Athabasca Oil Sands Of Alberta Research Articles

Polycyclic aromatic compounds in ambient air in the surface minable area of Athabasca oil sands in Alberta (Canada)

This study characterizes concentrations and describes the spatiotemporal patterns of ambient air polycyclic aromatic compounds (PACs) between 2011 and 2015 in the Athabasca oil sands region (AOSR). 24-hour integrated ambient air samples were collected at multiple sites and analyzed for 110 PACs. Alkylated polycyclic aromatic hydrocarbons (alk-PAHs) formed the majority of the PACs in air and correlated with unsubstituted PAHs, suggesting common emission source(s) and/or origin. Concentrations of individual PACs varied spatially and seasonally. Temporal variability of PAC concentrations was evident, however based on Seasonal Mann-Kendall test a monotonic increase in concentrations at the monitored sites was not significant at p < 0.05. PAC concentrations measured during wildfire events (which were excluded from the trend analysis above) were the highest and were enriched in higher molecular weight alk-PAHs. This enrichment in alk-PAHs has not been previously reported and is believed to be a unique phenomenon for the Athabasca region. Sulfur and petroleum coke stockpiles, mining and bitumen processing were identified as potential sources of PACs near the main production operations, while mining and diluent naphtha production stood out as possible sources at a site 16 km north of the main open-pit mining area.

Comprehensive study on cleaner production of heavy oil from Athabasca oil sands using chemical additives in biodiesel-assisted ambient-aqueous bitumen extraction process

The massive unconventional petroleum resources of Athabasca oil sands in Alberta, Canada are currently being excavated and processed using the hot water bitumen extraction (HWBE) process and steam-assisted gravity drainage (SAGD) technology. A major challenge associated with HWBE process is high energy intensity for maintaining an operation temperature of 40–55 °C. Solvent-assisted ambient aqueous bitumen extraction processes, in which a portion of solvent is added for oil sands pretreatment prior to extraction process, have been reported to be capable of reducing the energy intensity via ambient temperature oil sands extraction operations. However, there is still a gap between the current solvent-assisted process and industrial expectations. This study focuses on optimization of biodiesel-assisted ambient aqueous bitumen extraction, an example of the solvent-assisted process, by incorporating methyl isobutyl carbinol (MIBC) and ethylene oxide-propylene oxide (EO-PO) copolymer in oil sands pretreatment. The idea is to take advantage of such chemicals and demulsifiers used downstream of heavy oil (known as bitumen) extraction process by their addition upfront as in the case of biodiesel-assisted hybrid extraction process. With the incorporation of these chemicals and demulsifiers in the improved biodiesel-assisted process, both bitumen liberation and bitumen flotation efficiency were improved significantly with the addition of biodiesel/MIBC mixture at 10 wt% of bitumen. The results from bench-scale experiments revealed a higher bitumen recovery and a cleaner bitumen froth by the improved biodiesel-assisted process at ambient temperature as compared with the traditional biodiesel-assisted process, as well as current industrial HWBE process, featuring a cleaner production of heavy oil from Athabasca oil sands and other heavy oil resources.

Robust Polymer Nanocomposite Membranes Incorporating Discrete TiO2 Nanotubes for Water Treatment.

Polyethersulfone (PES) is a polymeric permeable material used in ultrafiltration (UF) membranes due to its high thermomechanical and chemical stability. The hydrophobic nature of PES membranes renders them prone to fouling and restricts the practical applications of PES in the fabrication of water treatment membranes. The present study demonstrates a non-solvent-induced phase separation (NIPS) approach to modifying PES membranes with different concentrations of discrete TiO2 nanotubes (TNTs). Zeta potential and contact angle measurements showed enhanced hydrophilicity and surface negative charge in TNTs/PES nanocomposite membranes compared to unmodified PES membranes. To discern the antifouling and permeation properties of the TNTs/PES membranes, steam assisted gravity drainage (SAGD) wastewater obtained from the Athabasca oil sands of Alberta was used. The TiO2 modified polymer nanocomposite membranes resulted in a higher organic matter rejection and water flux than the unmodified PES membrane. The addition of discrete TNTs at 1 wt% afforded maximum water flux (82 L/m2 h at 40 psi), organic matter rejection (53.9%), and antifouling properties (29% improvement in comparison to pristine PES membrane). An enhancement in fouling resistance of TNTs/PES nanocomposite membranes was observed in flux recovery ratio experiments.

