Tar Sand Deposits Research Articles

Feature selection in GC-MS, NMR and MALDI-TOF spectra of tar sand bitumen

Expectations from unconventional reservoirs are often overly optimistic when estimation criteria are transferred from one location to another but some of the many important elements of petroleum systems remain unaccounted for. Feature engineering used in model construction to improve the quality of the machine learning process can improve the performance of unconventional reservoir estimates.The compositions of petroleum fluids are represented by spectra obtained from various analyses, which vary greatly in shape and dimensions, contain large amounts of data, and cannot be processed as single numbers. Selection of relevant features in the spectra can simplify interpretation, reduce dimensionality, and improve data compatibility.The features have been selected in GC-MS, NMR and MALDI-TOF spectra of bitumen from the Bayan-Erkhet tar sand deposit in Mongolia for comparison with bitumens from other regions of the world. The GC-MS spectra have a similar baseline shape, either a triangle or two humps with peaks eluted to varying degrees. The comparison made it possible to isolate poorly eluted peaks of carbon number groups in the studied bitumen. Since NMR spectra of petroleum fluids are most often published without NMR parameters, simple indices are developed to compare the shapes of the spectra. The values of these indices are consistent with the characteristics of the samples. The sequences of hydrocarbon compounds determined in the MALDI-TOF spectrum are very similar to those of the Banik black shale, Iraq, which allowed to clarify the sequences. Some peaks are also found in the spectra of two other crude oil samples. The feature selection in spectral analyses enables revealing the hidden information.

Frequency domain electromagnetic and electrical resistivity geophysical investigation of tar sands deposits in the Ijebu Waterside area, Eastern Dahomey Basin, southwestern Nigeria

The use of electromagnetic conductivity and electrical resistivity geophysical techniques has been employed in this study to investigate the occurrence, thickness, and spatial distribution of bitumen deposit around Makun-Omi in the Ijebu Waterside area of southwestern Nigeria. Subsurface apparent conductivity distribution data obtained using Geonic 34-3 equipment along fifteen traverses which sounded from different depths of 7.5, 15, 30 and 60 m at inter-coil separation of 10, 20 and 40 m in vertical and horizontal coupling modes and ground resistivity distribution measurements, obtained using Geopulse Tiger Allied resistivity meter at fourteen Vertical Electrical Sounding (VES) stations, were processed and employed to characterize the subsurface in terms of tar sands distribution. The conductivity and resistivity distribution in the form of a 3D earth model, iso-depth maps, 2D sections generated from the processed conductivity and resistivity data indicate relatively low conductivity <20 mS/m and high resistivity >1300 Ωm values around tar/bitumen impregnated sands which mostly occurred in the southern part of the study area. Clearly defined conductivity and resistivity anomalies which delineate the lateral and vertical occurrence of tar impregnated sands underscore the efficacy of integrating electromagnetic and electrical resistivity geophysical techniques to identify occurrence of economic deposits of tar sands in parts of southwestern Nigeria.

Independent gilsonite vein, Uintah County

The Uinta Basin of northeastern Utah contains a wide variety of hydrocarbon resources including vast accumulations of crude oil and natural gas deposits, one of the largest oil shale resources in the world, and the largest tar sand deposit in the United States. In addition, unique solid hydrocarbons, including gilsonite, wurtzilite, tabbyite, and ozokerite, have a long and colorful history of exploration and/or production in the region. The most abundant of these, gilsonite, occurs in distinctive swarms of subparallel, northwest-trending veins. The lateral continuity of the veins is impressive, with relatively long, straight ribbons stretching across the hills of the eastern Uinta Basin. The veins are also vertically continuous, extending hundreds to more than 3000 feet (900 m) below the ground, commonly having only small variations in width. The Uinta Basin contains the world’s largest deposit of gilsonite and is the only place in the world where this unique resource is economically produced. Gilsonite is remarkable for its unusual geologic origin, chemical and physical properties, and industrial uses. Industry pioneers are noted for creating innovative uses for their product and for over 100 years have solved mining, processing, transportation, marketing, and other challenges to supply gilsonite to world markets. Accordingly, gilsonite has been studied and described in a large body of research dating back to the 1880s. Most recently, the Utah Geological Survey (UGS) published Special Study 141 (Boden and Tripp, 2012), which presents the latest mapping of gilsonite deposits and a compilation of existing data. To date, over 70 significant veins and vein systems, having a total combined vein length of over 170 miles (270 km), have been mapped by UGS geologists.

