Nigerian Tar Sand Research Articles

Unlocking Efficiency in Radio-Frequency Heating: Eigenfrequency Analysis for Resonance Identification and Propagation Enhancement in Nigerian Tar Sands.

Nigerian bituminous tar sands are among the world's largest deposits of bitumen and heavy oil. They are estimated to contain 38-40 billion barrels of heavy oil and bitumen, spanning approximately 120 km in length and 4-6 km in breadth. With global commitments to net zero emissions and various energy transition plans, improvements in the recovery methods for heavy oil and bitumen are being sought. To address this, renewable energy electrothermal enhanced oil recovery is considered an eco-friendly alternative. In our study, we introduce a novel Reservoir-Waveguide-Debye model. This model explores the enhancement of penetration for radio-frequency electromagnetic (EM) waves, which can be generated from renewable energy sources. These waves facilitate the viscosity reduction of heavy oil and bitumen. Through a comprehensive 2D numerical simulation employing the bulk properties of bituminous tar sands, we assess the propagation of EM fields within porous media. We utilize the industrial heating radio-frequency bandwidth of 1-60 MHz to conduct frequency domain investigations. Our analysis delves into propagation modes using eigenfrequency analysis, pinpointing the EM resonance of the tar sands. Furthermore, we investigate the impact of mesh refinement on the EM eigenfrequencies of porous media at both the microscale (400 μm) and macroscale (100 m in radial distance). Our results demonstrate the occurrence of resonance phenomena at complex eigenfrequencies around 27.12 and 54.24 MHz in both the microscale and macroscale models of the bituminous sands. This breakthrough research offers promising insights into harnessing renewable energy-driven EM waves for efficient thermal recovery processes in the Nigerian bituminous tar sands, thus fostering sustainable and eco-friendly energy solutions.

Preliminary Investigation On the Effect of Crumb Rubber (From Waste Tyre) On Nigerian Tar Sand Bitumen and Conventional 60/70

Preliminary Investigation On the Effect of Crumb Rubber (From Waste Tyre) On Nigerian Tar Sand Bitumen and Conventional 60/70

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.

The bitumen extraction from Nigerian tar sand using dense carbon dioxide

The need for alternative sources of energy has become even more acute in light of the recognition of the dwindling conventional world oil reserves. The interest in exploring other avenues of complimenting and/or eventually replacing this resource is growing quite rapidly. A ready alternative to conventional crude oil is oil sands which are abundant and vastly unexplored. The huge deposits of tar sand found in SouthWestern Nigeria remain untapped due to concerns about the environmental impact. The consequences of the methods in processing tar sand, ranging from water pollution to emission of greenhouse gases, especially in Canada bring in to sharp focus the urgent need for an alternative means of extracting oil from tar sand. A more effective and less environmentally damaging procedure could be the break through needed to open a new chapter in the exploitation of oil sands. The alternative recovery procedure is supercritical carbon dioxide extraction. Recent supercritical extractions use high temperatures and pressures. The upgrade in this research involves using high pressures and lower temperatures which saves energy and improves the process. The experimental study of the bitumen extraction from Nigerian tar sand by dense CO2 was carried out by high pressure extractor. The samples of tar sand were first heated in an oven at 120 °C to melt. A 50 g sample of melted tar sand with addition of 3 g of ethanol was placed into an extractor and heated to 80 °C to initiate the experiment. Carbon dioxide was injected in to the extractor to create 50 MPa of pressure in static mode for 20 min after which the extract was collected. In the presence of ethanol, the extract had a lighter colour than the usual black. Nigerian tar sand is known to be composed of 84 % sand, 17 % bitumen, 4 % water and 2 % mineral clay. Using this data, an extract of 19.47 % was calculated which makes the recovery achieved very encouraging. The experiment shows that recovery of bitumen from tar sand is possible under relatively low temperatures and can be possibly economically profitable.

