Stoakes Consulting Group Ltd

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ph: (403) 262-6003  fax: (403) 265-4662   email: fstoakes.scg@shawbiz.ca Replica Longines

Regional Mississippian Stratigraphy, Pekisko and Banff Formations – West Central Alberta

Overview

This study was undertaken to evaluate the Mississippian Banff and Pekisko formations underlying the plains of west central Alberta with respect to their hydrocarbon potential away from subcrop.

The Banff Formation is subdivided into three informal members: lower, middle and upper. The lower Banff is characterized by mostly outer and subordinate mid-ramp deposits that represent a significant period of regressive basin-fill. The overlying middle Banff encompasses grainy event beds and possibly isolate shoals that reflect mostly mid-ramp deposition. Dolomitized Middle Banff grainy strata, such as those that occur in the Sunchild-Ferrier field areas, comprise an established play-type in the study area. The upper Banff interval is dominated by upper inner ramp and tidal flat mixed carbonate and siliciclastic sediments.

The Pekisko Formation represents a transgressive-regressive sequence comprised of a widespread, shoaling-upward ‘carbonate’ succession, and also includes an unrecognized basinal ‘evaporite’ stratal package. The Pekisko ‘carbonate’ interval reflects rapid grainstone shoal progradation and aggradation across the study area, with a capping inboard lagoon-tidal flat system. Areal distribution of the overlying Pekisko ‘evaporite’ suggests that ‘evaporite’ deposition took place in a restricted westward deepening shallow basin following Pekisko ‘carbonate’ sedimentation.

Hydrocarbon production and significant shows from Pekisko Formation strata away from subcrop are generally related to stratigraphic and structural traps where dolostone-hosted porosity in thickness anomalies is sealed by up-dip tight limestone.

The study roughly encompasses an area from Township 35 to 63, between Ranges 5W5 and 20W5 (261 townships). At the time of the study 1920 wells penetrated the Pekisko in the study area, and 81 wells with cored intervals were logged at the AEUB Core Research Centre.

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Product – Five Volume Report

  • fully illustrated text (84 pages plus 61 figures & plates) documenting stratigraphy, geologic evolution, play types, core descriptions and database;
  • 17 regional stratigraphic cross sections (11 dip, 6 strike);
  • 24 maps including isopach and structure at 1:150,000 scale;
  • stratigraphic picks and isopach values from Base Cretaceous to Top Wabamun Grp., including Nordegg Fm., Montney Fm., Belloy Fm., Turner Valley Fm., Shunda Fm. (S1, S2 & S3 Units), Pekisko Fm. (Evaporite & Carbonate Units), Banff Fm. (Upper, Mid & Lower Units), Exshaw Fm., and Wabamun Grp.;
  • 1,920 well database available in digital and hardcopy formats;
  • core descriptions from 81 wells with internally consistent correlations.

For more information or to arrange a technical presentation, call (403) 262-6003, fax (403) 265-4662 or email: fstoakes.scg@shawbiz.ca