ENCIT2012-106 EXERGY AND ENVIRONMENTAL ANALYSIS OF A PETROLEUM PIPELINE TRANSPORTATION SYSTEM - PDF
George Stanescu, Danilo David de Souza Santos, UFPA, Brazil
Abstract: An exergetic and environmental analysis is perform on a low temperature conditions pipeline transportation system for petroleum. Problems of energy efficiency and also environmental problems in relation to the conservation of natural habitat are considered when transportation to the oil terminals is necessary. It is evaluated in this work the energy costs of oil pumping and heating during transportation throughout the pipelines. Losses generated by irreversibilities associated with the oil viscosity and the heat losses to the surroundings are considered. Environmental problems in this case are related to the need for conservation of the permafrost layer where the pipeline is buried at temperatures below 0 0C. Accounting for several thicknesses for the insulating layer on the outside of the pipeline and possible fees to be paid per kilogram of carbon dioxide emitted, estimated energy and monetary costs for an Arctic pipeline steady-state operation are calculated.
Keywords:petroleum; pipelines transportation system; exergy analysis; carbon dioxide emission.
Presentation Schedule: Thursday, 14:20-14:40. Session: OPO-2. Presenter: George Stanescu.
ENCIT2012-203 START-UP OF WAXY CRUDE OILS IN SUBSEA PIPELINES - PDF
Patricia Emídio de Azevedo, Priscilla Ribeiro Varges, Paulo Roberto de Souza Mendes, PUC-Rio, Brazil
Abstract: One of the main problems in the operation of subsea pipelines that convey paraffin oils is the startup flow after long stoppages. Along the path from the reservoir to the platform, the oil experiences significant heat losses, especially to the low-temperature water at the bottom sea. When there is no flow, the oil may reach very low temperatures. The cooling induces wax precipitation and hence gelification of the oil, which may cause blockage of the pipeline. Under these circumstances, pressures much higher than the usual ones may be needed the restart flow. The knowledge of the minimum pressure level that causes flow after prolonged stoppages is an important piece of information. In this work we analyzed the flow startup using a viscoplastic fluid, waxy crude oil.
Keywords:start-up; Waxy crude oil; Rheology.
Presentation Schedule: Wednesday, 16:20-16:40. Session: OPO-1. Presenter: Patricia Emidio de Azevedo.
ENCIT2012-043 NUMERICAL SIMULATION OF TRANSIENT PRESSURE DATA IN POROUS MEDIA BY MIXTURE THEORY AND DARCY LAW - PDF
Rodrigo Araujo Cardoso Dias, ESSS, Brazil
Thiago Judson Lima de Oliveira, Paulo Dore Fernandes, Petrobras, Brazil
Abstract: This article compares two different theoretical formulations used in reservoir simulations. One is the hydraulic diffusivity equation and the other is the mixture theory equation applied to fluid flow in porous media. The hydraulic diffusivity equation is widely used in reservoir simulations. This equation is found when Darcy's law is applied in the continuity equation. However, there is another theoretical approach for fluid flow in porous media, the mixture theory. Mixture theory allows a local description of the flow in a porous medium, supported by a thermodynamically consistent theory which generalizes the classical continuum mechanics. This article compares the results obtained by the equation based on the mixture theory with the hydraulic diffusivity equation. This comparison is made by pressure transient data analysis. A practical application for these types of pressure data is in well tests. Transient well testing has been a core competency of the oil industry for a long time because it provides petroleum engineers with valuable information about reservoirs. The article presents a study of pressure transient data by applying both theories. The numerical method for the solution of both theories was the finite volume method.
Keywords:Mixture Theory; Finite Volumes Method; Well Test; Darcy's Law.
Presentation Schedule: Wednesday, 15:00-15:20. Session: OPO-1. Presenter: Rodrigo Dias.
ENCIT2012-125 TURBULENT DISPLACEMENT FLOW IN ANNULAR SPACE - PDF
Simone Bochner de Araujo, Frederico Carvalho Gomes, Marcio da Silveira Carvalho, PUC-Rio, Brazil
Abstract: The cementing process is an important step in the construction of oil and gas wells. During cementing, it is necessary to displace the drilling mud by the cement slurry. To avoid mixing of these liquids, spacer fluids are usually used. Therefore, it is common to have three or more liquids flowing through the eccentric annular space. Non-uniform liquid displacement may lead to severe problems to the well structure and safety. Hence, fluid properties and process condition should be design to minimize non-uniformities on the displacement front. A complete analysis of the flow in the annular space that occurs during cementing is extreme complex, because of the presence of different liquids that often present non-Newtonian characteristic and the flow is three dimensional and transient. In some cases, the flow in the lower viscosity liquid phase may become turbulent. A complete model has a prohibitive high computational cost. Simplified models are available in the literature and are used by the oil industry in commercial simulation software for cementing. The available models are not able to accurately describe turbulent flow regime. In this work, we extend the lubrication based model in cylindrical coordinates developed by Gomes and Carvalho (2010) to include turbulent flow regimes. The predictions agree with experimental observations that turbulent flow may lead to unexpected stable displacement front.
Keywords:Cementing Process; Lubrication theory; Turbulent flow; Annular space.
Presentation Schedule: Wednesday, 15:20-15:40. Session: OPO-1. Presenter: Simone Bochner de Araujo.
ENCIT2012-130 A COMPUTATIONAL MODEL FOR MULTIPHASE FLOW INSIDE A METALLIC PROGRESSING CAVITY PUMP - PDF
Victor Wagner Freire Azevedo, João Alves de Lima, UFRN, Brazil
Emilio Ernesto Paladino, UFSC, Brazil
Abstract: Progressing Cavity Pumps (PCP) are widely used in oil artificial lift for low to moderate well depths, substituting in several cases the traditional reciprocating pumps. The flow characterization within these devices is of fundamental importance for both, product development and field operation. A successful CFD model for the transient 3D flow within a PCP which includes the relative motion between rotor and stator was recently developed. This work presents the extension of this model for the case of two-phase, gas-liquid flow, which is a very common situation on field operation. The governing equations are solved using an element based finite volume method in a moving mesh. The Eulerian-Eulerian approach is used to model the flow of the gas-liquid mixture. The compressibility of the gas is considered through an ideal gas state equation, as a first approach. The model is validated against results presented in literature, for a rigid stator PCP. The effects of the different gas fraction inside the pump on its efficiency were analyzed, according to the multiphase flow patterns established by the literature.
Keywords:PCP; Multiphase flow; CFD; Artificial lift; Pumps.
Presentation Schedule: Tuesday, 18:40-19:00. Session: FMR4-3. Presenter: Victor Wagner Freire de Azevedo.
ENCIT2012-267 EXERGETIC ANALYSIS APPLIED IN THE PRIMARY PROCESSING EQUIPMENTS IN OFFSHORE FIELDS - PDF
William Emidio Silva, Maria Isabella Henrique, Maria Luiza Renó, Rogério José da Silva, FEI, Brazil
Abstract: In the petroleum production is extracted a mixture of water, gas, oil and also impurities; so it is necessary to process this mixture in order to remove all the economically attractive phases, as oil and gas, as well as extracting water and impurities. This three-phase separation process of oil and gas is done in offshore fields with the use of various pieces of equipment such as biphasic separator, three-phase separators, hydrocyclones, electrostatics separators and centrifuges. This separation process, besides having an economic interest in oil phase, present also a great interest with respect to gas phase, since the combination of the gas with the water creates hydrates, which can difficult the transport through the ducts, and difficulty the posterior refining of oil remaining. The primary processing requires units with a large numbers of pieces of equipment with high energy consumption, and that still generate, large amounts of water for disposal depending of the characteristics of them. This water to be discarded have to be within quality standards pre-defined by the environmental issues, so, its treatment provides an important step in the primary processing due to high levels of oil and impurities in the water. Aiming to analyze the problem of the high energy consumption from the piece of equipment, to optimize the use of piece of equipment and their layout, can be used the exergetic analysis theory, that permit quantify the process lost, their economic costs and also, the generation of irreversibility that impacts the environment. With this concept it is possible to analyze the behavior of each stage of primary processing, pointing out its efficiency with respect to plants in general and, through an arrangement of these data, find a better arrangement or advanced technologies with respect to the effectiveness of processing. The present work computed a exergetic analyze to the primary process of oil separation in offshore platforms
Keywords:Oil; Primary Processing; Exergy; Exergetic Analysis.
Presentation Schedule: Thursday, 15:40-16:00. Session: OPO-2. Presenter: William Gabriel Emidio de Souza Silva.
ENCIT2012-303 EXPERIMENTAL INVESTIGATION OF THE INTERMITTENT FLOW CHARACTERISTICS IN AN HORIZONTAL PIPELINE - PDF
Walace Rosa Laurindo de Oliveira, Igor Braga de Paula, Fabio Jessen Werneck de Almeida Martins, Luis Fernando Alzuguir Azevedo, Paula Stofer Cordeiro de Farias, PUC-Rio, Brazil
Abstract: The characteristics of the intermittent flow are investigated experimentally for air-water flow in a horizontal 0.0508m pipe at atmospheric conditions. Digital imaging and shadow techniques are used for visualization of the liquid-gas interface. A set of photo gates are used for synchronization of the acquisitions. This allowed us to adopt ensemble average procedures. Thereby, a set of quantitative data about the slug frequency, velocity, length, and the shape of bubble front could be obtained. The range of flow rates covered regimes at the transition from elongated bubble to slug flow. The experimental findings are in agreement with the visual observations that are frequently reported in the literature. A linear relation of the bubble movement with the Froude number is observed.
Keywords:horizontal intermittent flow characteristics; optical technique; image processing.
Presentation Schedule: Wednesday, 16:00-16:20. Session: OPO-1. Presenter: Luis Fernando Alzuguir Azevedo.
ENCIT2012-397 OIL-WATER EMULSIONS INJECTION AS AN ENHANCED OIL RECOVERY METHOD - PDF
Bernardo Soares Engelke, Marcio da Silveira Carvalho, PUC-Rio, Brazil
Vladimir Alvarado, University of Wyoming, United States
Abstract: During the life of an oilfield, different oil recovery methods may be used to maintain the reservoir pressure and increase sweep efficiency. The method most commonly used is water injection. The efficiency of the method is limited due to the high mobility ratio between water and oil, that leads to water fingering. Mobility control agents can be used to minimize this effect. Among them, oil-water emulsions (O-W) present several benefits in cost, compatibility and efficiency. Several studies indicate a better sweep efficiency of the water phase with lower water-oil ratio in the production wells. If properly designed, the dispersed phase of the emulsion may block the pore throats and change the flow path at pore level, improving not only the sweep but also the displacing efficiency. The aim of this research is to study oil-water emulsion flooding and understand the mechanisms involving its use as a mobility control agent. The micro and macro effect of the emulsion injection is going to be evaluated experimentally by measuring the relative permeability curves of water-oil emulsions and oil in sandstone cores for different dispersed phase concentration, droplet size distribution and capillary number.
Keywords:emulsions; mobility control; enhanced oil recovery; sweep efficiency; displacing efficiency.
Presentation Schedule: Thursday, 15:20-15:40. Session: OPO-2. Presenter: Bernardo Soares Engelke.
ENCIT2012-028 UNCERTAINTY AND REPRODUCIBILITY ANALYSIS OF A LABORATORIAL SCALED PIPE PROVER - PDF
Marcelo Aiolfi Barone, Rogério Ramos, Márcio Coelho de Mattos, UFES, Brazil
Abstract: The work uses a laboratory scale prototype of primary pipe prover flowmeter in order to assess conformity with the requirements established by technical standards and examine the uncertainties of flow measurement performed, besides to check the reproducibility, the influence of operating parameters such as operating pressure variation and comparison with gravimetric test. The prototype is plastic made tubing and considering statically defined dimensions. Inside tubing, an interfering elastomer sphere is driven by flow provided by a centrifugal pump. The detection system uses infrared light sensors able to detect the spheres passage causing any pipeline interference or blockage. The acquisition data system is automatic and records the sphere transit time through each pulse signal detected as well as the pulses generated by a calibrated turbine meter, as comparison of the evaluation of process uncertainties.
Keywords:pipe prover; uncertainty; flow measurement; gravimetric method; reproducibility; primary meter.
Presentation Schedule: Wednesday, 14:20-14:40. Session: OPO-1. Presenter: Marcelo Aiolfi Barone.
ENCIT2012-042 ANALYSIS OF OIL DISPLACEMENT THROUGH WATER IN POROUS MEDIA USING INTEGRAL TRANSFORMS AND CFD PACKAGE - PDF
Rodrigo Araujo Cardoso Dias, ESSS, Brazil
Daniel José Nahid Maunsur Chalhub, UFF, Brazil
Thiago Judson Lima de Oliveira, Petrobras, Brazil
Leandro Alcoforado Sphaier, UFF, Brazil
Paulo Dore Fernandes, Petrobras, Brazil
Abstract: Abstract. Water injection into oil formations has a very wide application in the oil industry. The injection of water has as main objective: to maintain formation pressure and provide the recovery of oil by water displacement. This work compares two different theoretical formulations used in reservoir simulations. One is the saturation differential equation and the other is the mixture theory equation applied to fluid flow in porous media. The saturation differential equation is widely used in reservoir simulations. This equation is found when Darcy's Law for each phase is applied in the continuity equation for each phase. However, there is another theoretical approach for multiphase flows in porous media. Mixture theory allows a local description of the flow in a porous medium, supported by a thermodynamically consistent theory which generalizes the classical continuum mechanics. This article compares the results obtained by the equation based on the mixture theory with the saturation differential equation. To solve the saturation equation the Generalized Integral Transform Technique (GITT) was employed. The GITT has been successfully employed in various petroleum reservoir simulation problems. The numerical method for the solution of mixture theory was obtained using advanced, commercial, general-purpose CFD code: FLUENT.
Keywords:Integral Transform Technique; Finite Volumes Method; Waterflooding; Porous Media.
Presentation Schedule: Thursday, 15:00-15:20. Session: OPO-2. Presenter: Rodrigo Dias.
ENCIT2012-390 ON THE EXERGY DETERMINATION FOR PETROLEUM FRACTIONS AND SEPARATION PROCESSES EFFICIENCY - PDF
Julio Augusto Mendes da Silva, Silvio de Oliveira Junior, USP, Brazil
Jonathan Leon, Hector Arredondo Velazquez, Alejandro Molina, Universidad Nacional de Colombia, Colombia
Abstract: Petroleum separation processes are intensive in energy use. However, only a very small fraction of their input energy is required for separation. Due to this significant magnitude difference as well as to the unknown molecular structure of the involved streams, the calculation of specific exergy and exergy efficiency is a delicate topic that involves significant uncertainties. Comparison and explanation of several different ways to perform exergy evaluation of separation processes of petroleum fractions are conducted. The indication of advantages and disadvantages of each formulation is presented. The chemical and physical exergy calculation for petroleum and its fractions are covered. An application is performed and the results are disscussed.
Keywords:Distillation; Exergy; Exergy Analysis; Petroleum; Separation Process.
Presentation Schedule: Thursday, 14:40-15:00. Session: OPO-2. Presenter: Julio Augusto Mendes da Silva.
ENCIT2012-040 COMPUTATIONAL MODELING OF THE SUBMERGED PLATE WAVE ENERGY CONVERTER - PDF
Flávio Medeiros Seibt, Eduardo Costa Couto, Paulo Roberto de Freitas Teixeira, Elizaldo Domingues dos Santos, Liércio André Isoldi, FURG, Brazil
Luiz Alberto Oliveira Rocha, UFRGS, Brazil
Abstract: The growing search for clean and renewable energy sources has contributed to give relevance to the study of sea wave energy. This paper presents a computational model developed to analyze a submerged plate wave energy converter, that transforms sea wave energy into electric energy. The basic principle of this device consists in the passage of sea waves through a horizontal submerged plate, generating a flow under it, where a Wells type turbine is placed, converting mechanical energy into electric energy. The model developed uses the commercial codes "GAMBIT" and "FLUENT". In the latter, the methodology used to represent the air-water interaction in the numerical simulations of the device is the multiphase "volume of fluid" VOF. The objective of this paper is to contribute to a greater knowledge about this converter analyzing the influence of the distance from the plate to the bottom of the sea in the performance of the converter. To do so, the model developed, after a validation process, was used in four simulations that differ from each other only in the vertical position of the plate in a wave tank. The simulation showed that a 11\% decrease in the distance from the plate to the bottom may produce a 10\% of decrease in the average mass flow under the plate.
Keywords:submerged plate; wave energy; ocean waves; sea waves; FLUENT.
Presentation Schedule: Thursday, 16:00-16:20. Session: OPO-2. Presenter: Flávio Medeiros Seibt.
ENCIT2012-093 NUMERICAL STUDY ABOUT THE SHAPE INFLUENCE OF THE HYDRO-PNEUMATIC CHAMBER IN AN OWC WAVE ENERGY CONVERTER - PDF
Juliana do Amaral Martins Grimmler, Nathalia da Rosa Lopes, Jeferson Avila Souza, Elizaldo Domingues dos Santos, Liércio André Isoldi, FURG, Brazil
Mateus das Neves Gomes, IFPR, Brazil
Luiz Alberto Oliveira Rocha, UFRGS, Brazil
Abstract: The oceans represent one of the major energy natural resources, which can be used to supply the World energy demand. In the last decades some devices to convert the wave ocean energy into electrical energy have been studied. In this work the operating principle of an Oscillating Water Column (OWC) converter was numerically analyzed. The incident waves on the OWC hydro-pneumatic chamber cause an oscillation of the water column inside the chamber peoducing ans alternative air flow through the chimney. The air drives a turbine that is coupled to a electric generator. The aim of this work was to investigate the influence of the hydro-pneumatic chamber geometry in the air flow. In this draft paper only two cases were studied and the preliminary results showed that the variation of the OWC chamber shape can improve in 2\% the amount of air flow. Therefore, for the final version of this work other two cases will be investigated and compared, aiming to define the best geometry for the OWC chamber, i.e., the one that can generate more electrical energy.
Keywords:Wave Energy; Oscillating Water Column (OWC); Computational Modeling; FLUENT.
Presentation Schedule: Wednesday, 14:40-15:00. Session: OPO-1. Presenter: Juliana do Amaral Martins Grimmler.
ENCIT2012-216 GEOMETRIC OPTIMIZATION OF AN OVERTOPPING WAVE ENERGY CONVERTER FOR DEEP WATER FLOW - PDF
Bianca Neves Machado, FURG, Brazil
Mateus das Neves Gomes, UFRGS, Brazil
Jeferson Ávila Souza, Paulo Roberto de Freitas Teixeira, Liércio André Isoldi, FURG, Brazil
Luiz Alberto Oliveira Rocha, UFRGS, Brazil
Elizaldo Domingues dos Santos, FURG, Brazil
Abstract: Nowadays it is esteemed that ocean wave energy has a potential of nearly 10 TW, from this energy 10 \% to 25 \% can be converted into electrical one. As a consequence, there are several technologies being developed, an example is the overtopping converter. The device operational principle consists of a ramp which guides incoming waves into a reservoir raised slightly above sea level. The potential energy of the water trapped in the reservoir is then converted to electrical energy through a low head turbine connected to a generator. In this sense, the present work shows a numerical study concerned with the geometric optimization of an overtopping wave energy converter (WEC) for a deep water monochromatic wave (relative depth of h/\&\#955; = 0.62). The main purpose here is the achievement of a theoretical recommendation by means of Constructal Design for the ramp geometry (ratio between the ramp height and length: H1/L1) which increases the amount of water that insides the reservoir. Other goal is the comparison of the optimal geometry obtained here for h/\&\#955; = 0.62 with previous results of literature for h/\&\#955; = 0.5. In the present simulations, it is considered a two-dimensional laboratory scale wave tank with an overtopping device placed inside. The computational domain was generated in software GAMBIT and the governing equations (conservation equations of mass, momentum and an equation for the transport of volumetric fraction) were solved with a Computational Fluid Dynamics (CFD) package based on the finite volume method (MVF), FLUENT®. Concerning the wave generation, it was imposed velocity boundary conditions in the inlet of the wave tank using User Defined Functions (UDF) to mimics the effect of a wavemaker. To tackle with the mixture water-air it was used the multiphase model Volume of Fluid (VOF). For the relative depth of h/\&\#955; = 0.62, the preliminary results show a dependence of the mass of water that insides de reservoir as a function of the ramp geometry (ratio H1/L1), which is in agreement with the previous studies of literature for other relative depth of h/\&\#955; = 0.5. For example, the ratio H1/L1 = 0.4 leads to a performance 30 \% higher than that observed for the ratio H1/L1 = 0.3.
Keywords:Constructal design; optimization; overtopping WEC,; numerical study.
Presentation Schedule: Wednesday, 15:40-16:00. Session: OPO-1. Presenter: Bianca Neves Machado.