CHARACTERIZATION OF NAPHTHENIC ACID FRACTION COMPOUNDS IN AN OIL SANDS PIT LAKE USING ULTRA-HIGH RESOLUTION MASS SPECTROMETRY WITH ELECTROSPRAY IONIZATION

Abstract

Extraction and production of viscous petroleum or bitumen in Alberta, Canada has rapidly developed in the last 30 years, and in 2022 the average daily production was nearly 4 million barrels/day. As a result of the increased global demand of crude oil and technical improvements in the extraction process of surface mining and in situ technologies, this daily output of crude oil is expected to increase further. Surface mining operations are required to invest and implement long-term reclamation strategies in order to properly reduce/manage the large volumes of oil sands process-affected water (OSPW) and tailings and convert the surrounding mining area into an environment similar to its initial state. Commissioned in late 2012 within Syncrude’s Mildred Lake mining site is Base Mine Lake (BML), the first full-scale demonstration of Water Capped Tailings Technology. This aquatic reclamation environment serves as the first of many oil sands pit lakes proposed in the surrounding region, therefore, it is crucial that a comprehensive assembly of scientific pursuits are incorporated into the monitoring and research programs of BML. The presence of petroleum-associated organic compounds, such as Hydrocarbons and Naphthenic acid Fraction compounds (NAFC), remains a top priority for evaluating how BML meets surface water guidelines, but also plays a larger role in the scientific understanding of how biogeochemical and physical processes can impact the environmental fate and transport of these organic compounds in future oil sand pit lakes. This master’s dissertation is focused on the use of ultra-high resolution mass spectrometry to determine the molecular profile of NAFCs extracted from BML in 2019. In this thesis, electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT ICR MS) was used to investigate: i) how particular experimental variables impact the qualitative measurements of oil sand NAFCs, and ii) the spatial variability of NAFCs within the BML water cap and FFT with the aim of providing novel insights to key biogeochemical processes and potential transport mechanisms for continued NAFC inputs in the water column.