When estimating a waterflood performance and ultimate recovery, practitioners usually prepare a plot of log of water-oil ratio vs. cumulative production or recovery factor and extrapolate the linear section of the curve to a pre-established economic limit of water production. Following this practice, engineers take the risk of overestimating oil production and/or underestimating water production if the economic limit is optimistic. Engineers would be able to avoid that risk if they knew where the linear portion of the curve finishes. We called this linear portion the "straight-line zone" of simply SLZ. In this research, we studied that ―straight-line zone‖ and determined its boundaries (beginning and end) numerically using mathematics rules. We developed a new procedure and empirical correlations to predict oil recovery factor at any water/oil ratio. The approach uses the fundamental concepts of fluid displacement under Buckley-Leverett fractional flow theory, reservoir simulation, and statistical analysis from multivariate linear regression. We used commercial spreadsheet software, the Statistical Analysis Software, a commercial numerical reservoir simulator, and Visual Basic Application software. We determined generalized correlations to determine the beginning, end, slope, and intercept of this line as a function of rock and fluid properties, such as endpoints of relative permeability curves, connate water saturation, residual oil saturation, mobility ratio, and the Dykstra-Parsons coefficient. Characterizing the SLZ allows us to estimate the corresponding recovery factor and pore volumes injected at any water-oil ratio through the length of the SLZ . The SLZ is always present in the plot of log of water-oil ratio vs. cumulative production or recovery factor, and its properties can be predicted. Results were correlated in terms of the Dykstra-Parsons coefficient and mobility ratio. Using our correlations, practitioners can estimate the end of the SLZ without the risk of overestimating reserves and underestimating water production. Our procedure is also a helpful tool for forecasting and diagnosing waterfloods when a detailed reservoir simulation model is not available.

With a number of advantages newly recognized, use of surface-coated nanoparticles is being proposed for various upstream oil applications, such as for Enhanced Oil Recovery or as nanosensors. The first requirement for many of these applications is the ability to transport the nanoparticles a desired distance from the injection well. It means the particles should exhibit little retention in sedimentary rocks and minimal formation damage. Also, a certain amount of particles should adsorb at target locations such as water/oil interfaces for response measurement, if they are used as nanosensors. Three kinds of nanoparticle dispersions are tested for coreflood experiment in sedimentary rock cores: silica nanoparticles, commercial iron-oxide nanoparticles, and in-house synthesized paramagnetic nanoparticles. The quantitative retention measurements from corefloods offer insight into the mechanisms for nanoparticle transport in various sedimentary rocks (Boise sandstone, layered-Berea sandstone and Texas Cream limestone), and also with and without oil in the core. The coreflood experiments helped to develop a procedure to identify efficiently a surface coating to a given nanoparticle, that will allow both long-term dispersion stability and long-distance transportability in a given reservoir rock. To achieve this objective, seventy-six coreflood experiments were conducted to investigate transport of nanoparticles at rock grain surface and at water/oil interface. The parameters analyzed in this dissertation are: dialysis of the nanoparticle dispersion; cross-linking of polymer on coating; hydrophobicity/hydrophilicity of surface coating; oil type; nanocluster size; flow velocity; pH; ionic strength; rock lithology; and injected nanoparticle concentration. Our results show that surface coating, ionic strength, and specific surface/interfacial area were dominant factors for nanoparticle retention at rock grain surface and water/oil interface. Nanoparticle retention concentration (adsorption density) at rock grain surface decreases with decrease in nanocluster size and increase in flow velocity. Some retained nanoparticles can be recovered by increasing flow velocity or decreasing ionic strength. It indicates that the nanoparticle retention at the rock grain surface is unlike the generally irreversible adsorption of surfactant or polymer molecules. Ionic strength affects both reversible and irreversible adsorption of nanoparticles at rock grain surface; in these corefloods the irreversible retention is mainly due to the instability of nanoparticle dispersion and subsequent aggregation under high salinity conditions. The nanoparticle synthesis method, whether dialyzed or not, and cross-linking of coating polymer, all have significant impact on dispersion stability, especially for aqueous dispersion with high ionic strength. Nanoparticle adsorption at water/oil interface can be increased by increasing hydrophobicity of surface coating, or to a certain extent by increasing ionic strength of dispersion. / text

Deposition of noble metal and semiconductor nanocrystalline thin films has received much attention. CdS and CdSe are important semiconductors used in optical devices. A wet chemical route which uses the interface of two immiscible liquids to control the growth and deposition of nanocrystalline thin films forms the basis of the current study. In this method, a metal precursor dissolved in toluene or decane is held in contact with a water layer containing a reducing or sulphiding agent. The reaction proceeds at the interface of the liquids and results in deposits adhering to the interfacial region. The products of such reactions typically consist of nanocrystals forming a thin film. Stable sols of Au, Ag were found to metathesize on contact with alkylamine in oil to form monolayer films that spread across large areas at the water/oil interface. The nature and properties of interfacial thin films depend on the alkylamine. Nanocrystalline thin films consisting of CdS adhering to the interface starting with a polydispersed aqueous sol of crystallites and alkylamine were obtained. The optical band gaps of the films formed are dependent on the alkylamine chain length, with the shortest chain yielding the largest gap. A systematic increase in particle diameters following adsorption is responsible for changes in the electronic structure of films. The formation of nanocrystalline films of CdS adhering at the interface using a toluene solution of cadmium diethyldithiocarbamate and aqueous Na2S solution, in the presence of tetraoctylammonium bromide (TOAB) in the aqueous phase, was investigated under various reaction parameters, while CdSe was obtained using Na2SeSO3 solution and the influences of deposition temperature and solution concentration were studied. A ternary water/decane/2-butoxyethanol /salt system was used to grow deposits of CdSe and CdS. Nanostructured thin films were obtained at the upper interface of the ternary system, between the emulsive middle layer and oil rich top phase. The influence of deposition conditions such as precursor concentrations and temperature, as well as the nature of the medium on the properties of the deposits was studied. Deposits grown using the ternary system were compared with those obtained using water/decane and water/toluene systems. Reaction parameters such as temperature, solution concentration and the size of CdS and CdSe were controlled. A thin film of CdS and CdSe nanocrystals was formed at the interface. The grain size was found to be dependent on reaction temperature and solution concentration, with higher temperatures and solution concentration resulting in larger grains. The nature of thin films obtained at the interface of two immiscible liquids and of a water/decane/2-butoxyethanol/salt ternary system were studied using Scanning and Transmission electron microscopy, X-ray diffraction and UV-visible spectroscopy.

A descoberta de petróleo na camada do Pré-Sal fez com que a Petrobras envestisse cerca de 240 bilhões de dólares. Uma etapa crítica desta indústria é o transporte de petróleo, que envolve o sistema água-óleo. O objetivo do presente trabalho é estudar uma corrente água-óleo em um tubo reto e em uma curva, com o intuito de gerar perfis de velocidades, pressões e densidades em CFD. Para as simulações desenvolvidas foram considerados: fluxo 3D, escoamento turbulento na fase óleo e escoamento laminar na fase água, isotérmico e incompressível. Foram realizados estudos nos estados estacionário e transiente. Foi desenvolvido o estudo de convergência da malha. As ferramentas do Phoenics utilizadas para representar a interação entre as fases foram o IPSA e o Algebraic Slip. O IPSA resolve as equações de Navier-Stokes para cada fase. No Algebraic Slip, postula-se que existe um meio contínuo em que existem vários componentes da fase dispersos, podendo estes ser gotas, bolhas ou partículas sólidas. A turbulência foi avaliada utilizando os modelos K- padrão e o K-, porém só houve redução considerável dos resíduos para o K- Padrão. As densidades geradas nas simulações em CFD foram comparadas visualmente com os resultados experimentais obtidos em trabalho anterior para fluxo multifásico. As quedas de pressão obtidas em simulação foram comparadas com os dados da literatura, onde foi possível observar a grande redução da perda de carga ao utilizar a técnica de envolver o óleo com um anel de água na tubulação. As simulações realizadas com o modelo Algebraic Slip, e o modelo de turbulência foram consideradas como validadas. / With the discovery of oil in the pre-salt layer, Petrobras was encouraged to invest about 240 billion dollars. A critical point of this industry is the oil transport, which encompasses oil-water system. The objective of the present work is to study the flow of water and oil into a tube and an elbow, in order to generate distributions of velocity, pressure and density by using a CFD tool. To develop simulations the following is assumed: 3D flow, turbulent flow in oil phase and laminar flow in water phase, isotherm and incompressible flow. Steady-state and transient studies have been done. The mesh convergence has been carried out. The IPSA and Algebraic slip were the Phoenics tools that were used to represent the phases interaction. The IPSA solves the Navier-Stokes equations for each phase. In the Algebraic Slip model, one assumes that a continuum mean exists where the other components are dispersed, which can be bubbles or solid particles. The turbulence was evaluated by using K- standard and K- models; however, the considerable reduction of residue to the K- Standard was observed. The densities modeled by CFD were visually compared to the experimental results that were obtained in a previous work for a multiphase flow. The simulations of head loss were compared to literature data, and it can be seen a big difference between the head loss that was obtained by using water and that no using water. The simulations of Algebraic Slip model and the use of turbulence model were considered as validated.

Produced water is one of the major by products of oil and gas exploitation which is produced in large amounts up to 80% of the waste stream. Oil and grease concentration in produced water is the key parameter that is used for compliance monitoring, because it is easy to measure. For Canadian offshore operations, the current standard is a 30-day volume weighted average oil-in-water concentration in discharged produced water not exceeding 30 mg/L. Treatment of produced water may therefore be required in order to meet pre-disposal regulatory limits. The measurement of oil in produced water is important for both process control and reporting to regulatory authorities. Without the specification of a method, reported concentrations of oil in produced water can mean little, as there are many techniques and methods available for making this measurement, but not all are suitable in a specific application. The first part of this study focused on selecting a suitable analytical method for oil and grease measurement in oil field produced water. Petroleum ether was found to offer a comparative dissolution of crude oil as dichloromethane and hexane; it was therefore used as the solvent of choice for the UV-Vis spectrophotometric analysis of oil and grease in synthetic produced water. Results from the UV-Vis spectrophotometric and FTIR spectrometric analytical methods were found to be comparable; it confirmed that UV-Vis spectrometry could potentially serve as an alternative method for measuring oil and grease in oil field produced water. However, while the UV-Vis method may have limitations in measuring oil and grease concentrations below 30 mg/L, the FT-IR method was found to be equally efficient at measuring both high and low oil and grease concentrations. Dissolved air flotation (DAF) was the primary treatment technology investigated in this study for removing oil and grease from synthetic produced water. By itself, DAF achieved less than 70% oil and grease (OG) removal, and was not able to achieve a clarified effluent OG concentration of 30 mg/L required for regulatory discharge limits. At an optimum condition of 20 mg/L ferric chloride (FeCl3) at pH 8 (70.6% OG removal), coagulation was found to significantly improve the performance of the DAF unit (p < 0.05). At the optimum conditions of 100 mg/L PAC dose, pH 8 and a mixing time of 10 minutes (77.5% OG removal) and 300 mg/L OC dose, pH 8 and a mixing time of 10 minutes (78.1% OG removal), adsorption was also found to significantly improve the performance of the DAF unit (p < 0.05 in both cases). Adsorption with organoclay was recommended as the best pre-treatment for optimizing the performance of DAF in removing oil and grease from offshore oil field produced water. The bench-scale experiments showed that turbidity removal results were consistent with the OG removal results. Without pre-treatment, DAF achieved significant removal of benzene from produced water due to the volatile nature of benzene. Therefore comparable levels of benzene removal was observed by the DAF, FeCl3/DAF, PAC/DAF and OC/DAF treatment schemes; 79.3 %, 86.6 %, 86.5 %, 83.5% respectively. Finally, as benzene is known to be carcinogenic to humans, this study recommends the incorporation auxiliary equipment in its design, for the treatment of the off-gas (VOCs, particularly BTEX) released during the removal of dissolved oil from the oil field produced water.

Submitted by Maria Antonia de Sousa (mariaantoniade.sousa@gmail.com) on 2017-12-01T15:36:51Z No. of bitstreams: 1 SHEILA MIRELLE SILVA MACIEL - DISSERTAÇÃO PPGEQ 2013.pdf: 2172206 bytes, checksum: 77c3911216cdb2047645a9c342012b9c (MD5) / Made available in DSpace on 2017-12-01T15:36:51Z (GMT). No. of bitstreams: 1 SHEILA MIRELLE SILVA MACIEL - DISSERTAÇÃO PPGEQ 2013.pdf: 2172206 bytes, checksum: 77c3911216cdb2047645a9c342012b9c (MD5) Previous issue date: 2013-08-30 / Os óleos, principalmente os originários do setor petrolífero, são produtos que entre o seu processamento e transporte possuem misturas de outros componentes em sua composição, tais como gás, areia e o mais comum, a água. Dessa forma, a indústria petrolífera vem empregando diferentes processos de separação, dentre os quais vem se destacando os processos que utilizam movimentos circulares ou turbilhonares, como por exemplo, o hidrociclone. Os hidrociclones são usados com frequência na separação de água/óleo pela indústria de petróleo, devido à elevada capacidade de processamento, baixo custo de manutenção, exigência de pouco espaço para instalação e pela diferença de densidade entre fases. A presente pesquisa tem o objetivo de avaliar a influência dos parâmetros operacionais sobre a eficiência de separação água/óleo realizada por um hidrociclone. O trabalho partiu do desenvolvimento de uma malha estruturada representativa do domínio de estudo, e usando o modelo de turbulência RNG κ-Emodificado foram efetuadas simulações usando o programa comercial Ansys CFX®. Com os resultados numéricos gerados, foi possível avaliar e analisar sob a ótica da fluidodinâmica computacional. Os resultados obtidos foram confrontados com os dados experimentais reportados na literatura e apresentaram uma boa concordância. Os resultados indicaram que a dinâmica de escoamento era afetada pela concentração de óleo na entrada do hidrociclone. / Oils, mainly originating from the oil sector, are products that, among its processing and transportation have mixtures of other components in the composition, such as gas, sand and the most common, water. Thus, the oil industry has employed different separation processes, among which has been highlighting the processes using circular motions or swirling, for example, the hydrocyclone. The hydrocyclones are often used in the separation of water / oil by the oil industry due to high processing power, low maintenance, requiring little installation space and the density difference between phases. This research has the objective of evaluate the influence of operating parameters on the separation efficiency water/oil performed by hydrocyclone. The work started developing a structured mesh representative of the study domain, and using the turbulence model RNG κ-E modified simulations were performed using the commercial software Ansys CFX®. With the numerical results generated, it was possible to evaluate and analyze from the perspective of computational fluid dynamics. Results obtained were compared with experimental data reported in the literature and presented a good agreement. The results indicated that the dynamic flow was affected by the concentration of oil in the inlet of the hydrocyclone.

Offshore production fluids from the reservoir are often transported in pipelines from the wellheads to the platform and from the platform to process facilities. At low flow velocity water, sand or liquids like condensate could settle at the bottom of pipelines that may lead to grave implications for flow assurance. During shutdown the settled heavy liquid (e.g. water), could result in corrosion in pipelines, while following restart stages the settled water could form water plugs that could damage equipment, while settled sand could also form a blockage that needs to be purged. Furthermore, there is a requirement to know the quantity of water and base sediment for fiscal metering and custody transfer purposes. A series of experiments were carried out to observe low water cut in oil and water flows in four inch diameter pipeline. Similarly low sand concentrations in water and sand, water, air and sand flows were observed in two inch diameter pipelines. Conductive film thickness sensors were used to ascertain structural velocities, height and dense phase fractions. Comparisons are made between two cases in order to gain better understanding of the behaviours and dispersal process of low loading denser phase in multiphase flows. The arrangement enabled production of flow regime maps for low water cut oil and water flow, as well as water sand and water, air and sand flows, structural velocities and denser phase removal velocities were also ascertained. Actual in-situ liquid velocities were obtained experimentally. A novel detection of sand in water and water and sand flows was produced. The experimentally obtained film thickness was in agreement with two fluid model predictions. Thus, confirming use of conductive sensors for dense phase classification, film thickness, velocity and holdup measurements in pipelines.

Proteins can often adsorb irreversibly at fluid/fluid interfaces; the understanding of the adsorption mechanism has relevance across a variety of industrial (e.g. the creation of stable emulsions) and biological (e.g. biofilm formation) processes. I performed molecular dynamics simulations of two surfactant proteins as they interact with air/water and oil/water interfaces, describing the origin of the surface activity, the adsorption dynamics and the conformational changes that these proteins undergo at the interface. BslA is an amphiphilic protein that forms a highly hydrophobic coat around B. subtilis biofilms, shielding the bacterial community from an external aqueous solution. By investigating the behaviour of BslA variants at oil/water interfaces via coarse-grained molecular dynamics, I show that BslA represents a biological example of an ellipsoidal Janus nanoparticle, whose surface interactions are controlled by a local conformational change. All-atom molecular dynamics simulations then reveal the details of the conformational change of the protein upon adsorption, and the self-assembly into a two-dimensional interfacial crystal. Ranaspumin-2 is one of the main components of the tungara frog foam nest. Contrary to most surfactant proteins, its structure lacks any sign of amphiphilicity. All-atom simulations show that the adsorption proceeds via a two-step mechanism where firstly the protein binds to the interface through its flexible N-terminal tail and then it undergoes a large conformational change in which the hydrophobic core becomes exposed to the oil phase. I then developed a simple structure-based coarse-grained model that highlights the same adsorption mechanism observed in all-atom simulations, and I used it to compare the dynamics of adsorption and the underlying free energy landscape of several mutants. These results agree with and are used to rationalise the observations from Langmuir trough and pendant drop experiments. Colloids can often be considered simpler versions of proteins that lack conformational changes. I performed coarse-grained simulations of the compression of interfacial monolayers formed by rod-like particles. These simulations show a rich behaviour characterised by the flipping of adsorbed rods, nematic ordering and bilayer formation. I report the series of transitions that take place as the rod aspect ratio is increased from 3 to 15.

A descoberta de petróleo na camada do Pré-Sal fez com que a Petrobras envestisse cerca de 240 bilhões de dólares. Uma etapa crítica desta indústria é o transporte de petróleo, que envolve o sistema água-óleo. O objetivo do presente trabalho é estudar uma corrente água-óleo em um tubo reto e em uma curva, com o intuito de gerar perfis de velocidades, pressões e densidades em CFD. Para as simulações desenvolvidas foram considerados: fluxo 3D, escoamento turbulento na fase óleo e escoamento laminar na fase água, isotérmico e incompressível. Foram realizados estudos nos estados estacionário e transiente. Foi desenvolvido o estudo de convergência da malha. As ferramentas do Phoenics utilizadas para representar a interação entre as fases foram o IPSA e o Algebraic Slip. O IPSA resolve as equações de Navier-Stokes para cada fase. No Algebraic Slip, postula-se que existe um meio contínuo em que existem vários componentes da fase dispersos, podendo estes ser gotas, bolhas ou partículas sólidas. A turbulência foi avaliada utilizando os modelos K- padrão e o K-, porém só houve redução considerável dos resíduos para o K- Padrão. As densidades geradas nas simulações em CFD foram comparadas visualmente com os resultados experimentais obtidos em trabalho anterior para fluxo multifásico. As quedas de pressão obtidas em simulação foram comparadas com os dados da literatura, onde foi possível observar a grande redução da perda de carga ao utilizar a técnica de envolver o óleo com um anel de água na tubulação. As simulações realizadas com o modelo Algebraic Slip, e o modelo de turbulência foram consideradas como validadas. / With the discovery of oil in the pre-salt layer, Petrobras was encouraged to invest about 240 billion dollars. A critical point of this industry is the oil transport, which encompasses oil-water system. The objective of the present work is to study the flow of water and oil into a tube and an elbow, in order to generate distributions of velocity, pressure and density by using a CFD tool. To develop simulations the following is assumed: 3D flow, turbulent flow in oil phase and laminar flow in water phase, isotherm and incompressible flow. Steady-state and transient studies have been done. The mesh convergence has been carried out. The IPSA and Algebraic slip were the Phoenics tools that were used to represent the phases interaction. The IPSA solves the Navier-Stokes equations for each phase. In the Algebraic Slip model, one assumes that a continuum mean exists where the other components are dispersed, which can be bubbles or solid particles. The turbulence was evaluated by using K- standard and K- models; however, the considerable reduction of residue to the K- Standard was observed. The densities modeled by CFD were visually compared to the experimental results that were obtained in a previous work for a multiphase flow. The simulations of head loss were compared to literature data, and it can be seen a big difference between the head loss that was obtained by using water and that no using water. The simulations of Algebraic Slip model and the use of turbulence model were considered as validated.

During the last two decades, the applications of fluorocarbon based chemicals to provide soil resistant or soil release properties for automotive interior and upholstery have increased tremendously. But, recent studies showed that the soil resistant treatment based on fluorochemicals has detrimental effects on the environment as well as on humans due to the presence of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) content. PFOS and PFOA are toxic, bio accumulative and bio persistent fluoro-organic compounds. This project focus on PFOS and PFOA-free soil resistant chemicals and their application on interior textiles used for automotive. Literature study was done by keeping in mind all the aspects regarding soil and nature of soils, soil resistant mechanism, PFOA and PFOS-free soil resistant chemicals, chemistry of the chemicals, area of the application and the method of application. Experimental application of PFOA and PFOS-free soil resistant chemicals by using different concentrations on 100% Polyester dyed and unfinished fabric was performed with Pad-Dry-Cure method. Experimental application was carried out to evaluate the soil resistant treated samples for soil resistant, clean ability and colour change results. At the end, the comparison of the results of three mentioned evaluations gave us the best possible alternatives. / Program: Magisterutbildning i textilteknologi