--> --> Abstract: Petroleum Hydrogeology of Southwestern Saskatchewan, by Anatoly Melnik and Benjamin J. Rostron; #90124 (2011)

Datapages, Inc.Print this page

Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA

Petroleum Hydrogeology of Southwestern Saskatchewan

Anatoly Melnik1; Benjamin J. Rostron1

(1) Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB, Canada.

Petroleum migration, geothermal energy exploration and development, assessment of favourable locations for CO2 sequestration, and groundwater management and allocation all require the knowledge of regional hydrogeology. The Government of Saskatchewan initiated a project titled Saskatchewan Phanerozoic Fluids and Petroleum Systems Assessment (SPFPS) in order to investigate the movement of fluids in the Williston Basin portion of Saskatchewan. One of its objectives is to complete hydrogeological characterization of the area. As part of this task, this study has produced a suite of hydrogeological data and maps for southwestern Saskatchewan.

Twelve major hydrostratigraphic units (aquifers) have been identified: 7 Paleozoic; 1 Jurassic; and 4 Cretaceous aged units. Pressure and chemistry data obtained from Drill Stem Tests and water analysis reports were compiled for each aquifer. These data were culled for poor quality, production-influenced pressures and contaminated chemical data to ensure that only representative values were used to produce the final maps. Processed data were used to construct Potentiometric Surface and Total Dissolved Solids (TDS) maps.

Fluid flow in all Paleozoic aquifers is directed towards the north. Fluid flow in the Jurassic aquifer (Shaunavon) is also directed generally northwards. However, there is a prominent potentiometric low spatially associated with the producing Shaunavon oil and gas pools. In contrast to the deeper units, fluid flow in the Lower Cretaceous aquifers is directed towards the east and northeast, indicating the influence of inflow from the Alberta Basin to the west. Fluid flow in the Upper Cretaceous aquifer is controlled by local topography, with flow directed away from topographic highs towards low-lying subcrop areas.

TDS values in the Paleozoic aquifers range from 5 g/L in the south to over 300 g/L in the north. In the southern part of the study area, where TDS values are relatively low (< 50 g/L), the water's chemical concentration appears to be diluted by freshwater recharge from the Montana highlands. Overlying Jurassic and Cretaceous aquifers have relatively low TDS content ranging from 5 g/L to 30 g/L.

This study will be completed by construction of fresh water and density corrected driving force (DFR) maps and representative vertical hydraulic cross-sections. The combined results will be used to produce a complete regional characterization of subsurface fluid flow in southwestern Saskatchewan.