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1
Valle, Arne. "Three phase gas-oil-water pipe flow." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248608.
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Odozi, Utomi Ayodele. "Three-phase gas/liquid/liquid slug flow." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8444.
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Santos, Pedro Miguel Matos dos. "Investment in new HUB for Oil & Gas Engineering Centres by Oil & Gas Services Companies." Master's thesis, Instituto Superior de Economia e Gestão, 2014. http://hdl.handle.net/10400.5/7882.
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Mestrado em FinançasO renovado interesse na indústria petrolífera coloca-a no topo da lista de prioridades de investimento estrangeiro para alguns países. A competitividade empresarial é um factor bastante importante numa Sociedade global e, como tal, um factor que não pode ser descurado a este nível. O objectivo deste trabalho assenta no estudo de uma decisão de investimento referente à possível expansão da actividade de empresas prestadoras de serviços na indústria petrolífera. Além da definição do enunciado da situação, uma resolução é apresentada. Esta resolução assenta em três metodologias distintas: - Modelo Free Cash-Flow; - Análise Strengths, Weaknesses, Opportunities e Threats (SWOT); - Modelo Matriz Híbrida. O modelo de Free Cash-Flow permitiu considerar os custos de capital de cada empresa e chegar a uma conclusão sobre o país/local que apresenta as métricas financeiras mais apelativas. A análise SWOT oferece-nos uma visão mais generalista acerca dos países considerados sobre a perspectiva de investimento.. Com o intuito de analisar factores estratégicos induzidos por parâmetros externos (de forma a não considerar apenas métricas financeiras), foi criada uma Matriz Híbrida e foi realizada a respectiva análise. Neste seguimento, os resultados apresentados pelo Modelo de Matriz Híbrida deverão ser considerados aquando da decisão de expansão. Foi possível concluir que a melhor opção base é a criação de um escritório em Portugal. Apesar desta conclusão, a solução óptima é observada quando contabilizamos os custos de abrir um escritório em Portugal e quando, simultaneamente, consideramos os impostos que são pagos na Holanda (devido à sua política de impostos mais atractiva).
The renewed interest in the Oil & Gas sector places this Industry at the top of the list of priorities for some countries in order to attract foreign investment. Corporate competitiveness is, therefore, an extremely important vehicle for a globalized Society. The aim of the present work was to study the possible investment contemplated by an expansion decision taken by some Oil & Gas Services companies. Besides the definition of the problem, an adequate resolution is also presented. This resolution is sustained by three distinct methodologies: - Free Cash-Flow Model; - Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis; - Hybrid Matrix Model. The Free Cash-Flow Model enabled us to consider costs of capital and come to a decision regarding the country that presented the best financial results. The SWOT analysis provided a more generalist view over the several analysed countries. With the purpose of analysing strategic factors induced by external parameters (besides the financial field), the Hybrid Matrix Model was created and a study was carried out. Subsequently, the results presented by the Hybrid Matrix Model shall be taken into account when choosing a location for an international expansion. It was possible to conclude that the best base scenario is observed when opening an Office in Portugal. However, the optimal solution would be opening an Office in Portugal and account the profits/losses in the Netherlands, mixing the country that presents the lowest costs with the country that has the best taxation policies.
4
Camacho-Velázquez, Rodolfo Gabriel. "Well performance under solution gas drive /." Access abstract and link to full text, 1987. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8720613.
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Abdulkareem, Lokman Aziz. "Tomographic investigation of gas-oil flow in inclined risers." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546555.
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6
Darman, Nasir B. Haji. "Upscaling of two-phase flow in oil-gas systems." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/570.
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7
Labed, Ismail. "Gas-condensate flow modelling for shale gas reservoirs." Thesis, Robert Gordon University, 2016. http://hdl.handle.net/10059/2144.
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In the last decade, shale reservoirs emerged as one of the fast growing hydrocarbon resources in the world unlocking vast reserves and reshaping the landscape of the oil and gas global market. Gas-condensate reservoirs represent an important part of these resources. The key feature of these reservoirs is the condensate banking which reduces significantly the well deliverability when the condensate forms in the reservoir below the dew point pressure. Although the condensate banking is a well-known problem in conventional reservoirs, the very low permeability of shale matrix and unavailability of proven pressure maintenance techniques make it more challenging in shale reservoirs. The nanoscale range of the pore size in the shale matrix affects the gas flow which deviates from laminar Darcy flow to Knudsen flow resulting in enhanced gas permeability. Furthermore, the phase behaviour of gas-condensate fluids is affected by the high capillary pressure in the matrix causing higher condensate saturation than in bulk conditions. A good understanding and an accurate evaluation of how the condensate builds up in the reservoir and how it affects the gas flow is very important to manage successfully the development of these high-cost hydrocarbon resources. This work investigates the gas Knudsen flow under condensate saturation effect and phase behaviour deviation under capillary pressure of gas-condensate fluids in shale matrix with pore size distribution; and evaluates their effect on well productivity. Supplementary MATLAB codes are provided elsewhere on OpenAIR: http://hdl.handle.net/10059/2145.
8
Tay, Boon Li. "Forces on pipe bends due to intermittent gas-liquid flow." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289501.
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9
Kee, Kok Eng. "A Study of Flow Patterns and Surface Wetting in Gas-Oil-Water Flow." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1401985339.
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10
Mohammadi, Shahrokh. "Stochastic modelling of capillary dominated gas condensate flow in porousmedia." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1451.
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11
Shaidi, Salman Mohammed Al. "Modelling of gas-condensate flow in reservoir at near wellbore conditions." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/672.
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The behaviour of gas condensate flow in the porous media is distinctly different from that of gas-oil flow. The differences are attributed to the difference in fluid properties, phase behaviour, and condensation and vaporisation phenomena that distinguishes gas condensate fluids from the aforementioned fluid types. These differences manifest themselves into an important flow parameter that is typically known as relative permeability. Relative permeability is known to be related to the phase saturation, and the interfacial tension (EFT). Also, at high phase velocities, its reduction with increasing velocity, known as Forchheimer (turbulence) or inertia effect, is well documented. An unconventional behaviour of gas condensate fluids has been experimentally proven in Heriot-Watt laboratory and confirmed by other experimental studies performed elsewhere. These tests have shown that at intermediate velocities, before the inertia becomes significant, the gas and the condensate relative permeabilities are significantly improved by increase in velocity. This phenomenon is referred to as the rate-effect. None of the conventional relative permeability models include this experimentally proven favourable rate effect. In this work the flow of gas condensate fluids in porous media is modelled with emphasis on near wellbore conditions. Theoretical, empirical as well as simulational investigations are used to improve the present technology on the treatment of the flow of gas condensate in reservoirs. The use of X-ray or y-ray devices to monitor saturation profile during displacement experiments is investigated and the appropriate test conditions leading to reliable measured relative permeability data are determined. The regimes of the gas condensate flow at the core level, where the rate effect is evident, are investigated using the concept of Reynolds number. Then a mechanistic flow model, where the flow of gas condensate fluids is assumed to follow an annularmist flow criterion, is presented to capture the essence of the rate effect in perforations. The favourable EFT and rate effects are incorporated into the modelling of gas condensate relative permeability by correlating it with capillary number (I\Ic). Two forms of the correlation are presented. The impact of EFT and Ne together with the Forchheimer (inertia) on well deliverability is thoroughly investigated using the above correlation. The gas condensate relative permeability correlation is combined with the Forchheimer effect and used in a specially modified version of a commercial simulator, Eclipse 300V 98a development, to investigate the impact of IFT, Nc, and inertia on well productivity. The impact is found to accelerate production from gas condensate reservoirs. At practical production rates, the significance of the impact on phase recoveries cannot be ignored regardless of reservoir fluid richness or absolute permeability.
12
Mohammed, Shara Kamal. "Gas-high viscosity oil flow in vertical large diameter pipes." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43311/.
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Gas flow in columns of high viscosity liquids is found in heavy oil and bitumen production, polymer manufacturing and in Volcanology as silicate magmas in the volcanic conduit. Predicting the characteristics of the hydrodynamics of gas flow, under such conditions is essential in both design and safety assessments. In oil and gas industry, it is very important in the design of the equipment and the very long pipelines. Further, it is important in the design and safety of the industrial equipment and the pipelines in the polymer manufacturing. Finally, the ability to predict natural phenomenon and develop the knowledge about volcanoes activity and the nature of eruptions in volcanoes is important for the assessment of environmental risks. The majority of the works, which have studied gas-liquid flow in pipes, have been carried out mainly by using water or liquids of low viscosities (< 1 Pa.s). Knowledge, regarding the hydrodynamics of gas flow in high viscosity liquids and large diameter columns, is still limited though despite the importance of this subject. In this work, the characteristics of gas-high viscosity oils in large diameter columns were studied over a wide range of gas flow rates. Two column geometries were used: one of 240 mm and the other of 290 mm internal diameter. The columns were initially filled with stagnant Silicone oil of viscosities 360 and 330 Pa.s respectively. Electrical Capacitance Tomography (ECT) technique was employed for the data measurements besides a high-resolution camera. In general, 4 flow patterns are found over the selected range of gas flow rates. These are seen to differ from the ones in lower viscosity liquids. First, bubbly flow consists of single spherical bubbles that rise at a constant velocity in the centre of the column at low gas flow rates. Second, slug flow which consists of long bubbles (Taylor bubble) with rounded top and end, with a diameter almost equal to the column diameter and separated by liquid slugs. The third flow pattern is the transition to churn flow which occurs due to further increase of gas flow rate. The falling film, around the very long bubbles, accumulates to create regions of high frequency activity that consists of liquid bridges. These regions are named “churn” regions. The length of this region increases gradually with increasing the gas flow rate. At very high gas flow rates, the gas flows through an open wavy non-symmetrical core in the column of the viscous oil (churn regions). The length of the churn regions increases significantly at this flow regime which can be named churn flow regime. Small bubbles of millimetres to centimetres diameter are seen to accumulate in the column due to the high viscosity and low velocity of the liquid motion. These bubbles generate due to the bubble eruption at the top section, bubble coalescence along the column and at the gas injection points at the bottom of the column.
13
Hall, Andrew Robert William. "Multiphase flow of oil, water and gas in horizontal pipes." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/7612.
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Salisbury, Peter Evan. "Compositional multiphase vertical lift performance modelling of oil, gas and retrograde gas-condensate wells." Thesis, Heriot-Watt University, 1987. http://hdl.handle.net/10399/1587.
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Hatzignatiou, Dimitrios Georgios. "Advances in well testing for solution-gas-drive reservoirs /." Access abstract and link to full text, 1990. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/9033497.
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Donnelly, G. F. "An analytical evaluation of horizontal multiphase flow." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361244.
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17
Duruewuru, Anthony U. "Thermodynamic analysis of transient two-phase flow in oil and gas reservoirs /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1985.
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Al-Kharusi, Badr Soud. "Relative permeability of gas-condensate near wellbore, and gas-condensate-water in bulk of reservoir." Thesis, Heriot-Watt University, 2000. http://hdl.handle.net/10399/1098.
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Lima, P. C. R. "Modelling of transient gas-liquid flow and pigging in pipes." Thesis, Cranfield University, 1999. http://hdl.handle.net/1826/4176.
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More
and more transient gas-liquid operations in pipes are being successfully applied in the oil
and gas industry. Pigging in two-phase pipelines, to remove liquid accumulation or for cleaning
purposes, is an important transient operation. Another important operation is the injection of (-)-as
to transport the accumulated liquid in the pipeline to process facilities. Analysis of such transient
two-phase flow in a pipeline is necessary not only for designing the liquid and (Yas handling
facilities, but also for safe operating procedure. In pipeline-fiser system such operations cause
even more severe changes in flow conditions.
A two-fluid model has been developed to determine the transient behaviour of fluids during these
operations.T he derived one-dimensionasl et of equationsf or each flow pattern describet he flow
of fluids in all regions. Semi-implicit finite difference schemes were used to solve the initial and
boundary value problem for each phase of the process- gas/pig injection, gas shut-in, slug
production and gas flow out of the system.
An extensive experimental program has been carried out to acquire two-phase transient flow and
pigging data on a 67 m long, 0.0525 m diameter, 9.9 m high pipeline-riser system. A computer
based data acquisition system has been utilised to obtain rapidly changing and detailed information
of the flow behaviour during the transient tests. The model results compare well with the
experimental data for characteristics such as inlet pressure, hold-up and pig velocity.
20
Brini, Ahmed Salem Kalifa. "A study of gas lift on oil/water flow in vertical risers." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/8507.
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Gas lift is a means of enhancing oil recovery from hydrocarbon reservoirs. Gas
injected at the production riser base reduces the gravity component of the
pressure drop and thereby, increases the supply of oil from the reservoir. Also,
gas injection at the base of a riser helps to mitigate slugging and thus,
improving the performance of the topside facility. In order to improve the
efficiency of the gas lifting technique, a good understanding of the
characteristics of gas-liquid multiphase flow in vertical pipes is very important.
In this study, experiments of gas/liquid (air/water) two-phase flows, liquid/liquid
of oil/water two-phase flows and gas/liquid/liquid (air/oil/water) three-phase
flows were conducted in a 10.5 m high 52 mm ID vertical riser. These
experiments were performed at liquid and gas superficial velocities ranging from
0.25 to 2 m/s and ~0.1 to ~6.30 m/s, respectively. Dielectric oil and tap water
were used as test fluids. Instruments such as Coriolis mass flow meter, single
beam gamma densitometer and wire-mesh sensor (WMS) were employed for
investigating the flow characteristics. For the experiments of gas/liquid
(air/water) two-phase flow, flow patterns of Bubbly, slug, churn flow regimes and
transition regions were identified under the experimental conditions. Also, for
flow pattern identification and void fraction measurements, the capacitance
WMS results are consistent with those obtained simultaneously by the gamma
densitometer. Generally, the total pressure gradient along the vertical riser has
shown a significant decrease as the injected gas superficial velocity increased.
In addition, the rate of decrease in total pressure gradient at the lower injected
gas superficial velocities was found to be higher than that for higher gas
superficial velocities. The frictional pressure gradient was also found to increase
as the injected gas superficial velocity increased.
For oil-water experiments, mixture density and total pressure gradient across
the riser were found to increase with increasing water cut (ranging between 0 -
100%) and/or mixture superficial velocity. Phase slip between the oil and water
was calculated and found to be significant at lower throughputs of 0.25 and 0.5
m/s. The phase inversion point always takes place at a point of input water cut
of 42% when the experiments started from pure oil to water, and at an input
water cut of 45% when the experiment’s route started from water to pure oil.
The phase inversion point was accompanied by a peak increase of pressure
gradient, particularly at higher oil-water mixture superficial velocities of 1, 1.5
and 2 m/s.
The effects of air injection rates on the fluid flow characteristics were studied by
emphasizing the total pressure gradient behaviour and identifying the flow
pattern by analysing the output signals from gamma and WMS in air/oil/water
experiments. Generally, riser base gas injection does not affect the water cut at
the phase inversion point. However, a slight shift forward for the identified
phase inversion point was found at highest flow rates of injected gas where the
flow patterns were indicated as churn to annular flow. In terms of pressure
gradient, the gas lifting efficiency (lowering pressure gradient) shows greater
improvement after the phase inversion point (higher water cuts) than before and
also at the inversion point.
Also, it was found that the measured mean void fraction reaches its lowest
value at the phase inversion point. These void fraction results were found to be
consistent with previously published results.
21
Akartuna, Sevket Ersin. "Identification of phase flow rates in oil-gas-water flow from turbulent capacitance and pressure signals." Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321627.
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Hayes, D. G. "Tomographic flow measurement by combining component distribution and velocity profile measurements in 2-phase oil/gas flows." Thesis, University of Manchester, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501710.
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This thesis describes the development of a novel tomographic imaging system which can measure the concentration and velocity profiles in two-phase oil/gas flows. Two-phase flow measurement is a problem of great strategic and commercial importance to the oil industry. For example, an oilwell seldom produces just oil; there is often a significant quantity of gas and/or water present and it is very important to know how much of each is being produced. Unfortunately, this turns out to be a very demanding: task, particularly when the components have significantly different densities as in oil/gas flows. The fundamental problem with oil/gas flow measurement is that the individual components can arrange themselves in many different ways. This results in many possible concentration and velocity distributions, which in turn, render conventional flow measurement techniques inadequate. The tomographic system overcomes these problems by explicitly deriving the component distributions at two adjacent planes along a pipeline. These two images of the component distributions are then cross correlated on a pixel-by-pixel basis to obtain the velocity profile of the gaseous component. Multiplying the component concentration and velocity profiles yields a measure of the volumetric gas flow rate. The component distributions are obtained using two tomographic capacitance imaging systems. The problems caused by their interference have been examined in detail and this includes extensive electrostatic simulation studies. The field interactions are shown to affect the effective distance between the sensors and this varies with radial position, resulting in an effective separation profile". Numerous component distribution and velocity profile measurements are presented which were obtained from a 3" multi-phase flow loop, with superficial oil velocities ranging from 0.1m/s to 0.8m/s. and superficial gas velocities ranging from 0.05m/s to 0.5m/s. Void fractions range from 5% to 55%. The system is based on a combination of transputer and digital signal processor hardware and can reconstruct images at 180 frames per second. Techniques for real-time image correlation are examined and these, in combination with a number of suggestions for future work, will facilitate the development of a novel, real-time, multi-phase flow measurement system
23
Darwich, Tarek D. A. "A statistical technique for two-phase flow metering." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/7482.
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Jia, Ke S. M. Massachusetts Institute of Technology. "A coupled model for ring dynamics, gas flow, and oil flow through the ring grooves in IC engines." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/46383.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 127-129).
Oil flows through ring/groove interface play a critical role in oil transport among different regions the piston ring pack of internal combustion engines. This thesis work is intended to improve the understanding and modeling capability on this important oil transport mechanism for better analysis in engine oil consumption. A model incorporating ring dynamics, gas flow, and oil flow was developed to study oil transport in the piston ring-pack system. The major new element of this new model is adaptation of a mass conserved two phase oil/gas flow sub-model. Doing so, the present model can describe the oil flows through the ring/groove interface in a consistent manner. The model was applied to a heavy duty diesel engine at maximum power condition and to a SI engine at engine-braking and moderate load conditions. In the diesel application, the model demonstrates that oil can be released through the second ring/groove interface during second ring flutter and ring/groove interface plays positive role in reducing oil consumption and oil residence time. On the other hand, oil can be pumped up into the top ring groove and combustion chamber through the top ring/groove interface at engine braking conditions in the SI engine. Both applications show that oil flow rate through ring/groove interface is most prominent during the period of the engine cycle when the ring motion and gas pressure exhibit dynamic behaviors, and thus show that the coupling of the ring dynamics and gas/oil flows in the present model is essential to predict the oil pumping through ring/groove interface.
by Ke Jia.
S.M.
25
Oliveira, Paulo Jorge Dos Santos Pimentel de. "Computer modelling of multidimensional multiphase flow and application to T-junctions." Thesis, Imperial College London, 1992. http://hdl.handle.net/10044/1/8637.
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Fatemi, S. Mobeen. "Multiphase flow and hysteresis phenomena in oil recovery by water alternating gas (WAG) injection." Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/3148.
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Water flooding and gas injection are two widely used improved oil recovery techniques that can be applied individually or combined as water alternating gas (WAG) or simultaneous gas and water (SWAG) injection. Laboratory data on WAG and SWAG injections for non-water-wet systems are very limited especially for near-miscible (very low IFT) gas-oil systems. Near-miscible gas injection represents a number of processes of great importance to reservoir engineers including high pressure hydrocarbon gas injection and CO2 flooding. Simulation of these processes (WAG and SWAG injections) requires three-phase relative permeability (kr) data. Most of the existing three-phase relative permeability correlations (such as Stone-I, Stone-II or Baker) have been developed for water-wet conditions and are unable to adequately account for all the complex multi-phase and multi-physics processes involved in these oil recovery techniques. Another major problem in the prediction of the performance of Water Alternating Gas (WAG) process is the uncertainty associated with the changes in three-phase relative permeability (kr) values of oil, gas and water in different cycles, which is known as cyclic hysteresis. The current approach in the industry (except hysteresis model proposed by Larsen and Skauge) is to use two-phase bounding imbibition and drainage relative permeabilities along with a two-phase hysteresis model (such as Land, Carlson or Killough to generate two-phase scanning curves) and input the result into a three-phase correlation (Stone-I, Stone-II, Baker etc) to simulate hysteresis in WAG injection. The other approach in the industry to account for hysteresis in WAG injection is the WAG-hysteresis model (proposed by Larsen and Skauge) coupled with Stone-I correlation. None of these models and approaches is developed and assessed based for low oil/gas IFT and/or nonwater- wet system. Nevertheless, the majority of oil reservoirs are believed to be mixedwet and hence, prediction of the performance of WAG injection in these reservoirs is associated with significant uncertainties. Accurate determination of relative permeability values and their hysteresis behaviour is crucial for obtaining a reliable prediction of the performance of water-alternating-gas (WAG) injection in oil reservoirs. Performing reliable laboratory experiments is the key to evaluating the performance of these oil recovery techniques under different reservoir and operational conditions. The experimental data can be also used for assessment of different relative permeability and hysteresis models, and developing new methodologies for reliable simulation of WAG and SWAG injections (if required). The content of the thesis can be divided into two sections: a) two-phase flow and b) three-phase flow. I present the results of comprehensive series of two-phase and three-phase (WAG injections) coreflood experiments for a gas/oil system at near-miscible (IFT= 0.04 mN.m-1) conditions. Two different cores; a high-permeability (1000 mD) and a lower permeability (65 mD) core were used in the experiments and both water-wet and mixedwet conditions were examined. Experimental data have been used to obtain reliable relative permeabilities and investigate their cyclic hysteresis behavior. In the first section of the thesis (two-phase flow), effects of different parameters such as permeability, wettability (water-wet and mixed-wet), immobile water and saturation history on two-phase flow of oil and gas at near-miscible condition have been investigated. Contrary to the open literature reports which are based on high IFT oil/gas, the results (for very-low oil/gas IFT) showed the importance of the wettability and immobile water saturation on the recovery profiles and estimated relative permeabilities. In addition contrary to the near-miscible liquid-liquid systems, it was observed significant hysteresis effect in the gas-liquid system. I have also investigated different two-phase systems (gas-oil, gas-water and oil-water) in mixed-wet systems. This is crucial, considering the importance of the two-phase systems as a backbone to better understand three-phase flow as well as their importance as an input to two-phase hysteresis models (for simulation of WAG including hysteresis). The investigation in this study shows that currently available two-phase hysteresis models in simulators (Carlson and Killough) are not able to capture the observed cyclic hysteresis behavior in these systems. The results suggest that for mixed-wet systems, it is necessary to consider irreversible hysteresis loops for both the wetting and non-wetting phases. Such capability currently does not exist in reservoir simulators due to lack of appropriate predictive tools. Results highlight the differences between cyclic hysteresis behaviors of the relative permeabilities in these three systems. In the second section of the thesis, I first evaluated the performance of different injection scenarios in the mixed-wet system. These processes include primary waterflooding (WF), primary gasflooding (GF), WAG injection (either starting with water injection or gas injection), and SWAG injection (with different gas/water ratios). For some of these processes (WF, GF and WAG injection started with primary WF) the effect of wettability was also investigated. The results show that in both the water-wet and mixed-wet cores, the performance of WAG injection is better than water injection and gas injection alone. The results show that in mixed-wet core, oil recovery by the WAG test which had started with water injection was higher than the WAG test started with gas injection. WAG injections had superior performance over SWAG injections. SWAG performed better compared to primary gas injection. However, surprisingly, SWAG resulted in lower oil recovery compared to primary waterflood in the mixed-wet system. Compared to the other injection strategies, a very high pressure drop across the core was observed during SWAG injection indicating injectivity problems with the application of the process in mixed-wet rocks. Using results of the WAG injection experiments, I also investigated the cyclic hysteresis effect on three-phase relative permeabilities of each phase (gas, oil and water). The results show the importance of properly accounting for irreversible kr hysteresis loops in the processes involving cyclic injection under three-phase flow conditions. Gas relative permeability (krg) dropped in successive cycles under both water-wet and mixed-wet conditions. krg hysteresis was larger in the water-wet system compared to the mixed-wet case. The results also reveal saturation history dependency for oil relative permeability (kro), which tends to increase in successive gas injection periods. The improvement in kro was larger in the water-wet system. In both water-wet and mixed-wet systems, the largest krw hysteresis happens for the transition from two-phase (oil/water system) to three-phase system (from 1st water injection into 1st gas injection) and the subsequent WAG cycles does not show much hysteresis for krw in the experiments. I addressed some serious shortcomings of the existing reservoir simulators for reliable simulation of oil recovery processes involving three-phase flow and flow reversal.
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Hwang, Du-Hyun Dwayne. "Flow quality measurement based on stratification of flow in nitrogen gas-water and HFC-134a refrigerant-PAG oil two-phase flow systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58743.pdf.
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Kaul, Ashwini. "Study of Slug Flow Characteristics and Performance of Corrosion Inhibitors, in Multiphase Flow, in Horizontal Oil and Gas Pipelines." Ohio University / OhioLINK, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1203978425.
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Tucci, Alessandro. "Sviluppo di un separatore compatto per applicazioni Oil & Gas." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18629/.
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Lo scopo di questo elaborato è quello di illustrare l'analisi fluidodinamica che segue la progettazione di un separatore compatto tipo ILS (In-Line Separator), utilizzato nel campo dell'Oil & Gas. L'attività di tesi è stata svolta analizzando i flussi bifase sia con tecniche sperimentali che numeriche, con l'ausilio di un circuito di test e del software commerciale AnsysFluent. Lo studio sperimentale è stato svolto nei laboratori del di fluidodinamica applicata e miscelazione presso il DICAM, Università di Bologna. Lo studio ha avuto come punto di partenza la mappatura della regione di funzionamento del dispositivo. Successivamente, tramite un sistema PIV (Particle Image Velocimetry) ed alla tecnica di indagine a retroilluminazione, sono state effettuate campagne di acquisizione dati monofase e bifase, gas-liquido. I dati sperimentali così ottenuti sono stati utilizzati come benchmark per valutare i modelli e i metodi di soluzione numerica utilizzati per le seguenti simulazioni CFD (Computational FluidDynamics ). Infine è stato effettuato un confronto sia qualitativo che quantitativo tra i risultati ottenuti tramite i due diversi approcci di progettazione.
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Roberts, Ian Frank. "Modelling and experimental studies of transient stratified multiphase flows." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/7433.
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Owen, Joshua James. "Erosion-corrosion of carbon steel in complex flow geometries in oil & gas CO2 environments." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/21507/.
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When sand is present in carbon dioxide (CO2) corrosion environments in oil and gas pipe flow, wear rates of carbon steel pipelines can be severe. This wear mechanism is known as erosion-corrosion and consists of erosion and corrosion components, with degradation enhanced by interactions between the mechanisms. A lack of understanding of erosion-corrosion of carbon steel and the mechanisms contributing to enhanced degradation through erosion and corrosion interactions exists. Erosion-corrosion of carbon steel in CO2 conditions was the subject of investigation in this work. A submerged impinging jet (SIJ) was used to complete a case study of erosion-corrosion degradation of X65 carbon steel in field conditions at high flow velocities up to 20 m/s in a 60°C, pH 4.7, 2 wt.% NaCl solution containing up to 1000 mg/L of sand particles with an average diameter of 250 μm. High degradation rates, some in excess of 25 mm/yr, were measured and whilst corrosion inhibitors added to protect the X65 surface did reduce corrosion rates, they did not reduce erosion degradation, resulting in degradation rates remaining greater than 10 mm/yr in the most severe conditions evaluated. An investigation into the mechanisms of erosion-corrosion interactions revealed that work-hardened layers were thick and more refined on samples subject to erosion conditions compared with samples used in erosion-corrosion tests. This was explained by removal of the work-hardened layers, formed after particle impacts, through electrochemical dissolution, resulting in corrosion-enhanced erosion, which accounted for up to 20% of overall erosion-corrosion degradation at a flow velocity of 20 m/s in a 60°C, CO2-saturared solution containing 1000 mg/L of sand. Erosion-enhanced corrosion was shown not to be significant in the conditions tested. Flow geometry was also shown to have a significant influence on the erosion-corrosion degradation rates. A 90° elbow was designed to evaluate erosion-corrosion in pipe flow, CO2-saturated, pH 4 conditions at a flow velocity of 6 m/s that showed small erosion contributions to erosion-corrosion degradation on the outer radius of the elbow, with flow induced corrosion accounting for the majority of degradation. To fully understand erosion-corrosion conditions in both flow geometries, computational fluid dynamics (CFD) was used to predict mass transfer coefficients and sand particle trajectories in the flow. Predictions were used to define the erosion mechanisms in the different geometries and to explain why degradation rates could vary significantly between different flow geometries.
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Amin, Aram. "Well test analysis of infrequent flow behaviour of fractured wells in oil and gas reservoirs." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/24556.
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The purpose of hydraulic fracturing is to increase the contact area of the wellbore in the reservoir to maximise production rates. For modelling purposes, the induced fracture is assumed to be of infinite or finite conductivity. The modelled fracture tends to show either features of infinite conductivity with half slope or finite conductivity with quarter slope at early time. These flow behaviours are clear indications of a stimulated well. However, observations in some post-frac well tests report a single unit slope in early time, which indicates non-fractured well response. The objective of this study is to investigate the unusual flow behaviour associated with the testing of fractured wells following a proppant frac job and address reasons for this behaviour assuming the frac job has targeted the reservoir interval of interest. This infrequent behaviour is referred to briefly in a limited number of publications but with no clear explanation. Study suggests that the controlling factors are fracture length, fracture conductivity, non-Darcy flow in the case of gas wells and the damage caused by the fracture operation including choked fracture effect and less importantly fracture face skin. This study utilizes 3-D numerical black oil and compositional simulation in single and multi-layered reservoirs containing different fluid types. A range of factors are examined that may impact the introduced fracture flow behaviour based on actual fractured well flow features found in the literature. The main fracture and reservoir parameters investigated include: fracture half-length (xf), fracture conductivity (kfwf), fracture damage including fracture choke (Sfc) and fracture face skin (Sff), non-Darcy effect, formation permeability and many others. The study also examines fractured well behaviour in naturally fractured reservoirs and gas-condensate (lean and rich) reservoirs to investigate liquid drop out effect on the induced fracture flow behaviour. It is concluded that the investigated fracture behaviour is likely to be associated with damaged fractures of short lengths and low fracture conductivity values, which often result from poorly executed frac job on the well. Knowledge obtained from the study is applied to the analysis of well tests from actual fractured wells. Understanding the flow behaviour of fractured wells is crucial to operators and service companies in evaluating the effectiveness of stimulation work performed on the well.
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Lee, Ai Hsin. "A study of flow regime transitions for oil-water-gas mixtures in large diameter horizontal pipelines." Ohio : Ohio University, 1993. http://www.ohiolink.edu/etd/view.cgi?ohiou1175713378.
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PEREIRA, LUIZ OCTAVIO VIEIRA. "PERFORMANCE VERIFICATION METHODOLOGY OF MULTIPHASE FLOW METERS IN ALLOCATION MEASUREMENT IN THE OIL AND GAS INDUSTRY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2018. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=37027@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROO medidor de vazão de fluido multifásico (MM) se desenvolveu impulsionado principalmente pela necessidade da indústria de óleo e gás em medir a vazão da produção dos poços que comumente é composta por petróleo, gás e água. Em outubro de 2015, a Agência Nacional de Petróleo, Gás Natural e Biocombustíveis (ANP) publicou o Regulamento Técnico de Medição de Fluido Multifásico para Apropriação de Petróleo, Gás Natural e Água que apresenta os requisitos através de planos que as empresas operadoras de óleo e gás precisam preparar e submeter para obter a autorização para aplicar o MM na medição para apropriação. Contudo, esse regulamento não especifica a metodologia que deve ser utilizada no denominado plano de verificação de desempenho para avaliar desempenho do MM no campo, cabendo a cada operadora desenvolver a sua metodologia para esse fim e apresentar a ANP. Este trabalho propõe e aplica uma metodologia para verificação de desempenho para MM com resultados de testes realizados em laboratório com fluidos reais e em campo de produção de petróleo e gás. É observado que testes com tempo curto de duração, inferior a 1000 segundos, tendem a gerar incertezas mais elevadas do que testes com longa duração, com mais de 1000 segundos, como os realizados na plataforma. Sendo assim, os resultados de incerteza de medição maiores gerados no laboratório com tempos de integração curtos podem ser considerados mais conservativos que os resultados dos testes realizados na plataforma.
The multiphase flowrate (MM) was driven by the necessity of the oil and gas industry to measure the production flow of the wells that are commonly composed of oil, gas and water. In October 2015, the National Agency for Petroleum, Natural Gas and Biofuels (ANP) published the Technical Regulation for Measurement of Multiphase Fluid for Petroleum, Natural Gas and Water produced, which presents the requirements through plans that oil and gas companies need to prepare and submit for authorization to apply the MM in the measurement for allocation. However, this regulation does not specify the methodology that should be used in the so-called performance verification plan to evaluate the performance of the MM in the field, it being incumbent on each operator to develop its methodology for this purpose and present the ANP. This work proposes and applies a methodology for performance verification for MM with test results performed in the laboratory with real fluids and in oil and gas field. It was observed that short duration tests, below 1000 seconds, tend to generate higher uncertainties than long tests, higher than 1000 seconds, such as those performed on the platform. Thus, the higher measurement uncertainty results generated in the laboratory with short integration times can be considered more conservative than the results of the tests performed in the platform.
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Ismail, Idris. "Measurement of wet gas flow and other two-phase processes in oil industry using electrical capacitance tomography." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616964.
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Pressure drop and void fraction are important hydro-dynamic aspects for wet gas metering. Among differential pressure drop meters, Venturi meters are the most favoured devices for measuring unprocessed wet gas flows. However, Venturi meters are based on dry gas metering concepts, and various correlation factors have to be applied to the readings, Because the correction factors are flow-regime-dependent and only valid within specified operating flow conditions (preferably homogeneous or quasi-homogeneous flows), preconditioning or mixing devices are required. Electrical capacitance tomography (ECT) has been applied to measure wet gas separation processes. A combination of Venturi and ECT present the strengths of both principles and overcome the respective disadvantages. The combination also gives a possibility for wet gas pressure gradient calculation using void fraction measurement from ECT.
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Dupoiron, Marine Agnes Nicole. "The effect of gas on multi-stage mixed-flow centrifugal pumps." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273361.
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The production from an oil reservoir is a mixture of liquids (oil and water) and gas, and is often maintained by using a pump placed in the well to ensure a continuous flow to the surface. Electrical Submersible Pumps consist of stacked centrifugal pump stages, each comprising a bladed impeller (rotating part) and diffuser (stationary part). In multiphase conditions, the gas tends to accumulate in the impeller, severely reducing the pressure produced by the pump. Radial-flow pumps operate in a plane perpendicular to their rotation axis, while mixed-flow pumps are characterised by a lower meridional angle (generally 40 to 80 degrees), and are generally better at handling gas-liquid mixtures. We first describe the impact of gas on the whole pumping system, from the reservoir to the storage facility, and give context to the subject. The available literature shows that the size of the gas bubbles present in the fluid is critical to the pump performance. A transparent, full-scale pump was built in order to explore the flow features in single and multiphase flows. Laser Doppler Velocimetry and high speed imaging in single phase flow showed a high turbulence level in the wake of the impeller blades, and recirculation cells at low flow rates. In gas-liquid conditions, we demonstrated that the bubble size varies within a pump stage, as break-up occurs at the impeller tip, and coalescence is dominant in the diffuser, especially because of recirculation. The first impeller acted as a mixer, and at moderate to high gas fractions (10 to 30%), the flow patterns at the stage level alternated between bubbly and radially separated flows. Finally, a dispersed-gas model was developed to predict the pressure rise in a mixed-flow pump impeller under gas-liquid conditions. This model based on the forces acting on a single spherical gas bubble, was implemented with a simplified, parametric representation of the flow field in a mixed-flow impeller. In the meridional direction, the Coriolis force opposes the centrifugal force and the adverse pressure gradient. Both forces tend to retain the gas bubble within the impeller. The relative magnitude of the drag force strongly depends on the maximal bubble diameter, which was determined as a function of the flow conditions and used to calculate the gas velocity through the impeller. This method resulted in a better agreement with the experimental data than a one-dimensional two-fluid model where the gas phase follows the same path as the liquid. We used the dispersed-gas model to give quantitative evidence that low blade and meridional angles reduce the gas accumulation and the associated performance degradation.
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Subhono, Boya. "Deploying nanotechnology for oil and gas flow assurance : understanding the transport and penetration of nano-particles in porous media." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/9284/.
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Scaling problem is one of the common engineering challenges in ‘flow assurance’ in the oil and gas industry. Since mechanical or chemical treatment frequently requires sacrifice in fluid production, it is often preferable to avoid this problem, for example by conducting a scale squeeze treatment. This treatment includes an injection of scale inhibitor to hinder scale formation in the rock. Its effectiveness corresponds to its attachment lifetime in the rock formation. This is where nanotechnology has an important role for its capability to enhance the attachment of the scale inhibitor on the rock surface. The question that arises is how and where the injected nanoparticles are distributed and attached on the walls of the rock pores. It is difficult and costly to perform evaluations in pores of a rock formation in an actual oil field. Therefore developing a computer simulation is necessary. This research has successfully demonstrated a development of simulator to explore the science and engineering of nanoparticle transport in microchannels. The phenomenon in the system are explored using a combination of model experimental systems and novel Finite Element Analysis (FEA) computational simulations of fluid flow in microchannels of porous structures. The effect of the advection, diffusion, microchannel’s surface roughness and curvature variety to the nanoparticle transport in the system are investigated. It is discovered that the adsorption is encouraged by diffusion when the advection is insignificant. When advection is significant, a plenty of injected nanoparticle is needed to achieve similar adsorption in a system with diffusion domination. Nanoparticles are transported less effectively in microchannel with high curvature configuration. The density of the adsorption distribution in this type of microchannel is less uniform than in microchannel with simpler curvature. Rough surface increases the adsorption, where the distribution of nanoparticles into dead-end region in the microchannel system is governed by diffusion. The modelling framework in this thesis is versatile to use for modelling any transport that is coupled with surface phenomenon in microchannel system by changing the utilised governing equations and assumptions.
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Lee, Joshua. "Experimental Analysis on the Effects of Superficial Liquid and Gas Velocities in the Removal of Hydrogen Sulfide From a Brine/Oil Mixture." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2137.
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Hydrogen Sulfide (H2S) is a harmful gas produced during petroleum extraction that leads to corrosion of drilling tools and pipelines. However, a H2S-scavenging liquid compound, when added to pipelines, interacts with liquids that absorbed H2S to create a non-corrosive bi-product. The interaction is associated with the mixing of gases and liquids. This thesis is a study on the effect of superficial gas and liquid velocities on the scavenger's efficiency. This study employs two experimental setups designed to simulate the mixing of gases and liquids within pipelines. A high pressure closed loop was designed and fabricated to determine the influence of gas, liquid velocities and liquid volume on the scavenger's efficiency. All experiments were conducted in this high pressure loop with a thousand feet of coiled tubing to simulate the horizontal section of the pipeline that runs along the ocean floor from the reservoir. This provided practical understanding to petroleum companies to make a better forecast of how the scavenger used in eliminating the H2S, is affected in the process of transporting the liquids and gases from the reservoir to the surface. For an adequate analysis, experiments on four liquid and four gas velocities ranging from 0.2m/s to 0.5m/s and 0.4m/s to 1.1m/s respectively were conducted. Results in this study indicated that increases in superficial gas velocity at low superficial liquid velocity decreases the scavenger efficiency while the opposite is seen at high superficial liquid velocity. In addition, the H2S mass absorption was not a function of liquid volume as would be seen in static reservoirs but more of a function of superficial liquid and gas velocities. With the scavenger interacting with the liquid absorbed H2S, it was expected that the efficiency would increase with the increase in volume but in this study this was not the case. The second experiment is a flow visualization loop which was designed to understand the flow regimes at high pressures. This was done by constructing four 25ft section hoses together with four foot long breaks for visualization. This provided a more fundamental study of the fluid's behavior inside the pipelines allowing for the creation of appropriate flow regime maps in air-water flow. A hundred experiments for two different pressures were conducted at the 25ft location. At high pressures, the flow regime map appeared to shift the transition zones.M.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering MSME
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Roustaei, Ali. "Yield stress fluid flows in uneven geometries : applications to the oil & gas industry." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58049.
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We study a set of yield stress fluid flows in channels with geometric non-uniformities, motivated by theoretical aspects and industrial applications. Methodology is primarily computational and we try to analytically investigate as much as possible. Theoretical interest arises from the self-selection phenomenon, meaning that the original flow geometry is modified by the fluid itself. This occurs due to yield stress and is accomplished via stagnant zones of the fluid attached to the boundary of original geometry. Industrial motivations stem from oil/gas well construction operations: primary and squeeze cementing and hydraulic fracturing. In all we have drilling mud, cement or a gelled fluid which exhibit yield stress. Specifically, we model a washout along the well as a non-uniform channel and extensively study flows through it. This is an enlarged segment of the well where the wellbore is washed out or collapsed. The main industrial concern is the residual mud left in the washout after primary cementing which weakens the hydraulic sealing function of the cement. Self-selection has been analytically studied for duct flows, and not much in 2D flows. Chapter 2 is a study of self-selection in wavy walled channels as a model for smooth non-uniform channels. We find similar results to duct flows, however a complete understanding eludes us. Chapter 3 looks at the flow of Bingham fluid in fractures. We study the limits of validity of Darcy approach first and then focus at the minimal pressure drop required to mobilize the fluid in fracture. We demonstrate knowing self-selection properties can greatly improve approximations here. Chapters 4-6 are step by step investigation of the flows in washout, from Stokes to inertial and finally displacement flow. In Chapter 4 we show self-selection in Stokes flow of washout and use it to estimate the residual fluid in the washout. We study the effects of inertia on it in Chapter 5, illustrating only finite amount of inertia would help in better displacement of the mud which is counter intuitive. Chapter 6 is a preliminary study of the displacement flow and we report some interesting observations.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Vancko, Jr Robert M. "Effect of a drag reducing agent on pressure drop and flow regime transitions in multiphase horizontal low pressure pipelines." Ohio University / OhioLINK, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1184354301.
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Ochoa, Lara Ismael Orlando 1987. "Desenvolvimento de um simulador físico de gas lift intermitente e bombeio pneumático Zadson em escala de laboratório." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264372.
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Orientador: Sérgio Nascimento BordaloDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências
Made available in DSpace on 2018-08-22T17:35:33Z (GMT). No. of bitstreams: 1 OchoaLara_IsmaelOrlando_M.pdf: 12454353 bytes, checksum: de02a7be086b8fd068a57b93d2f5270a (MD5) Previous issue date: 2013
Resumo: Apesar dos avanços alcançados, alguns aspectos da operação do gas-lift intermitente (GLI) convencional permanecem inexplorados ou pouco estudados até o presente, como por exemplo, a concomitância de etapas do ciclo apresentada por Carvalho (2004), ou a estabilidade de ciclos em função da temporização da válvula motora e do ajuste da válvula operadora. Ao mesmo tempo, o bombeio pneumático de Zadson (BPZ) tem apresentado bons resultados em sua aplicação em campos no Brasil, motivando-se estudos para se desenvolverem simuladores computacionais para o projeto e análise destes sistemas. Neste trabalho, foi construído um simulador físico para os métodos GLI convencional e BPZ, para validar simuladores numéricos propostos anteriormente por outros autores. O aparato laboratorial é constituído por quatro conjuntos operacionais: o primeiro conjunto representa a coluna de produção do GLI convencional, o segundo conjunto representa a coluna do BPZ, o terceiro conjunto representa o acoplamento poço-reservatório e o quarto conjunto representa a injeção de gás comprimido. Para a medição, há transdutores de pressão localizados em vários pontos do aparato e tanques de medição do volume produzido. O sistema de aquisição de dados e atuação das válvulas operadora e motora é operado por uma placa micro-controlada. Testes foram realizados alterando-se as variáveis operacionais dos métodos. Como conclusões do trabalho foram identificadas a concomitância das etapas do ciclo GLI, avaliado o fallback para várias condições operacionais, estudada a estabilidade dos ciclos de GLI, e desenhado um mapa operacional das condições de um ciclo GLI regular. Além disso, foi testado o funcionamento de três modos de operação do BPZ
Abstract: Despite the advances achieved so far, some important aspects of the operation of the conventional intermittent gas-lift (IGL) remain unexplored or poorly studied, as for instance, the concurrency of cycle stages, as presented by Carvalho (2004), or the stability of cycles due to motor valve timing and adjustment of the gas-lift valve. At the same time, the Zadson pneumatic pump (ZPP) has presented good results in Brazilian fields, motivating studies to develop computational simulators for the design of this method. In the course of the present work, a physical simulator was built for the IGL and ZPP, to validate numerical simulators proposed by previous authors. The laboratory apparatus consists of four operational sets; the first set is the production column of conventional IGL, the second set is the column of ZPP, the third set represents the well-reservoir coupling and the fourth set is the injection of compressed gas. For measurement, there are pressure transducers located at various points of the apparatus and tanks for measuring the produced volume. The system of data acquisition and actuation of gas-lift and motor valves are operated by a microcontroller board. Tests were performed by changing the operating variables of the gas lift methods. The results of the study are: the identification of the concurrent stages during the IGL cycle, the fallback for various operating conditions, the stability of IGL cycles, and an operating map for the conditions of a stable IGL cycle. In addition, the operation of three lifting modes of the ZPP were tested
Mestrado
Explotação
Mestre em Ciências e Engenharia de Petróleo
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Morakinyo, Barnabas Ojo. "Flaring and pollution detection in the Niger Delta using remote sensing." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/4314.
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Through the Global Gas Flaring Reduction (GGFR) initiative a substantial amount of effort and international attention has been focused on the reduction of gas flaring since 2002 (Elvidge et al., 2009). Nigeria is rated as the second country in the world for gas flaring, after Russia. In an attempt to reduce and eliminate gas flaring the federal government of Nigeria has implemented a number of gas flaring reduction projects, but poor governmental regulatory policies have been mostly unsuccessful in phasing it out. This study examines the effects of pollution from gas flaring using multiple satellite based sensors (Landsat 5 TM and Landsat 7 ETM+) with a focus on vegetation health in the Niger Delta. Over 131 flaring sites in all 9 states (Abia, Akwa Ibom, Bayelsa, Cross Rivers, Delta, Edo, Imo, Ondo and Rivers) of the Niger Delta region have been identified, out of which 11 sites in Rivers State were examined using a case study approach. Land Surface Temperature data were derived using a novel procedure drawing in visible band information to mask out clouds and identify appropriate emissivity values for different land cover types. In 2503 out of 3001 Landsat subscenes analysed, Land Surface Temperature was elevated by at least 1 ℃ within 450 m of the flare. The results from fieldwork, carried out at the Eleme Refinery II Petroleum Company and Onne Flow Station, are compared to the Landsat 5 TM and Landsat 7 ETM+ data. Results indicate that Landsat data can detect gas flares and their associated pollution on vegetation health with acceptable accuracy for both Land Surface Temperature (range: 0.120 to 1.907 K) and Normalized Differential Vegetation Index (sd ± 0.004). Available environmental factors such as size of facility, height of stack, and time were considered. Finally, the assessment of the impact of pollution on a time series analysis (1984 to 2013) of vegetation health shows a decrease in NDVI annually within 120 m from the flare and that the spatio-temporal variability of NDVI for each site is influenced by local factors. This research demonstrated that only 5 % of the variability in δLST and only 12 % of the variability in δNDVI, with distance from the flare stack, could be accounted for by the available variables considered in this study. This suggests that other missing factors (the gas flaring volume and vegetation speciation) play a significant role in the variability in δLST and δNDVI respectively.
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El, Mellas Ismail. "Numerical simulation of wax deposition in pipelines." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Crude oils are complex mixtures of hydrocarbons. Among these components, high molecular weight paraffin (waxes) and asphaltenes may cause severe flow assurance issues in production and transportation subsea pipeline systems. Wax molecules are dissolved in the crude oil, when the temperature decreases, the solubility of high molecular weight paraffins decreases rapidly, and this results in the formation of gels of complex morphology, that deposit on the cold walls of the subsea pipelines during the flow of waxy crude oils, and this is a big problem for the subsea pipelines. The cost of wax management is enormous and rapidly increasing because of increased oil production in deep-sea areas. In this work, is presented a new numerical model for predicting wax deposition in oil pipes. While the almost part of the models existing in the literature are based on a separated two-fluid description of the oil/wax-oil flow, the model proposed is based on a mixture description, where wax is considered as a suspended phase surrounded by crude oil. When wax separates in the crude oil, the mixture becomes a gel-like fluid, and this mechanism is incorporated in the flow model by a specific rheological model where the mixture viscosity depends on both the local wax concentration and its “age”. In order to simultaneously model moving regions of different “ages”, our model solves a transport equation for the ageing time. Deposition is modelled by solving wax mass balance, dissolved asphaltenes mass balance, and energy. Wax generation and asphaltenes removal are modelled as a first-order reaction coupling mass balance between the species, where the local equilibrium saturation is given as a function of the mixture temperature. In this work, is present the implementation of the model in the open-source C++ library OpenFOAM and validation of the model between some similar works. Besides a discussion of the results for wax deposition and a parametric study about the critical parameters.
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Ozigagu, Christopher E. "Method Development for Corrosion Testing of Carbon Steel and Ni-based Alloy Coatings Exposed to Gas Hydrate Formation Environments." Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1538777/.
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Gas hydrate formation and corrosion can cause serious safety and flow assurance problems in subsea environments. One aspect that has been given less attention is the corrosion behavior of materials in gas hydrate formation environment (GHFE). This work introduces a new technique/method for corrosion testing of materials exposed to low temperatures GHFEs. This technique allows pH monitoring, and control of test conditions like temperature. In this work, GHFE is defined as an environment that includes water, methanol and its degraded products in the presence of corrosive agents like CO2 and chloride salt at gas hydrate formation temperatures (GHFT). After 20 hrs immersion in CO2-saturated salinity environment at GHFT, as-deposited Ni-Mo alloy coating has the highest corrosion resistance of 33.28 kΩ cm2. The corrosion resistance dropped to 14.36 kΩ cm2 and 11.11 kΩ cm2 in the sweet low-salinity and sweet high-salinity test solutions respectively. The combined results of SEM/EDX showed that the Ni-Mo coating oxide layer broke down quicker in sweet high-salinity environment than sweet low-salinity environment. When carbon steel was immersed in a CO2-saturated high salinity environment at GHFT, there was slight overall change in corrosion rate (CR) as salt concentration increase from 3 wt% to 25 wt%. In degraded methanol environment, methanol showed an inhibitive effect on the corrosion of carbon steel. Higher methanol content (up to 50 vol. %) increased the corrosion rate of carbon steel at gas hydrate formation temperature, however, the corrosion rates were lower with methanol contents between 10 to 20 vol%.
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Putri, Autie Minati, and Hadla Mostafa Al. "Organizational Learning and Project Portfolio Success : An Empirical Study in a Multinational Oil and Gas Company." Thesis, Umeå universitet, Företagsekonomi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-115224.
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This study aims to understand the impact of organizational learning on project portfolio success in a multinational Oil and Gas company operated in Indonesia. The Organizational Learning and Project Portfolio Success have been proven to have contribution to business performance and they might possess a relationship where enhancing one of them will strengthen the other. Exploring on this relationship might give beneficial input to the organization in order to maximize their success. Thus, our research question is formulated as: To what extent does Organizational Learning impact the Project Portfolio Success? We developed the study’s conceptual model based on the relevant previous literature. The conceptual model depicted the aim of the study to test the potential positive impact of each Learning Stocks (Individual, Group, and Organizational) on Project Portfolio Success, as well as the aim to test the potential negative impact of the misalignment between Learning Stocks and Learning Flows on Project Portfolio Success in the studied company. We adopted quantitative research method due to the nature of research question and the ontological and epistemological assumptions we hold toward the studied phenomena. Accordingly, we used a questionnaire as an instrument to collect the required data to test the hypotheses. The questionnaire was subject to a pilot test to ensure the clarity of statements before it was distributed to the targeted respondents which are the managers and the Project Management Office personnel in the studied company. The research hypotheses were tested by applying single and multi-regression analyses using SPSS software. Our findings showed that, independently, each learning stock type (Individual, Group and organizational) has a significant positive impact to project portfolio success. When we looked for the best model that gives the highest explanatory power, the result showed that the combination of all three learning stocks in one model can explain project portfolio success construct the most. Lastly, the study proved that the misalignment between learning stocks and flows gives negative impact to the project portfolio success. We concluded the study by stating the theoretical contribution and practical recommendations based on the results such as the need to have a balanced investment in the individual, group and organizational learning stocks; ensure the alignment between the organizational units’ strategies and goals; develop an “Internal Strategy Awareness Index”; and conduct a revision of the alignment between the company’s strategy and the project portfolio.
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Howard, Mitchell James. "Development of a machine-tooling-process integrated approach for abrasive flow machining (AFM) of difficult-to-machine materials with application to oil and gas exploration componenets." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/9262.
Full textAbstract:
Abrasive flow machining (AFM) is a non-traditional manufacturing technology used to expose a substrate to pressurised multiphase slurry, comprised of superabrasive grit suspended in a viscous, typically polymeric carrier. Extended exposure to the slurry causes material removal, where the quantity of removal is subject to complex interactions within over 40 variables. Flow is contained within boundary walls, complex in form, causing physical phenomena to alter the behaviour of the media. In setting factors and levels prior to this research, engineers had two options; embark upon a wasteful, inefficient and poor-capability trial and error process or they could attempt to relate the findings they achieve in simple geometry to complex geometry through a series of transformations, providing information that could be applied over and over. By condensing process variables into appropriate study groups, it becomes possible to quantify output while manipulating only a handful of variables. Those that remain un-manipulated are integral to the factors identified. Through factorial and response surface methodology experiment designs, data is obtained and interrogated, before feeding into a simulated replica of a simple system. Correlation with physical phenomena is sought, to identify flow conditions that drive material removal location and magnitude. This correlation is then applied to complex geometry with relative success. It is found that prediction of viscosity through computational fluid dynamics can be used to estimate as much as 94% of the edge-rounding effect on final complex geometry. Surface finish prediction is lower (~75%), but provides significant relationship to warrant further investigation. Original contributions made in this doctoral thesis include; 1) A method of utilising computational fluid dynamics (CFD) to derive a suitable process model for the productive and reproducible control of the AFM process, including identification of core physical phenomena responsible for driving erosion, 2) Comprehensive understanding of effects of B4C-loaded polydimethylsiloxane variants used to process Ti6Al4V in the AFM process, including prediction equations containing numerically-verified second order interactions (factors for grit size, grain fraction and modifier concentration), 3) Equivalent understanding of machine factors providing energy input, studying velocity, temperature and quantity. Verified predictions are made from data collected in Ti6Al4V substrate material using response surface methodology, 4) Holistic method to translating process data in control-geometry to an arbitrary geometry for industrial gain, extending to a framework for collecting new data and integrating into current knowledge, and 5) Application of methodology using research-derived CFD, applied to complex geometry proven by measured process output. As a result of this project, four publications have been made to-date – two peer-reviewed journal papers and two peer-reviewed international conference papers. Further publications will be made from June 2014 onwards.
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Valentini, Francesco. "Experimental and numerical study of methods to displace oil and water in complex pipe geometries for subsea engineering." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17528/.
Full textAbstract:
The purpose of the thesis is to study fluid displacement operations in complex pipe geometries utilized in offshore petroleum industry. Typically, MEG or Methanol is circulated through specific sections of the subsea production systems to lower the hydrocarbon content. This is often done at the beginning of production after a prolonged production shut-in, to avoid formation of hydrates or to minimize the emissions of chemicals to the environment.
Experimental and numerical analyses have been conducted modifying a previously built pipe system formed a U-shaped jumper, adding a fluid recirculation line, a jet pump, a centrifugal pump, some new valves and sensors. During the experiments the volume fraction in the U-shaped jumper of the displacing fluid was estimated versus time by measuring the level of the oil-water interface in each pipe segment. The system was filled and displaced with both distilled water with 3% water content of salt and Exxsol D60. Numerical simulations were performed using the one-dimensional transient multi-phase flow simulator LedaFlow. It has been investigated the necessary displacing time required to achieve target hydrocarbon concentration in the domain, optimal displacement rate for efficiently removal of hydrocarbons, and how these variables depend on two different fluids (oil and water) and their properties. The displacement has been also modelled including or removing the recirculation line.
After carrying out the simulations and performing the experiments, the results were compared, also against a new simplified mathematical model based on uniform mixing in a tank with the same volume as the pipe geometry. The results show that there is a fair agreement between the experimental results, and the results of the simplified model and the LedaFlow simulations. When including the recirculation line it took longer time to reach the target volume fraction, but the displacing rate can be lower than when the recirculation line is not present.
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Reimer, Mark. "Multimodal transportation systems analysis to characterize petroleum-related freight flows." Transportation Research Board of the National Academies, 2014. http://hdl.handle.net/1993/30288.
Full textAbstract:
The purpose of this research is to inform planning, engineering, and management decisions concerning transportation systems that serve the petroleum exploration and production industry in North America. The research applies the transportation systems analysis approach to characterize the petroleum activity system and transportation system in southwest Manitoba and to develop freight flows. The research develops a framework to estimate and assign petroleum-related truck traffic to the regional highway network taking into account the variability of the industry. This is done by integrating components of freight demand modeling and truck traffic monitoring processes to improve understanding of truck traffic flow characteristics related to the industry. The results of the research are presented in an interactive mapping data dissemination tool. The approach and methodologies of this research are transferable to other jurisdictions and can be used to address the needs of other industry-specific developments.
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Steimes, Johan. "Performance study and modelling of an integrated pump and gas-liquid separator system: Optimisation for aero-engine lubrication systems." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209365.
Full textAbstract:
A system able to simultaneously separate and pump a gas-liquid mixture was developed.It works efficiently and can be used in many applications (nuclear power plants,
pulp and paper processing, petroleum extraction, etc.). However, this pump and separator
system (PASS) was especially designed to handle air-oil mixture generated in
aero-engine lubrication systems. The PASS combines three important functions of the
scavenge part of the lubrication system: the deaeration and deoiling of the air-oil mixture
generated in the bearing and gearbox sumps and the pumping of the oil towards
the tank. These are critical functions for the engine. Indeed, a poor deoiling efficiency
leads to a high oil consumption. This reduces the flight endurance, increases the size
and weight of the oil tank and has a negative impact on the environment. Poor deaeration
and pumping characteristics lead to problems in the cooling and the lubrication of
the engine bearings.
Integrating a PASS into the lubrication system allows considerable improvements
(and simplification) to the lubrication system architecture. An important number of
components are suppressed: the vent lines, the deoiler, the cyclone deaerator and the
scavenge pumps. This reduces the size and the weight of the lubrication system and
increases its reliability. Furthermore, an important part of this PhD thesis focuses on
reducing the oil consumption in the PASS. This improves the flight endurance, reduces
engine maintenance and working costs and is profitable to the environment.
In addition to the development of an advanced PASS design system, the objective of
this thesis was to obtain a good understanding of the separation processes occurring in
the PASS and to develop theoretical models able to predict the separation performance
for every working condition encountered in a typical aircraft flight. To achieve this
goal, three main tasks were performed: the development of different two-phase measurement
systems, the experimental tests of four different PASS architectures and the
theoretical development (after an extensive literature review) of correlations predicting
the performance of the PASS in function of the working conditions. Five specific aspects
of the PASS were studied: the inlet flow, the deoiling efficiency, the deaeration efficiency,
the pumping efficiency and the pressure drop. Finally, the models that have been developed
with the help of the measurement systems and of the experiments have been
integrated in a complete model of the lubrication system (under the EcosimPro modelling
environment). This helps to predict real in flight PASS working conditions and
performance. Indeed, the PASS is very sensitive to the engine working conditions and
an optimisation of the prototype size and performance is only feasible with an accurate
knowledge of these working conditions and a complete lubrication system model.
Finally, with the results of this PhD thesis, a new PASS design, optimised for different
aero-engine lubrication systems, is presented.
Doctorat en Sciences de l'ingénieur
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Quites, Arthur Pinheiro. "Equity research - Galp Energia SGPS SA : using the expected cash flow approach." Master's thesis, Instituto Superior de Economia e Gestão, 2020. http://hdl.handle.net/10400.5/20800.
Full textAbstract:
Mestrado em FinançasO presente documento consiste num relatório premiado de um Equity Research sobre a GALP S.G.P.S., SA. Este documento foi utilizado no CFA Institute Research Challenge 2020, obtendo um 1o lugar a nível Local e um 2o lugar a nível Regional. O relatório segue o formato do CFA Institute e apenas foram consideradas informações públicas até 18/10/2020. Além do formato padrão escolhido, este relatório possui um capítulo adicional, que juntos consistem num Trabalho Final de Mestrado. O capítulo em causa explora em maior detalhe como definir o preço-alvo, usando a abordagem do expected cash flow. Entre a utilização de análises de sensibilidade e diferentes cenários de preços, em conjunto com uma metodologia matemática para definir probabilidades, este capítulo fornece mais um conjunto de informações para auxiliar os investidores na decisão de investimento. A GALP é a principal empresa petrolífera integrada portuguesa. A empresa foi avaliada com uma de soma de partes, onde um FCFF DCF foi feito para cada unidade de negócios, refletindo todas as idiossincrasias de cada unidade. O resultado foi somado, ajustamentos foram feitos e resultou num preço-alvo final de 12,1€ por ação. Para apoiar esta avaliação, outros métodos também foram utilizados. A avaliação foi sujeita a análises de sensibilidade. Adicionalmente, os riscos aos quais a empresa está exposta são explicados no relatório. Também é importante mencionar que o relatório foi finalizado em 15/01/2020. No entanto, foi criado um research snapshot atualizado para incluir novas informações, refletindo os impactos da pandemia COVID-19. Esta atualização reflete informações de Março 2020.
The present document consists of an award-winning report of an Equity Research on GALP S.G.P.S., SA. This document was used in the CFA Institute Research Challenge 2020, obtaining a 1st place at the Local level and a 2nd place at Regional level. The report follows the CFA Institute format and only public information until 18/10/2020 was considered. In addition to the standard format chosen, this report has one additional chapter, that all together form the Master Final Work. The said chapter explores further on how to define the price target, by using the expected cash flow approach. Between using sensitivity analysis and different price scenarios together with a mathematical methodology to define probabilities, another piece of information is provided to help investors make an investment decision. GALP is the leading Portuguese integrated oil company. It was valued with a Sum-of-the-Parts approach, where a FCFF DCF was made to each business unit, reflecting all the idiosyncrasies of each BU. The result was them summed up, adjustments were made, a final price target of 12.1€/sh was obtained. To support this valuation other methods were also used. The valuation was subject to sensitivity analysis in order to address risk. Additionally, the risks the company is subject to is thoroughly explained in the report. It is also important to mention that the report was finalized on January 15th, 2020. However, an updated research snapshot was made, to include new information, reflecting the impacts of the COVID-19 pandemic. This update reflects information from March 2020.
info:eu-repo/semantics/publishedVersion