Production and Cost of Cold Patch Road Mats with Bitumen Extracted From Nigerian Tar Sand

This paper reports the production of bituminous road mats with bitumen sourced from the Nigerian Tar sand , recycled waste rubber and paper , and rock mineral aggregates for cold patching of flexible pavement. The bitumen extracted was evaluated for yield , physical and mechanical properties in accordance with ASTM and AASHTO procedures . The bitumen was mixed with rubber chips to produce rubberized bitumen for production of road mats . The unit cost of production per square metre of the road mat was developed and compared with that of the imported Broom Road Product (BRP) . The bitumen extracted from the Nigerian tar sand is suitable as straight run bitumen and production of bituminous cold patch road mats at relatively cheaper cost than the BRP. An immediate action plan for exploitation of the untapped resources of bitumen should be instituted by government and private entrepreneurs for production of road mats for cold patching of flexible roads . http://dx.doi.org/10.4314/njt.v34i2.5

Upgrading and extraction of bitumen from Nigerian tar sand by supercritical carbon dioxide

The current experimental study describes the recovery of bitumen from Nigerian tar sand by the supercritical carbon dioxide method, which has the advantages of a substantial reduction in water consumption, an absence of chemicals, and an upgrading of the bitumen through the rejection of solids, petcokes and asphaltenes. The bitumen extraction from 50g piece of tar sand was carried out at 50, 60 and 65MPa and 110°C by pure carbon dioxide and with the addition of 10mL of fresh or salty water. The recovery decreased in the following order: with salty water, with fresh water, pure CO2. The maximum recovery of 29.6% was obtained at 50MPa with the addition of salty water declining at higher pressures. The heaviest fractions were extracted by pure carbon dioxide at 60 and 65MPa. The presence of bisnorhopane, a biomarker typical for source rocks formed in marine depositional environment, was detected in crude bitumen and all extracts by GC–MS TIC analysis.

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

Alberta’s Oil Sands: Hard Evidence, Missing Data, New Promises

Pitched battles are a regular occurrence in northern Alberta, Canada, as development of the province’s oil sands continues to expand. One ongoing battle—with another salvo launched in February 2011 with the leak of a European Commission report1—concerns how dirty oil sands are, relative to other fuels. Another concerns the influence of the oil sands industry in monitoring its own activity.2 In an effort to cut through the rhetoric of health advocates, industry representatives, environmentalists, government officials, and local residents, the Royal Society of Canada (RSC) selected and covered expenses for an expert panel to winnow out the facts. In a report issued 15 December 20103 the panel cited substantial evidence that efforts to extract oil from the Alberta deposits have degraded air, land, and water quality to varying degrees. The extent of the degradation is sometimes controversial; water quality data, in particular, are subject to differing interpretations and attributions of causality. However, the panel says that, based on publicly available evidence, there appear to be no significant human health threats to the general population either now or from development anticipated in the next decade or so. But the panel also warns that their conclusions come with a major caveat: there are major gaps in health and environmental data, risk assessments, government oversight, information transparency, industry efforts, and disaster preparedness. The health of the region could hinge on these gaps being addressed, particularly since, according to Travis Davies, a spokesman for the Canadian Association of Petroleum Producers, 97% of projected oil extraction and processing is still to come. After the RSC panel reviewed reams of publicly available information on factors such as health status, air and water pollution, greenhouse gas emissions, land disturbance, and energy and water consumption, it concluded that “[t]he claim by some critics of the oil sands industry that it is the most environmentally destructive project on earth is not supported by the evidence. However, for Canada and Alberta, the oil sands industry involves major environmental issues on many fronts which must be addressed as a high priority.”3p293

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.

Geochemical characterisation of heavily biodegraded tar sand bitumens by catalytic hydropyrolysis

Catalytic hydropyrolysis was used to release the aliphatic biomarkers covalently bound within the asphaltene structure of highly biodegraded Nigerian tar sand bitumens. Unlike the free aliphatic hydrocarbons extracted from the bitumen, the hydropyrolysis products of the asphaltenes afford aliphatic biomarkers having the characteristics of the initial unaltered oil, which had been trapped within the asphaltene matrix of the bitumen and protected from biodegradation processes. The biomarker profiles obtained allow proper characterisation of the bitumen in terms of source and thermal maturity. Catalytic hydropyrolysis is also capable of releasing aromatic hydrocarbons that can be used in the geochemical characterisation of the bitumen.

Corrosion Study of AISI 304, AISI 321 and AISI 430 Stainless Steels in a Tar Sand Digester

This work has investigated the corrosion properties of three types of stainless steels in a tar sand digester environment with the aim of establishing their relative resistances in the environment. The corrosion experiments for the stainless steels were conducted by the non-electrochemical immersion technique with corrosion rates expressed in mils per year (mpy). The spectroscopy analysis of the Nigerian tar sand was done by the energy dispersive x-ray analysis. The surface study of the corroded stainless steels was accomplished via a scanning electron microscopy (SEM) to reveal the form of corrosion. The results of the corrosion experiments show that all the stainless steels have a relatively low corrosion rates (<5mpy). The SEM analyses of their corroded surfaces however revealed great tendency in them to exhibit crevice and pitting corrosions. On the basis of resistance to the two forms of corrosion the AISI 321 stainless steel exhibited the best resistance in the environment.

Provenance Study Of Bituminous Sands In Eastern Dahomey Basin Sw Nigeria Based On Heavy Mineral And Quartz Varieties

One hundred and twenty (120) tar sand samples were collected at 8 localities along the Nigerian tar sand belt for both quartz variety and heavy mineral analyses. The quartz variety study carried out on 30 samples revealed both polycrystalline and monocrystalline quartz types occurring in all samples but in different proportions. Predominating are the subequant with straight boundaries and few scattered vacuoles indicative of the polycrystalline quartz. Forty samples were analyzed for heavy mineral assemblage determination. The separation of these heavy minerals using bromoform (specific gravity 2.85) and slide examination under the petrographic microscope indicated the presence of zircon, rutile, staurolite, sillimanite, kyanite, garnet and epidote. Opaque minerals dominate the assemblage and they occur in significant quantities in some locations. From the results of these analyses, it could be inferred that the bituminous sands of the Abeokuta Group might have been derived principally from a plutonic acid igneous rock with significant contribution from high-grade metamorphic rock. Ife Journal of Science Vol. 7(1) 2005: 123-130

Comparative study of the compositional characteristics of liquids derived by hydrotreating of Nigerian tar sand bitumen : Ukwuoma, O. Petroleum Science and Technology, 2002, 20, (5 & 6), 525–534

Extensive tar sands with reserves of about 41 billion barrels of oil are known to occur in Cretaceous terrigenous sediments in Ondo and Ogun States of Nigeria. The hydrocarbon occurs in two predominantly sandy zones separated by an 8 m thick oil shale. The lower (Horizon Y) is mostly quartz sand, 3–26 m thick. It shows an upward fining of grains and increased consolidation updip. The upper Horizon X is 10–22 m of sandstone with interbedded shales and siltstones. The sands are loosely consolidated. Cementing material is lacking, the grains being held together largely by the tarry oil. Porosity is about 30% and mean oil saturation in both zones is 12%.The recorded clay content (2–7%) is considerably lower than the average for Athabasca, Canada (10–25%) and may enhance the settling properties of the tailing ponds. The sands are water-wet, fine- to medium-grained, moderately well sorted, mesokurtic and positively skewed to near symmetrical. The Nigerian tar sands compare closely with the Athabasca sands in all the above textural parameters. They would thus be expected to show identical response to mining processing, except for the influence of higher ground-water table and the high humidity and ambient temperatures in Nigeria.

Comparative study of the compositional characteristics of liquids derived by hydrotreating of Nigerian tar sand bitumen. I. Simulated distillation : Ukwuoma, O. Petroleum Science and Technology, 2002, 20 (5 & 6), 525–534

Ultracentrifugation was investigated as a means to obtain solvent-free bitumen from oil sand. The bitumen from three oil sands of varying grades was separated by placing the sands in specially designed tubes and centrifuging for 2 h at 198 000 g at 20 °C. For all grades of oil sand, approximately 70% of the bitumen was recovered. The recovered bitumen was compared to the residual remaining on the sand, and to that extracted by the conventional Soxhlet technique. The ultracentrifuged bitumen contained some emulsified water and a small amount of fine solids. The solvent-extracted material was water-free, but contained a small amount of residual solvent and fine solids. The ultracentrifuge caused some fractionation of the bitumen, resulting in a product slightly enriched in asphaltene components compared to the solvent-extracted material. The residual bitumen remaining on the sand was correspondingly slightly depleted in asphaltenes. However, as evidenced by gas Chromatographic simulated distillation data, ultracentrifugation did retain the light (180–220 °C) components of the bitumen which were lost during the solvent removal step following solvent extraction. Other analyses such as density, viscosity and elemental composition verified that ultracentrifugation resulted in some fractionation of bitumen components.

Determination of oxygen, nitrogen, and silicon in Nigerian fossil fuels by 14 MeV neutron activation analysis

Classification, assessment, and utilization of coal and crude oil extracts are enhanced by analysis of their oxygen content. Values of oxygen obtained "by difference" from chemical analysis have proved inaccurate. The oxygen, nitrogen, and silicon content of Nigerian coal samples, crude oils, bitumen extracts, and tar sand samples were measured directly using instrumental fast neutron activation analysis (FNAA). The total oxygen in the coal ranges from 5.20% to 23.3%, in the oil and extracts from 0.14% to 1.08%, and in the tar sands from 38% to 47%. The nitrogen content in the coal ranges from 0.54% to 1.35%, in the crude oil and bitumen extracts from ≤; 0.014% to 0.490%, and in the tar sands from 0.082% to 0.611%. The silicon content in the coal ranges from 1.50% to 8.86%; in the oil and the bitumen extracts it is <1%, and in the tar sands between 25.1% and 37.5%. The results show that Nigerian coals are mostly sub-bituminous. However, one of the samples showed bituminous properties as evidenced by the dry ash-free (daf) percent of carbon obtained. This same sample indicated a higher ash content resulting in a comparatively high percentage of silicon. In oils and tar sands from various locations, a comparison of elements is made.

COMPARATIVE STUDY OF THE COMPOSITIONAL CHARACTERISTICS OF LIQUIDS DERIVED BY HYDROTREATING OF NIGERIAN TAR SAND BITUMEN. I. SIMULATED DISTILLATION

ABSTRACT Nigerian tar sand bitumen was hydrotreated at relatively low temperatures and initial hydrogen pressures. The liquid products derived from the hydrotreating process were characterized by the means of instrumental analysis of simulated distillation on gas chromatography. Results show that the liquid products are amenable to the characterization procedure and provided basic data that should be useful in formulating refining processes for Nigerian tar sand bitumen and the liquids derived from its hydrotreating operations. The liquids show differences in products distribution for different temperature but have almost identical structures for same temperatures and different pressures. Generally, increase in temperature caused an increase in conversion of bitumen to distillable products. The characterization data of the derived liquid products will serve as a basis for the identification of processes for upgrading bitumen and such other fossil fuels like coal liquids or heavy vacuum residua.

Thermal visbreaking of heavy oil from the Nigerian tar sand

Thermal visbreaking of heavy oil from the Nigerian tar sand

Simultaneous PIXE and PIGME Analysis of a Nigerian Tar Sand Sample from a Deep Borehole

Tar sands from a deep borehole in southwestern Nigeria were subjected to elemental analysis by simultaneous proton induced X-ray emission (PIXE) and proton induced gamma-ray emission (PIGME) techniques. The concentration of 22 major, minor and trace elements, namely Al, Ca, Cr, Cu, F, Fe, Ga, Ge, K, Li, Mg, Mn, Na, P, Pb, Rb, S, Si, Sr, Ti, Zn and Zr were determined. The accuracy and precision of the techniques for chemical analysis were assured by analysing the NBS 278 geological standard.

Thermal visbreaking of heavy oil from the Nigerian tar sand

Mild thermal visbreaking of heavy oil from the Nigerian tar sand was conducted at several temperatures for different lengths of time in the laboratory. The viscosity of the oil was found to reduce with thermal treatment. The reduction in viscosity was investigated deterministically in relation to the changes in the chemical composition of the oil after the mild thermal treatment.

STUDY OF COMPOSITION OF NIGERIAN TAR SAND BITUMEN

Compositional characterization techniques developed for high-boiling heavy ends of petroleum have been applied to Nigerian tar sand bitumen. The bitumen was subjected to ion-exchange and ferric chloride coordination chromatography to separate acids, bases and neutral nitrogen compounds. The remaining Hydrocarbon plus fraction was separated into saturates, monoarmatics, diaromatics and polyaromatic plus polar compounds on dual packed column of silica - alumina gels. Simulated distillation data were also obtained for the bitumen and were used to plot a boiling point distribution curve. Results of the characterization are compared with results in literature for tar sand bitumens and petroleum. Comparison of the results with the Utah and the Athabasca bitumens provides a basis for the evaluation of the Nigerian bitumen because considerable information about the processing characteristics of the Athabasca bitumen have been reported by many researchers. Simulated distillation and chromatographic separation data indicate that the bitumen used in this present study closely resembles the Athabasca and the Utah tar sand bitumens with respect to hydrocarbon/non-hydrocarbon distribution, and the high-boiling petroleum fraction with respect to non-distilling portion. Information about the composition of bitumens and heavy oils is needed because of the prospect of using heavy oils including bitumens as energy sources.