Asphalt Ridge Research Articles

Pyrolysis of Oils from Unconventional Resources

In this study, oils from various sources were subjected to pyrolysis conditions; that is, without oxidizer, as the samples were heated to 500 °C, and held at that temperature. The oils studied included: (1) heavy oil from Grassy Creek, Missouri; (2) oil from tar sands of Asphalt Ridge in Utah; (3) mid-continent oil shales of three formations (two of Chattanooga formation, Pennsylvanian (age) formation, and Woodford formation); and (4) a Colorado Piceance Basin shale. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) with either gas chromatography (GC) or mass spectrometry (MS) were used to quantify the produced gases evolved in the tests. Purge gases of helium, argon, and humid carbon dioxide were utilized. Larger scale pyrolysis tests were conducted in a tube furnace coupled to a MS and a GC. The results consistently showed that pyrolysis occurred between 300 °C and 500 °C, with the majority of gases being mainly hydrogen and light alkanes. This behavior was essentially consistent, regardless of the oil source.

A Thorough Study on the Molecular Weight Distribution in Natural Asphalts by Gel Permeation Chromatography (GPC): The Case of Trinidad Lake Asphalt and Asphalt Ridge Bitumen

The roadway performance is chiefly governed by the chemical composition of asphalt, which in turn depends on the molecular weight distribution in this product. Gel permeation chromatography is one of the most powerful and convenient analytical technique available for characterizing the entire molecular weight distribution of a bitumen. Molecular weight and polydispersity of two natural asphalts viz. Trinidad Lake asphalt (TLA) and Asphalt Ridge bitumen (ARB) have been determined. The number average molecular weight (Mn) of TLA was 893, whereas that of ARB was 993. It is predicted that TLA will deliver a smoother and higher-quality pavement than does ARB.

High-Resolution Stratigraphy of the lower portion of the Green River Formation at Raven Ridge and Red Wash Field, NE Uinta Basin, Utah, Colorado, USA: Facies and Stratigraphic Patterns in a High-Gradient, High-Energy Lacustrine System

Lacustrine strata of a portion of the Green River Formation studied in outcrops along Raven Ridge and in the subsurface around Red Wash Field in the northeastern Uinta Basin represent cyclic storm-dominated shoreface to deep lake deposition within a syntectonic embayment on the margin of Eocene Lake Uinta. The study interval consists of the lower Green River Formation, including the Douglas Creek, Garden Gulch, and lower Parachute Creek members, from the top of the underlying Wasatch to the Mahogany Zone of the Parachute Creek Member. Data consists of 11,900 ft (3627 m) of section measured at 23 locations across Raven Ridge, including 7,800 ft (2377 m) of hand-held gamma-ray scintillometer measurements, and over 500 wells in the greater Red Wash Field area, including pay zone analysis correlated to stratigraphy in the field. Facies analysis, as the basis for an integrated stratigraphic approach, reveals a seven-fold hierarchy of stratigraphic cycles ranging from two orders of large-scale cycles to five orders of progressively higher-frequency (smaller scale) shoreface-lake cycles across an 18-mile (29 km) long and 1900-ft (579 m) thick dip-oriented stratigraphic transect. This study recognized twenty-two facies grouped into eight facies tracts using Walther’s Law for two composite shoreface successions: one for a siliciclastic storm-graded shoreface profile that was dominant during times of regression and one for a carbonate profile that dominated in times of transgression. Two important regional facies trends across Raven Ridge include: 1) greater proportions of mudstone facies present in the southern, upper portion of the Green River Formation; and 2) significantly higher proportion of bioturbated sandstone in the northern, lower portion of the formation. The long-term 2nd-order transgression of Lake Uinta from base to top of the study interval results in an evolution from a low-gradient shoreline with marshes, ponds, and sand/mud flats to a high-gradient high-energy profile composed of spits and shorefaces that grew southward away from the emergent highlands. A composite storm-graded shelf profile shows how trough, hummocky, and swaley cross stratification type and amalgamation style change offshore proportionally to contain mud-dominated tempestites, erosional storm furrows, and oil shale. In the most offshore positions, diastasis cracks caused by differential loading are common. The lacustrine shoreface profile is compressed in the Green River Fm. in the study area with narrow facies tracts and large local gradient changes as a result of different responses to sediment supply. As a lake grows and shorelines migrate, the increase in accommodation is balanced, or in-phase, by a corresponding increase in sediment supply resulting in shoreface progradation keeping up with lake-level rise. As the shoreface stacks vertically during the rise, over steepening and failure of the profile generates gravity-flow sandstone facies. Little reworking of hummocky cross stratification high on the profile was observed, probably because wave power was limited by a shallow fair-weather wave-base. These differences also result in more symmetrical lacustrine shoreface cycles, with a large proportion of sediment partitioned into rise hemicycles, as opposed to the classical fall-asymmetric marine para-sequence which tends to have little to no strata preserved in the rise hemicycle along most of the shoreface profile. Landward-stepping lacustrine shoreface cycles are more common during the early rise portions of larger-scale 3rd-order megacycles for similar reasons. Strata at Raven Ridge support the concept that Eocene Lake Uinta was chemically stratified, or meromictic, at least during certain periods. The equable subtropical Eocene paleoclimate is interpreted to be the most important control on meromixis. Chemical stratification played a critical role in the development and preservation of organic matter, as evidenced by oil shale facies. The equable climate, however, might also have made the lake prone to thermal stratification. A paradox exists in the storm dominance of the lacustrine shorefaces and the coeval lake stratification: wave energy apparently was insufficient to break through the strong chemocline. Red Wash Field, directly downdip from the Raven Ridge outcrop belt, is an example of an oil field in a setting where the lake margin is not coincident with a structural feature: a “non-coincident” margin. Reservoirs mostly are present in the 6th-order aggradational shoreface cycles that are interpreted to have accumulated in the rise portions of 3rd-order megacycles. The best reservoir facies are trough, hummocky, and swaley cross-stratified sandstone deposited by storm processes and structureless sandstone probably derived from over steepening and failure of the shoreface during transgression. A petroleum accumulation model encompassing the Red Wash-Raven Ridge area proposes that lacustrine-sourced petroleum originated from an over-pressured mature cell in the Altamont-Bluebell field region. Oil migrated updip through leaky seals and became trapped in reservoirs within the non-coincident lake margin strata. An irregular shoreline configuration and compaction folds at Red Wash Field trapped petroleum. After reaching spill point at Red Wash Field, oil migrated farther updip to Raven Ridge and Asphalt Ridge, forming tar sand accumulations.

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)."

Supercritical fluid extraction of bitumens from Utah oil sands

The supercritical fluid extraction (SFE) of bitumens from four major Uinta Basin (Utah) oil sand deposits was studied with propane solvent. The deposits studied included Whiterocks, Asphalt Ridge, PR Spring and Sunnyside. The bitumens from these deposits differed widely in physical and chemical properties. The volatilities (components with boiling point <811 K) were 46.6, 53.5, 45.4 and 40.9 wt.%; the molecular weights were 653, 426, 670 and 593 kg/kg mol; and the asphaltene contents ( n-pentane insolubles) were 2.9, 6.8, 19.3 and 23.6 wt.% for the Whiterocks, Asphalt Ridge, PR Spring and Sunnyside bitumens, respectively. The SFE experiments were carried out at five conditions, combinations of three different pressures (5.6 MPa, 10.4 MPa, and 17.3 MPa) and three temperatures (339 K, 380 K and 422 K). The cumulative extraction yield increased with increase in solvent density at all operating conditions for the four bitumens. A maximum yield of 45 wt.% was obtained at the highest solvent density with the Whiterocks bitumen. The extraction products were significantly upgraded liquids relative to the bitumens. Comparatively lighter fractions were extracted in the earlier stages of extraction for all the four bitumens, whereas heavier extracts were obtained at higher extraction-solvent densities. The asphaltene contents of the residual fractions were significantly higher than the asphaltene contents predicted on a prorated basis for all four bitumens. This trend was due to the extraction of cosolubilizing components that kept the asphaltenes in suspension in the bitumen. It was concluded that solute polarity played a significant role in the extraction yields of the four bitumens. The Whiterocks bitumen, which was the least polar bitumen based on asphaltenes content, gave higher extraction yields compared to the bitumens from the other three deposits at all five operating conditions. The Sunnyside bitumen with the highest asphaltene content gave the lowest extraction yield at all five conditions. The Asphalt Ridge and PR Spring bitumens with intermediate polarity (based on asphaltene content) gave intermediate extraction yields with the Asphalt Ridge bitumen extraction yields higher than the PR Spring bitumen. Preliminary modeling of the extraction process using the Peng–Robinson cubic equation of state and a pseudocomponent lumping scheme provided a reasonable match with the experimental data for Whiterocks and PR Spring bitumens.

