MINERAL MATTER AND CLAY-ORGANIC COMPLEXES IN OIL SANDS EXTRACTION PROCESSES

ABSTRACT

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with the bitumen product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed.

The samples were obtained from Suncor's oil sands extraction plant located in Fort McMurray, Alberta. Samples were obtained from throughout the extraction process from the primary froth through to the final diluted bitumen product. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as well as with other techniques such as interfacial tension measurements. The data indicates that high water content products originate, to a great extent, from the presence of a very hydrophilic organic matrix attached to the surface of the clay and heavy metal minerals.     

CHARACTERIZATION OF OIL SANDS MINERAL COMPONENTS AND CLAY-ORGANIC COMPLEXES

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with the product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as veil as with other techniques such as interfacial tension measurements.     

MINERAL MATTER AND CLAY-ORGANIC COMPLEXES IN OIL SANDS EXTRACTION PROCESSES

Differences in oil sands processability and extraction yields can be dependent upon many factors including the composition of the mineral components and the organic complexes that are associated with certain minerals. These mineral-organic associations help provide the bridge which leads to carry over of bitumen with the tailings as well as carry over of water and mineral matter with the bitumen product. The nature of the organic component of clay-organic complexes extracted from various streams in an oil sands recovery process is discussed in relation to the stability of both water-in-oil and oil-in-water emulsions formed.

The samples were obtained from Suncor's oil sands extraction plant located in Fort McMurray, Alberta. Samples were obtained from throughout the extraction process from the primary froth through to the final diluted bitumen product. These samples have been studied with nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) as well as with other techniques such as interfacial tension measurements. The data indicates that high water content products originate, to a great extent, from the presence of a very hydrophilic organic matrix attached to the surface of the clay and heavy metal minerals.     

13NMR CHARACTERIZATION OF HUMIC MATTER PRESENT IN DIFFERENT OIL SANDS

ABSTRACT

Insoluble organic matter (humic matter) present in oil sands can alter the wettability of the inorganic matrix and thereby cause serious problems during bitumen recovery.

Using a cold water agitation test, solids rich in organic matter were isolated from various oil sands which were chosen to reflect different behavior in the hot water extraction process.¹³C NMR examination of these separated solids showed significant structural variations between samples isolated from different oil sands. Humic matter from Utah oil sand appeared to be more aliphatic than that derived from Athabasca oil sand.

Humic acids extracted from organic rich solids as a result of prolonged treatment with 2% NaOH show remarkable similarity in their ¹³C NMR spectra. Humins differ substantially in the relative contribution of the terrestrial and marine source material. There was apparent correspondence between poor bitumen separation and the presence of humin with highly paraffinic structures.     

Characteristic Properties of a Locally Produced Paraffinic Oil and Its Suitability as a Heat-Transfer Fluid

Abstract

The thermo-physical properties of a paraffinic mineral oil produced in a local refinery were experimentally determined over a wide temperature range of 30–360°C to determine its suitability for use as a heat-transfer fluid. The effect of temperature on the physical characteristics of the oil and two synthetic organic heat transfer fluids was evaluated at high temperatures (180–360°C). Comparison of the main properties of the mineral oil with other heating fluids revealed its compatibility with synthetic organic fluids, some other paraffinic and mineral oils employed as heat-transfer fluids. The study further confirmed that the investigated mineral oil which was produced locally can be used to replace the imported synthetic oils in heat transfer systems operating at a maximum application temperature of 310°C, as indicated by the thermal stability test.     

CHARACTERIZATION OF SOLVENT-INSOLUBLE ORGANIC MATTER ASSOCIATED WITH MINERAL MATTER FROM OIL SANDS∗

ABSTRACT

Considerable quantities of insoluble organic matter (IOM) are known to be associated with certain solid fractions found in oil sands. This organic matter is believed to be partly responsible for the intractability of the sludge generated by the hot water process used for the extraction of bitumen from Alberta oil sands. In previous investigations we had attempted to enrich the insoluble organic matter by dissolving the minerals in concentrated HCl/HF mixtures. As a result of this severe acid treatment the inorganic material is decomposed, but the organic constituents are also likely to undergo significant changes. In the present work we have used a milder HCl/HF treatment for mineral dissolution. The results from the current investigation are compared with the results of the previous study to assess the chemical alterations of the organic matter resulting from the two treatments.

The fractions obtained from the mild acid treatment were analyzed using solid state ¹³C NMR spectroscopy and elemental analysis. Latter results have been discussed in terms of a van Krevelen diagram which is derived by plotting the atomic H/C ratios against O/C. The NMR data were used to calculate the aromaticities of the various organic fractions. Based on the elemental compositions and the NMR data, it is suggested that the IOM associated with the sludge solids is derived from terrestrial sources.     

