Made available in DSpace on 2014-12-17T14:08:48Z (GMT). No. of bitstreams: 1 DaviMSBL_DISSERT.pdf: 4742258 bytes, checksum: 95c358d84716a6d20ba53990ae56c3f3 (MD5) Previous issue date: 2011-09-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The world has many types of oil that have a range of values of density and viscosity, these are characteristics to identify whether an oil is light, heavy or even ultraheavy. The occurrence of heavy oil has increased significantly and pointing to a need for greater investment in the exploitation of deposits and therefore new methods to recover that oil. There are economic forecasts that by 2025, the heavy oil will be the main source of fossil energy in the world. One such method is the use of solvent vaporized VAPEX which is known as a recovery method which consists of two horizontal wells parallel to each other, with a gun and another producer, which uses as an injection solvent that is vaporized in order to reduce the viscosity of oil or bitumen, facilitating the flow to the producing well. This method was proposed by Dr. Roger Butler, in 1991. The importance of this study is to analyze how the influence some operational reservoir and parameters are important in the process VAPEX, such as accumulation of oil produced in the recovery factor in flow injection and production rate. Parameters such as flow injection, spacing between wells, type of solvent to be injected, vertical permeability and oil viscosity were addressed in this study. The results showed that the oil viscosity is the parameter that showed statistically significant influence, then the choice of Heptane solvent to be injected showed a greater recovery of oil compared to other solvents chosen, considering the spacing between the wells was shown that for a greater distance between the wells to produce more oil / Existem no mundo diversos tipos de ?leo que apresentam uma diversidade de valores de densidade e viscosidade, essas s?o caracter?sticas para identificar se um ?leo ? leve, pesado ou at? mesmo ultrapesado. A ocorr?ncia de ?leo pesado vem aumentando sensivelmente e apontando uma necessidade de maiores investimentos na explora??o de jazidas e consequentemente em novos m?todos de recupera??o desse ?leo. Existem previs?es econ?micas de que, para o ano 2025, o ?leo pesado seja a principal fonte de energia f?ssil no mundo. Um desses novos m?todos seria a utiliza??o de solvente vaporizado conhecido como VAPEX que ? um m?todo de recupera??o que consiste em dois po?os horizontais paralelos entre si, sendo um injetor e outro produtor, que utiliza como inje??o solvente vaporizado que tem com o prop?sito reduzir a viscosidade do ?leo ou betume, facilitando o escoamento at? o po?o produtor. Esse m?todo foi proposto por Dr. Roger Butler, em 1991. A import?ncia do presente estudo ? analisar como influenciam alguns par?metros operacionais e de reservat?rio, importantes no processo VAPEX, tais como o acumulo de ?leo produzido, no fator de recupera??o, na vaz?o de inje??o e na taxa de produ??o. Par?metros como vaz?o de inje??o, espa?amento entre os po?os, tipo do solvente a ser injetado, permeabilidade vertical e a viscosidade do ?leo foram abordados neste estudo. Os resultados mostraram que a viscosidade do ?leo foi o par?metro que mais mostrou influ?ncia significativa estatisticamente, em seguida a escolha do Heptano como solvente a ser injetado mostrou uma maior recupera??o de ?leo em rela??o aos demais solventes escolhidos. Considerando o espa?amento entre os po?os, foi mostrado que para uma maior dist?ncia entre os po?os h? uma maior produ??o de ?leo

Prior to the passage of the 1976 Resource Conservation and Recovery Act (RCRA) 1.6 million bare steel Underground Storage Tanks (UST) were in use in the United States. Many of them were leaking. In Indiana approximately 13,000 UST remain but have been upgraded to meet current industry and regulatory standards. Cleaning up the petroleum releases from leaking UST has continued since it became evident that bare steel underground tanks leaked. In Northwest Indiana glacial moraine and outwash deposits from the Wisconsin Ice Age that retreated 10,000 years ago left 200 feet of glacial till above the underlying bedrock. Soil Vapor Extraction (SVE) and Air Sparging (AS) have proven to be effective and provide significant cost savings for remediation in the glacial deposits in Northwest Indiana. Indiana also has the Excess Liability Trust Fund (ELTF) to help pay for and to expedite clean-up of releases from registered UST. Cleaning up petroleum releases requires the appropriate technology for the localized geology, adequate funding, and appropriate guidance from state and federal regulations. This study discusses these issues at three sites in Northwest Indiana to demonstrate how technology, funding, and regulatory compliance must collaborate to work in the field.

Remediation of contaminated groundwater remains a high-priority national goal in the United States. Water is essential to life, and new sources of water are needed for an expanding population. Groundwater remediation remains a significant technical challenge despite decades of research into this field. New approaches are needed to address the most severely-polluted aquifers, and cost-effective solutions are required to meet remediation objectives that protect human health and the environment. Source reduction combined with Monitored Natural Attenuation (MNA) is a remediation strategy whereby the source of contamination is aggressively treated or removed and the residual groundwater plume depletes due to natural processes in the subsurface. The USEPA requires long-term performance monitoring of groundwater at MNA sites over the remediation timeframe, which often takes decades to complete. Presently, computational tools are lacking to adequately integrate source remediation with economic models. Furthermore, no framework has been developed to highlight the tradeoff between the degree of remediation versus the level of benefit within a cost structure. Using the Natural Attenuation Software (NAS) package developed at Virginia Tech, a set of formulae have been developed for calculating the TOR for petroleum-contaminated aquifers (specifically tracking benzene and MTBE) through statistical techniques. With the knowledge of source area residual saturation, groundwater velocity, and contaminant plume source length, the time to remediate a site contaminated with either benzene or MTBE can be determined across a range of regulatory maximum contaminant levels. After developing formulae for TOR, an integrated and interactive decision tool for framing the decision analysis component of the remediation problem was developed. While MNA can be a stand-alone groundwater remediation technology, significant benefits may be realized by layering a more traditional source zone remedial technique with MNA. Excavation and soil vapor extraction when applied to the front end of a remedial action plan can decrease the amount of time to remediation and while generally more expensive than an MNA-only approach, may accrue long-term economic advantages that would otherwise be foregone. The value of these research components can be realized within the engineering and science communities, as well as through government, business and industry, and communities where groundwater contamination and remediation are of issue. Together, these tools constitute the Sâ ªEâ ªEâ ªPâ ªAGE paradigm, founded upon the concept of sound science for an environmental engineering, effectual economics, and public policy agenda. The TOR formulation simplifies the inputs necessary to determine the number of years that an MNA strategy will require before project closure and thus reduces the specialized skills and training required to perform a numerical analysis that for one set of conditions could require many hours of simulation time. The economic decision tool, that utilizes a life cycle model to evaluate a set of feasible alternatives, highlights the tradeoffs between time and economics can be realized over the lifetime of the remedial project. / Ph. D.

O presente trabalho teve por objetivo apresentar e discutir um caso de identificação e remediação emergencial de compostos orgânicos voláteis, oclusos em camada arenosa do Terciário da Formação São Paulo, em decorrência do vazamento de tanques de combustíveis de um posto de serviços. A técnica de remediação adotada para o caso consistiu na extração in situ dos vapores do solo e no tratamento dos mesmos por adsorção em filtros de carvão ativado (SVE - soil vapor extraction). Os processos de seleção, projeto, implantação, operação e descomissionamento da tecnologia SVE seguiram as metodologias indicadas pela literatura, adaptadas às condições locais. O acompanhamento da eficiência da remediação foi baseado na quantificação inicial dos hidrocarbonetos totais de petróleo leves presentes no subsolo, através das técnicas de cromatografia gasosa e espectrometria de massa, e na medição em campo das concentrações de voláteis e dos respectivos teores de explosividade. O resultado da campanha laboratorial apresentou fortes indícios de que a contaminação local fosse proveniente do combustível gasolina e indicou a ocorrência do composto benzeno em concentrações superiores aos limites adotados como referência. As leituras realizadas em campo mostraram rápido declínio das concentrações de voláteis e dos teores de explosividade com a operação da tecnologia SVE, indicando baixa ocorrência de fatores limitantes do transporte de massa no local. Corroborou com tal hipótese, o fato das metas de remediação terem sido atingidas com poucas trocas de ar, parâmetro retro-analisado a partir de dados de ensaios geológico-geotécnicos. Assim, concluiu-se que, para áreas com características semelhantes à estudada, a tecnologia SVE pode ser eficiente como medida de remediação de voláteis e redução dos riscos de explosividade. / This work aims to present and to discuss a case study of identification and emergency remediation of volatile organic compounds, occluded in a sand layer of the São Paulo Tertiary Formation, as a result of the leakage of fuel tanks of a service station. The adopted remediation technique was in situ soil vapor extraction (SVE) and offgas treatment for adsorption in activated carbon filters. Selection, design, commissioning, operation and shutdown processes of SVE technology followed literature methodologies, which were adapted to local conditions. Remediation efficiency monitoring was based on the initial quantification of light total petroleum hydrocarbons in the subsoil, through gas chromatography and mass spectrometry techniques, and on measurement of the volatile concentrations and respective explosive contents in the field. The result of the laboratorial campaign presented strong indications that the local contamination proceeded from combustible gasoline and it indicated the occurrence of benzene in concentrations higher than the adopted reference. Field measurements showed fast decline of the volatile concentrations and explosive contents with the SVE technology operation, fact that indicated low occurrence of mass transfer limitations in the place. The fact that remediation goals were achieved with few air exchanges, parameter back-analyzed from geologicgeotechnical tests, contributed to reinforce such hypothesis. Thus, SVE technique can be considered efficient for volatile remediation and explosive risks reduction, for areas with characteristics similar to the studied one.

O presente trabalho teve por objetivo apresentar e discutir um caso de identificação e remediação emergencial de compostos orgânicos voláteis, oclusos em camada arenosa do Terciário da Formação São Paulo, em decorrência do vazamento de tanques de combustíveis de um posto de serviços. A técnica de remediação adotada para o caso consistiu na extração in situ dos vapores do solo e no tratamento dos mesmos por adsorção em filtros de carvão ativado (SVE - soil vapor extraction). Os processos de seleção, projeto, implantação, operação e descomissionamento da tecnologia SVE seguiram as metodologias indicadas pela literatura, adaptadas às condições locais. O acompanhamento da eficiência da remediação foi baseado na quantificação inicial dos hidrocarbonetos totais de petróleo leves presentes no subsolo, através das técnicas de cromatografia gasosa e espectrometria de massa, e na medição em campo das concentrações de voláteis e dos respectivos teores de explosividade. O resultado da campanha laboratorial apresentou fortes indícios de que a contaminação local fosse proveniente do combustível gasolina e indicou a ocorrência do composto benzeno em concentrações superiores aos limites adotados como referência. As leituras realizadas em campo mostraram rápido declínio das concentrações de voláteis e dos teores de explosividade com a operação da tecnologia SVE, indicando baixa ocorrência de fatores limitantes do transporte de massa no local. Corroborou com tal hipótese, o fato das metas de remediação terem sido atingidas com poucas trocas de ar, parâmetro retro-analisado a partir de dados de ensaios geológico-geotécnicos. Assim, concluiu-se que, para áreas com características semelhantes à estudada, a tecnologia SVE pode ser eficiente como medida de remediação de voláteis e redução dos riscos de explosividade. / This work aims to present and to discuss a case study of identification and emergency remediation of volatile organic compounds, occluded in a sand layer of the São Paulo Tertiary Formation, as a result of the leakage of fuel tanks of a service station. The adopted remediation technique was in situ soil vapor extraction (SVE) and offgas treatment for adsorption in activated carbon filters. Selection, design, commissioning, operation and shutdown processes of SVE technology followed literature methodologies, which were adapted to local conditions. Remediation efficiency monitoring was based on the initial quantification of light total petroleum hydrocarbons in the subsoil, through gas chromatography and mass spectrometry techniques, and on measurement of the volatile concentrations and respective explosive contents in the field. The result of the laboratorial campaign presented strong indications that the local contamination proceeded from combustible gasoline and it indicated the occurrence of benzene in concentrations higher than the adopted reference. Field measurements showed fast decline of the volatile concentrations and explosive contents with the SVE technology operation, fact that indicated low occurrence of mass transfer limitations in the place. The fact that remediation goals were achieved with few air exchanges, parameter back-analyzed from geologicgeotechnical tests, contributed to reinforce such hypothesis. Thus, SVE technique can be considered efficient for volatile remediation and explosive risks reduction, for areas with characteristics similar to the studied one.

In-situ vapor extraction is performed by applying a pressure differential across a hydrophobic porous membrane that forms a wall of the channel as a means of reducing the local quality of flow boiling within the channel. As the local quality is reduced, the heat transfer capability can be improve while large pressure drops and flow instability can be mitigated. The present study investigates the potential of vapor extraction, by examining the characteristics and mechanisms of extraction. The physics based models for transition among extraction regimes are developed which can be used as a basis for a regime-based vapor extraction rate model. The effects of vapor extraction on flow boiling in a microscale fractal-like branching network and diverging channels are studied by using a one-dimensional numerical model based on conservation of mass and energy, along with heat transfer and pressure drop correlations. The results show the improvement in reduced pressure drop and enhanced flow stability, and show the potential of heat transfer enhancement. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from March 25, 2013 - March 25, 2014

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.

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.