Modelagem de dados de falhas de equipamentos de sub-superfície em poços de petróleo da Bacia Potiguar

This master´s thesis presents a reliability study conducted among onshore oil fields in the Potiguar Basin (RN/CE) of Petrobras company, Brazil. The main study objective was to build a regression model to predict the risk of failures that impede production wells to function properly using the information of explanatory variables related to wells such as the elevation method, the amount of water produced in the well (BSW), the ratio gas-oil (RGO), the depth of the production bomb, the operational unit of the oil field, among others. The study was based on a retrospective sample of 603 oil columns from all that were functioning between 2000 and 2006. Statistical hypothesis tests under a Weibull regression model fitted to the failure data allowed the selection of some significant predictors in the set considered to explain the first failure time in the wells

Um sistema para estimação da vazão de gás de poços produzindo por Plunger Lift para vaso separador de teste em plataformas de petróleo

This work intends to analyze the behavior of the gas flow of plunger lift wells producing to well testing separators in offshore production platforms to aim a technical procedure to estimate the gas flow during the slug production period. The motivation for this work appeared from the expectation of some wells equipped with plunger lift method by PETROBRAS in Ubarana sea field located at Rio Grande do Norte State coast where the produced fluids measurement is made in well testing separators at the platform. The oil artificial lift method called plunger lift is used when the available energy of the reservoir is not high enough to overcome all the necessary load losses to lift the oil from the bottom of the well to the surface continuously. This method consists, basically, in one free piston acting as a mechanical interface between the formation gas and the produced liquids, greatly increasing the well s lifting efficiency. A pneumatic control valve is mounted at the flow line to control the cycles. When this valve opens, the plunger starts to move from the bottom to the surface of the well lifting all the oil and gas that are above it until to reach the well test separator where the fluids are measured. The well test separator is used to measure all the volumes produced by the well during a certain period of time called production test. In most cases, the separators are designed to measure stabilized flow, in other words, reasonably constant flow by the use of level and pressure electronic controllers (PLC) and by assumption of a steady pressure inside the separator. With plunger lift wells the liquid and gas flow at the surface are cyclical and unstable what causes the appearance of slugs inside the separator, mainly in the gas phase, because introduce significant errors in the measurement system (e.g.: overrange error). The flow gas analysis proposed in this work is based on two mathematical models used together: i) a plunger lift well model proposed by Baruzzi [1] with later modifications made by Bolonhini [2] to built a plunger lift simulator; ii) a two-phase separator model (gas + liquid) based from a three-phase separator model (gas + oil + water) proposed by Nunes [3]. Based on the models above and with field data collected from the well test separator of PUB-02 platform (Ubarana sea field) it was possible to demonstrate that the output gas flow of the separator can be estimate, with a reasonable precision, from the control signal of the Pressure Control Valve (PCV). Several models of the System Identification Toolbox from MATLAB® were analyzed to evaluate which one better fit to the data collected from the field. For validation of the models, it was used the AIC criterion, as well as a variant of the cross validation criterion. The ARX model performance was the best one to fit to the data and, this way, we decided to evaluate a recursive algorithm (RARX) also with real time data. The results were quite promising that indicating the viability to estimate the output gas flow rate from a plunger lift well producing to a well test separator, with the built-in information of the control signal to the PCV

Sistema inteligente para detecção de vazamentos em dutos de petróleo usando transformada Wavelet e redes neurais

This work consists in the use of techniques of signals processing and artificial neural networks to identify leaks in pipes with multiphase flow. In the traditional methods of leak detection exists a great difficulty to mount a profile, that is adjusted to the found in real conditions of the oil transport. These difficult conditions go since the unevenly soil that cause columns or vacuum throughout pipelines until the presence of multiphases like water, gas and oil; plus other components as sand, which use to produce discontinuous flow off and diverse variations. To attenuate these difficulties, the transform wavelet was used to map the signal pressure in different resolution plan allowing the extraction of descriptors that identify leaks patterns and with then to provide training for the neural network to learning of how to classify this pattern and report whenever this characterize leaks. During the tests were used transient and regime signals and pipelines with punctures with size variations from ½' to 1' of diameter to simulate leaks and between Upanema and Estreito B, of the UN-RNCE of the Petrobras, where it was possible to detect leaks. The results show that the proposed descriptors considered, based in statistical methods applied in domain transform, are sufficient to identify leaks patterns and make it possible to train the neural classifier to indicate the occurrence of pipeline leaks

Simulador computacional do comportamento em regime de poços de petróleo equipados com gas-lift contínuo

Amongst the results of the AutPoc Project - Automation of Wells, established between UFRN and Petrobras with the support of the CNPq, FINEP, CTPETRO, FUNPEC, was developed a simulator for equipped wells of oil with the method of rise for continuous gas-lift. The gas-lift is a method of rise sufficiently used in production offshore (sea production), and its basic concept is to inject gas in the deep one of the producing well of oil transform it less dense in order to facilitate its displacement since the reservoir until the surface. Based in the use of tables and equations that condense the biggest number of information on characteristics of the reservoir, the well and the valves of gas injection, it is allowed, through successive interpolations, to simulate representative curves of the physical behavior of the existing characteristic variable. With a simulator that approaches a computer of real the physical conditions of an oil well is possible to analyze peculiar behaviors with very bigger speeds, since the constants of time of the system in question well are raised e, moreover, to optimize costs with assays in field. The simulator presents great versatility, with prominance the analysis of the influence of parameters, as the static pressure, relation gas-liquid, pressure in the head of the well, BSW (Relation Basic Sediments and Water) in curves of request in deep of the well and the attainment of the curve of performance of the well where it can be simulated rules of control and otimization. In moving the rules of control, the simulator allows the use in two ways of simulation: the application of the control saw software simulated enclosed in the proper simulator, as well as the use of external controllers. This implies that the simulator can be used as tool of validation of control algorithms. Through the potentialities above cited, of course one another powerful application for the simulator appears: the didactic use of the tool. It will be possible to use it in formation courses and recycling of engineers

Aperfeiçoamento no projeto de um protótipo de misturador-decantador à inversão de fases visando aplicação na indústria do petróleo

In the oil industry the mixture oil/water occurs in the operations of production, transportation and refining, as well as during the use of its derivatives. The amount of water produced associated with the oil varies and can reach values of 90% in volume in the case of mature phase of the production fields. The present work deals with the development of new design of the Mixer Settler based on Phase Inversion (MDIF) in a laboratory scale. We envisage this application in industrial scale so the phases of project, construction and operation are considered. The modifications most significant, in comparison with the original prototype, include the materials of construction and the substitution of the equipment used in the mixing stage of the process. It was tested the viability of substitution of the original system of mechanical mixing by a static mixer. A statistical treatment by means of an experimental design of composed central type was used in order to evaluate the behavior of the main variables of the separation process as function of the efficiency of separation for the new device. This procedure is useful to delimit an optimal region of operation with the equipment. The variables of process considered on the experimental design were: oil concentration in the feeding water (mg/L); Total volumetric flow rate (L/h); Ratio organic/water on volumetric basis (O/A). The separation efficiency is calculated by comparison of the content of oil and greases in the inlet and outlet of the equipment. For determination of TOG (Total Oil and Grease), the method used was based in the absorption of radiation in the infra-red region. The equipment used for these determinations was InfraCal® TOG/TPH Model HATR-T2 of the Wilks Enterprise, Incorporation. It´s important to stand out that this method of measure has being used by PETROBRAS S.A. Results of global efficiency of separation oil/water varied from 75.3 to 97.7% for contaminated waters containing up to 1664,1 mg/L of oil. By means of tests carried out with a real sample of contaminated water supplied by PETROBRAS we have got an effluent specified in terms of the legal standards required for discharging. Thus, the new design of equipment constitutes a real alternative for the conventional systems of treatment of produced water in the oil industry

