ABSTRACT: Detailed Reservoir Characterization Based on Outcrop Analogs: Lower Cretaceous McMurray Formation, Northeast Alberta

STROBL, RUDY, and LI-PING YUAN, Alberta Geological Survey, Edmonton, Alberta, Canada, and WALID MUWAIS, Syncrude Canada Limited, Fort McMurray, Alberta, Canada

Outcrop analogs provide the basis for modeling on an interwell scale (i.e., 80 to 120 m). Permeabilities and geometries of major lithofacies and heterogeneities provide quantitative data for modeling purposes.

Sand wave reservoirs are characterized by stacked, cross bedded sands (15 cm to 65 cm bed sets), with a cumulative thickness of up to 20 m. Within this flow unit, thin toe sets extend laterally 5 m to 60 m and draping muds extend 1 m to 5 m. Cross beds make up the majority of the reservoir with absolute permeabilities between 8 and 20 darcys. Toe sets and draping muds act as staggered permeability baffles, with absolute permeabilities ranging from <1 darcy to 4 to 11 darcys, respectively.

Large-scale point bar reservoirs are 30 to 50 m thick, characterized by a trough cross bedded succession, a transition zone, and continuous heterolithic dipping beds associated with the lower, middle, and upper flow units, respectively. The lower unit consists of cross bed sets 1.0 m to 1.5 m thick with widths varying from 1.5 m to 6.0 m. Mud drapes and argillaceous toe sets have short lateral extent and are not significant permeability baffles. The transition unit has significantly lower permeabilities associated with smaller scale cross beds and argillaceous sands. The upper flow unit consists of heterolithic beds extending over 100 m and dipping 4 degrees to 12 degrees. Muddy heterolithic beds are significant, continuous permeability baffles. Permeabilities for cross bedded sands a e 12 to 18 darcys compared with 7 to 13 darcys for toe sets. Sandy inclined beds have 2 to 5 darcys compared to muddy beds with absolute permeabilities of less than 1 darcy. (This project is part of the AOSTRA/ARC Joint Geological Research Program.)

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)