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.

Development of advanced nanocomposite membranes using graphene nanoribbons and nanosheets for water treatment

Water-intensive industries have to comply with stringent environmental regulations and evolving regulatory frameworks requiring the development of new technologies for water recycling. Development of polymeric membranes may provide an effective solution to improve water recycling, but require finely-tuned pore size and surface chemistry for ionic and molecular sieving to be efficient. Additionally, fouling is a major challenge that limits the practical application of the membranes in water recycling in these industries. In this work, four different graphene oxide (GO) derivatives were incorporated into a polyethersulfone (PES) matrix via a non-solvent induced phase separation (NIPS) method. The GO derivatives used have different shapes (nanosheets vs nanoribbons) and different oxidation states (C/O = 1.05–8.01) with the potential to enhance water flux and suppress fouling of the membranes through controlled pore size, hydrophilicity, and surface charge. The permeation properties of the PES/GO membranes were evaluated using a water sample from the Athabasca oil sands of Alberta. The results for contact angle and streaming potential measurements indicate the formation of more hydrophilic and negatively charged PES/GO nanocomposite membranes. All graphene-based nanocomposite membranes demonstrated better water flux and rejection of organic matter compared to the unmodified PES membrane. The fouling measurement results revealed that fouling was impeded due to enhanced membrane surface properties. Longitudinally unzipped graphene oxide nanoribbons (GONR-L) at an optimum loading of 0.1 wt% (wt%) provided the maximum water flux (70 LMH at 60 psi), organic matter rejection (59%) and antifouling properties (30% improvement compared to pristine PES membrane). Flux recovery ratio experiments indicated a remarkable enhancement in the fouling resistance property of PES/GO nanocomposite membranes.

Forest Fertilization Associated with Oil Sands Emissions

The Athabasca Oil Sands in Alberta, Canada, is one of the largest point sources emitters of NOx and SO2 in Canada, and there have been widespread concerns over potential ecosystem acidification owing to the acid sensitivity of the base-poor sandy soils in the region. In this study we compared soil and vegetation properties at a jack pine (Pinus banksiana Lamb) forest adjacent to one of the largest mines in the region with a jack pine stand located approximately 15 km from the mine. At the site closest to the mine, throughfall deposition of SO4-S and DIN (NO3 + NH4) exceeds 30 and 20 kg ha−1 y−1, respectively, compared with less than 9 kg ha−1 y−1 for SO4-S and less than 2 kg ha−1 y−1 DIN at the distant site. However, on an equivalence basis, base cation (Ca + Mg + Na) deposition in throughfall at both sites exceeded the combined S and N deposition. Total S and N as well as Ca and Mg concentrations in epiphytic lichens and tree bark were significantly higher at the site adjacent to the mine, reflecting the higher acidic and base cation throughfall deposition. The forest floor at the stand close to the mine had a significantly higher pH, exchangeable Ca, Mg, K and total S concentrations compared with the distant site. The chemistry of deeper mineral soil horizons was more consistent between the two sites. Foliar concentrations of S, Ca, Mg, Fe and Al in jack pine, Vaccinium vitis-idaea, Vaccinium myrtilloides and Arctostaphylos uva-ursi were also higher at the site close to the mine, but these differences were not always significant. Coincidental with differences in atmospheric deposition, herbaceous cover and biomass, especially A. uva-ursi, was significantly higher, and terricolous lichen cover was several fold lower at the site closest to the mine. This work indicates that despite high S and N emissions from oil sands activities, forest fertilization and alkalization may be of greater concern than acidification owing to large dust emissions from the mines and the Acid Deposition Management Framework for the region should be modified accordingly.

Feasibility of electromagnetic methods to detect and image steam-assisted gravity drainage steam chambers

We have investigated the use of electric and electromagnetic (EM) methods to monitor the growth of steam-assisted gravity drainage (SAGD) steam chambers. SAGD has proven to be a successful method for extracting bitumen from the Athabasca oil sands in Alberta, Canada. However, complexity and heterogeneity within the reservoir could impede steam chamber growth, thereby limiting oil recovery and increase production costs. Using seismic data collected over an existing SAGD project, we have generated a synthetic steam chamber and modeled it as a conductive body within the bitumen-rich McMurray Formation. Simulated data from standard crosswell electrical surveys, when inverted in three dimensions, show existence of the chamber but lack the resolution necessary to determine the shape and size. By expanding to EM surveys, our ability to recover and resolve the steam chamber is significantly enhanced. We use a simplified survey design procedure to design a variety of field surveys that include surface and borehole transmitters operating in the frequency or time domain. Each survey is inverted in three dimensions, and the results are compared. Importantly, despite the shielding effects of the highly conductive cap rock over the McMurray Formation, we have determined that it is possible to electromagnetically excite the steam chamber using a large-loop surface transmitter. This motivates a synthetic example, constructed using the geology and resistivity logging data of a future SAGD site, where we simulate data from single and multiple surface loop transmitters. We have found that even when measurements are restricted to the vertical component of the electric field in standard observation wells, if multiple transmitters are used, the inversion recovers three steam chambers and discerns an area of limited steam growth that results from a blockage in the reservoir. The effectiveness of the survey shows that this EM methodology is worthy of future investigation and field deployment.

Characterizing dominant controls governing evapotranspiration within a natural saline fen in the Athabasca Oil Sands of Alberta, Canada

AbstractNatural Boreal saline fens provide analogues for reclaimed wetland systems constructed with sodium‐rich tailings materials. These natural analogues can improve our understanding of vegetative controls on dominant ecohydrological processes (i.e. evapotranspiration (ET)) in constructed landscapes. Therefore, the objective of this study is to characterize ET within a natural boreal saline fen over a growing season to determine the primary hydro‐climatic controls using community‐scale ET measurements targeting dominant vegetation communities within different microforms along with environmental controls.ET rates were highest during periods of peak vegetation growth and temperatures between June and August, with rates decreasing slightly in July. Vegetation species' physiology was the dominant variable governing ET. The more salt tolerant species maintained higher ET rates despite the lower leaf area index and water table levels found within these species. The lower ET rates measured in July can be attributed to high water tables from above average precipitation causing soil inundation and salt stress, increasing stomatal closure. However, community plots containing Triglochin maritima maintained transpiration rates under the coupled stress conditions. Therefore, this is a potentially important species for use in boreal reclamation planting schemes. Last, the findings emphasize that the dominant vegetation selected for reclamation projects must coincide with the materials used (peat and subsurface materials), as results within this study demonstrate that some native boreal fen species (Calamagrostis inexpansa, Hordeum jubatum, and Juncus balticus) were unable to maintain transpiration rates during flood and saline conditions that can occur within the mining area of this region. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Improved reservoir characterization and monitoring of the Long Lake heavy oil SAGD project using time-lapse multicomponent seismic data

Kelsey Schiltz, Loren Zeigler and David Gray demonstrate how the integration of timelapse compressional and multi-component seismic data has resulted in a geologic model of low permeability shales and enhanced the understanding of the steam chamber through imaging of the heat and pressure fronts in the Long Lake bitumen field in Alberta, Canada. Long Lake is a bitumen field covering 63,000 acres within the Athabasca oil sands in Alberta, Canada. Bitumen is a special type of heavy oil that is less than 10 API and is immobile at in situ conditions. Long Lake bitumen (~8 API) is produced from the Lower Cretaceous McMurray Formation using an in situ thermal recovery method called steam-assisted gravity drainage (SAGD).

Robust Aqueous–Nonaqueous Hybrid Process for Bitumen Extraction from Mineable Athabasca Oil Sands

Mining and processing of Athabasca oil sands in Alberta, Canada, is a great success story of government–industry collaboration, fulfilling increased domestic and worldwide demands for oil. However, economic and environmental incentives still exist in the oil sands industry to enhance oil recovery and reduce energy consumption and water use, while minimizing green-house gas emissions and tailings ponds. The current industrial bitumen extraction processes, after surface mining, are exclusively water-based and operate at elevated temperatures, typically between 45 and 50 °C. Robust low-temperature processes, with reduced in-take of feedwater, that are less sensitive to ore characteristics are in a strong demand from both environmental and economical point of views. In response to this demand, we propose a robust aqueous–nonaqueous hybrid bitumen extraction process, in which diluent such as kerosene and naphtha is added to the oil sands prior to oil sands slurry preparation to decrease bitumen viscosity and enhance bitumen liberation. With the proposed hybrid bitumen extraction process, the oil sand processing temperature can be reduced to ambient temperature. To prove this concept, bitumen recovery tests were carried out on four Athabasca oil sand ores of good to poor processability, using a Denver flotation cell operated at ambient temperature. Adding kerosene or naphtha to oil sands at 4–11 wt % of the bitumen content was found to significantly enhance flotation recovery of bitumen and bitumen froth quality, especially for poor processing ores. It was found that kerosene addition not only increased bitumen liberation kinetics determined using our novel in situ bitumen liberation visualization flow cell (BLVFC) but also improved bitumen aeration measured by induction time apparatus.

Parameter estimation for partially observable systems subject to random failure

In this paper, we present a parameter estimation procedure for a condition‐based maintenance model under partial observations. Systems can be in a healthy or unhealthy operational state, or in a failure state. System deterioration is driven by a continuous time homogeneous Markov chain and the system state is unobservable, except the failure state. Vector information that is stochastically related to the system state is obtained through condition monitoring at equidistant sampling times. Two types of data histories are available — data histories that end with observable failure, and censored data histories that end when the system has been suspended from operation but has not failed. The state and observation processes are modeled in the hidden Markov framework and the model parameters are estimated using the expectation–maximization algorithm. We show that both the pseudolikelihood function and the parameter updates in each iteration of the expectation–maximization algorithm have explicit formulas. A numerical example is developed using real multivariate spectrometric oil data coming from the failing transmission units of 240‐ton heavy hauler trucks used in the Athabasca oil sands of Alberta, Canada. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Recognition of down-valley translation in tidally influenced meandering fluvial deposits, Athabasca Oil Sands (Cretaceous), Alberta, Canada

The vast Athabasca Oil Sands of Alberta, Canada has an estimated resource of more than 1.7 trillion barrels of bitumen in-place, the majority of which is hosted in the Lower Cretaceous McMurray Formation. Despite its economical significance the depositional environment of the formation, and particularly the middle part that is the primary reservoir in most areas, is still a matter of considerable debate. These strata of interest are widely known to comprise fluvial and estuarine point bar deposits that were subject to varying degrees of marine influence. The orientation of point bar strata from the formation is tabulated and the majority is observed to dip paleo-basinward, to the north. This observation has proven difficult to explain by geologists attempting to build predictive models for the formation over the last two decades. However, the basinward-dipping point bar strata can be attributed to widespread down-valley translation of point bars in confined north-south oriented valleys, which have previously been delineated in the region. Differentiating the deposits of lateral point bar migration and down-valley translation in the rock record is not possible at the facies scale, and thus translated point bars have not been previously recognized or interpreted in the rock record, despite their prevalence in numerous modern fluvial valley systems. Their identification in the McMurray Formation has important implications for the delineation and development of Canada’s economically significant oil sands resources.

