Petroleum Hydrogeology of Saskatchewan

Abstract

Fluid migration, water chemistry and hydraulic heads play a major role in hydrocarbon migration and entrapment. Therefore, the government of Saskatchewan initiated a province wide hydrogeological and geological mapping project entitled; The Saskatchewan Phanerozoic Fluids and Petroleum Systems Assessment (SPFPS). This project was designed to better understand the movement of fluids and the regional geology in the province of Saskatchewan. One of objectives was to complete the hydrogeological characterization of the province utilizing previous hydrogeological studies completed at the University of Alberta, and mapping portions that had yet to be done and to then compile all the information to form a series of hydrogeological maps for the entire province of Saskatchewan. The Saskatchewan geological framework was refined into a hydrostratigraphic column consisting of 13 major aquifers and 11 aquitards. Detailed mapping of hydraulic head and water chemistry has been conducted on aquifers ranging in age from Cambrian to the upper Cretaceous. A strict culling process of the raw data was completed to eliminate contaminated, poor quality, and production influenced samples. Flow directions determined from maps of equivalent fresh-water hydraulic-head indicate generally that flow conditions are updip from SW to NE across the province. Mapped formation water salinities range from 2 to 471 g/L and indicate significant density variations between formations and across the province. Four distinct formation water types are identified based on ion chemistry: (1) Ca-SO4 fresh, (2) Na-SO4 brackish, (3) Na-Cl brines, and (4) Na-HCO3 fresh waters brines. This province wide hydrogeological characterization has provided new insights into the vertical and spatial distribution and mixing of formation waters. The interaction between the two converging basins is also observed in flow patterns of relatively fresh formation waters and highly saline brines. This study will be completed by construction of density corrected driving force (DFR) maps. DFR maps could aid in new oil discoveries in the province. The results from this project will help in a better understanding of the fluid migration in the province as well as aid in investigating reservoir response for enhanced oil recovery techniques such as water flooding and CO₂ injection.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016