Identification of Key Petroleum System Risks in Grandview Hills, Northwest Territory Exploration Play

Michael A. Abrams¹, Michal Nemcok², Richardson Allen³, Kenneth Shaw⁴, and Robert W. Potter^5
1 University of Utah Energy and Geoscience Institute, Salt Lake City, UT
² Energy and Geoscience Institute, University of Utah, Salt Lake City, UT
³ Energy & Geoscience Institute at the University of Utah, Salt Lake City, UT
⁴ University of Utah Energy and Geoscience Institute, Calgary, AB
⁵ Vintage Petroleum, Tulsa, OK

The Grandview Hills area appears to have considerable petroleum potential with petroleum systems to the north (Mackenzie Delta), east (Colville/Tweed Lake region), and southeast (Norman Wells). An evaluation of key petroleum systems elements and processes identifies several major problems with trap formation and hydrocarbon charge timing.

Two viable structural traps from inversion and transpression stresses are identified in adjacent exploration areas that resulted from Laramide reactivation of Precambrian faults. Unfortunately, the study area appears to be too far from the Cordillean thrust front and is without suitable pre-existing structures for reactivation from stress transfer. Stratigraphic pinchouts appear to be the only viable traps within the study area.

Proven reservoirs in Devonian Ramparts Formation carbonates and Cambrian Mount Clark Formation clastics were identified by drilling. Other possible reservoirs include vuggy porosity in the Franklin Mountain and Mount Kindle Formations, Bear Rock Group dolomite breccias, Ramparts Formation sandy members, and/or isolated pinnacle reefs.

Several source rocks are documented in the region: Middle Devonian Canol and Bluefish, and Cambrian Mount Clark Formations. Shows in Middle and Upper Devonian drill well sections, numerous surface oil and gas seeps (Devonian sourced), and updip gas-condensate accumulations in Cambrian sandstones (Cambrian sourced) prove hydrocarbons have been generated. Detailed maturation and migration pathway analysis indicate the source rocks generated hydrocarbons too early and are currently in the gas window.

Thus despite the fact that there are several regional working petroleum systems, abundant local shows, and near-surface seeps, the exploration potential in the Grandview Hills Area is limited.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005