Distribution of naphthenic acids in tissues of laboratory-exposed fish and in wild fishes from near the Athabasca oil sands in Alberta, Canada

Naphthenic acids, which have a variety of commercial applications, occur naturally in conventional crude oil and in highly biodegraded petroleum such as that found in the Athabasca oil sands in Alberta, Canada. Oil sands extraction is done using a caustic aqueous extraction process. The alkaline pH releases the naphthenic acids from the oil sands and dissolves them into water as their soluble naphthenate forms, which are anionic surfactants. These aqueous extracts contain concentrations of naphthenates that are acutely lethal to fishes and other aquatic organisms. Previous research has shown that naphthenic acids can be taken up by fish, but the distribution of these acids in various tissues of the fish has not been determined. In this study, rainbow trout ( Oncorhynchus mykiss) were exposed to commercial (Merichem) naphthenic acids in the laboratory. After a 10-d exposure to approximately 3 mg naphthenic acids/L, the fish were dissected and samples of gills, heart, liver, kidney, muscle, and eggs were extracted and analyzed for free (unconjugated) naphthenic acids by a gas chromatography–mass spectrometry method. Each of the tissues contained naphthenic acids and non-parametric statistical analyses showed that gills and livers contained higher concentrations than the muscles and that the livers had higher concentrations than the hearts. Four different species of fish (two fish of each species) were collected from the Athabasca River near two oil sands mining and extraction operations. No free naphthenic acids were detected in the muscle or liver of these fish.

Reserve Growth in Oil Pools of Alberta: Model and Forecast

Abstract Reserve growth is recognized as a major component of additions to reserves in most oil provinces around the world, particularly in mature provinces. It takes place as a result of the discovery of new pools/reservoirs and extensions of known pools within existing fields, improved knowledge of reservoirs over time leading to a change in estimates of original oil-in-place, and improvement in recovery factor through the application of new technology, such as enhanced oil recovery methods, horizontal/multilateral drilling, and 4D seismic. A reserve growth study was conducted on oil pools in Alberta, Canada, with the following objectives: 1) evaluate historical oil reserve data in order to assess the potential for future reserve growth; 2) develop reserve growth models/functions to help forecast hydrocarbon volumes; 3) study reserve growth sensitivity to various parameters (for example, pool size, porosity, and oil gravity); and 4) compare reserve growth in oil pools and fields in Alberta with those from other large petroleum provinces around the world. The reported known recoverable oil exclusive of Athabasca oil sands in Alberta increased from 4.5 billion barrels of oil (BBO) in 1960 to 17 BBO in 2005. Some of the pools that were included in the existing database were excluded from the present study for lack of adequate data. Therefore, the known recoverable oil increased from 4.2 to 13.9 BBO over the period from 1960 through 2005, with new discoveries contributing 3.7 BBO and reserve growth adding 6 BBO. This reserve growth took place mostly in pools with more than 125,000 barrels of known recoverable oil. Pools with light oil accounted for most of the total known oil volume, therefore reflecting the overall pool growth. Smaller pools, in contrast, shrank in their total recoverable volumes over the years. Pools with heavy oil (gravity less than 20° API) make up only a small share (3.8 percent) of the total recoverable oil; they showed a 23-fold growth compared to about 3.5-fold growth in pools with medium oil and 2.2-fold growth in pools with light oil over a fifty-year period. The analysis indicates that pools with high porosity reservoirs (greater than 30 percent porosity) grew more than pools with lower porosity reservoirs which could possibly be attributed to permeability differences between the two types. Reserve growth models for Alberta, Canada, show the growth at field level is almost twice as much as at pool level, possibly because the analysis has evaluated fields with two or more pools with different discovery years. Based on the models, the growth in oil volumes in Alberta pools over the next five-year period (2006–2010) is expected to be about 454 million barrels of oil. Over a twenty-five year period, the cumulative reserve growth in Alberta oil pools has been only 2-fold compared to a 4- to- 5-fold increase in other petroleum producing areas such as Saskatchewan, Volga-Ural, U.S. onshore fields, and U.S. Gulf of Mexico. However, the growth at the field level compares well with that of U.S. onshore fields. In other petroleum provinces, the reserves are reported at field levels rather than at pool levels, the latter basically being the equivalent of individual reservoirs.

Estimating naphthenic acids concentrations in laboratory-exposed fish and in fish from the wild

Naphthenic acids (NAs) are the most water-soluble organic components found in the Athabasca oil sands in Alberta, Canada, and these acids are released into aqueous tailing waters as a result of bitumen extraction. Although the toxicity of NAs to fish is well known, there has been no method available to estimate NAs concentrations in fish. This paper describes a newly developed analytical method using single ion monitoring gas chromatography–mass spectrometry (GC–MS) to measure NAs in fish, down to concentrations of ∼0.1 mg kg −1 of fish flesh. This method was used to measure the uptake and depuration of commercial NAs in laboratory experiments. Exposure of rainbow trout ( Oncorhynchus mykiss) to 3 mg NAs l −1 for 9 d gave a bioconcentration factor of ∼2 at pH 8.2. Within 1 d after the fish were transferred to NAs-free water, about 95% of the NAs were depurated. In addition, the analytical method was used to determine if NAs were present in four species of wild fish – northern pike ( Esox lucius), lake whitefish ( Coregonus clupeaformis), white sucker ( Catostomus commersoni), walleye ( Sander vitreus) – collected from near the oil sands. Flesh samples from 23 wild fish were analyzed, and 18 of these had no detectable NAs. Four fish (one of each species) contained NAs at concentrations from 0.2 to 2.8 mg kg −1. The GC–MS results from one wild fish presented a unique problem. However, with additional work it was concluded that the NAs concentration in this fish was <0.1 mg kg −1.

Laboratory and Pilot Experience in the Development of a Conventional Water-Based Extraction Process for the Utah Asphalt Ridge Tar Sands

Abstract The belief that the Utah tar sands deposits are oil-wet has led to a focus on solvent-based bitumen extraction processes, or some form of solvent assisted water-based extraction process for these types of materials. However, under certain conditions, this ore is in fact amenable to a conventional water-based extraction process. The thermal, mechanical and chemical environments necessary to make the Asphalt Ridge ore behave like an Alberta Athabasca oil sand are outlined, along with the typical criteria which must be satisfied for a novel extraction process to be viable. Laboratory-scale demonstrations of the efficacy of a Clark-style hot water extraction process for the Asphalt Ridge tar sands were subsequently confirmed on a twenty tonne per hour pilot scale. In addition, the scarcity of water at the mining and extraction operation in Utah led to the development of an aggressive tailings treatment process, which also offers lessons for tailings handling in the surface-mined oil sands in Alberta. Introduction The CANMET Energy Technology Centre in Devon, Alberta, became involved in the Asphalt Ridge tar sands project when it was a solvent-based extraction operation hampered by a significant emulsion buildup in the recycle water. In working to develop a solution to the emulsion buildup, it became apparent that, using the solvent-based extraction process, solvent losses associated with clay mineral-solvent interactions would be unacceptably high. As a result, a series of standard tests(1, 2) were applied to Asphalt Ridge tar sand samples in order to assess the potential for a solvent-free, water-based extraction process(3, 4). Surprisingly, some of these nominally oil-wet tar sands performed very well, indicating that the Asphalt Ridge tar sand bitumen could be extracted using commercially proven technology developed over the last 40 years in Alberta(5–10). In order to achieve bitumen recoveries similar to those for Athabasca oil sands, significantly higher mechanical energy levels were required, along with high temperatures. Since the early 1990s, the operating temperature used in commercial processing of Athabasca oil sands has been reduced from about 80 °C to less than 50 °C while increasing the mechanical energy input(1, 2, 11, 12). By maintaining both mechanical and thermal energy inputs at high levels, the ‘difficult to process’ Asphalt Ridge tar sand showed bitumen recoveries of approximately 90%; similar to the Athabasca commercial operations. The Asphalt Ridge tar sand samples that did not perform well in bench-top laboratory assessments were found to be weathered or oxidized; conditions that also inhibit extractability in the Athabasca oil sands in Alberta(13–17). The difficulties encountered by earlier researchers in using Canadian technology, or a modified water-based extraction process for the Asphalt Ridge tar sand (without pre-treatment with an organic diluent before ore conditioning), may have been due to improper handling of cores or bulk samples resulting in bitumen oxidation or weathering(18–24). In referring to the differences between the Utah tar sands and those in the Athabasca deposit, "These differences preclude the direct application of the Canadian mining and recovery technology to Utah's tar sands and to other United States tar sands(18)."

Field Test of SAGD as Follow-Up Process to CSS in Liaohe Oil Field of China

Abstract The Du 84 block of the Shu-1 area in the Liaohe Oil Field is located in Panjin City, Liaoning Province, China. The production formation, Guantao, contains extra heavy oil with a depth of 530–640 m. The reservoir is characterized in thick pay, with high permeability and a very active aquifer. The dead oil viscosity is 230,000 mPa.s at 50 °C. Although the Cyclic Steam Stimulation (CSS) process using vertical wells has been applied successfully in producing oil from the reservoir, the anticipated ultimate oil recovery is less than 29% of the original oil in place (OOIP). To enhance oil recovery beyond that of the CSS, physical and numerical modeling studies were carried out. The Steam Assisted Gravity Drainage (SAGD) process using a combination of vertical and horizontal wells was proposed as a follow-up process to CSS. An additional 27% recovery is anticipated with the proposed follow-up process. This would give a total recovery of 56%. A pilot with four horizontal producers was implemented in the field. CSS was used initially in the horizontal wells for establishing the communication with the surrounding vertical wells. The pilot was then converted successfully to SAGD operations with horizontal wells as continuous producers and some of the surrounding vertical wells as continuous injectors. A total of 44,500 m3 of oil has been produced over the 12 months of SAGD operations between June 2005 and June 2006. The field implementation process and pilot performance, as well as the challenges with this project, are presented in this paper. Introduction This paper is the continuation of an earlier work(1) in which a field pilot was proposed for testing Steam Assisted Gravity Drainage (SAGD) as a follow-up process to CSS based on a reservoir model and feasibility studies. Two field pilot projects were constructed in 2003 in the Du 84 block of the Su-1 area in the Liaohe Oil Field. One pilot is producing from the Xinglongtai formation and the other one is producing from the Guantao formation. The pilot in the Guantao formation was converted to SAGD operations in early 2005 and the field results are encouraging. The field performance from this pilot is reported in this paper. The Steam Assisted Gravity Drainage (SAGD) process, which was described by Dr. R.M. Butler in the late 1970's(2), has been applied successfully for the production of bitumen and heavy oil since it was tested in the Underground Test Facility (UTF) in the Athabasca oil sands of Alberta, Canada(3). Several commercial projects have been implemented in the field in Canada since then. The Liaohe Oilfield Company constructed its first SAGD pilot in China in 1996 in the Xinlongtai formation, which contains extra heavy oil at a depth of 750 m from the surface. The pilot consisted of one stacked well pair and was operated for about one and a half years. The suspension of the pilot test was due to:insufficient lift capacity provided by the gas lift system; and,difficulties in communication resulting from too large a vertical separation between the injector and the producer.

Diethylaminoethyl-cellulose clean-up of a large volume naphthenic acid extract

The Athabasca oil sands of Alberta, Canada contain an estimated 174 billion barrels of bitumen. During oil sands refining processes, an extraction tailings mixture is produced that has been reported as toxic to aquatic organisms and is therefore collected in settling ponds on site. Investigation into the toxicity of these tailings pond waters has identified naphthenic acids (NAs) and their sodium salts as the major toxic components, and a multi-year study has been initiated to identify the principal toxic components within NA mixtures. Future toxicity studies require a large volume of a NA mixture, however, a well-defined bulk extraction technique is not available. This study investigated the use of a weak anion exchanger, diethylaminoethyl-cellulose (DEAE-cellulose), to remove humic-like material present after collecting the organic acid fraction of oil sands tailings pond water. The NA extraction and clean-up procedure proved to be a fast and efficient method to process large volumes of tailings pond water, providing an extraction efficiency of 41.2%. The resulting concentrated NA solution had a composition that differed somewhat from oil sands fresh tailings, with a reduction in the abundance of lower molecular weight NAs being the most significant difference. This reduction was mainly due to the initial acidification of tailings pond water. The DEAE-cellulose treatment had only a minor effect on the NA concentration, no noticeable effect on the NA fingerprint, and no significant effect on the mixture toxicity towards Vibrio fischeri.