SUPERCRITICAL FLUID EXTRACTION OF BITUMEN FREE SOLIDS SEPARATED FROM ATHABASCA OIL SAND FEED AND HOT WATER PROCESS TAILINGS POND SLUDGE

ABSTRACT

The presence of strongly bound organic matter (SOM), in association with certain solids fractions, causes serious problems in the processability of Athabasca oil sands as well as in the settling and compaction of Hot Water Process tailings pond sludge. It has been demonstrated that a substantial amount of this SOM can be separated from oil sands feed and sludge solids, after removal of bitumen by toluene, using a supercritical fluid extraction (SFE) method. The extracted material is soluble in common organic solvents which allows a direct comparison, between the SOM separated from oil sands and sludges, from the point of view of both gross analysis of the major compound types and detailed analysis of chemical structures.     

Athabasca oil sands: effect of organic coated solids on bitumen recovery and quality

The Canadian oil sands deposits in northern Alberta contain about 1.3 trillion barrels of crude oil equivalent. The largest of the four major formations is found in the Athabasca region where bitumen is heterogeneously distributed throughout an unconsolidated mineral matrix. About one-tenth of the oil sands in this deposit is economically recoverable by conventional surface mining techniques.The Hot Water Extraction Process (HWEP) is used commercially to recover bitumen from surface mined oil sands ore. The viability of this process relies on the existence of a thin water film around each solid particle in the ore matrix. However, a completely water-wet mineral condition is not generally the case for oil reservoirs, including oil sands deposits. In the latter case, it has been shown that certain solid fractions are associated with significant amounts of toluene insoluble organic matter (TIOM), physically or chemically adsorbed onto particle surfaces. These fractions are generically described as ‘organic rich solids’ (ORS). In bitumen separation processes, the organic matter associated with various ORS fractions represents an impediment to optimum bitumen separation and upgrading. In this sense, these solids are considered to be ‘active’ relative to the ‘inactive’ water wetted quartz particles comprising the bulk of the oil sands ore. Preliminary results indicate that the ORS content of an ore appears to be a better predictor for ore processability than the traditional use of bitumen or fines (−44 μm) contents.Two types of ORS have received particular attention. The first is a coarser fraction, usually less than 44 μm but also occurring as particles greater than 100 μm in diameter. This material typically occurs as aggregates of smaller particles bound together by humic matter and precipitated minerals. During the bitumen separation process, these heavy aggregates carry any associated bitumen into the aqueous tailings, thus reducing overall bitumen recovery. The second important fraction comprises very thin, ultra-fine clay particles with a major dimension of <0.3 μm. These ultra-fine clays, with a surface coating of organic matter, remain with bitumen during the separation process. In bitumen upgrading, these solids may be entrained with volatile overheads and cause problems in downstream operations. This paper summarises the protocols developed to separate and characterise these intractable components from HWEP process streams and discusses their role in determining bitumen recovery and quality.     

KINETICS OF HYDRODESULFURIZATION OF HEAVY GAS OIL DERIVED FROM OIL-SANDS BITUMEN

ABSTRACT

With gradual shortage in the supply of crude oil, the importance of producing synthetic crude oil from oil sands and shale oil is increasing day by day. In the present paper, the effects of various process variables such as temperature, liquid hourly space velocity and hydrogen/heavy gas oil volumetric ratio on the removal of sulfur compounds from oil sands derived heavy gas oil has been studied. The experiments have been carried out in a micro scale trickle bed reactor over a commercial Ni–Mo catalyst. The temperature, liquid hourly space velocity and hydrogen/heavy gas oil volumetric ratio have been varied from 365 to 415°C, 0.5 to 1.9 h^?1 and 400 to 1000 ml, respectively. Under optimum reaction conditions over 96% conversion of sulfur compounds was achieved. The kinetics of the rate of sulfur removal from the oil sands derived heavy gas oil has also been discussed in this article.     

The Mild Oxidative Degradation of the Heavy Constituents in Viscous Crude Oils/Oil Sands and Its Prospect in Oil Recovery

Abstract

Viscous crude oils and oil sands are important energy resources, but it is difficult to exploit them due to the dominated heavy constituents such as asphaltenes. In this work, the mild oxidative degradation of the heavy constituents (oxidized by NaIO₄/NaH₂PO₄ and 30% H₂O₂/CH₃COOH) has been carried out. In the viscous oils, more than 45% asphaltenes has been degraded, and the asphaltenes are mainly chemically changed into the resin fractions, which is favorable to the stability of viscous crude oils. After the degradation, the total amount of extractable organic compounds from oil sands has been markedly increased than that of the blank experiment. The experimental results indicate that the mild oxidative degradation of asphaltenes can improve the physicochemical properties of the viscous oils and oil sands, which is particularly in favor of the exploitation of these energy resources.     

The Comparison of Bitumens from Oil Sands with Different Recovery Profiles

Abstract

It has been proposed that, regardless of origin, the recovery of bitumen from oil sands is related to its viscosity. Asphaltene and resin contents are known to affect the viscosity of bitumen. In this article we compare the composition of solvent-extracted bitumens from several Athabasca oil sands with very different recovery profiles. After careful removal of any associated mineral matter by ultra-centrifugation, each bitumen sample was separated into saturate, aromatic, resin, and asphaltene (SARA) fractions by an enhanced SARA technique. The individual components were then characterized by several complementary analytical techniques, including carbon, nitrogen, nitrogen, sulfur, size exclusion chromatography molecular weight (MW_n) plus proton and ¹³C nuclear magnetic resonance spectroscopy. Based on this comparison, we see no correlation between the recovery of bitumen and its composition.     

Study on the process of oil recovery from oil sludge and tailing oil sands by blending extraction

Abstract

The raw materials of this study were oilfield sludge and the tailings extracted from the oil sands of Yumen. The mineral composition and particle size distribution were characterized by X-ray diffraction and gradient screening. In this study, we put forward a new process of oil sludge and oil sand tailings blending extraction. Tailings mainly contained high crystallinity of quartz and calcium carbonate. Tailings with particle size greater than 75?μm accounted for more than 95%. Oil sludge mainly contained clay minerals. Through the co-extraction experiment of different proportions of oil sludge and tailings, we can get the best condition of blending extraction. The results showed that m (tailing oil sands): m (oil sludge) = 0.5, v (solvents): m (sample) = 2, temperature 60?°C and contact time 20?minutes were the optimum technological conditions. Under the optimum conditions, the yield of the first stage co-extraction was up to 81.8%. The total yield of secondary co-extraction oil was up to 89.4%. This study overcame the problem of low yield of oil extracted from oil sludge.     

MANAGEMENT OF OIL SANDS TAILINGS

ABSTRACT

In Alberta, oil sands bitumen is utilized for synthetic crude oil (SCO) production by surface mining, bitumen extraction followed by primary (coking) and secondary (catalytic hydrotreating) upgrading processes. SCO is further refined in specially designed or slightly modified conventional refineries into transportation fuels. Oil sands tailings, composed of water, sands, silt, clay and residual bitumen, is produced as a byproduct of the bitumen extraction process. The tailings have poor consolidation and water release characteristics. For twenty years, significant research has been performed to improve the consolidation and water release characteristics of the tailings. Several processes were developed for the management of oil sands tailings, resulting in different recovered water characteristics, consolidation rates and consolidated solid characteristics. These processes may affect the performance of the overall plant operations. Apex Engineering Inc. (AEI) has been developing a process for the same purpose. In this process oil sands tailings are treated with Ca(OH)₂ lime and CO₂ and thickened using a suitable thickener. The combination of chemical treatment and the use of a thickener results in the release of process water in short retention times without accumulation of any ions in the recovered water. This makes it possible to recycle the recovered water, probably after a chemical treatment, as warm as possible, which improves the thermal efficiency of the extraction process. The AEI Process can be applied in many different fashions for the management of different fractions of the tailings effluent, depending on the overall plant operating priorities.     

ANALYSIS AND PHYSICO-CHEMICAL CHARACTERIZATION ON CHINESE OIL SAND BITUMENS

Abstract

The extraction of four Chinese oil sands from Sinjiang and Inner Mongolia Autonomous Regions with Dean-Stark extractor were investigated. The mineral composition and sand grain distribution were determined and the bitumens were separated into saturates, aromatics, resin-I and resin-II, asphaltenes. The structure parameters and molecular model were made for the bitumens. Elemental analysis, molecular weight, FTIR, 1H-NMR were made for the bitumen fractions. The results show that the molecular structure of Mongolia bitumens have more polycyclic aromatics than that of Sinjiang bitumen. It is believed that the extraction of Sinjiang oil sand bitumen by hot alkaline water is much easier than Mongolia oil sand due to the difference of the viscosity of bitumen, the molecular structure and other physico-chemical properties of the bitumens.     

FURTHER INVESTIGATIONS ON THE USE OF BITUMEN AND HEAVY OILS TO PROCESS COAL

ABSTRACT

The use of oil sands bitumen, heavy oil and liquids derived therefrom can be successfully used to liquefy an Alberta subbituminous B coal. The data indicate that by co-processing coal with these solvents, coal conversions and yields of liquid products are favorably compared with those obtained using anthracene oil as solvent.     

Design and Numerical Study of a New Hybrid CSS-SAGD Process Using Horizontal Wells for Recovering Heavy Oil

Abstract

The cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD) processes have extensively been applied as standard methods for Canadian oil sands extraction. Recently, many studies have been concentrated on CSS with horizontal wells and hybrid CSS-SAGD processes. In this article, a new hybrid CSS-SAGD process with two CSS horizontal wells and a single SAGD well is developed and investigated for shallow reservoirs by using the fourth SPE Comparative Solution Project adapted for oil sands reservoirs. Compared with the conventional CSS process, it is shown from simulation results that this new hybrid CSS-SAGD process is a more efficient recovery process.     

A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT,ALBERTA PART 2: DISTILLATION CUTS AND CHROMATOGRAPHIC FRACTIONS

ABSTRACT

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. The analytical data for the distillation cuts and chromatographic fractions from a core sample and a number of produced oil samples revealed significant changes as a result of the recovery process, particularly for the naphtha and middle distillate cuts. The residue cut did not exhibit any increase in heteroatom or asphaltene content. None of the changes to the produced oil samples would be expected to negatively impact on the subsequent upgrading process. The relationship between the observed changes to the fractionated oil samples and the dynamics of the in situ combustion process are discussed.     

A PHYSICAL CHEMICAL EXPLANATION FOR DETERIORATION IN THE HOT WATER PROCESSABILITY OF ATHABASCA OIL SAND DUE TO AGING

ABSTRACT

The oxidation of sulphide minerals during storage of Athabasca oil sands causes solubilization of inorganic salts which affect recovery of bitumen during hot water extraction. DLVO and Ionizable Surface Group Model theories accurately predict that the level of soluble salts produced is sufficient to cause coagulation of the fine particles during the process which leads to a deterioration in froth quality and loss of bitumen recovery. The rate of aging is specific to each oil sand but storage of oil sands under an inert atmosphere in air-tight container at sub-zero temperatures will minimize oxidation.     

PYROLYSIS OF SUNNYSIDE (UTAH) TAR SAND: CHARACTERIZATION OF VOLATILE COMPOUND EVOLUTION

ABSTRACT

Sunnyside (Utah) tar sand was subjected to programmed temperature pyrolysis and the volatile products were detected by tandem on-line mass spectrometry (MS/MS) in real time analyses. A heating rate of 4°C/min from room temperature to 900°C was employed.

Evolution of hydrogen, light hydrocarbons, nitrogen-, sulfur-, and oxygen-containing compounds was monitored by MS or MS/MS detection. Evolution of volatile organic compounds occurred in two regimes: 1) low temperature (maximum evolution at 150 to 175°C), corresponding to entrained organics, and 2) high temperature (maximum evolution at 440 to 460°C), corresponding to cracking of large organic components. Alkanes and alkenes of two carbons and higher had temperatures of maximum evolution at approximately 440°C, and methane at approximately 474°C. Aromatic hydrocarbons had temperatures of maximum evolution slightly higher, at approximately 450° C. Some nitrogen-, sulfur-, and oxygen-'ccntaining compounds were also detected in the volatile products.

Comparing the Sunnyside pyrolysis to the pyrolysis of other domestic tar sands indicated the following for hydrocarbon evolution: 1) the evolution of entrained organics relative to the total evolution was much less for Sunnyside tar sand, 2) the temperatures of maximum evolution of hydrocarbons due t o cracking reactions were slightly lower, and 3) the temperatures of maximum evolution for benzene and toluene are slightly higher than observed for other tar sands.

In general, the noncondensible gases, H₂, CO, and CO₂, exhibited evolution associated with hydrocarbon cracking reactions, and high temperature evolution associated with mineral decomposition, the water-gas shift reaction, and gasification reactions. Pyrolysis yields were dominated by the evolution of carbon oxides and water. The CO₂ primarily appeared t o cane from the decomposition of carbonate minerals. Compared t o other domestic tar sands, the gas evolution reflected more mineral decomposition character for Sunnyside tar sand.     

A DETAILED CHEMICAL ANALYSIS OF CHANGES TO BITUMEN PRODUCED BY THE IN SITU COMBUSTION PROCESS AT THE OXYGEN WOLF LAKE PROJECT,ALBERTA PART 1: WHOLE OIL SAMPLES.

ABSTRACT

The detailed chemical changes in bitumen brought about over a one year period by an in situ combustion process in an oil sands reservoir have been investigated. Relative to a core sample, the fireflood-produced oils exhibited a significant reduction in density and viscosity which began early in the production cycle. This behaviour was correlated with a marked increase in material boiling in the naphtha and middle distillate ranges and a concomitant decrease in the residue cut. The sulfur and nitrogen contents in the produced oils decreased relative to the core sample. A reduction in the acid number of the produced oil samples was coupled with an increase in the oxygen content as the firefiood proceeded. The relationship between these changes and the dynamics of the in situ combustion process are discussed.