A Multidisciplinary Approach to Evaluating Shale Gas Potential of the Upper Colorado Group, Southeastern Alberta
Geology and Geophysics, University of Calgary, Calgary, Alberta;
Unconventional gas resources are gaining attention as more conventional sources of gas are on the decline, and as unconventional gas resources become more economic. One of the main targets for shale gas production in the Western Canada Sedimentary Basin is the Upper Cretaceous Colorado Group, a thick package of primarily marine shales with lesser intervals of sandstone. These shales are studied in southeastern Alberta in order to determine ways in which gas may be produced from these fine-grained units. This requires a multi-disciplinary approach. Shales are analyzed for organic matter type and maturity, total gas content, gas composition, grain size distribution, palynology, gas chromatography-mass spectrometry, pore size distribution, rock mechanical attributes, and mineralogy. Organic matter type for Upper Colorado Group shales is typically a combination of Type III (gas prone) and Type II/III (oil and gas prone), with shales being relatively immature with respect to the oil window. Geochemical analyses help elucidate the gas generating potential of the shales while natural fracture systems or coarser-grained intervals within the shales may act as permeability conduits. This study focuses on identifying characteristics within the Colorado Group shales which may be favorable for future exploration and production efforts.
AAPG Search and Discovery Article #90070 © 2007 AAPG Foundation Grants in Aid