Numerical Simulation Results for the Electrical Heating of Athabasca Oil-Sand Formations

Summary Electrical preheating has been proposed as a method of overcoming many of the problems inherent in using a steamdrive in very viscous oil reservoirs—such as the Athabasca oil sands of Alberta, Canada. A numerical simulator was developed to study the process of electrically heating oil reservoirs consisting of several layers with different electrical resistivities. This simulator was used to study the effects of electrode placement on the final temperature contours resulting from electrically heating realistic reservoirs. Three cases illustrating the development of a hot-oil communication path low in the formation are described.

Electrophoretic Properties of Oil Sands Tailings And Constituent Clays In Aqueous Suspensions

Abstract Electrophoretic mobilities of various clays and their mixtures were measured atseveral temperatures in solutions having different pH values and differentconcentrations of added electrolytes (NaCI and CaCI2). Similarmeasurements have been made on kaolinite suspended in both real and syntheticoil sands tailings water. Further electrophoretic measurements have been madeon oil sands tailings sludge solids suspended in " clean" solutions and inboth real and synthetic tailings water. Results of these measurementsand others that are cited are consistent with the view that the stability ofsuspensions of fine minerals (mostly clays) in oil sand tailings issubstantially due to the properties of mixed clay colloids and possibly also tointeractions of these clays with bituminous organic substances that are sotightly bound to the clays that they are not removed by " ordinary" chemical treatment. Introduction Present commercial recovery of bitumen from the Athabasca oil sands of Alberta is accomplished by way of treatment of mined oil sands with largeamounts of hot water, as reviewed by Camp(J) and by Berkowitz and Speight(2). We are here concerned with the tailings or " pondwater" problem associated with this process, as reviewed by Camp(3) and by Kessick(4). This pondwater problem can be described concisely as thelarge-scale accumulation of water. fine minerals (mostly clays) and unrecoveredbitumen from the hot water process that is used for recovery of bitumen frommined oil sands; much of the water contains too much suspended solids forrecycling, and the slowly settling " solids" contain too much water forappropriate disposal. Similar tailings problems involving fine clays are commonin other mineral processing industries. Previous investigations of oil sands tailings have focussed either on the water(including dissolved substances) or on the suspended solids (including theirinteractions with the water). Results of investigations of the aqueous phasehave been reported recently by Burchfield and Hepler(5), who havealso reviewed earlier related investigations. Investigations of the suspendedsolids have been reviewed extensively by Kessick(4); here we citeonly some more recent investigations(6–19), with titles thatgenerally indicate the kinds of investigations carried out. Although there are substantial differences between the analytical results fromdifferent investigators, partly because different investigators have workedwith different samples, it is now well established that the principalconstituents of tailings fines from the Athabasca oil sands are clays(kaolinite, illite, montmorillonite, etc.) and silica. These findingshave led to our choices of specific systems for investigations. (Figure in full paper) Because our investigations are concerned with the electrophoreticproperties of oil sands tailings and of certain clays in aqueous suspensions, we call particular attention to the following earlier investigations. May and Smelley(13) have reported the results of their electrophoreticinvestigations of Florida phosphatic day wastes and have cited earlierinvestigations that illustrate the relevance of such investigations to theirproblem which is partly similar to our tailings problem. We also callattention to four investigations(20–23) of electrophoreticproperties of aqueous day suspensions and the relationships of theseelectrophoretic properties to other properties.