Aplicação de microemulsões na solubilização de frações pesadas de petróleo

This work presents studies related to the use of microemulsions in the solubilization of heavy crude oil fractions responsible by the formation of deposits. The first stage of the work was addressed to the construction of phases diagrams, with the intention of determining the area within which the microemulsion is formed. The following systems were studied: UNITOL L 90 n-Butanol - Water - Kerosene (system 1); UNITOL L 90 - n-Butanol - Water - Xylene (system 2); UNITOL L 90 n-Butanol - Water - Kerosene/Xylene 10% (system 3); UNITOL L 90 - Sec-Butanol - Water - Xylene (system 4). In parallel experiments of physical adsorption were carried out by the static method, with the intention of simulating natural conditions of reservoirs. Crude oil of the Fazenda Belém field (Rio Grande do Norte), was used as solute, xylene as solvent and the Assu sandstone (Rio Grande do Norte, Brazil) and Botucatu sandstone (Paraná, Brazil) as rock reservoirs. The curves of adsorption presented the S format type, in agreement with the classification proposed by Giles, Smith and Huitson (1974). The solubilization process was accomplished in the batch method, by varying the time of agitation, the microemulsions and the solid/solution ratio. The experiments showed that the microemulsions presented high efficiency in the solubilization of the crude oil adsorbed on the sandstones. System 2 presented an efficiency of 99% for the Assu sandstone and 97% for the Botucatu sandstone

Limonologia e qualidade ambiental de um corpo lêntico receptor de efluentes tratados da indústria de petróleo

Environmental pollution has become a subject of public interest throughout the world. Not only have developed countries been affected by environmental problems but also the developing nations have started to suffer from the serious impacts of pollution. Within this context it is necessary to collect simplified environmental data to assist in the management of water resources by the appropriate authorities. These data are obtained through an environmental index that allows a space-time comparison of points distributed in the same aquatic body, or between different water bodies, for physico-chemical and bacteriological parameters. The aim of this present study was to determine the environmental status of the Lagoa de Baixo at Guamaré/RN, where a production unit of PETROBRAS RN/CE is located. For this purpose the Water Quality Index (WQI) was used in both an add and multiply form, the Trophic State Index (TSI) and the Environmental Quality Quotient (EQQ), as well as determining the concentrations of metals. The average values obtained for the WQI, in its two forms were 68,67 and 62,76 respectively which were inside the good qualification. According to the TSI the lagoon showed characteristics of a middle trophic state, and an impact level of regular as determined by the EQQ

Planejamento experimental aplicada a um novo separador líquido-líquido utilizado no tratamento de águas residuais contaminadas com petróleo

The present work had as objective to apply an experimental planning aiming at to improve the efficiency of separation of a new type of mixer-settler applied to treat waste water contaminated with oil. An unity in scale of laboratory, was installed in the Post-graduation Program of Chemical Engineering of UFRN. It was constructed in partnership with Petrobras S.A. This called device Misturador-Decantador a Inversão de Fases (MDIF) , possess features of conventional mixer-settler and spray column type. The equipment is composed of three main parts: mixing chamber; chamber of decantation and chamber of separation. The efficiency of separation is evaluated analyzing the oil concentrations in water in the feed and the output of the device. For the analysis one used the gravimetric method of oil and greases analysis (TOG). The system in study is a water of formation emulsified with oil. The used extractant is a mixture of Turpentine spirit hydro-carbons, supplied for Petrobras. It was applied, for otimization of the efficiency of separation of the equipment, an experimental planning of the composite central type, having as factorial portion fractionary factorial planning 2 5-2, with the magnifying of the type star and five replications in the central point. In this work, the following independents variables were studied: contents of oil in the feed of the device; volumetric ratio (O/A); total flowrate ; agitation in the mixing chamber and height of the organic bed. Minimum and maximum limits for the studied variables had been fixed according previous works. The analysis of variance for the equation of the empirical model, revealed statistically significant and useful results for predictions ends. The variance analysis also presented the distribution of the error as a normal distribution and was observed that as the dispersions do not depend on the levels of the factors, the independence assumption can be verified. The variation around the average is explained by 98.98%, or either, equal to the maximum value, being the smoothing of the model in relation to the experimental points of 0,98981. The results present a strong interaction between the variable oil contents in the feed and agitation in the mixing chamber, having great and positive influence in the separation efficiency. Another variable that presented a great positive influence was the height of the organic bed. The best results of separation efficiency had been obtained for high flowrates when associates the high oil concentrations and high agitation. The results of the present work had shown excellent agreement with the results carried out through previous works with the mixer-settler of phase inversion

Caracterização de água produzida na indústria de petróleo para fins de descarte e otimização do processo de separação óleo/água

The oil industry has several segments that can impact the environment. Among these, produced water which has been highlight in the environmental problem because of the great volume generated and its toxic composition. Those waters are the major source of waste in the oil industry. The composition of the produced water is strongly dependent on the production field. A good example is the wastewater produced on a Petrobras operating unit of Rio Grande do Norte and Ceará (UO-RNCE). A single effluent treatment station (ETS) of this unit receives effluent from 48 wells (onshore and offshore), which leads a large fluctuations in the water quality that can become a complicating factor for future treatment processes. The present work aims to realize a diagnosis of a sample of produced water from the OU - RNCE in compliance to certain physical and physico-chemical parameters (chloride concentration, conductivity, dissolved oxygen, pH, TOG (oil & grease), nitrate concentration, turbidity, salinity and temperature). The analysis of the effluent is accomplished by means of a MP TROLL 9500 Multiparameter probe, a TOG/TPH Infracal from Wilks Enterprise Corp. - Model HATR - T (TOG) and a MD-31 condutivimeter of Digimed. Results were analyzed by univariated and multivariated analysis (principal component analysis) associated statistical control charts. The multivariate analysis showed a negative correlation between dissolved oxygen and turbidity (-0.55) and positive correlations between salinity and chloride (1), conductivity, chloride and salinity (0.70). Multivariated analysis showed there are seven principal components which can explain the variability of the parameters. The variables, salinity, conductivity and chloride were the most important variables, with, higher sampling variance. Statistical control charts have helped to establish a general trend between the physical and chemical evaluated parameters

Aplicação de microemulsão na recuperação de petróleo de reservatórios carbonáticos

The large investment in exploration activities offshore Brazil has generated new findings, generally in carbonate reservoirs, with different wettability conditions usually considered in the sandstone, strongly water-wet. In general, the carbonates reservoirs tend to be oil-wet, it difficult to mobilize of oil these reservoirs. These oils can be mobilized by different methods, or it may reverse the wettability of the surface of the reservoir and facilitate the flow of oil, improving production rates. Thus, the objective of this work was to study the influence of inversion on the wettability of the rock in the production and recovery of petroleum from carbonate reservoirs, using microemulsions. Three systems were chosen with different classes of surfactants: a cationic (C16TAB), an anionic (SDS) and nonionic (Unitol L90). Studies of the influence of salinity on the formation of the microemulsion as well as the characterization of fluids using density and viscosity measurements were also performed. To verify the potential of microemulsion systems in changing the wettability state of the chalk oil-wet to water-wet, contact angle measurements were performed using chalk of neutral-wet as surface material. Overall, with respect to the ionic character of the surfactants tested, the cationic surfactant (C16TAB) had a greater potential for reversal in wettability able to transform the rock wettability neutral to strongly water-wet, when compared with the anionic surfactant (SDS) and nonionic (Unitol L90), which showed similar behavior, improving the wettability of the rock to water. The microemulsions of all surfactants studied were effective in oil recovery, resulting in 76.92% for the system with C16TAB, 67.42% for the SDS and 66.30% for Unitol L90 of residual oil

Obtenção e aplicação de sistemas microemulsionados na recuperação avançada de petróleo

Due to the need of increasing production in reservoirs that are going through production decline, methods of advanced recovery have frequently been used in the last years, as the use of conventional methods has not been successful in solving the problem of oil drifting. In this work, the efficiency of different microemulsionated systems in the flow of oil from cores from Assu and Botucatu formations. Regarding drifting tests, cores were calcinated at a temperature of 1000°C, for 18 hours, with the aim of eliminating any organic compound present in it, increasing the resultant permeability. Following, the cores were isolated with resin, resulting in test specimens with the following dimensions: 3.8 cm of diameter and 8.7 cm of length. Cores were saturated with brine, composed of aqueous 2 wt % KCl, and oil from Guamaré treatment station (Petrobras/RN). A pressure of 20 psi was used in all tests. After core saturation, brine was injected again, followed by oil at constant flow rate. The system S3 - surfactant (anionic surfactant of short chain), isoamillic alcohol, pine oil, and water - presented the best drift efficiency, 81.18%, while the system S1E commercial surfactant, ethyl alcohol, pine oil, and distilled water presented low drift efficiency, 44,68%

O Circuito espacial de produção do biodiesel: configuração no território brasileiro e uso do território Norte-Rio-Grandense

This research aims to understand the use of the territory from the Rio Grande do Norte to the circuit spatial of production from the Biodiesel understanding it as part of the national context. The introduction of biodiesel into the Brazilian energy matrix begins to take shape in the year 2005 with the implementation of the National Program for Production and Use of Biodiesel (NPPB). This is anchored on three pillars: social inclusion (through family agriculture), environmental sustainability and economic viability. The NPPB consists of a set of standards, which turned into shares and distributed by almost all the national territory. Our reflection assumes that the places accommodating different forms of productive activities and, thus, the performance of the circuit space of biodiesel production depends on several factors, including the configuration of the territory they receive this new nexus economic. Understanding that the places by their technical content determine the realization of productive activities, it was found that the inclusion of this circuit space production in Rio Grande do Norte, reveals the reality expressed in the national territory, where some places are endowed with a privileged technical content and other extremely poor infrastructure. As our research could confirm the circuit space of biodiesel production that is expressed in the way plants are distributed within the country (mostly in South-Central), in more significant participation of small farmers in the South in the supply of raw material for the production of biodiesel and the main raw material used for the production of agrofuels (soybeans, whose production sector is highly consolidated and technified). Already the project materialization of NPPB regarding the settlements and communities of the Rio Grande do Norte State, we observed that the "event" or advent of realization encountered a technical means lacking in infrastructure that need to be molded to the needs of production, or is to cultivate castor beans or sunflower would be needed inputs and implements that farmers don´t have. Given the above, the research concludes that, as proposed previously, the use of the territory of Rio Grande do Norte to this circuit has summarized the performance of experiments, either with regard to the participation of family farmers as suppliers of raw materials, including the development of related research in the stage of production fuel oil by Petrobras. This finding came from research done from the concept of "spatial circuits of production," which allowed the verification of the circuit that steps outlined in Potiguar territory. Regarding the inclusion of family farmers in the productive circuit in RN, research reveals that, in the manner as has been done, it is doomed to failure. Furthermore, we dare say that this persistence in trying to put these family farmers, the way is being made, and the resulting successive failures, indicating that social inclusion advocated by NPPB not take place, and that this production circuit relies on the same logic circuit concentrated and exclusive space for ethanol production

Estudo paramétrico da injeção de polímeros em reservatórios de petróleo

Developing an efficient methodology for oil recovery is extremely important . Within the range of enh anced oil recovery, known as EOR, the injection of polymer solutions becomes effective in controlling the mobility of displacing fluid . This method consists of adding polymers to the injection water to increase its viscosity, so that more water diffuses in to the porous medium and increasing the sweep efficiency in the reservoir. This work is studied by numerical simulation , application of the injection polymer solution in a homogeneous reservoir , semisynthetic with similar characteristics to the reservoirs of the Brazilian Northeast , numerical simulations were performed using thermal simulator STARS from CMG (Computer Modelling Group ). The study aimed to analyze the influence of some parameters on the behavior of reservoir oil production, with the response to cumulative production. Simulations were performed to analyze the influence of water injection, polymer solution and alternating injection of water banks and polymer solution, comparing the results for each simulated condition. The primary outcomes were: oil viscosity, percentage of injected polymer, polymer viscosity and flow rate of water injection. The evaluation of the influence of variables consisted of a complete experimental design followed a Pareto analysis for the purpose of pointing out which va riables would be most influential on the response represented b y the cumulative oil production . It was found that all variables significantly influenced the recovery of oil and the injection of polymer solution on an ongoing basis is more efficient for the cumulative production compared to oil recovery by continuous water injection. The primary recovery show ed low levels of oil production , water injection significantly improves the pro duction of oil in the reservoir , but the injection of polymer solution em erges as a new methodology to increase the production of oil, increasing the life of the well and possible reduction of water produced.

Os limites constitucionais ao exercício de direito de patente e seus reflexos na indústria do petróleo, gás natural e biocombustíveis

This dissertation deals with the constitutional limits on the exercise of patent rights and its effects on the oil, natural gas and biofuels. Held with the support of ANP / PETROBRAS, It seeks to show how the law will limit the exercise of industrial property, based on a reinterpretation of private law by the constitutional development perspective . Today it is a fact that Petrobras, a Brazilian joint venture, has the latest technology in various sectors of the oil industry, and is one of the highest investments in developing new technologies. The overall objective of this thesis is to establish the relationship between the public interest of the Petroleum Industry, