Thermal Release Of Arsenic, Metals And Organic Compounds From Aquifer Sediments During In Situ Bitumen Extraction

Thursday, December 6, 2018: 11:00 a.m.
Exhibit Hall- C4 & C5 (Las Vegas Convention Center)
Michael Moncur, PhD , Water Management, InnoTech Alberta, Calgary, AB, Canada
Jean Birks, PhD , Water Management, InnoTech Alberta, Calgary, AB, Canada
John Gibson, PhD , Water Management, InnoTech Alberta, Victoria, BC, Canada
Dogan Paktunc, PhD , CanmetMINING, Natural Resources Canada, Ottawa, ON, Canada

The Athabasca Oil Sands (AOS) deposits in Alberta, Canada, are estimated to contain approximately 1700 billion barrels of oil of which 170 billion barrels are recoverable with existing technology. Only 20 % of the oil sands are recoverable through surface mining, whereas the remaining 80 % of the oil sands are located at depths (>80m) that require in situ methods. Bitumen is immobile at reservoir temperatures, however when heated to 200°C, it approaches the viscosity of water. To reduce the viscosity of bitumen for recovery, enhanced thermal recovery methods (e.g. steam injection) are used to increase the temperature of the bitumen to decrease its viscosity. The transfer of radiant and advective heat from steam injection well casings to the adjacent aquifer sediments can increase groundwater temperatures, increasing the solubility of some mineral phases. The dissolution of minerals or mobilization of poorly sorbed elements from the sediments may release arsenic and other metal(oid)s to the groundwater. These mobilized elements and heat may be transported down-gradient, away from the injector well, along groundwater flowpaths. This study heated glacial fluvial aquifer sediments from the AOS under controlled laboratory conditions with the objective of gaining a better understanding of the mechanisms for the release of dissolved metal(loid)s and organic compounds to groundwater. Heating of the sediments and water showed a rapid release of As, with As(III) being the dominate mobile species. Other dissolved ions (Ba, Li, Mo, Si and Al) and dissolved organic carbon (including organic acids) were also released, and some of these elements could be useful for tracing groundwater thermal plumes. The information from these thermal tests is capable of identifying the aquifers with the greatest potential for impacting water quality or releasing gases, which would allow these aquifers to be targeted for more intensive monitoring and risk assessment.

Michael Moncur, PhD, Water Management, InnoTech Alberta, Calgary, AB, Canada
Mike is a Hydrogeochemist at InnoTech Alberta. He holds a BSc. (Geology), MSc. (Hydrogeology) and a Ph.D. (geochemistry) from the University of Waterloo. His is interested in water-rock interaction and the release and transport of metals in groundwater and surface water environments. Mike incorporates geochemical, mineralogical, isotopic, biological, modeling and physical processes to develop strategies for the sustainable management of water resources. His recent research includes geochemical investigations on impacts to groundwater from surface and in situ oil sands mines, base metal and diamond mines, as well as tracing pharmaceuticals and artificial sweeteners in groundwater and surface water.

Jean Birks, PhD, Water Management, InnoTech Alberta, Calgary, AB, Canada
Dr. Birks’s expertise is in the development and application of isotope tracer techniques to better understand the hydrological cycle. Specific projects have focused on aquitards as groundwater archives, paleogroundwaters as indicators of climate change, groundwater inputs to saline lakes, hydroclimate variability in Western Canada, geochemical modeling of surface and groundwater evolution, isotope tracing of water yield and chemical loadings in the Athabasca oil sands region. She is an adjunct professor at the University of Waterloo, former chair of the CGU Committee on Isotope Tracers, and coordinator of the Canadian Network for Isotopes in Precipitation.

John Gibson, PhD, Water Management, InnoTech Alberta, Victoria, BC, Canada
Dr. Gibson is a Senior Research Scientist and Team Lead for Water Management, InnoTech Alberta as well as a Research Professor affiliated with University of Victoria, Department of Geography. He is a specialist in isotope tracer techniques with extensive experience in regional, national and international water projects. Dr. Gibson is Past President of the International Commission on Tracers of the International Association of Hydrological Sciences, is founding member of the Canadian Geophysical Union – Committee on Isotopic Tracers, and has been employed to coordinate research programs on behalf of Environment Canada, the IAEA, and the Australian Nuclear Science and Technology Organization.

Dogan Paktunc, PhD, CanmetMINING, Natural Resources Canada, Ottawa, ON, Canada
Dr. Paktunc research interests include both fundamental-level and applied research to advance our understanding of mineral and metal(loid) characteristics at the molecular-scale and their behaviour in mineral processing/metallurgy circuits and the environment, and to develop stabilization technologies for mine wastes. His research emphasizes applications of quantitative mineralogy and the development of new and improved mineralogical tools and applications for metallurgical and environmental research.