Print this pageMICHAEL, K.1, S. BACHU2, and H. G. MACHEL1
1University of Alberta, Edmonton, AB
2Alberta Geological Survey, Edmonton, AB
Abstract: Influence of the Rocky Mountain Foothills on Fluid Flow in the West-Central Part of the Alberta Basin, Canada
Hydrogeochemical and fluid pressure data from oil and gas wells have been investigated in order to determine to what extent the three major hydrogeological systems in the Alberta Basin are affected by possible fluid influx from the Rocky Mountain foothills. The three systems have been previously identified on the basis of hydrogeological data. They are separated from each other by major shaly aquitards, and each is characterized by its distinctive fluid chemistry and hydrodynamics.
One or several of the following aspects of the foothills region may influence fluid flow in the Alberta Basin. (1) This area represents a regional topographic high, and thus may be the cause for present gravity-driven flow. (2) Thrust faults, the dominant structural element in the foothills, represent unconformities in the hydrostratigraphic framework and disrupt otherwise regionally extensive aquifers and aquitards. These thrusts and associated faults may act individually as barriers or conduits to fluid flow. (3) A postulated, tectonically induced paleo-flow regime in the deeper part of the basin is still in the process of equilibrating to the present topography.
Our preliminary results suggest that there is a recognizable influx of fluids from the foothills into the basin at least in the deeper hydrogeological systems. This influx of formation water from the foothills seems to be channeled either along zones of highly permeable lithology, by permeable faults, and/or at the termination of thrust faults. Once timing, flow rates, and exact location of fluid pathways have been better characterized, this may aid in exploration and development for hydrocarbons in the area in and adjacent to the Rocky Mountain foothills of west-central Alberta.
AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas