Bitumen Extraction Research Articles

Study of the effect of ultrasonic technology on the extraction of bitumen from bituminous rocks

Background: Nowadays, there are few studies focused on the extraction of targeted products from bituminous rocks. Published research on the on the use of ultrasound for bitumen extraction refers to unconventional technologies. A distinctive feature of the bituminous rocks under study is their exposure at the surface, where they are situated in open areas. Due to various technogenic factors and prolonged atmospheric, light fractions are lost, while the heavier components undergo oxidation. These processes lead to the formation of heavy oils and hard bitumens with complex composition. Aim: To study the effect of ultrasonic technology on the bitumen extraction of from bituminous rocks and to determine the physical and chemical properties of the product obtained. Materials and methods: Thу ultrasonic method has many benefits, in particular energy and water savings, high productivity within a short period of time, and possibility of organizing a mobile unit installation at the production site. The main process parameters includes the determination of the required frequency and power depending on the object of ultrasound technology research. The results of the work have demonstrated that ultrasonic cavitation of bituminous rocks in an alkaline medium increases the degree of bitumen extraction. Results: The physical and chemical properties of bitumen obtained as a result of studying the effect of ultrasonic technology on bitumen extraction from oil-bituminous rocks were determined. Conclusion: The study identified the optimal process parameters based on the specific research object. When selecting the ultrasonic power it was found that clay compounds of bituminous rocks have a direct effect on the extraction of natural bitumen. It was demonstrated that ultrasound technology is a promising and industrially applicable technology for extracting bitumen from the bituminous rocks of the Munaily Mola field.

Petrographic and geochemical signatures of the Upper Permian Gondwana coals: Newcastle Coal Measures, Northern Sydney Basin, Australia

This research presents an integrated approach to organic petrographical and geochemical characteristics of the Upper Permian Newcastle Coal Measures outcropping in the northern Sydney Basin, southeast Australia. Twenty-seven coal, coaly mudstone and mudstone samples were collected and analyzed by using organic petrography (maceral composition and vitrinite reflectance) techniques, Rock–Eval pyrolysis, bitumen extraction and gas chromatography - mass spectrometry (GC–MS). The obtained results indicate that the samples exhibit promising gas-prone source rock potential and contain a predominantly terrestrial in origin organic matter, with limited contribution by marine organisms. The prevalence of terrestrial organic matter is inferred by the presence of collotelinite and sporinite macerals in most of the samples and the ternary plot of C27, C28 and C29 regular steranes. Further, the low C27/C29 ratio, the cross-plots of C27/(C27 + C29) regular steranes vs. Pr/Ph ratio, the C27/C29 vs. Pr/Ph and the C24 tetracyclic/C26 tricyclic terpane ratio point also to the terrestrial origin of the organic matter. The obtained values of vitrinite reflectance, Tmax, OEP27–31 and CPI25–33, along the cross plots of 20S/(20S + 20R) versus ββ/(ββ + αα) suggest that the samples are immature and were subjected to a low burial depth. The examined samples indicate accumulation in a delta-plain environment of deposition, under fluctuating oxic/anoxic conditions, in a humid climatic zone that is characterized by dry periods, interrupting the longer-termed humid climatic regime. This research adds knowledge on the source rock potential in the northern Sydney Basin and on the environmental and climatic setting of a time interval just prior to the major Permian - Triassic climatic crisis.

Geochemical characteristics of crude oils and source rocks in the Malaysia-Thailand Joint Development Area (MTJDA), North Malay Basin

The Malaysia-Thailand Joint Development Area (MTJDA) that located in the North Malay Basin has been investigated in this study to resolve few issues concerning to petroleum potential and resources which has been abandon for decades. Despite Malay Basin having been proven to contain prolific oil and gas resources, the MTJDA which located in the Northern area however contains mainly gas with very minor oil. Thus, this study aimed to investigate the main factor that controls the hydrocarbon generation, type and distribution in this basin. The investigation involves biomarker characterization, thermal maturity assessment of source rock, crude oil and condensate, together with oil-oil and oil-source correlation that has never been established before. The geochemical data as indicated by bitumen extraction, GC-MS and Py-GC analyses on 40 cutting samples and 8 liquid samples (six oil samples and two condensate samples) revealed that the cutting samples were moderate in quality with variable richness based on TOC (total organic carbon) and a variable degree of maturity based on the biomarker proxy parameters of isoprenoid, hopanoid and steroid. The organic matter input for the source rock was derived from a mixed marine-terrestrial and terrestrial source and deposited in fluvial-deltaic/estuarine settings having oxic to sub-oxic depositional conditions. Based on biomarker fingerprints and proxy parameters, the oil and condensate samples were essentially of the same group, originating from a similar source rock, with some facies variation due to variations in organic matter input and degree of maturity. The results also indicated that the crude oil samples were originated from the coaly and carbonaceous shales of Group I, with mixed kerogen of type II/III that could produce gas with minor oil. There is also the possibility that these hydrocarbons were generated from a deeper interval of Group E (higher thermal maturity), deposited in a similar setting as Group I.

The effect of rhizosphere pH on removal of naphthenic acid fraction compounds from oil sands process-affected water in a willow hydroponic system

The extraction and processing of bitumen from the oil sands in northern Alberta, Canada generates large volumes of oil sands process-affected water (OSPW). OSPW contains a complex mixture of inorganic and organic compounds, including naphthenic acid fraction compounds (NAFCs) that are of particular concern due to their toxicity to aquatic organisms. Phytoremediation is a cost-effective, scalable approach that has the potential to remove NAFCs from OSPW and reduce OSPW toxicity. Environmental pH influences the chemical form and bioavailability of NAFCs. However, little is known about the influence of pH on the uptake of NAFCs in plant systems. This study sought to elucidate the impact of rhizosphere pH on the uptake of NAFCs using a sandbar willow (Salix interior) hydroponic system. To mimic and maintain the naturally low pH conditions of the root, OSPW solutions in these systems were adjusted to a low pH level (pH 5.0) and their NAFC uptake from solution was compared to that of OSPW at native pH (pH 8.0). Our findings revealed that the lower pH hydroponic systems demonstrated enhanced NAFC removal from solution as determined by LC-MS analysis, where up to 26% of NAFCs were removed from OSPW over 72 h at pH 5.0 compared to 8% removed at pH 8.0. Similarly, analysis of spike-in 13C-labeled NAs demonstrated that the OSPW hydroponic system rapidly removed a relatively labile NA (13C-cyclohexane carboxylic acid) from solution at both pH levels, whereas near complete removal of a recalcitrant NA (13C-1-adamantane carboxylic acid) was observed in pH 5.0 solutions only. These results provide insight into the importance of rhizosphere pH on efficient NAFC uptake by plant root systems. Further research will determine whether OSPW phytoremediation efficiency can be enhanced using field treatment conditions that promote low rhizosphere pH levels.

Toxicity Evaluation of Water and Pore Water from a Pilot-Scale Pit Lake in the Alberta Oil Sands Region to Daphnia Species.

Significant amounts of tailings and oil sands process-affected water (OSPW) are generated by bitumen extraction in the Alberta Oil Sands region. These by-products are potentially toxic to aquatic organisms and require remediation. The study site was Lake Miwasin, a pilot-scale pit lake integrated into broader reclamation efforts. It consists of treated tailings overlaid with blended OSPW and freshwater, exhibiting meromictic conditions and harboring aquatic communities. This study assessed the potential toxicity of Lake Miwasin surface water (LMW) and pore water (LMP) using saline-acclimated Cladocera, including lab strains of Daphnia magna and Daphnia pulex and native Daphnia species collected in brackish Humboldt Lake (HL) and Lake Miwasin (LM). The pore water evaluation was used to represent a worst-case water quality scenario during pond stratification. Additionally, the inclusion of native organisms incorporated site-specific adaptations and regional sensitivity into the toxicity evaluation. Our results showed that LMW did not display acute or chronic toxicity to lab species and native Daphnia sp. (HL). Conversely, LMP was acutely toxic to both lab species and native D. pulex (LM). In chronic tests (12days exposure), LMP negatively affected reproduction in D. pulex (lab), with reductions in the number of offspring. Limited ability to acclimated organisms to the high salinity levels of LMP resulted in a shortened exposure duration for the chronic toxicity test. In addition to salinity being identified as a stressor in LMP, toxicity identification evaluation (TIE) phase I findings demonstrated that the observed toxicity for D. magna (lab) and D. pulex (LM, native) might be attributed to ammonia and metals in LMP. Further investigations are required to confirm the contributions of these stressors to LMP toxicity.

Making sense of wildlife habitat use on active oil sands mines: Quasi‐experiments, occupancy models, trends assessments and upland habitat reclamation

Abstract Intensive resource extraction activity in the oil sands of Canada alters the quantity, structure and distribution of native ecosystems, which in turn creates substantive challenges for conservation, land management and habitat reclamation. Progressive reclamation occurs on active mine sites in the Athabasca oil sands region (AOSR) of Canada, along with concurrent assessments of reclamation effectiveness. Yet, little is known about the ability of reclaimed habitats to mitigate for the short‐ and long‐term impacts associated with open‐pit mines and provide functional habitat for wildlife. We used a robust quasi‐experiment that combined camera trap data from an observational study with an innovative occupancy model to assess the effectiveness of upland reclamation to provide habitat for wildlife in the AOSR. The dynamic occupancy models were applied to 15 years of camera trap data to assess wildlife usage patterns of nine species of wildlife over seven types of habitats. The habitats sampled ranged from mining‐disturbed habitats reclaimed to upland forest ecosites common in the region, habitats disturbed by natural (fire) and human disturbances (clear‐cut logging), with comparisons to mostly intact mature forests. Our results indicate that the nine species of wildlife assessed used habitats in a manner consistent with expectations: some preferred disturbance‐dominated habitats while others used mature forest to a higher degree. We demonstrate that the application of dynamic occupancy models to camera trap data reliably discerned these trends, providing the means to predict wildlife usage patterns in an ever‐changing landscape, including one containing bitumen extraction as a contributor to landscape‐level modifications. Practical implication: Our work illustrates how continued monitoring of wildlife using camera traps contributes to assessments of reclamation effectiveness with respect to wildlife occurrence, distribution and usage patterns in anthropogenically and naturally disturbed landscapes. Evaluating the effectiveness of reclamation is especially important given the expected increase in habitat reclamation on active oil sands mines over the next several decades, coupled with the need to ensure that disturbed habitats regain ecological function able to sustain wildlife in the future.

Geochemical Characteristics of Mature to High-Maturity Shale Resources, Occurrence State of Shale Oil, and Sweet Spot Evaluation in the Qingshankou Formation, Gulong Sag, Songliao Basin

The exploration of continental shale oil in China has made a breakthrough in many basins, but the pure shale type has only been found in the Qingshankou Formation, Gulong Sag, Songliao Basin, and the evaluation of shale oil occurrence and sweet spot faces great challenges. Using information about the total organic carbon (TOC), Rock-Eval pyrolysis, vitrinite reflectance (Ro), kerogen elemental composition, carbon isotopes, gas chromatography (GC), bitumen extraction, and component separation, this paper systematically studies the organic geochemical characteristics and shale oil occurrence at the Qingshankou Formation. The G1 well, which was cored through the entire section of the Qingshankou Formation in the Gulong Sag, was the object of this study. On this basis, the favorable sweet spots for shale oil exploration are predicted. It is concluded that the shale of the Qingshankou Formation has high organic heterogeneity in terms of organic matter features. The TOC content of the source rocks in the Qingshankou Formation is enhanced with the increase in the burial depth, and the corresponding organic matter types gradually changed from Ⅱ2 and Ⅱ1 types to the Ⅰ type. The distribution of Ro ranges from 1.09% to 1.67%, and it is the mature to high-mature evolution stage that generates a large amount of normal crude oil and gas condensate. The high-quality source rocks of good to excellent grade are mainly distributed in the Qing 1 member and the lower part of the Qing 2 member. After the recovery of light hydrocarbons and the correction of pyrolytic heavy soluble hydrocarbons, it is concluded that the occurrence state of shale oil in the Qingshankou Formation is mainly the free-state form, with an average value of 6.9 mg/g, and there is four times as much free oil as adsorbed oil. The oil saturation index (OSI), mobile hydrocarbon content, Ro, and TOC were selected to establish the geochemical evaluation criteria for shale oil sweet spots in the Qingshankou Formation. The evaluation results show that interval 3 and interval 5 of the Qingshankou Formation in the G1 well are the most favorable sections for shale oil exploration.

A multi-step approach: Coupling of biodegradation and UV photocatalytic oxidation TiO2 for the treatment of naphthenic acid fraction compounds in oil sands process-affected water

Bitumen extraction in Alberta's oil sands region uses large volumes of water, leading to an abundance of oil sands process-affected water (OSPW). OSPW contains naphthenic acid fraction compounds (NAFCs) which have been found to contribute to OSPW toxicity. This study utilized a multistep treatment, coupling biological degradation with UV photocatalytic oxidation, and nutrient addition to boost the native microbial community's degradation capacity. OSPW initially contained 40–42 mg/L NAFCs with a toxicity of 3.8–3.9 TU. Initial biodegradation (Step 1) was used to remove the easily biodegradable NAFCs (11–25% removal), followed by a light or heavy dose of oxidation (Step 2) to breakdown the recalcitrant NAFCs (66–82% removal). Lastly, post-oxidation biodegradation with nutrients (Step 3) removed the residual bioavailable NAFCs (16–31% removal). By the end of the multistep treatment, the final NAFC concentrations and toxicity ranged from 5.3 to 6.8 mg/L and 1.1–1.2 TU. Analysis showed that OPSW was limited in phosphorus (below detection limit), and the addition of nutrients improved the degradation of NAFCs. Two treatments throughout the multistep treatment never received nutrients and showed minimal NAFC degradation post-oxidation. The native microbial community survived the stress from UV photocatalytic oxidation as seen by the post-oxidation NAFC biodegradation. Microbial community diversity was reduced considerably following oxidation, but increased with nutrient addition. The microbial community consisted predominately of Proteobacteria (Gammaproteobacteria and Alphaproteobacteria), and the composition shifted depending on the level of oxidation received. Possible NAFC-degrading microbes identified after a light oxidation dose included Pseudomonas, Acinetobacter and Xanthomonadales, while Xanthobacteracea and Rhodococcus were the dominant microbes after heavy oxidation. This experiment confirms that the microbial community is capable of degrading NAFCs and withstanding oxidative stress, and that degradation is further enhanced with the addition of nutrients.

Effects of naturally sourced bitumen samples from Alberta oil sands region (Canada) on aquatic benthic invertebrates: A case study with Chironomus riparius

Athabasca oil sands in Alberta, Canada, are large bitumen deposits and are one of the world's largest petroleum reserves. This research contributes to the growing body of knowledge on the influence of this naturally occurring bitumen on freshwaters. Using laboratory-based exposure studies, we examined the life cycle responses of the aquatic midge Chironomus riparius to both naturally formed solid bitumen incorporated in the sediment and its corresponding aqueous extracts, denominated as elutriates. The 28-day partial life cycle assay involved bitumen samples from two distinct geological origins in the Athabasca River Basin (Clearwater and McMurray formations), comprising both weathered and freshly collected bitumen from a total of 4 different rivers. Our results demonstrate a measurable impact of sediment-embedded bitumen on C. riparius life history traits, namely on their growth and emergence patterns. Furthermore, we observed that bitumen samples from the Ells River (McMurray formation), which were freshly collected from exposed river bank soil deposits, exerted the strongest effects on most studied eco-physiological endpoints. Bitumen extracts from the Steepbank River and Athabasca River in the McMurray Formation and Steepbank River in the Clearwater Formation followed, underscoring the geographical variance in bitumen-induced toxicity. Exposure to elutriates, simulating “weathered” bitumen generally did not induce adverse effects in C. riparius life-cycle endpoints compared to elutriates prepared from freshly eroded bank soils. This emphasizes the importance of considering bitumen sources, their age, and the aquatic receiving environment when assessing potential adverse exposure effects. Our study shows that exposure to freshly eroded soils/sediments can potentially affect benthic invertebrates. More research is needed to understand how hydrological changes affect bitumen sediment exposure and the associated risks to aquatic biota.

