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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.
71

CFD modeling of auxiliary fuel injections in the blast furnace tuyere-raceway area

Vuokila, A. (Ari) 08 December 2017 (has links)
Abstract The blast furnace process is the most common way throughout the world to produce pig iron. The primary fuel and reducing agent in a blast furnace is coke. Coke is a fossil fuel and the most expensive raw material in iron production. Blast furnace ironmaking is an energy-intensive process, which results in high energy costs. Auxiliary fuels are injected into the blast furnace to replace expensive coke. They provide energy for the blast furnace operation and act as a source of reduction agents for iron oxides. Coke replacement with high auxiliary fuel injection levels leads to permeability changes in a blast furnace shaft, because of the increased amount of unburnt coal. In this thesis, fuel injection with two different auxiliary fuels, heavy oil and pulverized coal, was studied using computational fluid dynamics (CFD) modeling. The aim was to improve the combustion of auxiliary fuels by increasing the understanding of the phenomena in the blast furnace tuyere-raceway area. The atomization model for modeling the heavy oil combustion was selected and validated using the results of an experimental rig from the literature. The atomization model was applied to study the effect of different nozzles on heavy oil mixing with the air blast. In addition, the model was used to study the effect of lance position on the combustion efficiency of heavy oil. A pulverized coal combustion model was developed and validated with experimental data from the literature. Pulverized coal combustion was modeled with different lance positions to evaluate its effect on combustion efficiency. Based on the results, heavy oil mixing in the air blast can to a great extent, be boosted by the nozzle design. Furthermore, the heavy oil combustion is more efficient when the lance position is farthest from the tuyere nose. But the increasing temperature inside the tuyere causes ablation of the tuyere walls, which creates a constraint for the lance position. The results from the pulverized coal combustion study show that the model works well for the tuyere-raceway area. In addition, the effect of lance position on the combustion efficiency of the pulverized coal is very small, and the lance should be positioned as close to the tuyere nose as possible to avoid fouling of the tuyere walls and the ignition inside the tuyere. / Tiivistelmä Suurin osa maailman raakaraudasta valmistetaan masuuniprosessilla. Masuunin ensisijainen polttoaine ja rautaoksidien pelkistin on koksi. Koksi on fossiilinen polttoaine ja kallein raaka-aine masuunissa. Raudanvalmistus on erittäin energiaintensiivistä, joten valmistuksen energiakustannukset ovat korkeat. Lisäpolttoaineinjektiota käytetään masuunissa korvaamaan osa koksista sekä energian tuottajana että pelkistimenä. Injektiomäärät pyritään kasvattamaan mahdollisimman suuriksi, mutta injektiomäärien kasvaessa palamattoman kiinteän polttoaineen määrä kasvaa ja koksipatjan kaasunläpäisevyys heikkenee. Väitöskirjatutkimuksessa luotiin virtauslaskentamalli hormin ja palo-onkalon alueelle kahta lisäpolttoainetta (raskas polttoöljy, kivihiilipöly) varten. Sen avulla tutkittiin palamista hormin ja palo-onkalon alueella tavoitteena lisätä tietoa palamista rajoittavista tekijöistä. Pisaroitumismalli valittiin ja validoitiin kirjallisuusdatan perusteella raskaan polttoöljyn toimiessa lisäpolttoaineena. Mallia käytettiin tutkittaessa erilaisia suuttimia palamisilman ja polttoaineen sekoittumisen tehostamiseen. Lisäksi sitä käytettiin mallinnettaessa lanssin sijainnin vaikutusta raskaan polttoöljyn palamistehokkuuteen. Kivihiilipölylle luotiin palamismalli, joka validoitiin olemassa olevan kokeellisen datan perusteella. Tätä mallia hyödynnettiin tutkittaessa kaksoislanssin sijainnin vaikutusta palamistehokkuuteen. Tulosten perusteella voidaan todeta, että öljylanssin suuttimella on suuri vaikutus palamisilman ja polttoaineen sekoittumiseen. Lisäksi voidaan päätellä, että raskaan polttoöljyn palaminen tehostuu siirrettäessä lanssia syvemmälle hormiin, mutta syttyminen tapahtuu liian aikaisin ja kasvava lämpötila voi sulattaa hormin seinämät. Tämä aiheuttaa rajoituksen lanssin sijainnille hormissa. Kivihiilipölyn palamisen mallin todettiin toimivan erittäin hyvin hormin ja palo-onkalon alueilla. Tämän ohella havaittiin, että lanssin sijainnilla oli hyvin pieni vaikutus palamisasteeseen, jolloin lanssi kannattaa sijoittaa mahdollisimman lähelle hormin suuta, jotta vältetään hormiin kohdistuva ylimääräinen lämpökuorma ja hormin likaantuminen.
72