VISCOSITY OF BITUMEN-CRUMB RUBBER BLEND (NEW PAVING MATERIAL)

ABSTRACT The feasibility of blending scrap tire rubber with Asphalt Ridge and Circle Cliffs (Utah, USA) tar sand bitumens was studied. Viscosity of the blended mixtures was analyzed as a function of composition, and coprocessing variables including processing temperature and time. Coprocessing of tar sand bitumens with crumb rubber at elevated temperatures has been shown to increase the viscosity of the bitumens with the exception of the bitumen-rubber sample prepared at 380°C. Optimum viscosity behavior was exhibited for an oil-extended bitumen blended with crumb rubber at 200°C for 0.5 hours. The viscosity of the bitumen-rubber blend prepared under these conditions met ASTM specifications of a viscosity-graded AC-30 asphalt binder. Viscosity increase was most noticeable at low temperature, providing the benefit of high viscosity at pavement temperatures experienced during summer months without concession of processability at pavement construction temperatures. A difference in viscosity was observed between bitumen modified with whole-tire crumb and tread-rubber crumb, due to the compositional differences that exist between the two materials.

Examination of Neumann's Equation-of-State for Interfacial Tensions

Advancing contact angles for water, glycerol, diiodomethane, and ethylene glycol on polytetrafluoroethylene, polyethylene, Asphalt Ridge bitumen, Circle Cliffs bitumen, Whiterocks bitumen resins, and Whiterocks bitumen asphaltenes were measured and the "surface tension" of these low energy solids was calculated using Neumann's equation-of-state. Also, the surface tension of several polymers and self-assembled monolayers was analyzed based on Neumann's approach and using advancing contact angle values reported in the literature. It is demonstrated that the equation-of-state for surface tension determination may only be used for systems with apolar liquids involving interactions of a physical nature. Reasonable surface tension values were obtained for polymers when advancing contact angles for diiodomethane were used in the calculations. Nevertheless, there appears to be an inconsistency in the surface tension values determined for self-assembled monolayers as calculated with the equation-of-state using contact angle data for different apolar liquids, diiodomethane and hexadecane.

AN EVALUATION OF OIL PRODUCED FROM ASPHALT RID (UTAH) TAB SAND AS A FEEDSTOCK FOR THE PRODUCTION OF ASPHALT AND TURBINE FUELS

Abstract In this article an evaluation is made of the potential end uses of an oil produced from Asphalt Ridge tar sand by wet forward combustion. The oil is evaluated with respect to its potential to produce a specification-grade asphalt and aviation turbine fuels. To accomplish this the oil was vacuum distilled to produce a distillate and a residue. The distillation residue meets all of the ASTM D 3381 Table 1 specification tests for an AC-10 asphalt. However, the viscosity at 135°C (275°F) is low when compared with the more stringent D 3381 Table 2 requirements. This indicates that the residue has a higher temperature susceptibility than allowed for by Table 2. The residue also has an unusually low aging index. This indicates that it may not set properly. However, it may also mean that it may be resistant to rapid age hardening. The results from successive freeze-thaw cycling indicate that the residue, when coated on appropriate aggregates, is comparable to or better than some petroleum asphalts coated...

AN EVALUATION OF ASPHALT RIDGE (UTHA) TAR SAND BITUMEN AS A FEEDSTOCK FOR THE PRODUCTION OF ASPHALT AND TURBINE FUELS

ABSTRACT The purpose of this study was two-fold. The first was to produce vacuum distillation residues and determine if their properties met ASTM asphalt specifications. The second was to determine if the distillates could serve as potential feedstocks for the production of aviation turbine fuels. The bitumen used for this study was the oil produced during an in situ steamflood project at the Northwest Asphalt Ridge (Utah) tar sand deposit. Two distillation residues were produced, one at +316 °C (+600°C)and one at +399°C (+750°F). However, only the lower boiling residue met ASTM specifications, in this case, as an AC-30 asphalt. The original oil sample met specifications as an AC-5 asphalt. These residue samples exhibited some unique properties with respect to aging. It is suggested that the low aging indexes and high flow properties of the samples may be beneficial for pavements that require good low-temperature performance. Two distillate samples were produced, one at IBP-316°C (IBP-600°F) and one at IBP-399°C (IBP-750°F). The chemical and physical properties of these samples were determined, and it was concluded that both samples appear to be potential feedstocks for the production of conventional and high-density aviation turbine fuels.

Tar sand pretreatment with diluent

Important aspects of kerosene penetration into tar sand have been investigated. The natural tar sand porosity was measured and used to analyze the performance of the hot water process. Subsequently, pretreatment experiments, using 20-kg tar sand samples (Asphalt Ridge and Whiterocks, Utah) and kerosene as a diluent were carried out at the expected summer temperature (26°C) and the expected winter temperature (−14°C). The natural tar sand porosity accessible by diluent has a crucial impact on the reduction of bitumen viscosity and influences the penetration time required for successful bitumen separation from tar sand by hot water processing. Thus, the tar sand porosity is a critical variable that determines appropriate operating conditions. Experimental results indicate that diluent penetration into the Asphalt Ridge tar sand (high porosity) is almost complete after 30 min, whereas for the Whiterocks tar sand (low porosity) the penetration process is much slower, being still incomplete after 15 hours regardless of the ambient temperature.

Characterization and Potential Utilization of the Asphalt Ridge Tar Sand Bitumen I. Gas Chromatography - Mass Spectrometry and Pyrolysis-Mass Spectrometry Analyses

ABSTRACT The native Asphalt Ridge bitumen was separated into several boiling range fractions for detailed analysis and characterization. The lighter fraction (477–617 K) was evaluated for use as an aviation turbine fuel and the residue (>617 K) was evaluated for use as an asphalt. The 477–617 K fraction appeared to meet most of the specifications for high density aviation turbine fuels. The 617 K plus residue from the Asphalt Ridge bitumen can be classified as a viscosity grade AC-30 asphalt. Several physical properties were also measured to evaluate the potential of the 477–617 K fraction as high density-energy aviation turbine fuel after mild hydrotreating. The detailed structure of the low molecular weight fractions of the Asphalt Ridge bitumen (477–617 K and 617–711 K) was determined by combined gas chromatography and mass spectrometry. Additional insight regarding the chemical structure of the bitumen was also obtained by Fourier transform infrared analysis. The tentative identification of saturated ...

Moderate-temperature water-based bitumen recovery from tar sand

A moderate-temperature water-based separation process for the recovery of bitumen from tar sand (with an emphasis on tar sands containing bitumen of high viscosity) is presented. The new approach was evaluated using samples of Asphalt Ridge and Whiterocks tar sands, originating from the Uinta Basin in Utah. Digested tar sand slurry, subjected to dilution, was sedimented in a gravity cell and the stratified layers investigated under a microscope. Different layers formed in the gravity cell were characterized in terms of the extent of bitumen separation from sand. Selected problems associated with the design of the processing strategy are briefly discussed.

Electrophoretic characterization and processing of Asphalt Ridge and Sunnyside tar sands

Batch hot water digestion-flotation experiments, using the Asphalt Ridge and Sunnyside tar sands from the Uinta Basin in Utah, were carried out at temperatures of 30°, 60° and 90°–195°C in order to obtain fine mineral particles and tailings water necessary for the electrophoretic mobility investigation. The bitumen in all runs but one was prepared by toluene extraction of the tar sand. For both Asphalt Ridge and Sunnyside tar sands negative surface charges were observed for all particles and droplets in the pH range from 3 to 10. It was found that fine mineral particles were effectively floated with bitumen droplets, but at a slower rate. Therefore a shorter flotation time was found to produce a higher grade of bitumen concentrate. The comparable negative electrical charge for both bitumen droplets and mineral particles suggests that bitumen gravity separation should precede flotation. Thus flotation would be used as a scavenging operation for the recovery of finely dispersed bitumen and the smallest possible zeta potential for bitumen droplets is desired for most efficient flotation.

A 1H CRAMPS n.m.r. investigation of chemically and thermally treated asphalt ridge tar sand

An exploratory investigation was conducted using the n.m.r. technique CRAMPS (combined rotation and multiple-pulse spectroscopy) to provide information on the types of organic hydrogen functionality present on the surface of tar sand residues. These residues were obtained from solvent extraction using solvents of different polarity and isothermal pyrolysis at four different temperatures. The solvents hexane, toluene, and methylene chloride were used to extract the bitumen from a native tar sand. From carbon and hydrogen analyses, all three solvents removed essentially all of the bitumen from the mineral matrix. However, solid-state 1H n.m.r. and diffuse reflectance infrared spectra show the presence of a small amount of organic material still in contact with the mineral matrix. After extraction with methylene chloride, the most polar solvent, tar sand residues contain less organic material than the tar sand residues obtained after solvent extraction with hexane, the least polar of the solvents. The hydrogen spectra of the tar sand residues show a greater amount of aromatic hydrogens than aliphatic hydrogens presumably because heteroaromatics associate more strongly with the mineral matrix. The 1H CRAMPS spectra of the tar sand residues obtained from the isothermal pyrolysis of the native tar sand show that a relatively large amount of unpyrolysed bitumen still remains with the mineral matrix even at a temperature of 380 °C. For the native tar sand pyrolysed above 400 °C, the 1H spectrum changed dramatically, but the spectrum of the pyrolysate tar sand residues still did not have the chemical shift resolution that was apparent in the spectra of the tar sand residues from solvent extraction. The major change in the 1H spectrum of the tar sand residue after pyrolysis above 400 °C was the loss of paraffinic hydrogens, as expected.

Rate of intermolecular association of Asphalt Ridge tar sand bitumen after thermal dissociation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRate of intermolecular association of Asphalt Ridge tar sand bitumen after thermal dissociationDaniel A. Netzel and Peggy T. CooverCite this: Energy Fuels 1989, 3, 2, 259–262Publication Date (Print):March 1, 1989Publication History Published online1 May 2002Published inissue 1 March 1989https://doi.org/10.1021/ef00014a023RIGHTS & PERMISSIONSArticle Views60Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (516 KB) Get e-Alerts Get e-Alerts

CHARACTERIZATION OF NICKEL AND VANADIUM COMPOUNDS IN TAR SAND BITUMEN BY UV-VIS SPECTROSCOPY AND SIZE EXCLUSION CHROMATOGRAPHY COUPLED WITH ELEMENT SPECIFIC DETECTION

ABSTRACT Previously, we have examined the Ni and V in heavy crude oils, residua, and processed products by several metal speciation techniques to ascertain molecular structure and processing behavior. Two classes of metal compounds were found -metallopetroporphyrins and metallo-nonporphyrins - each having unique reactivity during processing. In efforts to better understand the binding of metals in the oil medium, we have now examined Ni and V in tar sand bitumens, the bitumen was solvent extracted from the sand matrix and was separated by column chromatography and the petro-porphyrin content was quantitated by UV-vis spectroscopy. The petroporphyrin contents ranged from virtually none to over 36% of the total metals. Asphalt Ridge (Utah) has primarily Ni petroporphyrins; Big Clifty (Kentucky) and Athabasca (Canada) have primarily V petroporphyrins; Arroyo Grande and McKittrick (California) have roughly equal amounts of both types; and Surmyside (Utah) has virtually none of either. Size characteristic profiles (SEC-ICP) were generated for the extracted bitumens. The profiles are generally bimodal in shape and resemble several different specific heavy crude oils and residua. For examples, Arroyo Grande and McKittrick appear to be similar to Kern River (California) 650°F+ residuum, while Athabasca resembles Morichal (Venezuela) 650°F+ residuum.

THE POTENTIAL USE OF TAR SAND BITUMEN AS PAVING ASPHALT

ABSTRACT In this paper several research reports describing the preparation of potential paving asphalts from tar sand Bitumen are reviewed and the results of the studies compared. The tar sand asphalts described in the studies were prepared from 1) hot water-recovered bitumen from deposits near San Luis Obispo, California (Edna deposits), and deposits near Vernal and Sunny-side, Utah; and 2) bitumen recovered from the Northwest Asphalt Ridge deposits near Vernal, Utah, by both in situ steamflood and in situ combustion recovery processes. Important properties of the tar sand asphalts compare favorably with those of specification petroleum asphalts. Laboratory data suggest that some tar sand asphalts may have superior aging characteristics and produce more water-resistant paving mixtures than typical petroleum asphalts.

CSAMT Mapping of a Utah Tar Sand Steamflood

The mapping of thermal fronts associated with EOR techniques from the surface has important application to improved reservoir stimulation. Real-time knowledge of how a thermal EOR front is developing would help and operator to optimize production well placement as well as to take corrective steps to maximize production. The surface mapping technique that we are evaluating is the controlled-source audio frequency magnetotelluric (CSAMT) electromagnetic (EM) induction geophysical prospecting technique. The analysis of the field data, using results from laboratory studies, is described. Normalized maps show the location of the steam front that is in agreement with production data, temperature data from monitoring wells, and posttest coring data. The location of a major bypass of steam into an underlying formation was also mapped. The results indicate that the CSAMT technique shows promise for monitoring steam-front locations.

Isolation and f.i.m.s. analysis of saturated hydrocarbons from tar sand bitumens

Saturated hydrocarbons in two Utah tar sand bitumens were determined via compound-type isolation and mass spectral analyses. Four analytical methods for isolating saturated hydrocarbons were evaluated: 1. 1) dewaxing, 2. 2) modified deasphaltening, 3. 3) adsorption and complexation chromatography, 4. 4) desorptive Soxhlet extraction followed by complexation chromatography. The latter method was preferred for concentrating the greatest amount of saturated hydrocarbons without overlap from aromatic or heteroatom-containing species. Field ionization mass spectrometry (f.i.m.s.) adequately profiled these hydrocarbons by molar mass (m/z) and by Z-series type. The sample of Northwest Asphalt Ridge bitumen was comprised of a wax of mostly acyclic and monocycloalkanes; whereas, the saturates from the sample of Asphalt Ridge bitumen were mostly tetracyclo- and penatcycloalkanes. Based upon a comparison of the saturate distributions in the samples of bitumen, the sample from the Northwest Asphalt Ridge deposit was found to have undergone less biodegradation. This wax-like sample of bitumen may have migrated to the deposit at a later time than the major bitumen generation and/or resulted from physicochemical segregation of waxy organic matter in the reservoir.

Recovery of Bitumen From Tar Sand Deposits With the Radio Frequency Process

Summary The IIT Research Institute (IITRI) radio frequency (RF) process for tar sands consists of two steps: (1) the deposit is volumetrically heated with RF energy to lower the viscosity of the bitumen, and (2) the bitumen is produced by one of several petroleum recovery methods. The RF heating step is accomplished by inserting tubular electrodes into boreholes and by energizing them with an RF power source. The electrode pattern is designed so that the deposit between the electrodes is uniformly heated with a minimum energy loss. The operating frequency is selected on the basis of the electromagnetic characteristics of the deposit. The recovery techniques that we investigated include replacing the heated bitumen with sodium silicate solutions, by gravity drainage, and by autogenously developed steam and hydrocarbon gases. Two small-scale field experiments were conducted in the Asphalt Ridge tar sand deposit near Vernal, UT. About 25 m3 [33 cu yd] of the deposit was heated with RF energy, and about 35% of the total in-place bitumen was recovered during the 3-week test period.