Reservoir geology and effects on exploitation of natural bitumen deposits (Nigerian deposits as a case study)

Geological investigation have led to discovery of huge tar sand deposits within Afowo Formation of the Turonian–Maastrichtianage (95.9–66.0 Ma) in the Nigerian sector of the Eastern Dahomey Basin. This study aims at determining the feasibility of exploiting the major hydrocarbon resource steam assisted gravity drainage enhanced recovery technique. Samples from three core holes were dry sievied to determine the particle size distribution and their sections studied using a petrographic microscope. Clay mineral content was determined using X-ray diffraction scanning electron microscopy. The granulometric analysis shows the bituminous sediments to be generally fine grained and moderate to well sorted, and the grains are angular to subangular. Porosity ranges from 15.5 to 33.6 ɸ with average value of 26.4 ɸ, while permeability ranges from 270 to 4800 mD, with an average value of 4800 mD (very high) recorded for the sandstones. Petrographic study, scanning electron microscopy and X-ray diffractometry showed quartz as the dominant mineral component, with subordinate feldspar and other accessory minerals. The predominance of quartz is probably due to its mechanical stability. The low frequency of feldspar is attributable to its susceptibility to chemical breakdown and alteration, respectively, during transport and after deposition, with latter accounting for the observed secondary porosity. Kaolinite is the common clay mineral present in the oil sands and may not have sufficiently reduced the reservoir quality to negatively impacting enhanced recovery operation by steam assisted gravity drainage.

Geology and hydrocarbon potential of the East African continental margin: a review

The East African margin has a complex structure due to multiple phases of rifting with different stretching directions. The main phase of rifting leading to Indian Ocean opening lasted from the Late Pliensbachian to the Bajocian ( c. 183 – 170 Ma). This occurred during impingement of the Bouvet hotspot which weakened the lithosphere sufficiently to allow continental break-up. Thick salt and marine shales were deposited during the Toarcian in the Majunga, Ambilobe and Mandawa basins and the onshore Ogaden Basin; marking the onset of the Indian Ocean marine incursion, when good quality oil-prone source rocks were deposited at this time. The recent giant gas discoveries in Tanzania and Mozambique are believed to be sourced from overmature Jurassic or, possibly, deeper Permian age Karoo shales. The margin from the Lamu Basin in the north to the Zambesi Delta in the south is covered by thick Tertiary and Cretaceous sediment derived from the East African rift shoulders, and Lower Jurassic source rocks are predicted to be in the gas window along most of the margin. However, the margins in South Africa, south Mozambique, northern Somalia and Madagascar are less deeply buried, and have better oil potential. The large Tsimimo and Bemolanga tar sand deposits and the recent announcement of an oil rim in the Inhasorro Field indicate that there are good oil-prone source rocks in the Karoo rifts and in the Albian Domo shales; and the search for oil continues with companies exploring in areas where Jurassic source rocks may be less deeply buried, and/or potential Albian–Turonian-aged source rocks are sufficiently buried to generate oil. Supplementary material: Figures S1–S3 are available at: https://doi.org/10.6084/m9.figshare.c.3894931

Spatial distribution and lifetime cancer risk due to naturally occurring radionuclides in soils around tar-sand deposit area of Ogun State, southwest Nigeria

Anthropogenically enhanced naturally occurring radionuclides 238U, 232Th and 40K present in the tar-sand soil samples were measured by gamma ray spectrometer using a highly shielded NaI (TI) detector with the aim of evaluating the environmental radiological hazards. Mineralogical analysis and characterization was carried out using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. The results obtained showed that the average activity concentrations of 238U, 232Th and 40K ranges from BDL↔76.00 ± 12.00, BDL↔204.48 ± 13.02 and BDL↔755.6 ± 40.15 Bqkg−1 respectively. Eleven other radiological and hazard parameters were estimated to know the complete hazardous nature of the samples. The values obtained for radionuclides and all its associated radiological and health hazard parameters were all higher than the world's average set by UNSCEAR. Five different minerals were identified and characterized as major and minor minerals. The mean radionuclides activity concentrations, radium equivalent and dose rate of measured radionuclides were compared with other literature values. RESRAD computer code was used to calculate the probability of excess lifetime cancer incurred by dwellers of the tar-sand deposit site, the level of which was determined to be 2.3 × 10−3(2310000). Spatial distribution of natural radionuclides in the study area was also investigated for radioactivity disequilibrium. Multivariate statistics were applied to establish the effect of mineralogy on radionuclides activity. Therefore, the tar-sand soil samples are considered to pose serious radiological hazard and cancer risk to human through the multiple routes of exposure and significant soil remediation action need to be taken for future use of the soils.

Stratigraphic Intervals for Oil and Tar Sand Deposits in the Uinta Basin, Utah

To better understand oil and bitumen generation and migration in the Paleogene lacustrine source rocks of the Uinta Basin, Utah, analyses of 182 oil samples and tar-impregnated intervals from 82 core holes were incorporated into a well-established stratigraphic framework for the basin. The oil samples are from the U.S. Geological Survey Energy Resources Program Geochemistry Laboratory Database; the tar-impregnated intervals are from core holes drilled at the Sunnyside and P.R. Spring-Hill Creek tar sands deposits. The stratigraphic framework includes transgressive and regressive phases of the early freshwater to near freshwater lacustrine interval of Lake Uinta and the rich and lean zone architecture developed for the later brackish-to-hypersaline stages of the lake. Two types of lacustrine-sourced oil are currently recognized in the Uinta Basin: (1) Green River A oils, with high wax and low β-carotane contents thought to be generated by source rocks in the fresh-to-brackish water lacustrine interval, and (2) much less common Green River B oils, an immature asphaltic oil with high β-carotane content thought to be generated by marginally mature to mature source rocks in the hypersaline lacustrine interval. Almost all oil samples from reservoir rocks in the fresh-to-brackish water interval are Green River A oils; however four samples of Green River A oils were present in the hypersaline interval, which likely indicates vertical migration. In addition, two samples of Green River B oil are from intervals that were assumed to contain only Green River A oil. Tar sand at the P.R. Spring-Hill Creek deposit are restricted to marginal lacustrine and fluvial sandstones deposited during the hypersaline phase of Lake Uinta, suggesting a genetic relationship to Green River B oils. Tar sand at the Sunnyside deposit, in contrast, occur in marginal lacustrine and alluvial sandstones deposited from the early fresh to nearly freshwater phase of Lake Uinta through the hypersaline phase. The Sunnyside deposit occurs in an area with structural dips that range from 7 to 14 degrees, and it is possible that some tar migrated stratigraphically down section.

THE REVIEW OF UNCONVENTIONAL OIL PRICE FLUCTUATIONS AND FORECASTING

Relevance of the research.Due to the effect of globalization and integration processes, it isimpossible toimagine a world without oil, as the oil price changes affect not only the financial markets butalso international trade circulation (Babatunde et al., 2013;Bastiani et al.,2016.; Caporale,et al.,2016.;Humphrey et al.,2016). Oil demand is growing rapidly.It is necessary formineral-based fuels, lubricants,plastics and various products of the chemical industry and other uses.Highconsumer demandled tosyntheticoil production, known as non-traditional oil productionmethods (Grushevenko, E., Grushevenko, D., 2012a).Unconventional oil is a synthetic energy product designed to convert one fuel source (fuel oil, shale, sandresin) to another, but it requires a tremendous amount of heat and fresh water, however, synthetic oil is muchcheaper to extract than conventional oil from deep sources in the context of limited resources.Furtherincreasing investor interest in oil production from unconventional reserves (oil, shale, sand) for a much lowerproduction costs and cost dynamics and higher return on investment projects in returnhas been reportedoccasionally. Since the period of 2006–2011breakeven price of oil, extracted from the shalehas changed, thecost has doubled–from 105 US dollars/barrel to 48 US dollars/barrel. During the same period, the cost-effectiveness of oil extracted from tar sand deposits price increased by 20% and accounted for around 73 USdollars/barrel. Based on the present state of international trade realities and trends itcan besuggestedthatfluctuations in oil prices is becoming a major factor in rising geopolitical tensions and fears of financial marketturmoil.Theresearch problemis posed by the question of what are the impactsof unconventional oil pricesand demand in the global oil market.Research subject:unconventional oil market and methods.Research purposewas toanalyseand define unconventional oil prices on the world market. Thefollowingobjectiveswere formulated to achieve the purpose:1. Formulatethe methodological research concept ofoil prices and demand.2. Overview of unconventional oil price assessments.Research methods.The article is prepared applying the methods of systemic analysis of academicliterature, logical analysis and synthesis oftheoretical research carried out. Unconventional oil price changesand methodswerereviewed according to the basis of the last decadeforeignstudies published in EBSCOHostEmerald and Science Direct databases.Outcomes and conclusions.A detailedglobal economic and energy trends analysis model and ERIRAS program, investigating oil demand over the long term, is the most useful research not only in the Russianenergy concern examination of the situation, but also in the global oil market forecasts.In order to more accurately predict the oil prices in the future, creating a probabilistic model, it isnecessary to monitor not only the monthly changes, and various events and draw attention to the weekly andmonthly events and their changes, because studies suggest that it is extremely important to the future priceprediction. Theestablishment ofthe correct price of oil patterns needsto be based on long-term data, as thismakes it much easier to provide for increases in prices and at the same time toavoid them.Unconventional oil production potential should unfold in the future perspective. Since thedevelopment of unconventional oil major impact on global trade flows, and declining US import demand andsubsequent stagnation of operating the oil demand for energy-efficient technology late entry, should increasecompetition among suppliers in the Asia-Pacific oil market. Such a concentration in one of the oil market inthe region may lead to significant differences between the different regions of theworld oil price fluctuations,but there is an even greater risk of oil producers and consumers.Review of the literature showed thatthereprevails statistically significant correlation between oil priceshocks and fluctuations in the stock market and theinverse relationship prevails in the Gulf countries. GulfCooperation Council countries, the stock market indices are closely correlated and have a common tendencyto gradually increase or decrease in different periods.Keywords:unconventional oil, pricefluctuation, oil world market.

THE REVIEW OF UNCONVENTIONAL OIL PRICE FLUCTUATIONS AND FORECASTING

Relevance of the research.Due to the effect of globalization and integration processes, it is impossible to imagine a world without oil, as the oil price changes affect not only the financial markets but also international trade circulation (Babatunde et al., 2013; Bastiani et al.,2016.; Caporale, et al.,2016.; Humphrey et al.,2016). Oil demand is growing rapidly. It is necessary for mineral-based fuels, lubricants, plastics and various products of the chemical industry and other uses. High consumer demandled to synthetic oil production, known as non-traditional oil production methods (Grushevenko, E., Grushevenko, D., 2012a). Unconventional oil is a synthetic energy product designed to convert one fuel source (fuel oil, shale, sandresin) to another, but it requires a tremendous amount of heat and fresh water, however, synthetic oil is much cheaper to extract than conventional oil from deep sources in the context of limited resources.Further increasing investor interest in oil production from unconventional reserves (oil, shale, sand) for a much lower production costs and cost dynamics and higher return on investment projects in return has been reported occasionally. Since the period of 2006–2011 break even price of oil, extracted from the shale has changed, the cost has doubled –from 105 US dollars/barrel to 48 US dollars/barrel. During the same period, the cost-effectiveness of oil extracted from tar sand deposits price increased by 20% and accounted for around 73 US dollars/barrel. Based on the present state of international trade realities and trends it can be suggested that fluctuations in oil prices is becoming a major factor in rising geopolitical tensions and fears of financial market turmoil.

Evaluation of the natural radioactivity level of Nigerian tar sand deposits, eastern Dahomey basin, southwestern Nigeria

The specific activities of natural radionuclides in twenty seven samples collected from the eastern Dahomey basin in southwestern Nigeria were evaluated. Experimental results were obtained by using a 3" x 3" sodium iodide NaI(Tl) detector. A major trace element assessment of the samples was made by Inductively Coupled Plasma Mass Spectrometry techniques. Gamma ray radioactive standard sources, 137Cs and 60Co, were used to calibrate the measurement system and the International Atomic Energy Agency SOIL-375 radioactive standard source was also used to analyze and compute the specific activities of desired natural radionuclides. Three radioelements, viz. 238U, 232Th and 40K, were identified in the samples with the following specific activities of 238U ranging from 9.88 ? 4.70 Bq/kg to 69.15 ? 12.37 Bq/kg with an average of 26.50 ? 7.18 Bq/kg; 232Th from 12.78 ? 5.16 Bq/kg to 36.86 ? 13.35 Bq/kg with an average of 22.77 ? 4.28 Bq/kg; 40K ranging from 189.82 ? 79.51 Bq/kg to 518.77 ? ? 119.54 Bq/kg with an average of 297.69 ? 16.21 Bq/kg. The result was compared with the world mean values of 35, 30 and 400 Bq/kg, respectively, specified by the United Nations Scientific Committee on the Effects of Atomic Radiation. The mean result obtained for the radium equivalent, total absorbed dose rate, external hazard index, internal hazard index, and the annual effective dose equivalent, were 79.90 Bq/kg, 38.50 ?Sv/h, 0.22 Bq/kg, 0.29 Bq/kg, and 47.22 ?Sv, respectively. With respect to radiological risk to human health, the absorbed gamma dose rate in air was estimated to be in the range of 21.7 ? 0.4 to 155.7 ? 2.2 ?Sv/h; the outdoor annual effective dose equivalent was evaluated to vary from 26.6 ? 0.4 to 190.9 ? ? 2.7 ?Sv with the arithmetic mean value of 79.06 ? 33.23 ?Sv and compared to the world-wide effective dose of 70 ?Sv. Also, the values of the radium equivalent and the external hazard index for all samples in the study area were found to be lower than the accepted safety limit value of 370 Bq/kg and equally below the limit of unity, respectively. The results indicate that, at present, the radiation hazard from radionuclides in all samples analyzed is within permissible limits.

Geotechnical Properties of Some Soils in a Tar Sand Area of Southwestern Nigeria

Engineering properties of some soil samples in Idiobilayo and Idiopopo areas of Southwestern Nigeria were studied with the aim of determining their geotechnical properties which can aid in the exploitation plan of the tar sands deposits in the area. A total of six sampling locations with three samples each were established in the study area. Samples of soil both disturbed and undisturbed were obtained from the trial pits to a depth of about 1.5m at 0.5m vertical interval. The disturbed samples were subsequently subjected to classification tests such as grain size distribution and consistency limits using British standards 1377 procedure. However, the undisturbed samples were subjected to permeability test. Results obtained in this study showed that the area of study is underlain essentially by sandy soils, with substantial silty content. Clay and gravel content are quite minimal. The particle size distribution curves confirmed a general dominance of silt to coarse-grained sand size particles in the soil matrix with minor but complimentary clayey and gravelly materials. Amounts of fines in the soils are less than 50% except in trial pts 4 and 5 where they are slightly above 50%. The soils consist of sand (60.0 %) and silt (35.0 %). The percentage of fines (silt and clay sized fraction) in the soils was about 38.0 %, and makes the soils good base for landfill, since recommended percentage of fines, should not be less than 20.0 %. However the obtained values of permeability coefficient of 5.5 X 10 -6 mm/s to 1.2 X 10 -4 mm/s call for the lining of the base to avoid groundwater pollution by leachates.

Keystone XL

I drive a hybrid car and set my thermostat at 80°F in the Washington, DC, summer. I use public transportation to commute to my office, located in a building given “platinum” design status by the U.S. Green Building Council. The electric meter on my house runs backward most months of the year, thanks to a large installation of solar panels. I am committed to doing my part to cut greenhouse gas (GHG) emissions and minimize global warming. At the same time, I believe it is time to move forward on the Keystone XL pipeline to transport crude oil from the tar sands deposits of Alberta, Canada, and from the Williston Basin in Montana and North Dakota to refineries on the U.S. Gulf Coast.

Application of high resolution aeromagnetic data for basement topography mapping of Siluko and environs, southwestern Nigeria

The discovery of hydrocarbon in commercial quantity in the Niger Delta, southern Nigeria, has since the early fifties shifted the attention of exploration/active geological studies from the Dahomey basin and the adjacent basement terrain in south-western Nigeria towards the south and this has left some gaps in information required for the discovery and exploitation of the economic potential of the region. This study mapped the Siluko transition zone in south-western Nigeria in terms of structures, geometry and basement topography with the object of providing requisite geological information that will engender interest in the exploration and exploitation of the numerous economic potentials of south-western part of Nigeria.Acquired high resolution aeromagnetic data were filtered, processed and enhanced, the resultant data were subjected to qualitative and quantitative magnetic interpretation, depth weighting analyses and modelling to generate the subsurface basement topography across the study area. The obtained results indicate regions of high and low magnetic anomalies with residual magnetic intensity values ranging from −100.8nT to 100.9nT. Euler Deconvolution indicates generally undulating basement topography with depth range of 125–1812m. The basement relief is generally gentle and flat lying within the basement terrain with depth ranging from 125 to 500m. However the sedimentary terrain is undulating and generally steeps south, down the basin with depth range of 300–1812m. A basement topography model of the magnetic data constrained by Euler solutions correlate positively with the geology of the study area and indicates a generally increasing sedimentary deposits’ thickness southward toward the western part of Dahomey basin.The revealed basement topography and structures as well as the delineated direction of continuous increase in thickness of sedimentary deposit provide insight to the controlling factor responsible for tar sand deposit and bitumen/oil shows associated with the study area. The results also point to the southern and south-western part of the basin as the appropriate direction to focus at for meaningful hydrocarbon potential development.

