ABSTRACT: The Control of Fracturing on Reservoir Quality and Productivity within the Sukunka-Bullmoose Playtrend of the NE British Columbia Foothills

MORRISON, MICHAEL L., and MARK A. COOPER, BP Canada Resources Limited, Calgary, Alberta, Canada

The Sukunka Bullmoose area lies within the foothills of the Canadian Rockies in northeastern British Columbia. The area has been explored for natural gas since the mid-1950s and contains a number of fields producing natural gas from the platform carbonates of the Upper Triassic Pardonet and Baldonnel formations. These largely dolomitized carbonates are deformed into a series of fault propagation folds with steep-dipping to overturned forelimbs, shallow-dipping backlimbs, and tight hinge zones.

The reservoir quality within the producing zones is typically poor with matrix porosity less than 4% and permeability-to-air less than 0.1 md. As a result, the presence of fracturing to enhance reservoir quality is essential to the success of the play.

Through the evaluation of several successful wells using such tools as spinner surveys and the Formation Microscanner, in conjunction with the typical suite of electrical and acoustic logs, the importance of fracture density and aperture on reservoir quality and productivity can be assessed. Fracture type, density, and aperture are controlled primarily by the position within the structure. This conclusion is supported by an outcrop study on structures of similar facies and geometry to those drilled in the subsurface. The results indicate that thick dolomite layers within the hinge zone of the fault propagation folds have the greatest fracture density and aperture values. The same dolomitic layers tend to have lower fracture densities and aperture values in the backlimb and lower fract re densities and high aperture values in the steep forelimb.

The results of this study will enable better definition of future drill targets and high grade perforation intervals.

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