and the surrounding area such as the Gaspé Peninsula and New Brunswick.

This project investigates the origin and distribution of these dolomites, particularly the St. George Group of western Newfoundland, which has been affected by significant meteoric diagenetic alterations due to a major subaerial exposure (St. George Unconformity) that likely increased the rock porosity and enhanced dolomitization. Dolomitization of carbonate sediments is a crucial diagenetic process, which influences the secondary porosity development and fluid flow characterization in rock strata.

The St. George carbonates have all the features that make them a possible potential hydrocarbon reservoir that might contain significant hydrocarbon accumulations. The most recent test production (315 barrels per day), by the CIVC in early 2007, indicates high API (50-56°) oil and significant volume of natural gas (106 ft3/ day).

This investigation will involve approaches, which utilize traditional and novel techniques (e.g., UV microscopy, leach analysis of fluid inclusions, stable isotopes and rare earth elements geochemistry) that have not been combined together in previous studies. The combination of such techniques, using new sophisticated instruments, has been proven very effective in understanding the origin of diagenetic fluids and water-rock interaction. Onshore studies will also allow modeling porosity distribution and predictions of possible economic accumulations in equivalent offshore sequences.

Dates
2009-2011

Keywords
Reservoir Engineering, Geosciences, Dolomites, Reservoir characterization, Water rock interaction

Locations
Newfoundland and Labrador, Canada
St. John's
Avalon Peninsula

Industry Sectors
Geology Research and Development Laboratories (Professional, Scientific and Technical Services — Scientific Research and Development Services — Research and Development in the Physical, Engineering and Life Sciences)

Thematic Categories
Reservoirs (Mining — Oil & Gas)
Earth Sciences (Science Research)

Departments
Earth Sciences, Faculty of Science (STJ)