Seismic Refraction Survey of Tar Sands Deposits in Ijebu East of Ogun State Southwestern Nigeria

The interest in unconventional oil resources such as tar sands and oil shale is known as great economic importance by the governments and industries have encouraged researches in the development of these resources. Vast tar sands resources have not been adequately explored and exploited by the Nigeria Government except for accumulation of oil, natural gas and other minerals but bitumen has proven to be of great value. This motivated this study to map the ttar sands deposit at Imeri in Ijebu-Imushin within the Ijebu- East Local government area in Ogun State using seismic refraction survey. A seismic refraction survey at Imeri, Ijebu-Imushin of Ijebu-east carried out using ABEM seismograph Terraloc Mark 6 Version 2.22. Thirteen (13) traverse were taken along five profiles in which both forward and backward shooting were measured to cover a spread of 72m in each of the traverse. Pickwin software was adopted to analyze the results obtained in order to give information on first arrival time and velocity of the first and second layers. A model of the earth structure was achieved by the used of ploterrafa (refraction) software and interpretation to determine the thickness of the first layer from the processed data based on the known geology of the area. The velocities of the first layers of five profiles ranges from (0.75-1.30)km/s and the second layers velocities ranges were from (1.31-2.51)km/s. The presence of tar sands was observed in traverse 6, 7, 8, 9&12, with velocity values (1.12-1.44)km/s, (1.12- 1.86)km/s and (1.10-1.47)km/s respectively. The depth of the first layer of the above profile ranges from (5.00- 7.10)m. traverses 1-5, 10,11 and 13 shows the presence of clayed sand, sand, sand stone clay and sand with water saturation respectively was observed. The information provided by the analysis and interpretation of the first arrival time and velocities of the first and second layers concise with geologic trends of the rock type in the study area. It was observed that the velocities of the first and second layers were related to the velocities of different earth materials and their depth to the surface.

Screening of Fungal Isolates from Nigerian Tar Sand Deposit in Ondo State for Novel Biocatalysts

Screening of Fungal Isolates from Nigerian Tar Sand Deposit in Ondo State for Novel Biocatalysts

Recovery of Bitumen from Utah Tar Sands Using Ionic Liquids

Hot or warm water processes are used to extract bitumen from Canadian oil or tar sands. The application of these methods to the processing of tar sand deposits found in the Western United States, notably Utah, has not been commercially successful, however, because of the consolidated nature of the deposits and the high viscosity of the bitumen. It is demonstrated here that a previously developed method employing ionic liquids (ILs) together with a nonpolar solvent such as toluene can effect a separation at ambient temperatures (∼25 °C), although with greater difficulty than Canadian oil sands. Essentially, a multiphase system consisting of a sand and clay slurry, an ionic liquid layer, and an organic layer containing the bitumen can be formed by simply mixing the components. More than 90% of the bitumen is released from the sand, but only in successive extractions. Water is not used in this stage of the separation, but relatively small amounts are used to separate entrained IL from the sand and clays.

Modelling Safety Factors of Slope Stability for Open-Pit Mining of Nigerian Tar-Sand Deposits

Slope failure might lead to loss of lives and valuable equipment which would increase overall operational cost of running a mine. The need to have stable slopes in open-pit mining of Nigerian tar sand deposits of Dahomey Basin, Southwestern Nigeria is emphasized in this study. At Loda village, Southwestern Nigeria, samples of the laterite soil and alluvial sand which overlie the tar sand occurrence were subjected to geotechnical tests. Computer simulation of bench face angles was carried out using SLOPE/W Software to determine the bench face angle(s) with the least susceptibility to failure. Unit weight (o), cohesion (c) and angle of internal friction (0) values for the laterite soil were 25 kN/m, 45 kPa and 41 respectively for laterite. The corresponding values for the laterite, soil were 18 kN/m 3 , 0kPa and 34°. These values were used to run the software programme to simulate different bench face angles that could be cut into the two lithologic units. Factors of safety values between 3.58 and 1.73 were obtained for bench face angles between 10° and 30° which are least susceptible to failure even when inundation is considered. This research results have enabled us to recommend the use of bench slope angles ranging from 10° and 30° coupled with adequate drainage conditions which should guaranty optimum output.

Diagenetic and epigenetic alteration of Cretaceous to Paleogene organic-rich sedimentary successions in northwestern Jordan, typical of the western margin of the Arabian Plate

ABSTRACTFour reference sections through the calcareous-siliciclastic rocks of the Lower Cretaceous Kurnub Group and the Amman and Muwaqqar formations of the Upper Cretaceous to Paleogene Belqa Group in Jordan document the various processes of accumulation and alteration of organic matter (OM). Sections at Jerash, Sultani, Wadi Isal, and in the Kharazeh area were investigated by means of sedimentary petrography/mineralogy, organic petrography, and organic chemistry, and correlated with equivalent deposits in Syria and Egypt. The impacts of oxidation potential (Eh), acidity/basicity (pH) and temperature variations during the post-depositional alteration of these organic concentrations were assessed using x-y plots. Syngenetic Aptian-Albian coaly and organic-rich amber beds near Jerash developed in a tide-dominated delta under marginally alkaline conditions and were altered under slightly acidic conditions at temperatures of less than 100°C. Environmental analysis focused on Maastrichtian-Paleocene (?), oil shales in the Sultani area that were deposited in a small restricted basin on the continental shelf of the Neo-Tethys Ocean. Abnormally high contents of vanadium (V), phosphorus (P), zinc (Zn), and uranium (U) gave rise to yellow uranium ore minerals, phosphates and zinc sulfides and so bridge the gap between OM concentrations and those of uranium. The western part of the Arabian Peninsula is known for its uraniferous phosphorites and U-bearing calcretes. Reducing conditions during deposition of syngenetic OM in the oil shales may have shifted, in places, toward more oxidizing conditions in the course of post-depositional alteration at temperatures well below 200°C. Epigenetic fault-related concentration of OM was responsible for the Wadi Isal Aptian-Albian tar sand deposit and the oil seepage system in calcareous wall rocks of the Kharazeh Fault. The alteration of the tar sands (fluvial sandstones) is designated a high-sulfidation type (introduced aluminum sulfate minerals), whereas the oil seepage in Campanian shallow-marine carbonates is a low-sulfidation type (removal of aluminum sulfate minerals). Both alteration patterns may have implications for structure-bound base- and precious-metal deposits whose emplacement involves hydrocarbons as a carrier of metals in the mineralizing fluids. The Jordanian oil shales, tar sands, and uranium mineralization are possible sources of energy. Recent economic deals on the recovery and use of oil shales and uranium in Jordan are reviewed.

Article size distribution and control on Bitumen saturation of some Tar Sand Deposits in parts of South-Western Nigeria

Sedimentological analysis of some Afowo oil sands was carried out with the aim of characterising the reservoirs vis-à-vis their bitumen saturation and recovery efficiencies. Fourty-four samples of tar sands of the Afowo formation (collected at three different localities namely; Idiobilayo, Idiopopo and Igbotako) were subjected to granulometric and petrological analyses to determine the particle size distribution as well as other textural characteristics. The bitumen saturation analysis was carried out with the use of toluene. The result of sedimentological and particle size distribution studies showed that the sands are medium grained, moderately sorted and mesokurtic. The grain morphology can be described as having low to high sphericity, with shapes generally sub-angular to sub-rounded indicating a fairly long period of transportation. The result of bitumen saturation analysis showed that both Idiobilayo and Idiopopo oil sands have an average oil saturation of 17.2% and 16.9% respectively, while Igbotako sands have an average oil saturation of 12.3%. Consequently, Idiobilayo and Idiopopo oil sands deposits are therefore expected to have better reservoir quantities and possibly good oil recovery efficiencies. Keywords: Article size, distribution, Bitumen, Tar Sand Deposits, South-western Nigeria.Global Journal of Pure and Applied Sciences Vol. 14 (3) 2008: pp. 307-318

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)."