Central AB
SACA
January 31, 2006

The focus of this report is rock stress in Central Alberta, from T. 25-80, R. 1W4M to R. 13W6M, in reservoirs that range in age from the Tertiary to the Triassic. The observed trends in the minimum principal stress are discussed in terms of geological association, overburden removal, basement tectonics, and Laramide compression and extension. Over 200 maps, and 40 figures were used to determine the stress variation, the stress state of the reservoirs (normal fault, strike-slip, or thrusting), and whether the stress differential was large enough to result in the production of natural fractures. The relationship of stress to productivity was considered, and found to be quite complex. The maps of the minimum principal stress and stress gradient should be useful to the completion engineer in planning a more effective frac program. Theory supports the association of improved reservoir productivity with low levels of stress, and experience shows that as the level of stress in a reservoir declines, it becomes easier to drill, complete and stimulate. From this point of view, the areas of reduced stress defined on the effective stress ratio maps and the maps of the minimum principal stress gradient should be of interest to exploration and development geologists and engineers. Benefits of this study include:

  • A comprehensive understanding of regional stress distributions
  • Potential for more cost-effective well stimulations by understanding the minimum principal stress trends and levels
  • Benefit for geophysical interpretation in the context of understanding anisotropy
  • A better understanding of basement geology and its relationship to stress patterns
  • Highlighting anomalous areas of stress in the context of other attributes, both geological and geophysical
  • The opportunity for clients to perform correlations of stress and other geologically significant data against proprietary corporate information (tight wells, reserves or internal production estimates, guarded knowledge of geological parameters, etc.)
Area: 
Central AB
DLS/NTS: 
T25-80, R1W4-14W6