Hidrodinamica do escoamento bifasico oleo pesado - agua em um tubo horizontal

Obregon Vara, Rosa Maribel 17 August 2001 (has links)
Orientador: Antonio Carlos Bannwart / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-07-31T15:13:41Z (GMT). No. of bitstreams: 1 ObregonVara_RosaMaribel_M.pdf: 3876695 bytes, checksum: eab8e9bdc7ff92684aba33d3163bff1a (MD5) Previous issue date: 2001 / Resumo: Considerados de grande importância na indústria petroleira, os óleos pesados constituem uma grande reserva a ser explotada e produzida. Devido a dificuldades associadas às propriedades do óleo como densidade e viscosidade, tem-se procurado métodos para produzí-lo e transportá-lo de forma econômica. Uma dessas técnicas é o corejIow, que é basicamente a injeção lateral de pequenas quantidades de água, com o fim de lubrificar o óleo, formando uma configuração concêntrica anular, onde o óleo ocupa o centro e a água a parte externa. Neste trabalho fizeram-se testes experimentaispara obter diversas informaçõessobre os padrões de fluxo em duto horizontal de um escoamento óleo pesado - água, com ênfase no padrão corejIow. Estabeleceuse uma análise de estabilidade unidimensional geral para o padrão anular liquido - líquido horizontal, através da qual chegou-se a um critério geral de estabilidade, o qual inclui o critério de Kelvin-Helmhotz, conseguindo representar bem os resultados experimentais. Os dados coletados no laboratório também permitiram desenvolver um modelo para cálculo das perdas de pressão e da fração volumétrica com correlações que consideram os fenômenos fisicos relevantes: turbulência do anel, escorregamento entre as fases, molhabilidade e rugosidade da parede e as ondulações no núcleo de óleo. O uso do corejIow consegueu reduzir a perda de pressão em até 225 vezes em comparação com o óleo sozinho / Abstract: Heavy oi! has a growingimportancein the oi! industry,given the amountof its largeand unexploited reserves. Because of the natural difficulties reIated to its physical properties - higb viscosity and density - researchhas been focusedon how to produce and transportheavyoi] economically. Oneofthemostpromisingtecbniquesinvestigated, nownascore-annularflow 01 coreflow, is based on the lateral injection of few amounts of water, so as to lubricate the oil and form an annular liquid-liquid flow pattern, with the oi! in the center, surrounded by a watel annulus. In this work, experiments were performed in a horizontal pipe, in order to obtain detailed information on different heavy oil-water flow patterns, with special interest on the core flow pattern. A one- dimensional approach to the stability ofhorizontalliquid-liquid annular flow was developed and a general stability criterion was derived, which incIudes the Kelvin-HelInholtz criterion as a special case, and gives good agreement with the laboratory measurements. The data coIlected also allowed to develop pressure drop and holdup models taking into account alI relevant physical phenomena: annulus turbulence, slip between the phases, wall wettability and roughness and interface waviness. In the present experiments, pressure drop was reduced up to 225 fold in core flow compared with the flow of an equal amount of the oi! / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
73