Potential of biochar and humic substances for phytoremediation of trace metals in oil sands process affected water

Oil sands process affected water (OSPW) is produced during bitumen extraction and typically contains high concentrations of trace metals. Constructed wetlands have emerged as a cost effective and green technology for the treatment of metals in wastewaters. Whether the addition of amendments to constructed wetlands can improve metal removal efficiency is unknown. We investigated the synergistic effects of carbon based amendments and wetland plant species in removal of arsenic, cadmium, cobalt, chromium, copper, nickel, and selenium from OSPW. Three native wetland species (Carex aquatilis, Juncus balticus, Scirpus validus) and two amendments (canola straw biochar, nano humus) were investigated in constructed wetland mesocosms over 60 days. Amendment effect on metal removal efficiency was not significant, while plant species effect was. Phytoremediation resulted in removal efficiencies of 78.61–96.31 % for arsenic, cadmium, and cobalt. Carex aquatilis had the highest removal efficiencies for all metals. Amendments alone performed well in removing some metals and were comparable to phytoremediation for cadmium, cobalt, copper, and nickel. Metals were primarily distributed in roots with negligible translocation to shoots. Our work provides insights into the role of plants and amendments during metal remediation and their complex interactions in constructed treatment wetlands.

Microstructural characterization and corrosion behaviour of heat treated standard stainless steels in tar sand

This paper aims to investigate the corrosion behaviour of heat-treated standard duplex stainless steel (UNS S32205) in the recovery of bitumen from Nigerian-rich tar sand, using sodium hydroxide (NaOH) as the process solution. Appropriate material family needs to be identified for the exploitation of tar sand resources to ensure sustainable extraction of bitumen. UNS S32205 offers exceptional mechanical properties and excellent corrosion resistance which makes it a great material choice for demanding applications, including offshore platforms and construction projects. Samples of UNS 32205 were heat-treated and immersed in the digested tar sand, maintaining a process temperature of 90°C. The microstructure of the corrosion coupons was studied using SEM/EDS (Scanning Electron Microscope/Energy Dispersive Spectroscope), and the corrosion rate of the samples was derived using gravimetric technique following ASTM G31 standard. The SEM micrographs indicated varying degrees of pits associated with the passivity of UNS 32205 and an imbalance between its ferrite and austenite phases due to the presence of secondary precipitates formed during heat treatment.The normalized sample, having a corrosion rate of 0.053 mm/year, exhibited the best corrosion resistance, followed by oil quenching (0.054 mm/year), then annealing (0.076 mm/year), and water quenching (0.077 mm/year), where they all showed improved corrosion resistance over the as-received sample having a corrosion rate of 0.078 mm/year.

Comparative study on the extraction strength of solvents on tar sand from Okitipupa, Ondo State

Tar sand, an aggregate of sand, clay, water and bitumen was sampled from Okitipupa area of Ondo State, Nigeria, extracted and optimized using n-hexane and toluene in a soxhlet extractor todetermine solvent effectiveness in extracting the bitumen content and their environmental effect. The experiment was carried out by heating the solvent at and above their boiling temperatures solely to get an optimum yield at a temperature and time of extraction of oil from the tar sand. The analysis gave an optimal yield of 9.07 % at 75oC in 4 h when n-hexane was used and an optimal yield of 21.27 % at 120oC in 4 h when toluene was used. A drastic change in colour was also notice in the sand residue to almost sandy soil nature when toluene was used as solvent compare to when n-hexane was used which shows a slight change from its blackish nature. The change in colour of the black tar sand is an indication of high extraction efficiency. Hence, owing to high demand for conventional oil supply in the country and the urgent need for an alternative source of oil, the bitumen extract can serve as an alternative source of unconventionaloil supply in Nigeria and feedstock in refineries.

Liquid-Liquid equilibrium measurements analysis of synthetic multicomponent solvent (n-Pentane, n-Hexane, n-Heptane, Cyclo-Hexane, Toluene)/Bitumen System: Implications for solvent-aided in-situ bitumen extraction

Understanding the Liquid-Liquid Equilibrium (LLE) of multicomponent solvent/bitumen systems is pivotal in optimizing in-situ bitumen extraction. While Vapor-Liquid Equilibria (VLE) of solvent-bitumen systems has been extensively studied, LLE data and predictive models for these mixtures, especially those involving synthetic multicomponent solvents, are scarce. This study provides comprehensive LLE measurements of bitumen and a multicomponent synthetic solvent (n-pentane + n-hexane + n-heptane + cyclo-hexane + toluene) conducted under controlled equilibrium conditions at temperatures of 295 to 352 K, solvent concentrations up to 70 wt% at 1.291 MPa. Application of common correlation used in the construction of solvent-aided process fluid models exhibited average absolute relative deviations (AARDs) of 0.37 % for density and 8.87 % for viscosity. We identified the boundaries marking the shift from homogenous single-phase liquid to two-phase (LLE) states, which occurs within the synthetic multicomponent solvent concentration range of 50 to 60 wt%. We also successfully constructed calibration curves to measure solvent concentrations in both phase regions. The molecular weight distribution and saturates, aromatics, resins, and asphaltene (SARA) fractionation of both liquid phases were determined, highlighting that the heavy liquid phase is primarily asphaltene (∼46 wt%). The insights gained from the measurements and analysis find applications in designing and optimizing solvent-assisted thermal recovery processes for bitumen extraction.

Идентификация компонентного состава твердой углеводородной фазы в пласте и оценка ее влияния на поведение подвижного флюида баженовской свиты в процессе разработки залежи

The purpose of the work is to identify the composition of the initial reservoir hydrocarbon (HC) system of the Bazhenov formation, as well as to assess the influence of the presence of a heavy solid hydrocarbon phase (bitumen) in the formation on the production of mobile fluids using PVT modeling methods. The article describes the necessary experiments to determine the component composition of the C81+ fraction and the PVT properties of the formation mobile fluid taken from the well and the bitumen extract from the rock, and also presents their results. In addition, the properties of fractions up to C81+ were calculated depending on the molecular weight for PVT modeling (extension of the Katz-Firuzabadi table). One of the important parts of the article is the assessment of the ratio of bound and free oil in the original reservoir system. Based on geochemical research data, an analysis was performed to assess the component composition of the original system (using the example of the Bazhenov Formation) using rock pyrolysis and studying formation fluid and bitumen. Using the results of studies of reservoir fluid samples, a PVT model was built and tuned. This PVT model was used to assess the properties of the initial reservoir hydrocarbon system and was adjusted to the fraction of the solid phase in the reservoir at the initial reservoir conditions. After this, based on the PVT model, an assessment was made of the influence of the presence of a solid phase in the composition of the reservoir system on the behavior of a mobile hydrocarbon fluid during reservoir development for depletion, as well as on the use of enhanced oil recovery methods (injection of associated petroleum gas and thermal methods of influencing the reservoir).

Characterization and acid treatment of silica and organics in evaporator blowdown wastewater arising from SAGD operations

The evaporator blowdown (EBD) wastewater from high-pressure steam generation for the steam-assisted gravity drainage (SAGD) bitumen extraction process contains elevated concentrations of dissolved inorganic and organic compounds, of which silica and organics pose challenges in its treatment and disposal. This study investigated treatment options for EBD before its disposal. Following detailed physical and chemical characterization of the EBD, we examined its acid treatment with HCl and H2SO4 at pHs ranging from 12 to 2. The acid treatment performance was evaluated in terms of silica and organic removal efficiencies along with the filtration rate and filtrate recovery. Both acids gave similar silica and organic removal efficiencies; however, the filtration performance following the HCl-treatment was better than the H2SO4-treatment. In practice, the acids would likely perform comparably with regard to silica removal and the final process selection would more likely be influenced by other factors such as storage, material compatibility, cost, and downstream or subsurface compatibility. The HCl-treatment was investigated further with both the EBD and prepared silica solutions for the silica removal efficiency and filtration performance. The experiments conducted at ∼20 °C demonstrated higher silica removal efficiencies at pHs 10 and 8, whereas higher organic removal efficiencies were obtained at pHs 4 and 2. The experiments conducted at ∼80 °C showed enhanced silica removal at pH = 8 and higher organic removal at pH = 2. The precipitated solids were characterized using XRD and ATR-FTIR spectroscopy to identify the minerals and functional groups. The XRD patterns demonstrated that the solids generated were amorphous. The ATR-FTIR spectra revealed the predominance of siloxane, silanol, carboxylate and carbonyl compounds. These results confirmed a substantial removal of silica and organic constituents from the EBD through the acid treatment process.

Digital twin and control of an industrial-scale bitumen extraction process

This article presents a digital twin solution for bitumen extraction process required to study process dynamics, control, and optimization of this critical oil sands process. It captures the actual process interconnectivity and scale, enabling the bidirectional data connection between the virtual and physical entities. The proposed model was validated using data from an oil sands extraction facility. Results demonstrate the model well mimics real process behavior in both steady-state and dynamic conditions, with tunable parameters tailored for any further adaption. The model was used to study extraction performance under various production scenarios. It enables analyzing process behavior and testing strategies to optimize bitumen recovery.

Uncovering Anaerobic Hydrocarbon Biodegradation Pathways in Oil Sands Tailings from Two Different Tailings Ponds via Metabolite and Functional Gene Analyses.

Oil sands tailings, a slurry of alkaline water, silt, clay, unrecovered bitumen, and residual hydrocarbons generated during bitumen extraction, are contained in ponds. Indigenous microbes metabolize hydrocarbons and emit greenhouse gases from the tailings. Metabolism of hydrocarbons in tailings ponds of two operators, namely, Canadian Natural Upgrading Limited (CNUL) and Canadian Natural Resources Limited (CNRL), has not been comprehensively investigated. Previous reports have revealed sequential and preferential hydrocarbon degradation of alkanes in primary cultures established from CNUL and CNRL tailings amended separately with mixtures of hydrocarbons (n-alkanes, iso-alkanes, paraffinic solvent, or naphtha). In this study, activation pathway of hydrocarbon biodegradation in these primary cultures was investigated. The functional gene analysis revealed that fumarate addition was potentially the primary activation pathway of alkanes in all cultures. However, the metabolite analysis only detected transient succinylated 2-methylpentane and 2-methylbutane metabolites during initial methanogenic biodegradation of iso-alkanes and paraffinic solvent in all CNUL and CNRL cultures amended with iso-alkanes and paraffinic solvent. Under sulfidogenic conditions (prepared only with CNUL tailings amended with iso-alkanes), succinylated 2-methylpentane persisted throughout incubation period of ~ 1100days, implying dead-end nature of the metabolite. Though no metabolite was detected in n-alkanes- and naphtha-amended cultures during incubation, assA/masD genes related to Peptococcaceae were amplified in all CNUL and CNRL primary cultures. The findings of this present study suggest that microbial communities in different tailings ponds can biodegrade hydrocarbons through fumarate addition as activation pathway under methanogenic and sulfidogenic conditions.

Smectite-bitumen interactions in non-aqueous bitumen extraction process

The non-aqueous extraction (NAE) is an alternative to the commercial water-based extraction technology used to liberate bitumen from oil sands. Although the impact of kaolinite, illite, chlorite, illite-smectite and montmorillonite on NAE process has been previously studied, the effect of different types of smectites has not been fully understood yet. In this work, mixtures of bitumen with bentonites dominated by saponite, hectorite, nontronite, beidellite and montmorillonite were reacted for several days and then washed with solvent (cyclohexane) to remove bitumen from the bentonites. The main goal was to better understand the impact of different smectites properties (specific surface area, pore structure characteristics, particle size, crystallite thickness, swelling ability, cation exchange capacity, layer charge and crystal-chemistry of smectites) on NAE process. The results showed that the porosity, particle size and swelling ability were the key parameters affecting the solvent-based bitumen recovery under the studied conditions. Samples with larger initial total pore volume and smaller particle size displayed reduced solvent bitumen extractability. The particle size of studied samples was affected primarily by swelling of smectites during the solvent bitumen extraction experiments. Smectites were swelling in water but not in cyclohexane. Swelling of smectite caused splitting of larger clay particles into many smaller particles. As a consequence, the efficiency of solvent bitumen extraction was significantly lower for fine grained samples, consisting of thin delaminated smectite particles, in which the bitumen was distributed among small-sized clay particles.

A Comprehensive Assessment of the Integration of Solvent and Steam for the Extraction of Bitumen Through the Development of Novel Process Models

Summary Solvent-steam bitumen extraction technology has the potential to reduce energy consumption and greenhouse gas (GHG) emissions. It is based on gravity drainage, wherein a steam and vaporized solvent mixture is used to extract bitumen from a reservoir. This can reduce the environmental impact compared with processes that use only steam for bitumen extraction [i.e., steam-assisted gravity drainage (SAGD)]. No techno-economic analysis of solvent-steam extraction has been made available in the public domain. In this study, a process simulation model was developed to assess costs. A capacity of 25,000 B/D of bitumen was considered with hexane as the solvent. Sensitivity and uncertainty analyses were conducted to assess how the supply cost of bitumen produced with diluent (dilbit) changes with changes in input parameters. The supply cost for the base case scenario is 55.5 CAD/bbl at a 10% internal rate of return (IRR). The scale factor was estimated to be 0.80, which suggests that oil production will be economically viable on a large scale. Capital cost, solvent price, and transportation and blending cost affect the supply cost. The most probable supply cost range is 53.0–65.4 CAD/bbl at a 90% confidence interval. The results also indicate that dilbit supply costs from the solvent-steam process are economically attractive compared with the current oil price.

Naphthenic acid fraction compounds, produced by the extraction of bitumen from oil sands, alter survival and behaviour of juvenile yellow perch (Perca flavescens)

We evaluated whether naphthenic acid fraction compounds (NAFCs) extracted from oil sand tailings adversely affect fish survival and behaviour. Following a before–after-control-impact design, we housed wild-caught juvenile yellow perch ( Perca flavescens) in outdoor mesocosms to assess survival and behaviour under baseline conditions, then exposed fish to one of three treatments: negative control, 2 mg/L NAFC, or 15 mg/L NAFC. We performed behavioural assays (no-stimulus activity, food stimulus, and predator stimulus using a model bird) and assessed a comprehensive suite of endpoints (equilibrium losses, activity, shoaling, burst swimming, freezing, and space use). We found that exposure to 15 mg/L NAFCs substantially reduced fish survival and impaired fish equilibrium in all three behavioural tests. Furthermore, exposure to NAFCs impaired anti-predator behaviour: while the activity of control fish increased by two-fold in response to a predator stimulus, fish exposed to 2 or 15 mg/L NAFC did not change their activity levels after stimulation. No significant changes were observed in other behavioural endpoints. Overall, our findings suggest that a week-long exposure to NAFCs at concentrations commonly found in tailings ponds, constructed wetlands, and other mining-impacted waters may affect multiple facets of fish behaviour that could ultimately lead to reduced fitness in fish populations.