Athabasca Oil Sands Research Articles

Corrigendum: Salt tectonism and distribution of brackish-water trace fossils in the Cretaceous McMurray Formation, Athabasca Oil Sands, Alberta Foreland Basin

A proposed salt tectonism-saline seep model provides a novel alternative to the two widely accepted but irreconcilable depositional models for middle McMurray Formation strata of the Lower Cretaceo...

Oil-in-water emulsification of Athabasca bitumen with pyrrolidine solution

This paper presents an experimental study of use of pyrrolidine solutions to induce the oil-in-water (o/w) emulsion of Athabasca bitumen without using synthetic surfactants. Pyrrolidine, an organic alkali, acts not only as an alkali that generates natural surfactants from acidic oil components in bitumen, but also as a cosolvent that improves the fluidity of the o/w emulsions.Experimental results show that the o/w emulsions created by pyrrolidine solutions can result in a large mobility increase of bitumen because of their low viscosity and high bitumen content. O/w emulsions were observed at low pyrrolidine concentrations (below 20 wt% and as low as 0.5 wt%) and low salinities (0 and 1000 ppm). For example, the sample of 0.5 wt% pyrrolidine in 1000-ppm NaCl brine with 7:3 water-oil-ratio showed a single-phase o/w emulsion at all experimental temperatures from 298 K to 373 K. In comparison to the original bitumen, the o/w emulsion was 4–6 orders of magnitude less viscous at 298 K, 2–3 orders of magnitude less viscous at 323 K, and 1–2 orders of magnitude less viscous at 353 K.The affinity of the organic alkali for asphaltic bitumen is important for o/w emulsification at a wide range of temperatures. Pyrrolidine is superior to the other organic alkalis tested, diethylamine and triethylenetetramine, likely because the cyclic structure makes pyrrolidine more compatible with the asphaltic bitumen. The favorable result with pyrrolidine is also confirmed by the Hansen solubility dispersion parameter.

Impact of reservoir heterogeneity on oil migration and the origin of oil-water contacts: McMurray Formation type section, Alberta, Canada

Abstract This study documents and attempts to describe the processes leading to the formation and preservation of exposed oil, water, and paleo-gas contacts at the McMurray Formation type section, Alberta, Canada. The McMurray Formation type section, a part of the Athabasca Oil Sands Deposit (AOSD), the largest exhumed oil reservoir on Earth, is unparralled, still underutilized, natural laboratory for veryfing and refining existing, and developing new concepts, for oil migration and post oil-emplacement fluid diffusion and biodegradation processes in a sedimentologically complex reservoir setting. Exposures, coupled with adjacent borehole data, provide a three-dimensional insight into reservoir heterogeneities and their influence on oil migration, entrapment, post-emplacement fluid mixing, and biodegradation processes and products, in a hierarchical and chronological order from early charge to present-day conditions. The principles of oil above water and of horizontal or tilted oil/water contacts are challenged by outstanding examples of: (i) centimetre to decimetre scale inter-fingering oil-water stringers/contacts, created by capillary pressure differences and partial charge; (ii) irregular oil-water contacts in both clean and heterogeneous reservoirs characterized by gravitational effects caused by severe biodegradation that caused the formation of extra heavy-oil commonly referred to as “bitumen” that sank through the water column; (iii) occurrences of multiple metre-scale intervals with less than 50% oil saturation, commonly referred to as lean zones that formed during microbial gas generation following oil entrapment. Studied contacts provided excellent opportunity to study oil migration and charging mechanisms from pore and sedimentary bed to reservoir scale at various stages of oil migration into the reservoir, as well as oil, water, and gas re-migration within the reservoir (trap). Described exposures can play an additional role in advancing geoscience education, petroleum exploration, reservoir characterization, field development, and production optimization studies.

Determination of binary diffusion coefficients between hot liquid solvents and bitumen with X-ray CT

Abstract The Steam Assisted Gravity Drainage (SAGD) process has been used for in-situ thermal bitumen recovery in Canada. Nevertheless, there are several drawbacks that could impair the SAGD performance. One of the main drawbacks of SAGD is nontrivial consumption of energy to generate steam. To curtail the consumption of steam, many SAGD variants have been proposed. For example, Vapor Extraction (VAPEX) was proposed as a solvent-based cold production method and Solvent-Assisted SAGD (SA-SAGD) was proposed as a solvent-assisted hybrid method. In those solvent-based/assisted methods, the dissolution of solvents in bitumen enhances the in-situ oil mobility. The speed of the mixing between solvents and bitumen in solvent-based/assisted recovery processes is dictated by dispersive mass flux which is proportional to the transverse dispersion coefficient. Diffusion coefficient, tortuosity and transverse dispersivity should be quantified to characterize the transverse dispersion coefficient. In this research, the diffusion coefficients of solvents in Athabasca bitumen were determined with X-ray computed tomography (CT). A medical X-ray CT scanner was used to capture the diffusion phenomenon occurring between fresh liquid solvents and bitumen. The experiments were designed to reproduce the in-situ high pressure, high temperature condition (3.5 MPa, 135C) where solvent and bitumen actually interact at the vapor chamber edge in the SA-SAGD process. Using our new °experimental system, we successfully measured molecular diffusion coefficients at the condition of the vapor chamber edge for the first time. In conclusion, the binary diffusion coefficients between solvents and bitumen were successfully measured at the condition where the mixing of solvents and bitumen actually occurs in the SA-SAGD process. The characterized diffusion coefficients will be input parameters for the reservoir simulation and semi-analytical models.

Deterioration of oil quality during sample storage: Are stored reservoir core samples a viable resource for oil viscosity determination?

The physical and chemical properties of oil residing in reservoir core samples are strongly susceptible to evaporative processes during storage. In a case study from the Peace River oil sands of Alberta, we performed dead oil viscosity measurements on oils recovered by mechanical extraction of fresh core, the equivalent cores stored for 7 months frozen plus 3 months at ambient conditions (time 1) and for 7 months frozen plus 8 months at ambient conditions (time 2). The dead oil viscosity of oil recovered from fresh core material (8100 cP at 20 °C) was more than an order of magnitude lower than that of the oil subsequently recovered from an equivalent core sample stored frozen for 7 months and then at ambient temperature for 8 months (313,500 cP at 20 °C). The evaporation of light hydrocarbons such as toluene and xylenes during storage is a continuous process responsible for progressive increase in dead oil viscosity. Meanwhile, when comparing the oils recovered from fresh core and aged core samples, the composition of the heavy (low volatility) hydrocarbons remains essentially the same. Because biodegradation is the primary control on oil viscosity and variation in hydrocarbon compositions for this oil sample suite, partial least squares models based on viscosity versus geochemical data may still be used to predict viscosity. Although the physical properties of the oil may be compromised during storage, the distributions of the high molecular weight components retain characteristics, similar to a bar code, that are inherited and representative of the original (fresh) core sample. Therefore, with the proviso that the distributions of high molecular weight components are comparable between fresh cores and aged cores, the viscosity of oil residing in stored core samples can be effectively restored by chemometric-based correlation methods.

Deposition and Source Identification of Nitrogen Heterocyclic Polycyclic Aromatic Compounds in Snow, Sediment, and Air Samples from the Athabasca Oil Sands Region.

Polycyclic aromatic compounds (PACs) can have multiple sources in the Athabasca Oil Sands Region (AOSR). The current study was designed to identify and explore the potential of nitrogen heterocyclic PACs (NPACs) as source indicators in snowpack, lake sediment and passive air samples from the AOSR during 2014-2015. Source samples including petroleum coke (petcoke), haul road dust, and unprocessed oil sands were also analyzed. Samples were analyzed using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry, and liquid chromatography-high resolution Orbitrap mass spectrometry. Over 200 NPACs were identified and classified into at least 24 isomer groups, including alkylated carbazoles, benzocarbazoles, and indenoquinolines. Levels of NPACs in environmental samples decreased with distance from the main developments and with increasing depth in lake sediments but were detected within 50 km from the major developments. The composition profiles of several NPAC isomer classes, such as dimethylcarbazoles, showed that petcoke had a distinct distribution of NPACs compared to the haul road dust and unprocessed oil sands ores and was the most similar source material to near-field environmental samples. These results suggest that petcoke is a major contributing source for the identified NPACs and that these compounds have the potential to be used as source indicators for future research in the AOSR.

Microbial metabolic strategies for overcoming low-oxygen in naturalized freshwater reservoirs surrounding the Athabasca Oil Sands: A proxy for End-Pit Lakes?

The success and sustainability of aquatic ecosystems are driven by the complex, cooperative metabolism of microbes. Ecological engineering strategies often strive to harness this syntrophic synergy of microbial metabolism for the reclamation of contaminated environments worldwide. Currently, there is a significant knowledge gap in our understanding of how the natural microbial ecology overcomes thermodynamic limitations in recovering contaminated environments. Here, we used in-situ metatranscriptomics and associated metataxonomic analyses on sediments collected from naturalized freshwater man-made reservoirs within the Athabasca Oil Sands region of Alberta, Canada. These reservoirs are unique since they are untouched by industrial mining processes and serve as representative endpoints for model landscape reconstruction. Results indicate that a microbial syntrophic cooperation has been established represented by the oxygenic and anoxygenic phototrophs, sustained through the efficient use of novel cellular mechanistic adaptations tailored to these unique thermodynamic conditions. Specifically, chemotaxis transcripts (cheY & MCPs-methyl-accepting chemotaxis proteins) were highly expressed, suggesting a highly active microbial response to gradients in environmental stimuli, resulting indirectly from hydrocarbon compound alteration. A high expression of photosynthetic activity, likely sustaining nutrient delivery to the similarly highly expressed methanogenic community acting in syntrophy during the breakdown of organics. Overall the more diversified functionality within sub-oxic sample locations indicates an ability to maintain efficient metabolism under thermodynamic constraints. This is the first study to holistically identify and characterize these types of in-situ, metabolic processes and address their thermodynamic feasibility within a global context for large landscape reconstruction. These characterizations of regional, natural landscapes surrounding the oil sands mining operation are severely lacking, but truly provide invaluable insight into end-point goals and targets for reclamation procedures.

Temporal and Spatial Trends of Polycyclic Aromatic Compounds in Air across the Athabasca Oil Sands Region Reflect Inputs from Open Pit Mining and Forest Fires

Results of a passive air monitoring study for polycyclic aromatic compounds (PACs) in the Athabasca oil sands region (AOSR) in Alberta, Canada, are reported. Polyurethane foam disk passive air samplers were deployed for consecutive 2-month periods from November 2010 to January 2016 at 15 sites. Samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs (alkPAHs), and dibenzothiophene and its alkylated derivatives (DBTs). Concentrations in air were in the ranges of 0.3–43, 0.15–460, and 0.04–130 ng/m3 for ∑PAHs, ∑alkPAHs, and ∑DBTs, respectively. The increase in the levels of PACs in air at most sites was small but statistically insignificant over this 5-year period, which is consistent with expectations as in situ bitumen extraction techniques have become predominant over open pit mining in the area. Significant increases in PAC levels were observed at a site that is within a few kilometers of open pit mining that expanded over the study period. The 5-year regional trend for PACs in...

Nitrogen Retention of Terricolous Lichens in a Northern Alberta Jack Pine Forest

The Athabasca Oil Sands in Alberta, Canada, is one of the largest point sources of nitrogen oxides in Canada. There are concerns that elevated nitrogen (N) deposition will adversely impact forest ecosystems located downwind of emission sources. The role of the forest floor in regulating these potential eutrophication effects was investigated following a 5-year enrichment study in which N was applied as NH4NO3 above the canopy of a jack pine (Pinus banksiana Lamb) stand in northern Alberta close to Fort McMurray at rates ranging from 5 to 25 kg N ha−1 y−1 in addition to background deposition of approximately 2 kg N ha−1 y−1. Chemical analysis of lichen mats revealed that the N concentration in the apical (upper) lichen tissue and necrotic tissue increased with treatment. When expressed as a N pool, the fibric–humic material held the largest quantity of N across all treatments due to its relatively large mass (172–214 kg N ha−1), but there was no significant treatment effect. Soil net N mineralization and net nitrification rates did not differ among N treatments after five years of application. A 15N tracer applied to the forest floor showed that N is initially absorbed by the apical lichen (16.6% recovery), FH material (29.4% recovery), and the foliage of the vascular plant Vaccinium myrtilloides (31.7% recovery) in particular. After 2 years, the FH 15N pool size was elevated and all other measured pools were depleted, indicating a slow transfer of N to the FH material. Applied 15N was not detectable in mineral soil. The microbial functional gene ammonia monooxygenase (amoA) responsible for catalyzing the first step in nitrification was undetectable using PCR screening of mineral soil microbial communities in all treatments, and broad fungal/bacterial qPCR assays revealed a weak treatment effect on fungal: bacterial ratios in mineral soil with decreasing relative fungal abundance under higher N deposition. This work suggests that terricolous lichen mats, which form the majority of ground cover in upland jack pine systems, have a large capacity to effectively retain elevated N deposition in soil humus.

Brackish and marginal marine phytoplankton from the Athabasca Oil Sands (Lower Cretaceous) of north-east Alberta, Canada

Four new species and one new variety of dinoflagellate cysts and one new acritarch species are described from the Lower Cretaceous Athabasca Oil Sands of northern Alberta, Canada. The new taxa are Batioladinium? vestigium var. vestigium, Batioladinium? vestigium var. granulatum, Craspedodinium robustum, Nyktericysta inflata, Oligosphaeridium tuberculatum and Fromea? plicata. They characterise brackish to stressed marine environments in the McMurray, Clearwater and Grand Rapids formations.

Hydrologic function of a moderate-rich fen watershed in the Athabasca Oil Sands Region of the Western Boreal Plain, northern Alberta

Peatlands are a dominant land feature in the Athabasca Oil Sands Region (AOSR) of the Western Boreal Plain (WBP), comprising >50% of the total land area, many of which are moderate-rich fens. The carbon stocks of moderate-rich fens in the WBP are susceptible to degradation through anthropogenic- and climate-related factors, yet, few studies have aimed to understand their hydrologic function. This study, located in a meltwater channel belt characterized by relatively thin outwash sand and gravel (∼6 m) underlying the peat, provides the first hydrological assessment of a moderate-rich fen in the AOSR. The lithology, hydrological function and groundwater geochemistry all point to the dominance of a local flow system supplying groundwater to the fen areas, evidenced by a thick (∼16 m) and shallow (∼7 m below ground surface) aquitard underlying the outwash, restricting hydrological connectivity between the fen and underlying regional aquifers. Vertical hydraulic gradients between the peat and underlying outwash aquifer, and horizontal hydraulic gradients between the fen and upland varied in response to both short-term and seasonal precipitation trends. Groundwater discharge to the fen was enhanced during wet periods characterized by high rainfall. Conversely, flow reversals (groundwater recharge; fen to underlying aquifer and upland), and subsequently, enhanced fen water table drawdown persisted during extended dry periods. This local groundwater flow-system influences recharge/discharge patterns at Poplar Fen, with hydraulic head in the underlying outwash aquifer highly susceptible to fluctuations in the presence and absence of precipitation-driven recharge from adjacent uplands. Moderate-rich fens similar to that studied here will likely become more susceptible to drying in the future due to a changing climate, leading to enhanced water table drawdown, peat oxidation and subsequent decomposition, vulnerability to wildfire, and seral succession to a more ombrogenous peatland system.

The impact of Aptian glacio‐eustasy on the stratigraphic architecture of the Athabasca Oil Sands, Alberta, Canada

AbstractHigh‐frequency incised valley systems and subaerial exposure surfaces are prevalent in Aptian‐aged units, having been documented in numerous basins around the world. In light of a growing body of palynological, geochemical and sedimentological evidence, a glacio‐eustatic mechanism for their generation has been suggested, driven by the waxing and waning of polar ice caps. The densely‐penetrated McMurray Formation of north‐eastern Alberta, Canada, provides a unique opportunity to test for an Aptian glacio‐eustatic signal within the Western Canadian Foreland Basin. This study combines detailed drill core description with wireline log‐based stratigraphic analysis to map and evaluate a series of drainage networks located along the cratonic edge of the Western Canadian Foreland Basin. Four stratigraphically distinct composite channel‐form bodies are documented across an area >14 000 km2. Composite channel‐form bodies are up to 50 km wide and locally exceed 70 m thick, subtending from upward‐coarsening parasequence sets 2 to 12 m thick; bounding marine flooding surfaces are mappable over distances exceeding 280 km along the north–south trending basin. Detailed internal fill characterization of the four composite channel‐form bodies suggests that three represent tidal–fluvial incised valley networks, and one represents a deltaic distributary system. At least six cycles of transgression and regression are apparent within the McMurray Formation stratigraphy. Recent biostratigraphic assessment has constrained deposition of the McMurray Formation between ca 125 Ma and 118 Ma, and periods on the order of 0·7 to 1·7 Ma are estimated for the mapped transgressive–regressive cycles. The high frequency nature of these Aptian sequences suggests that the sea‐level oscillations recorded in McMurray Formation strata are consistent with a glacio‐eustatic driver. Linking the internal stratigraphic architecture of the McMurray Formation with interpreted global cooling events and sea‐level drops provides the first evidence of glacio‐eustasy within Early Cretaceous strata of western Canada.

Costly Fix: Power, Politics, and Nature in the Tar Sands by Ian Urquhart

Reviewed by: Costly Fix: Power, Politics, and Nature in the Tar Sands by Ian Urquhart Kyle Conway Costly Fix: Power, Politics, and Nature in the Tar Sands. By Ian Urquhart. Toronto: University of Toronto Press, 2018. ix + 351 pp. Map, tables, references, index. $39.95 paper. Two things flow in Ian Urquhart's Costly Fix—oil and money—and if there is a lesson to be learned, it's that capital is even more liquid than the sticky bitumen found in Alberta's tar sands. The book traces the history of the tar sands, from the late 19th century when Canada's settler government first surveyed oil-rich northern Alberta, to the present day when international oil companies have taken full advantage of the land (and favorable tax arrangements). It situates Alberta in the global oil trade and shows how international markets shape local and regional governments in Canada's northern Great Plains. The Albertan and Canadian governments, Urquhart argues, have acted in the name of development, wealth, and North American energy independence, but they have sold access to their resources at a bargain price. The key idea in Costly Fix is that of market fundamentalism, or the paradoxical belief that the solution to problems caused by unfettered markets is the removal of still more fetters. The challenge governments face is that oil companies can always take their business—and the jobs they create—elsewhere. The threat of capital flight pits governments of resource-rich areas against each other. As a result, regional economies are anything but regional, as in the case of Alberta, where successive provincial and federal governments have sought to accommodate international oil companies, all the while reacting to changes in the United States as it has sought to decrease its dependence on oil from the Middle East. Over the years, Alberta's government, Urquhart writes, has renegotiated its leasing terms with oil companies, always in the companies' favor, even when Albertans have demanded that their government protect their environmental and financial interests better. Even groups opposed to development have been hampered in their efforts. For instance, the specific terms limiting who can address Alberta's regulator, the Energy Resources and Conservation Board (ERCB), have prevented most environmental groups from testifying. Groups must demonstrate that they would be "directly and adversely affected" by a company's actions, a test the ERCB interprets in the narrowest possible way. First Nations have faced similar structural restrictions. In their case, they have also taken a pragmatic approach to allowing oil exploration on their land: money from oil companies helps them solve problems related to immediate material needs, but at the cost of long-term environmental damage. Overall, Costly Fix is a thorough and well-argued polemic. Although it would benefit by engaging with similar books (such as Jon Gordon's Unsustainable Oil or Dominique Perron's L'Alberta autophage, both of [End Page 172] which describe similar structural and discursive contradictions), it provides a detailed account of Alberta's tar sands and demonstrates the degree to which money and oil move through Alberta, linking it inextricably to the larger network of global capital. Kyle Conway Department of Communication University of Ottawa Copyright © 2019 Center for Great Plains Studies, University of Nebraska–Lincoln

Beyond Oil: The Emergence of the Energy Humanities

Beyond OilThe Emergence of the Energy Humanities Jamie L. Jones (bio) Ross Barrett and Daniel Worden, eds. Oil Culture. Minneapolis: University of Minnesota Press, 2014. 456 pp. Cloth, $90.00; paper, $30.00. Amitav Ghosh. The Great Derangement: Climate Change and the Unthinkable. Randy L. and Melvin R. Berlin Family Lectures. Chicago: University of Chicago Press, 2016. 176 pp. Paper, $15.00; e-book, $15.00. Bob Johnson. Carbon Nation: Fossil Fuels in the Making of American Culture. Culture America. Lawrence: University Press of Kansas, 2014. 264 pp. Hardcover, $39.95; paper, $22.95. Stephanie LeMenager. Living Oil: Petroleum Culture in the American Century. New York: Oxford University Press, 2014. 288 pp. Hardcover, $56.00; paper, $26.95. Matthew Schneider-Mayerson, Peak Oil: Apocalyptic Environmentalism and Libertarian Political Culture. Chicago: University of Chicago Press, 2015. 280 pp. Cloth, $85.00; paper, $27.50; e-book, $27.50. Imre Szeman, Jennifer Wenzel, and Patricia Yaeger, eds. Fueling Culture: 101 Words for Energy and Environment. New York: Fordham University Press, 2017. 440 pp. Hardcover, $125.00; paper, $34.95; e-book, $33.99. Sheena Wilson, Adam Carlson, and Imre Szeman, eds. Petrocultures: Oil, Politics, and Culture. Montreal: McGill-Queen’s University Press, 2017. 544 pp. Cloth $120.00; paper, $37.95. [End Page 155] At least since Foucault, scholars in the humanities have produced research about power; only recently have we begun to investigate energy. Energy humanities is a new field, and it is late. In fact, it has already become so conventional for energy scholars to remark on their own belatedness that the field seems to arise from a lament: we might be too late. Distress is galvanizing the energy humanities, however; and the field is emerging around a vibrant group of recent publications by Stephanie LeMenager, Matthew Schneider-Mayerson, Bob Johnson, Ross Barrett, Daniel Worden, Imre Szeman, Jennifer Wenzel, Sheena Wilson, Adam Carlson, Patricia Yaeger, Amitav Ghosh, and others. Like the larger field of the environmental humanities, the energy humanities holds an environmentalist mandate: climate change and the violence of resource extraction render it critical that we use all available means to address energy extraction and consumption. Humanities research is well suited to the tasks of imagining a future beyond fossil fuels and of understanding exactly how and why we have become so deeply enmeshed in destructive energy systems. The humanities are late to energy research because energy is, paradoxically, both everywhere and hard to see. According to editors Ross Barrett and Daniel Worden, “oil’s signature cultural ubiquity and absence is the occasion” for their collection called Oil Culture—and the same can be said for the other works assembled here.1 Disaster breaks the spell of invisibility, and highly spectacular oil spills like the 1969 Santa Barbara oil spill and the 2010 disaster aboard the Deepwater Horizon drilling rig feature prominently in energy humanities scholarship. The mass media have produced a highly recognizable visual vernacular for these disasters: oil-soaked birds; beach cleanup crews in hazmat suits; images of oil gushing, leaking, and coagulating into greasy clots in the ocean. As Sheena Wilson warns, though, the spectacularization of oil spills produces complacency by naturalizing the much more violent and dangerous “ordinary” processes of extracting, shipping, and consuming oil.2 Under those ordinary circumstances, the material and conceptual [End Page 156] infrastructures of oil production keep oil invisible. This insight owes in large part to Timothy Mitchell, whose Carbon Democracy: Political Power in the Age of Oil connects the materiality of different energy resources to the political forms that emerged from them.3 Oil is more easily controlled by a centralized authority and less vulnerable to labor stoppages and sabotage than, say, coal; oil is extracted and shipped by highly mechanized processes that take place out of sight in underground oil wells and inside opaque pipelines.4 Some of the most important recent work on energy infrastructures comes from Canada, where scholars are using their proximity to the Alberta tar sands as a mandate for research. The essay collection Petrocultures: Oil, Politics, Culture, edited by Sheena Wilson, Adam Carlson, and Imre Szeman, collects important and deeply informed insight on infrastructures, cultural artifacts, and political problems arising from the...

The importance of considering multiple interacting species for conservation of species at risk.

Conservation of species at risk of extinction is complex and multifaceted. However, mitigation strategies are typically narrow in scope, an artifact of conservation research that is often limited to a single species or stressor. Knowledge of an entire community of strongly interacting species would greatly enhance the comprehensiveness and effectiveness of conservation decisions. We investigated how camera trapping and spatial count models, an extension of spatial-recapture models for unmarked populations, can accomplish this through a case study of threatened boreal woodland caribou (Rangifer tarandus caribou). Population declines in caribou are precipitous and well documented, but recovery strategies focus heavily on control of wolves (Canis lupus) and pay less attention to other known predators and apparent competitors. Obtaining necessary data on multispecies densities has been difficult. We used spatial count models to concurrently estimate densities of caribou, their predators (wolf, black bear [Ursus americanus], and coyote [Canis latrans]), and alternative prey (moose [Alces alces] and white-tailed deer [Odocoileus virginianus]) from a camera-trap array in a highly disturbed landscape within northern Alberta's Oil Sands Region. Median densities were 0.22 caribous (95% Bayesian credible interval [BCI] = 0.08-0.65), 0.77 wolves (95% BCI = 0.26-2.67), 2.39 moose (95% BCI = 0.56-7.00), 2.64 coyotes (95% BCI = 0.45-6.68), and 3.63 black bears (95% BCI = 1.25-8.52) per 100km2 . (The white-tailed deer model did not converge.) Although wolf densities were higher than densities recommended for caribou conservation, we suggest the markedly higher black bear and coyote densities may be of greater concern, especially if government wolf control further releases these species. Caribou conservation with a singular focus on wolf control may leave caribou vulnerable to other predators. We recommend a broader focus on the interacting species within a community when conserving species.

Principal component analysis of summertime ground site measurements in the Athabasca oil sands with a focus on analytically unresolved intermediate-volatility organic compounds

Abstract. In this paper, measurements of air pollutants made at a ground site near Fort McKay in the Athabasca oil sands region as part of a multi-platform campaign in the summer of 2013 are presented. The observations included measurements of selected volatile organic compounds (VOCs) by a gas chromatograph–ion trap mass spectrometer (GC-ITMS). This instrument observed a large, analytically unresolved hydrocarbon peak (with a retention index between 1100 and 1700) associated with intermediate-volatility organic compounds (IVOCs). However, the activities or processes that contribute to the release of these IVOCs in the oil sands region remain unclear. Principal component analysis (PCA) with varimax rotation was applied to elucidate major source types impacting the sampling site in the summer of 2013. The analysis included 28 variables, including concentrations of total odd nitrogen (NOy), carbon dioxide (CO2), methane (CH4), ammonia (NH3), carbon monoxide (CO), sulfur dioxide (SO2), total reduced-sulfur compounds (TRSs), speciated monoterpenes (including α- and β-pinene and limonene), particle volume calculated from measured size distributions of particles less than 10 and 1 µm in diameter (PM10−1 and PM1), particle-surface-bound polycyclic aromatic hydrocarbons (pPAHs), and aerosol mass spectrometer composition measurements, including refractory black carbon (rBC) and organic aerosol components. The PCA was complemented by bivariate polar plots showing the joint wind speed and direction dependence of air pollutant concentrations to illustrate the spatial distribution of sources in the area. Using the 95 % cumulative percentage of variance criterion, 10 components were identified and categorized by source type. These included emissions by wet tailing ponds, vegetation, open pit mining operations, upgrader facilities, and surface dust. Three components correlated with IVOCs, with the largest associated with surface mining and likely caused by the unearthing and processing of raw bitumen.

Visbreaking of Deasphalted Oil from Bitumen at 280–400 °C

The time-dependent thermal conversion of vacuum residue deasphalted oil was studied at 280, 320, 360, and 400 °C. The vacuum residue deasphalted oil was an industrial product produced by vacuum distillation of Athabasca bitumen followed by solvent deasphalting using n-pentane. This type of visbreaking process was of interest for partial upgrading of bitumen to facilitate pipeline transport. Practically useful cracking conversion and viscosity reduction for upgrading were found only at 360 and 400 °C. The viscosity measured at 40 °C could be reduced by 3 orders of magnitude from 3720 Pa s in the feed to 2–5 Pa s in the product. The density of the product was not reduced by much, despite vacuum residue cracking conversions of 34% at 360 °C and 45–47% at 400 °C before the onset of coking. The liquid yield was 88–89%. A heavier product fraction was formed during thermal conversion. The heavy material was not necessarily asphaltenes, but an increase in n-pentane-insoluble material was also found that appeared ...

Using regional datasets of isotope geochemistry to resolve complex groundwater flow and formation connectivity in northeastern Alberta, Canada

In the southern Athabasca Oil Sands (SAOS) Region, located in Alberta Canada, individual in-situ oil sands operators have conducted local geochemical and isotope groundwater studies to establish baseline characteristics and to improve understanding of the connectivity of water supply and disposal formations within individual leases. Canada's Oil Sands Innovation Alliance (COSIA) initiated this study to combine the data from these individual studies along with public information into a comprehensive unified dataset to evaluate conceptual models of regional groundwater flow and the degree of interaction and separation between important water supply and disposal aquifers. The unified dataset comprised over 293 groundwater samples from the main water source and disposal hydrostratigraphic units and included geochemical and isotopic tracers that can be used to identify sources (δ18O and δ2H) and age of water (3H) and associated solutes (14CDIC, 36Cl), as well as the sources of salinity and diagenetic processes (δ13CDIC, δ34SSO4, 87Sr/86Sr, δ11B, δ37Cl and δ81Br) and dissolved organics (δ13CDOC). The TDS and stable isotope composition (δ18O and δ2H) of groundwater from several Cretaceous formations were used to identify three main mixing controls. i) Areas where locally recharged groundwater mixes with glaciogenic water were identified by lower δ18O and δ18O values, high TDS, Cl:Br and δ34SSO4, 87Sr/86Sr, and δ37Cl values consistent with dissolution of evaporites. These areas were situated where vertical pathways through otherwise competent formations are likely to occur. ii) Mixing with paleo-waters characterized by high TDS and higher δ18O and δ2H signatures indicating groundwater recharged under warmer climate periods and/or evaporative enrichment were identified in the south, and southwestern portions of the study area. The presence of these paleo-waters indicate slow-moving groundwater zones with limited lateral and vertical connectivity. iii) Areas with potential connectivity to shallow aquifers were identified by their lower TDS values, modern meteoric δ18O and δ2H signatures, HCO3 type waters, and δ34SSO4 and 87Sr/86Sr signatures, consistent with weathering of shallow aquifer material. Geochemical and isotopic indicators suggest that in areas where the Colorado Group aquitard is thin or absent, there is greater connectivity between the Grand Rapids Formation and the shallower aquifers. Interpretation of the new unified dataset has improved understanding of the extent that glacial recharge had on Devonian aquifers, and overlying Cretaceous formations, and identified zones with relatively stagnant groundwater flow, both of which have implications for regional groundwater resource development, monitoring and potential wastewater disposal.

Hydrocracking of Fischer‐Tropsch wax and its mixtures with heavy vacuum gas oil

In this study, Fischer‐Tropsch (F‐T) wax and bitumen‐derived hydrotreated heavy vacuum gas oil (HVGO) blends were co‐hydrocracked over a commercial catalyst in an autoclave reactor at a temperature of 360 °C and an initial hydrogen pressure of 4.2 MPa. 100 % F‐T wax and 100 % HVGO were hydrocracked under similar operating conditions as the reference feedstocks. The results revealed that the conversion of 360 °C+ materials decreased from 0.79 g/g (79 mass%) to 0.71 g/g (71 mass%) when the F‐T wax/HVGO blending ratio increased from 0/100 to 25/75 (g/g), then increased dramatically from 0.71 g/g (71 mass%) to almost 1 g/g (100 mass%) when the F‐T wax/HVGO blending ratio continued to increase to 100/0 (g/g). As the F‐T wax/HVGO blending ratio in the feed increased, the contents of cycloparaffins and aromatics decreased, whereas those of iso‐paraffins and n‐paraffins in the products increased. The research octane number and the motor octane number of the naphtha fraction also increased from 76 to 95 and from 76 to 82 when the F‐T wax/HVGO blending ratio increased from 0/100 to 100/0 (g/g), respectively. The product obtained from pure F‐T wax, which contained 0.8 g/g (80 mass%) of C5–C11 iso‐paraffins, was tested for diluent compatibility with Athabasca bitumen. The P‐value at 0.3 L/L (30 vol%) dilution was 2.11, close to that of 2.17 for natural gas condensate. Meanwhile, both the API gravity and viscosity met pipeline specifications, which indicates that the product hydrocracked from F‐T wax is a suitable diluent for bitumen.

Mapping water yield distribution across the South Athabasca Oil Sands (SAOS) area: Baseline surveys applying isotope mass balance of lakes

Study regionSurveys of stable isotopes of water in 121 lakes were conducted between 2007 and 2009 to assist in characterizing baseline hydrology of the South Athabasca Oil Sands area, Alberta, a 35,000 km2 boreal forest region with subdued relief, about 70% wetland cover, and a mosaic of lakes, rivers and buried channel networks. The region, currently under rapid development for in-situ oil sands, was close to baseline conditions at the time of survey. Study focusUsing an isotope mass balance approach, isotope data were applied to estimate water yield to lakes across the region. High-resolution maps were created to illustrate the spatial distribution of water yield and to compare observed patterns to geologic and physiographic features. New hydrological insights for the regionSite-specific differences in water yield were found in relation to geologic and physiographic features. Notably, high water yields were found in lakes underlain by Colorado shale, lower runoff was found in proximity to incised and buried channels. Consistent patterns from year-to-year reveal zones of low runoff which may be more susceptible to development-related impacts including changes in surface/groundwater interaction and pressurization or depressurization of aquifers or formations. The approach may be helpful for informing design of new monitoring programs to ensure runoff variability is considered. Periodic reassessments are recommended to capture potential development and/or climatic change impacts on the water cycle.