Mass Transfer Mechanisms during the Solvent Recovery of Heavy Oil

James, Lesley 18 June 2009 (has links)
Canada has the second largest proven oil reserves next to Saudi Arabia which is mostly located in Alberta and Saskatchewan but is unconventional heavy oil and bitumen. The tar sands are found at the surface and are mined, yet 80% of the 173 billion barrels of heavy oil and bitumen exist in-situ according to the Canadian Association of Petroleum Producers (CAPP). Two factors inhibit the economic extraction and processing of Canadian heavy oil; its enormous viscosity ranging from 1000 to over 1 million mPa.s and the asphaltene content (high molecular weight molecules containing heavy metals and sulphur). Heavy oil and bitumen were only included in the reserves estimates through the efforts of Canadian enhanced oil recovery (EOR) research. Viscosity reduction is the one common element of in-situ methods of heavy oil recovery with the exception of cold production. Currently, steam assisted gravity drainage (SAGD) and cyclic steam stimulation (CSS) are being used commercially in the field where the oil’s viscosity is reduced by injecting steam. Thermal methods are energy intensive requiring vast volumes of water such that any improvement would be beneficial. Solvent extraction is one alternative requiring no water, the solvent is recoverable and reusable, and depending on the mode of operation the heavy oil is upgraded in-situ. Vapour Extraction (VAPEX) and enhanced solvent extraction (N-SolvTM) are two such methods. VAPEX and N-Solv reduce the bitumen’s viscosity via mass transfer and a combination of mass and heat transfer, respectively. A light hydrocarbon solvent (instead of steam) is injected into an upper horizontal well where the solvent mixes with the heavy oil, reduces its viscosity and allows the oil to drain under gravity to a bottom production well. The idea of using solvents for heavy oil extraction has been around since the 1970s and both VAPEX and N-Solv are patented processes. However, there is still much to be learned about how these processes physically work. Research to date has focused on varying system parameters (including model dimensions, permeability, heavy oil viscosity, solvent type and injection rate, etc.) to observe the effect on oil production from laboratory scale models. Based on an early mass balance model by Butler and Mokrys (1989) and an improvement by Das (1995), molecular diffusion alone cannot account for the produced oil rates observed from laboratory models. Until recently, very little progress had been made towards qualifying and quantifying the mass transfer mechanisms with the exception of the diffusivity of light hydrocarbons in heavy oil. Mass transfer can only be by diffusion and convection. Differentiating and quantifying the contribution of each is complex due to the nature and viscosity of the oil. The goal of this thesis is to investigate the mass transfer mechanisms during the solvent recovery of heavy oil. Quantifying the diffusion of light hydrocarbon solvents has been an active topic of research with limited success since the mid 1990’s. The experimental approach presented here focused on capturing the rate of solvent mass transfer into the bitumen by measuring the bitumen swelling and the butane uptake independently. Unlike early pressure decay methods, the pressure is held constant to not violate the assumed equilibrium solvent concentration at the interfacial boundary condition. The high solubility of solvent in heavy oil complicates the physical modeling because simplifying assumptions of a constant diffusion coefficient, constant density and a quiescent liquid should not be used. The model was developed from first principles to predict the bitumen swelling. The form of the concentration dependent diffusivity was assumed and the diffusivity coefficients initially guessed. The swelling (moving boundary) was fixed by defining a new dimensionless space coordinate and the set of partial differential equations solved using the method of lines. Using the non-linear regression (lsqnonlin) function in MATLAB®, optimising for the difference in predicted and experimentally found bitumen heights and independently validating the result using the solvent uptake, the diffusivity of butane in heavy oil (at 25oC) was found to be Dsb = 4.78 x 10-6ωs + 4.91 x 10-6 cm2/s where ωs is the solvent mass fraction. Diffusion alone has proven inadequate in predicting oil recovery rates from laboratory scale models. It is logical to assume that convective mass transfer plays a role at mixing the solvent and bitumen while draining via gravity through the reservoir porous matrix. Solvent extraction experiments were conducted in etched glass micromodels to observe the pore scale phenomena. The pore scale mechanisms were found to differ depending on how the solvent extraction was operated, with non-condensing (VAPEX) or condensing (N-SolvTM) solvent. Observations show increased convective mixing and an increased rate of interface advancement when the solvent condenses on the bitumen surface. Evidence of trapped butane vapour being mobilised with the draining live oil and a technique of observing solvent extraction using UV light confirm that the draining live oil is on average one pore deep. While the interface appears from a distance to be uniform, at the pore scale it is not. Live oil can drain from one to two pores via capillary displacement mechanisms in one section of the interface and via film flow only in another area (James and Chatzis 2004; James et al. 2008). This work also shows the detrimental impact of having a non-condensable gas present during solvent extraction (James and Chatzis 2008). In summary, this work emphasises the mass transfer and drainage displacement mechanisms of non-condensing (VAPEX) and condensing (N-Solv) solvent extraction methods of heavy oil recovery.
74

Mass Transfer Mechanisms during the Solvent Recovery of Heavy Oil

James, Lesley 18 June 2009 (has links)
Canada has the second largest proven oil reserves next to Saudi Arabia which is mostly located in Alberta and Saskatchewan but is unconventional heavy oil and bitumen. The tar sands are found at the surface and are mined, yet 80% of the 173 billion barrels of heavy oil and bitumen exist in-situ according to the Canadian Association of Petroleum Producers (CAPP). Two factors inhibit the economic extraction and processing of Canadian heavy oil; its enormous viscosity ranging from 1000 to over 1 million mPa.s and the asphaltene content (high molecular weight molecules containing heavy metals and sulphur). Heavy oil and bitumen were only included in the reserves estimates through the efforts of Canadian enhanced oil recovery (EOR) research. Viscosity reduction is the one common element of in-situ methods of heavy oil recovery with the exception of cold production. Currently, steam assisted gravity drainage (SAGD) and cyclic steam stimulation (CSS) are being used commercially in the field where the oil’s viscosity is reduced by injecting steam. Thermal methods are energy intensive requiring vast volumes of water such that any improvement would be beneficial. Solvent extraction is one alternative requiring no water, the solvent is recoverable and reusable, and depending on the mode of operation the heavy oil is upgraded in-situ. Vapour Extraction (VAPEX) and enhanced solvent extraction (N-SolvTM) are two such methods. VAPEX and N-Solv reduce the bitumen’s viscosity via mass transfer and a combination of mass and heat transfer, respectively. A light hydrocarbon solvent (instead of steam) is injected into an upper horizontal well where the solvent mixes with the heavy oil, reduces its viscosity and allows the oil to drain under gravity to a bottom production well. The idea of using solvents for heavy oil extraction has been around since the 1970s and both VAPEX and N-Solv are patented processes. However, there is still much to be learned about how these processes physically work. Research to date has focused on varying system parameters (including model dimensions, permeability, heavy oil viscosity, solvent type and injection rate, etc.) to observe the effect on oil production from laboratory scale models. Based on an early mass balance model by Butler and Mokrys (1989) and an improvement by Das (1995), molecular diffusion alone cannot account for the produced oil rates observed from laboratory models. Until recently, very little progress had been made towards qualifying and quantifying the mass transfer mechanisms with the exception of the diffusivity of light hydrocarbons in heavy oil. Mass transfer can only be by diffusion and convection. Differentiating and quantifying the contribution of each is complex due to the nature and viscosity of the oil. The goal of this thesis is to investigate the mass transfer mechanisms during the solvent recovery of heavy oil. Quantifying the diffusion of light hydrocarbon solvents has been an active topic of research with limited success since the mid 1990’s. The experimental approach presented here focused on capturing the rate of solvent mass transfer into the bitumen by measuring the bitumen swelling and the butane uptake independently. Unlike early pressure decay methods, the pressure is held constant to not violate the assumed equilibrium solvent concentration at the interfacial boundary condition. The high solubility of solvent in heavy oil complicates the physical modeling because simplifying assumptions of a constant diffusion coefficient, constant density and a quiescent liquid should not be used. The model was developed from first principles to predict the bitumen swelling. The form of the concentration dependent diffusivity was assumed and the diffusivity coefficients initially guessed. The swelling (moving boundary) was fixed by defining a new dimensionless space coordinate and the set of partial differential equations solved using the method of lines. Using the non-linear regression (lsqnonlin) function in MATLAB®, optimising for the difference in predicted and experimentally found bitumen heights and independently validating the result using the solvent uptake, the diffusivity of butane in heavy oil (at 25oC) was found to be Dsb = 4.78 x 10-6ωs + 4.91 x 10-6 cm2/s where ωs is the solvent mass fraction. Diffusion alone has proven inadequate in predicting oil recovery rates from laboratory scale models. It is logical to assume that convective mass transfer plays a role at mixing the solvent and bitumen while draining via gravity through the reservoir porous matrix. Solvent extraction experiments were conducted in etched glass micromodels to observe the pore scale phenomena. The pore scale mechanisms were found to differ depending on how the solvent extraction was operated, with non-condensing (VAPEX) or condensing (N-SolvTM) solvent. Observations show increased convective mixing and an increased rate of interface advancement when the solvent condenses on the bitumen surface. Evidence of trapped butane vapour being mobilised with the draining live oil and a technique of observing solvent extraction using UV light confirm that the draining live oil is on average one pore deep. While the interface appears from a distance to be uniform, at the pore scale it is not. Live oil can drain from one to two pores via capillary displacement mechanisms in one section of the interface and via film flow only in another area (James and Chatzis 2004; James et al. 2008). This work also shows the detrimental impact of having a non-condensable gas present during solvent extraction (James and Chatzis 2008). In summary, this work emphasises the mass transfer and drainage displacement mechanisms of non-condensing (VAPEX) and condensing (N-Solv) solvent extraction methods of heavy oil recovery.
75

Mathematical and Statistical Investigation of Steamflooding in Naturally Fractured Carbonate Heavy Oil Reservoirs

Shafiei, Ali 25 March 2013 (has links)
A significant amount of Viscous Oil (e.g., heavy oil, extra heavy oil, and bitumen) is trapped in Naturally Fractured Carbonate Reservoirs also known as NFCRs. The word VO endowment in NFCRs is estimated at ~ 2 Trillion barrels mostly reported in Canada, the USA, Russia, and the Middle East. To date, contributions to the world daily oil production from this immense energy resource remains negligible mainly due to the lack of appropriate production technologies. Implementation of a VO production technology such as steam injection is expensive (high capital investment), time-consuming, and people-intensive. Hence, before selecting a production technology for detailed economic analysis, use of cursory or broad screening tools or guides is a convenient means of gaining a quick overview of the technical feasibility of the various possible production technologies applied to a particular reservoir. Technical screening tools are only available for the purpose of evaluation of the reservoir performance parameters in oil sands for various thermal VO exploitation technologies such as Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS), Horizontal well Cyclic steam Stimulation (HCS), and so on. Nevertheless, such tools are not applicable for VO NFCRs assessment without considerable modifications due to the different nature of these two reservoir types (e.g., presence and effects of fracture network on reservoir behavior, wettability, lithology, fabric, pore structure, and so on) and also different mechanisms of energy and mass transport. Considering the lack of robust and rapid technical reservoir screening tools for the purpose of quick assessment and performance prediction for VO NFCRs under thermal stimulation (e.g., steamflooding), developing such fast and precise tools seems inevitable and desirable. In this dissertation, an attempt was made to develop new screening tools for the purpose of reservoir performance prediction in VO NFCRs using all the field and laboratory available data on a particular thermal technology (vertical well steamflooding). Considering the complex and heterogeneous nature of the NFCRs, there is great uncertainty associated with the geological nature of the NFCRs such as fracture and porosity distribution in the reservoir which will affect any modeling tasks aiming at modeling of processes involved in thermal VO production from these types of technically difficult and economically unattractive reservoirs. Therefore, several modeling and analyses technqiues were used in order to understand the main parameters controlling the steamflooding process in NFCRs and also cope with the uncertainties associated with the nature of geologic, reservoir and fluid properties data. Thermal geomechanics effects are well-known in VO production from oil sands using thermal technologies such as SAGD and cyclic steam processes. Hence, possible impacts of thermal processes on VO NFCRs performance was studied despite the lack of adequate field data. This dissertation makes the following contributions to the literature and the oil industry: Two new statistical correlations were developed, introduced, and examined which can be utilized for the purpose of estimation of Cumulative Steam to Oil Ratio (CSOR) and Recovery Factor (RF) as measures of process performance and technical viability during vertical well steamflooding in VO Naturally Fractured Carbonate Reservoirs (NFCRs). The proposed correlations include vital parameters such as in situ fluid and reservoir properties. The data used are taken from experimental studies and also field trials of vertical well steamflooding pilots in viscous oil NFCRs reported in the literature. The error percentage for the proposed correlations is < 10% for the worst case and contains fewer empirical constants compared with existing correlations for oil sands. The interactions between the parameters were also considered. The initial oil saturation and oil viscosity are the most important predictive factors. The proposed correlations successfully predicted steam/oil ratios and recovery factors in two heavy oil NFCRs. These correlations are reported for the first time in the literature for this type of VO reservoirs. A 3-D mathematical model was developed, presented, and examined in this research work, investigating various parameters and mechanisms affecting VO recovery from NFCRs using vertical well steamflooding. The governing equations are written for the matrix and fractured medium, separately. Uncertainties associated with the shape factor for the communication between the matrix and fracture is eliminated through setting a continuity boundary condition at the interface. Using this boundary condition, the solution method employed differs from the most of the modeling simulations reported in the literature. A Newton-Raphson approach was also used for solving mass and energy balance equations. RF and CSOR were obtained as a function of steam injection rate and temperature and characteristics of the fractured media such as matrix size and permeability. The numerical solution clearly shows that fractures play an important role in better conduction of heat into the matrix part. It was also concluded that the matrix block size and total permeability are the most important parameters affecting the dependent variables involved in steamflooding. A hybrid Artificial Neural Network model optimized by co-implementation of a Particle Swarm Optimization method (ANN-PSO) was developed, presented, and tested in this research work for the purpose of estimation of the CSOR and RF during vertical well steamflooding in VO NFCRs. The developed PSO-ANN model, conventional ANN models, and statistical correlations were examined using field data. Comparison of the predictions and field data implies superiority of the proposed PSO-ANN model with an absolute average error percentage < 6.5% , a determination coefficient (R2) > 0.98, and Mean Squared Error (MSE) < 0.06, a substantial improvement in comparison with conventional ANN model and empirical correlations for prediction of RF and CSOR. This indicates excellent potential for application of hybrid PSO-ANN models to screen VO NFCRs for steamflooding. This is the first time that the ANN technique has been applied for the purpose of performance prediction of steamflooding in VO NFCRs and also reported in the literature. The predictive PSO-ANN model and statistical correlations have strong potentials to be merged with heavy oil recovery modeling softwares available for thermal methods. This combination is expected to speed up their performance, reduce their uncertainty, and enhance their prediction and modeling capabilities. An integrated geological-geophysical-geomechanical approach was designed, presented, and applied in the case of a NFCR for the purpose of fracture and in situ stresses characterization in NFCRs. The proposed methodology can be applied for fracture and in situ stresses characterization which is beneficial to various aspects of asset development such as well placement, drilling, production, thermal reservoir modeling incorporating geomechanics effects, technology assessment and so on. A conceptual study was also conducted on geomechanics effects in VO NFCRs during steamflooding which is not yet well understood and still requires further field, laboratory, and theoretical studies. This can be considered as a small step forward in this area identifying positive potential of such knowledge to the design of large scale thermal operations in VO NFCRs.
76

Mathematical and Statistical Investigation of Steamflooding in Naturally Fractured Carbonate Heavy Oil Reservoirs

Shafiei, Ali 25 March 2013 (has links)
A significant amount of Viscous Oil (e.g., heavy oil, extra heavy oil, and bitumen) is trapped in Naturally Fractured Carbonate Reservoirs also known as NFCRs. The word VO endowment in NFCRs is estimated at ~ 2 Trillion barrels mostly reported in Canada, the USA, Russia, and the Middle East. To date, contributions to the world daily oil production from this immense energy resource remains negligible mainly due to the lack of appropriate production technologies. Implementation of a VO production technology such as steam injection is expensive (high capital investment), time-consuming, and people-intensive. Hence, before selecting a production technology for detailed economic analysis, use of cursory or broad screening tools or guides is a convenient means of gaining a quick overview of the technical feasibility of the various possible production technologies applied to a particular reservoir. Technical screening tools are only available for the purpose of evaluation of the reservoir performance parameters in oil sands for various thermal VO exploitation technologies such as Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS), Horizontal well Cyclic steam Stimulation (HCS), and so on. Nevertheless, such tools are not applicable for VO NFCRs assessment without considerable modifications due to the different nature of these two reservoir types (e.g., presence and effects of fracture network on reservoir behavior, wettability, lithology, fabric, pore structure, and so on) and also different mechanisms of energy and mass transport. Considering the lack of robust and rapid technical reservoir screening tools for the purpose of quick assessment and performance prediction for VO NFCRs under thermal stimulation (e.g., steamflooding), developing such fast and precise tools seems inevitable and desirable. In this dissertation, an attempt was made to develop new screening tools for the purpose of reservoir performance prediction in VO NFCRs using all the field and laboratory available data on a particular thermal technology (vertical well steamflooding). Considering the complex and heterogeneous nature of the NFCRs, there is great uncertainty associated with the geological nature of the NFCRs such as fracture and porosity distribution in the reservoir which will affect any modeling tasks aiming at modeling of processes involved in thermal VO production from these types of technically difficult and economically unattractive reservoirs. Therefore, several modeling and analyses technqiues were used in order to understand the main parameters controlling the steamflooding process in NFCRs and also cope with the uncertainties associated with the nature of geologic, reservoir and fluid properties data. Thermal geomechanics effects are well-known in VO production from oil sands using thermal technologies such as SAGD and cyclic steam processes. Hence, possible impacts of thermal processes on VO NFCRs performance was studied despite the lack of adequate field data. This dissertation makes the following contributions to the literature and the oil industry: Two new statistical correlations were developed, introduced, and examined which can be utilized for the purpose of estimation of Cumulative Steam to Oil Ratio (CSOR) and Recovery Factor (RF) as measures of process performance and technical viability during vertical well steamflooding in VO Naturally Fractured Carbonate Reservoirs (NFCRs). The proposed correlations include vital parameters such as in situ fluid and reservoir properties. The data used are taken from experimental studies and also field trials of vertical well steamflooding pilots in viscous oil NFCRs reported in the literature. The error percentage for the proposed correlations is < 10% for the worst case and contains fewer empirical constants compared with existing correlations for oil sands. The interactions between the parameters were also considered. The initial oil saturation and oil viscosity are the most important predictive factors. The proposed correlations successfully predicted steam/oil ratios and recovery factors in two heavy oil NFCRs. These correlations are reported for the first time in the literature for this type of VO reservoirs. A 3-D mathematical model was developed, presented, and examined in this research work, investigating various parameters and mechanisms affecting VO recovery from NFCRs using vertical well steamflooding. The governing equations are written for the matrix and fractured medium, separately. Uncertainties associated with the shape factor for the communication between the matrix and fracture is eliminated through setting a continuity boundary condition at the interface. Using this boundary condition, the solution method employed differs from the most of the modeling simulations reported in the literature. A Newton-Raphson approach was also used for solving mass and energy balance equations. RF and CSOR were obtained as a function of steam injection rate and temperature and characteristics of the fractured media such as matrix size and permeability. The numerical solution clearly shows that fractures play an important role in better conduction of heat into the matrix part. It was also concluded that the matrix block size and total permeability are the most important parameters affecting the dependent variables involved in steamflooding. A hybrid Artificial Neural Network model optimized by co-implementation of a Particle Swarm Optimization method (ANN-PSO) was developed, presented, and tested in this research work for the purpose of estimation of the CSOR and RF during vertical well steamflooding in VO NFCRs. The developed PSO-ANN model, conventional ANN models, and statistical correlations were examined using field data. Comparison of the predictions and field data implies superiority of the proposed PSO-ANN model with an absolute average error percentage < 6.5% , a determination coefficient (R2) > 0.98, and Mean Squared Error (MSE) < 0.06, a substantial improvement in comparison with conventional ANN model and empirical correlations for prediction of RF and CSOR. This indicates excellent potential for application of hybrid PSO-ANN models to screen VO NFCRs for steamflooding. This is the first time that the ANN technique has been applied for the purpose of performance prediction of steamflooding in VO NFCRs and also reported in the literature. The predictive PSO-ANN model and statistical correlations have strong potentials to be merged with heavy oil recovery modeling softwares available for thermal methods. This combination is expected to speed up their performance, reduce their uncertainty, and enhance their prediction and modeling capabilities. An integrated geological-geophysical-geomechanical approach was designed, presented, and applied in the case of a NFCR for the purpose of fracture and in situ stresses characterization in NFCRs. The proposed methodology can be applied for fracture and in situ stresses characterization which is beneficial to various aspects of asset development such as well placement, drilling, production, thermal reservoir modeling incorporating geomechanics effects, technology assessment and so on. A conceptual study was also conducted on geomechanics effects in VO NFCRs during steamflooding which is not yet well understood and still requires further field, laboratory, and theoretical studies. This can be considered as a small step forward in this area identifying positive potential of such knowledge to the design of large scale thermal operations in VO NFCRs.
77

Remo??o de fra??es de ?leo leve e pesado de rocha calc?ria atrav?s de sistemas microemulsionados

Santos, Giliane Cristina Medeiros do Nascimento 25 June 2013 (has links)
Made available in DSpace on 2014-12-17T15:42:08Z (GMT). No. of bitstreams: 1 GilianeCMNS_DISSERT.pdf: 1750841 bytes, checksum: cedbb003a4fc658825db6f8e66611748 (MD5) Previous issue date: 2013-06-25 / In this research the removal of light and heavy oil from disintegrated limestone was investigated with use of microemulsions. These chemical systems were composed by surfactant, cosurfactant, oil phase and aqueous phase. In the studied systems, three points in the water -rich microemulsion region of the phase diagrams were used in oil removal experiments. These microemulsion systems were characterized to evaluate the influence of particle size, surface tension, density and viscosity in micellar stability and to understand how the physical properties can influence the oil recovery process. The limestone rock sample was characterized by thermogravimetry, BET area, scanning electron microscopy and X-ray fluorescence. After preparation, the rock was placed in contact with light and heavy oil solutions to allow oil adsorption. The removal tests were performed to evaluate the influence of contact time (1 minute, 30 minutes, 60 minutes and 120 minutes), the concentration of active matter (20, 30 and 40 %), different cosurfactants and different oil phases. For the heavy oil, the best result was on SME 1, with 20 % of active matter, 1 minute of contact time, with efficiency of 93,33 %. For the light oil, also the SME 1, with 20 % of active matter, 120 minutes of contact time, with 62,38 % of efficiency. From the obtained results, it was possible to conclude that microemulsions can be considered as efficient chemical systems for oil removal from limestone formations / O presente trabalho objetivou estudar a remo??o de fra??es de ?leo leve e pesado em rocha calc?ria desintegrada atrav?s de sistemas microemulsionados, comparando as efici?ncias de remo??o em diferentes concentra??es de mat?ria ativa (C/T) e tempo de contato. Os sistemas microemulsionados (SME) s?o constitu?dos por tensoativo, cotensoativo, fase oleosa e fase aquosa. Nos sistemas estudados, tr?s pontos ricos em ?gua da regi?o de microemuls?o foram utilizados para verificar a efici?ncia de remo??o. Os sistemas foram caracterizados para avaliar a influ?ncia do tamanho do agregado, tens?o superficial e viscosidade na estabilidade micelar e compreender como as propriedades f?sicas podem influenciar o processo de remo??o de ?leo. A amostra de rocha calc?ria foi caracterizada por Termogravimetria, ?rea BET, Microscopia Eletr?nica de Varredura, Difra??o de Raios-X e Fluoresc?ncia de Raios-X. A rocha preparada foi colocada em contato com solu??o de ?leo leve e pesado em xileno para permitir a adsor??o de ?leo. Os testes de remo??o foram realizados a fim de avaliar a influ?ncia do tempo de contato (1, 30, 60 e 120 minutos), da concentra??o de mat?ria ativa (20, 30 e 40%), do cotensoativo e da fase oleosa. Para o ?leo pesado, o melhor resultado foi para o SME 1, com 20 % de mat?ria ativa, no tempo de 1 minuto, com 93,33 % de efici?ncia. Para o ?leo leve, o SME 1 no percentual de 20 %, com 120 minutos apresentou o melhor rendimento, com 62,38 %. A partir dos resultados obtidos, concluiu-se que os sistemas microemulsionados apresentam-se como uma alternativa eficaz para remo??o de ?leo em forma??es calc?rias
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Phase behaviour prediction for ill-defined hydrocarbon mixtures

Saber, Nima 06 1900 (has links)
Phase behaviour information is essential for the development and optimization of hydrocarbon resource production, transport and refining technologies. Experimental data sets for mixtures containing heavy oil and bitumen are sparse as phase behaviour data are difficult to obtain and cost remains prohibitive for most applications. A computational tool that predicts phase behaviours reliably for mixtures containing such ill-defined components, over broad temperature, pressure and composition ranges would play a central role in the advancement of bitumen production and refining process knowledge and would have favourable impacts on the economics and environmental effects linked to the exploitation of such ill-defined hydrocarbon resources. Prior to this work, predictive computational methods were reliable for dilute mixtures of ill-defined constituents. To include a much wider range of conditions, three major challenges were addressed. The challenges include: creation of a robust and accurate numerical approach, implementation of a reliable thermodynamic model, and speciation of ill-defined constituents like Athabasca Bitumen Vacuum Residue (AVR). The first challenge was addressed by creating a novel computational approach based on a global minimization method for phase equilibrium calculations. The second challenge was tackled by proposing a thermodynamic model that combines the Peng-Robinson equation of state with group contribution and related parameter prediction methods. The speciation challenge was addressed by another research group at the University of Alberta. Pseudo components they proposed were used to assign groups and estimate thermodynamic properties. The new phase equilibrium computational tool was validated by comparing simulated phase diagrams with experimental data for mixtures containing AVR and n-alkanes. There is good qualitative and quantitative agreement between computed and experimental phase diagrams over industrially relevant ranges of compositions, pressures and temperatures. Mismatch was only observed over a limited range of compositions, temperatures and pressures. This computational breakthrough provides, for the first time, a platform for reliable phase behaviour computations with broad potential for application in the hydrocarbon resource sector. The specific computational results can be applied directly to solvent assisted recovery, paraffinic deasphalting, and distillation and refining processes for Athabasca bitumen a strategic resource for Canada. / Chemical Engineering
79

Phase behaviour prediction for ill-defined hydrocarbon mixtures

Saber, Nima Unknown Date
No description available.
80

Estudo comparativo da utiliza??o do nitrog?nio como fluido alternativo ap?s a inje??o de vapor

Silva, Dayana de Lima e 31 July 2009 (has links)
Made available in DSpace on 2014-12-17T14:08:34Z (GMT). No. of bitstreams: 1 DayanaLSpdf.pdf: 1986697 bytes, checksum: 096c92db6f636c1bab0aeee590522e53 (MD5) Previous issue date: 2009-07-31 / Petr?leo Brasileiro SA - PETROBRAS / Currently, due to part of world is focalized to petroleum, many researches with this theme have been advanced to make possible the production into reservoirs which were classified as unviable. Because of geological and operational challenges presented to oil recovery, more and more efficient methods which are economically successful have been searched. In this background, steam flood is in evidence mainly when it is combined with other procedures to purpose low costs and high recovery factors. This work utilized nitrogen as an alternative fluid after steam flood to adjust the best combination of alternation between these fluids in terms of time and rate injection. To describe the simplified economic profile, many analysis based on liquid cumulative production were performed. The completion interval and injection fluid rates were fixed and the oil viscosity was ranged at 300 cP, 1.000 cP and 3.000 cP. The results defined, for each viscosity, one specific model indicating the best period to stop the introduction of steam and insertion of nitrogen, when the first injected fluid reached its economic limit. Simulations in physics model defined from one-eighth nine-spot inverted were realized using the commercial simulator Steam, Thermal and Advanced Processes Reservoir Simulator STARS of Computer Modelling Group CMG / Atualmente, pelo fato de parte do mundo estar voltada para a ind?stria do petr?leo, as pesquisas na ?rea t?m avan?ado de modo a tornar poss?vel at? mesmo a produ??o em reservat?rios at? ent?o vistos como invi?veis. Em virtude dos desafios geol?gicos e operacionais apresentados para recuperar o ?leo, cada vez mais se intensifica a busca por m?todos mais eficientes e lucrativos. Neste cen?rio, a inje??o de vapor merece destaque, sobretudo, quando combinada com outros procedimentos visando assim, reduzir os custos, ao mesmo tempo em que aumenta o fator de recupera??o. O presente trabalho utilizou o nitrog?nio como fluido alternativo ap?s a inje??o de vapor a fim de ajustar a melhor combina??o de altern?ncia desses fluidos em termos do tempo e vaz?o de inje??o. Para tra?ar um perfil econ?mico simplificado do processo, realizaram-se an?lises com base na produ??o acumulada l?quida. O intervalo de completa??o e as vaz?es dos fluidos de inje??o foram fixados e variou-se a viscosidade do ?leo em 300 cP, 1.000 cP e 3.000 cP. Os resultados definiram, para cada viscosidade, um modelo espec?fico indicando o melhor per?odo para interrup??o do vapor e inser??o do nitrog?nio, quando o primeiro fluido injetado atingiu seu limite econ?mico. As simula??es foram realizadas em um modelo f?sico definido a partir de 1/8 (um oitavo) do padr?o nine-spot invertido, utilizando o simulador comercial Steam, Thermal and Advanced Processes Reservoir Simulator STARS do Computer Modelling Group CMG

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