Jeffrey P. Reinprecht1,
S. George Pemberton1,
Dale A. Leckie2
(1) University of Alberta, Edmonton, AB
(2) Canadian Occidental Petroleum Ltd, Calgary, AB
Abstract: Reservoir architecture and key stratigraphic surfaces in the Bluesky Formation of the Chinchaga region, northwest Alberta
The Albian Bluesky Formation of northwest Alberta was deposited in a marginal-marine setting during the final stages of the Lower Cretaceous boreal Moosebar transgression. In the Chinchaga region of northwest Alberta, the Bluesky has initial established reserves of 57 Bcf of natural gas. This gas is trapped in estuarine sediments deposited along the southern margin of the Mississppian Keg River carbonate highlands. Bluesky sediments were transported by longshore currents and deposited by a mixture of refracted, low-energy wave processes and tidal energy. Eighteen core were examined and six cross sections were generated to delineate key stratigraphic surfaces. A Glossifungites demarcated-discontinuity is regionally correlative along the upper boundary of the deposit. This surface is overlain by a ravinement and is interpreted to represent a transgressive surface of erosion. The basal boundary of the deposit represents a 2nd order angular unconformity. The exposure of differing underlying lithologies along this unconformity, evident from cross section data, are interpreted to have a direct influence on the preservation of the overlying Bullhead and Fort St. John Group sediments. Understanding of Bluesky depositional processes and key stratigraphic surfaces are important in developing a better regional understanding of the Formation.
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana