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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Experimental investigation of in situ upgrading of heavy oil by using a hydrogen donor and catalyst during steam injection

Mohammad, Ahmad A A 10 October 2008 (has links)
Experiments were conducted to investigate the feasibility of in situ upgrading of heavy oil by the use of an orgametallic catalyst and a hydrogen donor (tetralin). The experiments used a vertical injection cell into which a mixture of sand, water, and Jobo oil was thoroughly mixed and packed. Two types of runs were conducted: a run where the tetralin and catalyst were mixed within the mixture before packing into the cell, and the other was conducted by injecting a slug of the tetralin-catalyst solution before commencing with the steam injection. The Jobo oil used had an oil gravity of 12.4° API and a viscosity of 7800 cp at 30°C. The injection cell was placed in a vacuum jacket and set to a reservoir temperature of 50°C. Superheated steam at 273°C was then injected into the injection cell at a rate of 5.5 cc/min (cold water equivalent). The cell outlet pressure was maintained at 500 psig. Produced liquid samples were collected periodically through a series of separators. The produced oil was divided into two halves and several measurements and analyses were carried out on them. These included viscosity, density, elemental analysis and liquid composition. Experimental results indicated that tetralin alone was a worthy additive and increased recovery by 15% compared to that of pure steam. The premixed tetralincatalyst run showed improved recovery to that of pure steam by 20%. Experiments also showed that, when the tetralin-catalyst solution was injected rather than mixed, the results were equivalent to tetralin injection runs. Oil production acceleration was displayed by all the runs with tetralin and tetralin-catalyst but was more pronounced with the availability of catalyst.
2

Steam-flood modelling

Al-Abbasi, Adel January 1988 (has links)
No description available.
3

Biomass Integrated Gasification Combined Cycles (BIGCC)

Yap, Mun Roy 17 December 2004 (has links)
Conversion of biomass to energy does not contribute to the net increase of carbon dioxide in the environment, therefore the use of biomass waste as a clean and renewable fuel source is an attractive alternative to the use of fossil fuels. Biomass can be converted to energy via direct combustion or via thermo-chemical conversion to liquid or gas fuels. This study focuses on employing gasification technology to convert biomass waste to producer gas, which is then cleaned and fed as gaseous fuel into the gas turbine. Since the producer gases are usually low caloric values, the power plants performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for a 5MWe and a 20MWe power plants using commercial software ThermoFlow. The power plants considered including simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems (STIG) using the producer gas with low caloric values at approximately 30% and 15% of the natural gas heating value. The low caloric value fuels are shown to impose high back compressor pressure and increased power output due to increased fuel flow. Power augmentations under four different weather conditions are also calculated by employing gas turbine inlet fog cooling. Different capacity options for the heat recovery steam generator (HRSG) that provides the steam for STIG are analyzed.
4

A simulation study of steam and steam-propane injection using a novel smart horizontal producer to enhance oil production

Sandoval Munoz, Jorge Eduardo 15 November 2004 (has links)
A 3D 8-component thermal compositional simulation study has been performed to evaluate the merits of steam-propane injection and a novel vertical-smart horizontal well system for the Lombardi reservoir in the San Ardo field, California. The novel well system consists of a vertical steam injector and a horizontal producer, whose horizontal section is fully open initially, and after steam breakthrough, only one-third (heel-end) is kept open. A 16x16x20 Cartesian model was used that represented a quarter of a typical 10acre 9-spot inverted steamflood pattern in the field. The prediction cases studied assume prior natural depletion to reservoir pressure of about 415 psia. Main results of the simulation study may be summarized as follows. First, under steam injection, oil recovery is significantly higher with the novel vertical-smart horizontal well system (45.5-58.7% OOIP at 150-300 BPDCWE) compared to the vertical well system (33.6-32.2% OOIP at 150-300 BPDCWE). Second, oil recovery increases with steam injection rate in the vertical-smart horizontal well system but appears to reach a maximum at about 150 BPDCWE in the vertical well system (due to severe bypassing of oil). Third, under steam-propane injection, oil recovery for the vertical-smart horizontal well system increases to 46.1% OOIP at 150 BPDCWE but decreases to 51.6% OOIP at 300 PDCWE due to earlier steam breakthrough that resulted in reduced sweep efficiency. Fourth, for the vertical well system, steam-propane injection results in an increase of oil recovery to 35.4-32.6% OOIP at 150-300 BPDCWE. Fifth, with steam-propane injection, for both well systems, oil production acceleration increases with lower injection rates. Sixth, the second oil production peak in the vertical-smart horizontal well system is accelerated by 24-50% in time for 150-300 BPDCWE compared to that with pure steam injection.
5

Adequate description of heavy oil viscosities and a method to assess optimal steam cyclic periods for thermal reservoir simulation

Mago, Alonso Luis 16 August 2006 (has links)
A global steady increase of energy consumption coupled with the decline of conventional oil resources points to a more aggressive exploitation of heavy oil. Heavy oil is a major source of energy in this century with a worldwide base reserve exceeding 2.5 trillion barrels. Management decisions and production strategies from thermal oil recovery processes are frequently based on reservoir simulation. A proper description of the physical properties, particularly oil viscosity, is essential in performing reliable modeling studies of fluid flow in the reservoir. We simulated cyclic steam injections on the highly viscous Hamaca oil, with a viscosity of over 10,000 cp at ambient temperature, and the production was drastically impacted by up to an order of magnitude when using improper mixing rules to describe the oil viscosity. This thesis demonstrates the importance of these mixing rules and alerts reservoir engineers to the significance of using different options simulators have built in their platforms to describe the viscosity of heavy oils. Log linear and power mixing rules do not provide enough flexibility to describe the viscosity of extra heavy oil with temperature. A recently implemented mixing rule in a commercial simulator has been studied providing satisfactory results. However, the methodology requires substantial interventions, and cannot be automatically updated. We provide guidelines to improve it and suggest more flexible mixing rules that could easily be implemented in commercial simulators. We also provide a methodology to determine the adequate time for each one of the periods in cyclic steam injection: injection, soaking and production. There is a lot of speculation in this matter and one of the objectives of this thesis is to better understand and provide guidelines to optimize oil production using proper lengths in each one of these periods. We have found that the production and injection periods should be similar in time length. Nevertheless, the production period should not be less than the injection period. On the other hand, the soaking period should be as short as possible because it is unproductive time in terms of field oil production for the well and therefore it translates into a negative cash flow for a company.
6

Adequate description of heavy oil viscosities and a method to assess optimal steam cyclic periods for thermal reservoir simulation

Mago, Alonso Luis 16 August 2006 (has links)
A global steady increase of energy consumption coupled with the decline of conventional oil resources points to a more aggressive exploitation of heavy oil. Heavy oil is a major source of energy in this century with a worldwide base reserve exceeding 2.5 trillion barrels. Management decisions and production strategies from thermal oil recovery processes are frequently based on reservoir simulation. A proper description of the physical properties, particularly oil viscosity, is essential in performing reliable modeling studies of fluid flow in the reservoir. We simulated cyclic steam injections on the highly viscous Hamaca oil, with a viscosity of over 10,000 cp at ambient temperature, and the production was drastically impacted by up to an order of magnitude when using improper mixing rules to describe the oil viscosity. This thesis demonstrates the importance of these mixing rules and alerts reservoir engineers to the significance of using different options simulators have built in their platforms to describe the viscosity of heavy oils. Log linear and power mixing rules do not provide enough flexibility to describe the viscosity of extra heavy oil with temperature. A recently implemented mixing rule in a commercial simulator has been studied providing satisfactory results. However, the methodology requires substantial interventions, and cannot be automatically updated. We provide guidelines to improve it and suggest more flexible mixing rules that could easily be implemented in commercial simulators. We also provide a methodology to determine the adequate time for each one of the periods in cyclic steam injection: injection, soaking and production. There is a lot of speculation in this matter and one of the objectives of this thesis is to better understand and provide guidelines to optimize oil production using proper lengths in each one of these periods. We have found that the production and injection periods should be similar in time length. Nevertheless, the production period should not be less than the injection period. On the other hand, the soaking period should be as short as possible because it is unproductive time in terms of field oil production for the well and therefore it translates into a negative cash flow for a company.
7

A comparative analysis of numerical simulation and analytical modeling of horizontal well cyclic steam injection

Ravago Bastardo, Delmira Cristina 29 August 2005 (has links)
The main objective of this research is to compare the performance of cyclic steam injection using horizontal wells based on the analytical model developed by Gunadi against that based on numerical simulation. For comparison, a common reservoir model was used. The reservoir model measured 330 ft long by 330 ft wide by 120 ft thick, representing half of a 5-acre drainage area, and contained oil based on the properties of the Bachaquero-01 reservoir (Venezuela). Three steam injection cycles were assumed, consisting of a 20-day injection period at 1500 BPDCWE (half-well), followed by a 10-day soak period, and a 180-day production period. Comparisons were made for two cases of the position of the horizontal well located on one side of the reservoir model: at mid-reservoir height and at reservoir base. The analytical model of Gunadi had to be modified before a reasonable agreement with simulation results could be obtained. Main modifications were as follows. First, the cold horizontal well productivity index was modified to that based on the Economides-Joshi model instead of that for a vertical well. Second, in calculating the growth of the steam zone, the end-point relative permeability??s of steam and oil were taken into consideration, instead of assuming them to be the same (as in the original model of Gunadi). Main results of the comparative analysis for both cases of horizontal well positions are as follows. First, the water production rates are in very close agreement with results obtained from simulation. Second, the oil production rates based on the analytical model (averaging 46,000 STB), however, are lower than values obtained from simulation (64,000 STB). This discrepancy is most likely due to the fact that the analytical model assumes residual oil saturation in the steam zone, while there is moveable oil based on the simulation model. Nevertheless, the analytical model may be used to give a first-pass estimate of the performance of cyclic steam injection in horizontal wells, prior to conducting more detailed thermal reservoir simulation.
8

Experimental Evaluation of the Effect of Inlet Gas Humidification on Fuel Cell Performance

Evans, John P. 06 October 2003 (has links)
The development and evaluation of a fuel cell test stand incorporating various methods for controlling the temperature and humidity of fuel cell reactants is described. The test stand is capable of accurately metering gas flows, controlling the temperature and humidity of the gases, and delivering the gases to the fuel cell in a safe manner. Additionally, the test stand can measure the voltage and current produced by the fuel cell during operation. Two test stands were constructed and evaluated, one using steam injection for fuel cell stacks and the other using flash evaporation for individual fuel cells. Both test stands were shown to provide adequate control at the upper end of the design range. The flash evaporation test apparatus was used to investigate the effect of inlet gas humidity on fuel cell performance. The results from this investigation showed that, for a fuel cell and reactant temperature of 75°C, the best performance was achieved with a high relative humidity (90%RH) for the hydrogen and a comparatively low relative humidity (60%) for the air. / Master of Science
9

A Study for Remediation of MTBE and Diesel Contaminated Soils by Soil Heating/Air Stripping and Steam Injection/Vacuum Extraction- One Dimensional Mass Transfer Analysis and Verification

Hsien, Adren 02 August 2000 (has links)
This research reports on an experimental and theoretical study of soil heating/air stripping and steam injection/vacuum extraction for remediation of MTBE and Diesel Contaminated Soils. Two one-dimensional mass transfer models were using to simulate the process of remediaction. Contaminant kinds(MTBE and Diesel)¡A contaminant concentration (152~13,912 mg/kg soil)¡Asoil temperature(38~120¢J)¡Asteam injection pressure(0.5~1.0 atm)¡A and the mass of steam used(0.379~0.730 kg/h)were employed as the experimental factors in this study. In soil heating/air stripping study, rising soil temperature will enhance the MTBE removed efficiency¡A it was shown in the concentration of effluent gas. Further, the flow rate at outlet of column was higher than that at inlet of column, it revealed MTBE transfers from liquid phase to gas phase and was removed by gas flow. The concentration of effluent gas curve in low initial MTBE concentration test was similar with high concentration test, but the mechanisms was quiet different¡Ait need advanced adsorption test to find the reasons. In medium initial MTBE concentration test¡Athe concentration of effluent gas curve showed linear shape. When using steam injection/vacuum extraction treating MTBE contaminated soil, it showed 90¢Mefficiency can be reached in one hour. In steam injection/vacuum extraction study, it showed higher initial diesel contaminant concentration¡Ahigher initial concentration of effluent gas. Further, in high initial diesel concentration test (13.912 g diesel/kg soil test and about 5g/ kg soil tests)¡Athe concentration of effluent gas curves had a dominant drop at early time in remediation, it revealed the injection steam flow was quiet large, so diesel didn¡¦t has enough time to transfer to gas phase, that the gas couldn¡¦t been saturation at outlet of column. But in low initial diesel concentration test (about 1 g diesel/kg soil tests), the concentration of effluent gas curves showed the typical NAPL remediation curve. The different with in high and low initial concentrations might from the complex composition of diesel. Because at the early time in remediaction of high initial diesel concentration, the low carbon numbers diesel could abundantly evaporate, it caused the high concentration of effluent gas. With the remediation time go by, the low carbon numbers diesel exhaust. So the main composition of effluent gas transfer to high carbon numbers diesel, that the concentration of effluent gas curve showed the slowly decline. For high initial diesel concentration test (13.912 g diesel/kg soil)¡A the efficiency was the highest (73.7¢M). For low initial diesel concentration test (about 1 g diesel/kg soil), the efficiency was the lost (about 20¢M). Further, the remediation of diesel contaminated soil exited a rapid removed period. Under the conditions of this study, the rapid removed period could remove more than 95¢Mcontaminant of diesel removed at hold remediation time. The experiment results also showed that larger the mass of steam injection, shorter the rapid removed period, and larger the steam injection pressure, longer the rapid removed period. When using soil heating/air stripping treating diesel contaminated soil, the removed efficiency was worse 10-20¢Mthan the same initial diesel contaminated concentration. In simulating remediation process, the prediction with the MTBE measured concentration yielded good agreement in NAPL model. But to get the better fit of diesel in NAPL model, it might set the ¡§could removed mass¡¨ to initial condition of model. In non-NAPL model, MTBE also showed good agreement with model, and the model enabled the prediction of the initial contaminant level in the soil.
10

Adi??o de vermiculita expandida m?cron em pastas de baixa densidade para cimenta??o de po?os de petr?leo

Nunes, Eduardo Raimundo Dias 22 February 2010 (has links)
Made available in DSpace on 2014-12-17T14:06:54Z (GMT). No. of bitstreams: 1 EduardoRDN_TESE_partes autorizadas.pdf: 117966 bytes, checksum: 56c76d5875d3c3fa1d24b36b9cf97b87 (MD5) Previous issue date: 2010-02-22 / The northeastern region of Brazil has a large number of wells producing oil using a method of secondary recovery steam injection, since the oil produced in this region is essentially viscous. This recovery method puts the cement / coating on thermal cycling, due to the difference in coefficient of thermal expansion between cement and metal coating causes the appearance of cracks at this interface, allowing the passage of the annular fluid, which is associated with serious risk socioeconomic and environmental. In view of these cracks, a correction operation is required, resulting in more costs and temporary halt of production of the well. Alternatively, the oil industry has developed technology for adding new materials in cement pastes, oil well, providing high ductility and low density in order to withstand the thermo-mechanical loads generated by the injection of water vapor. In this context, vermiculite, a clay mineral found in abundance in Brazil has been applied in its expanded form in the construction industry for the manufacture of lightweight concrete with excellent insulation and noise due to its high melting point and the presence of air in their layers lamellar. Therefore, the vermiculite is used for the purpose of providing low-density cement paste and withstand high temperatures caused by steam injection. Thus, the present study compared the default folder containing cement and water with the folders with 6%, 8% and 10% vermiculite micron conducting tests of free water, rheology and compressive strength where it obtained the concentration of 8 % with the best results. Subsequently, the selected concentration, was compared with the results recommended by the API standard tests of filtered and stability. And finally, analyzed the results from tests of specific gravity and time of thickening. Before the study we were able to make a folder with a low density that can be used in cementing oil well in order to withstand the thermo-mechanical loads generated by steam injection / A regi?o nordeste do Brasil possui uma grande quantidade de po?os produtores de ?leo que utilizam como m?todo de recupera??o secund?ria a inje??o de vapor, j? que o ?leo produzido nesta regi?o possui natureza essencialmente viscosa. Este m?todo de recupera??o coloca a interface cimento / revestimento sobre ciclagem t?rmica que, devido ? diferen?a de coeficiente de expans?o t?rmica entre o cimento e o revestimento met?lico provoca o surgimento de trincas nesta interface, possibilitando assim a passagem de fluidos pelo anular, que est? associado a s?rios riscos s?cioecon?mico e ambiental. Diante destas trincas, uma opera??o de corre??o ? requerida, acarretando em mais custos e parada tempor?ria da produ??o do po?o. Como alternativa, a ind?stria do petr?leo tem desenvolvido tecnologia para a adi??o de novos materiais em pastas de cimento para po?os de petr?leo, proporcionando maior ductilidade e baixa densidade, de forma a resistir ?s cargas termomec?nica gerada na inje??o de vapor de ?gua. Nesse contexto, a vermiculita, um argilomineral encontrado em abund?ncia no Brasil tem sido aplicado na sua forma expandida na constru??o civil para confec??o de concretos leves com excelentes propriedades de isolamento t?rmico e ac?stico devido ao seu alto ponto de fus?o e a presen?a de ar em suas camadas lamelares. Portanto, a vermiculita ser? utilizada com a finalidade de proporcionar baixa densidade a pasta de cimento e resistir ?s altas temperaturas causadas pela inje??o de vapor. Desta forma, o presente trabalho, comparou a pasta padr?o contendo cimento e ?gua com as pastas com 6%, 8%, e 10% de vermiculita expandida m?cron realizando os ensaios de ?gua livre, reologia e resist?ncia a compress?o onde obteve a concentra??o de 8% com os melhores resultados. Posteriormente, a concentra??o escolhida, foi comparada com os resultados recomendados pela norma API nos ensaios de filtrado e estabilidade. E por ?ltimo, analisaram-se os resultados obtidos nos ensaios de peso espec?fico e tempo de espessamento. Diante do estudo realizado conseguiu-se formular uma pasta com baixa densidade que pode ser utilizada na cimenta??o de po?o de petr?leo com o objetivo de suportar as cargas termo-mec?nica gerada pela inje??o de vapor

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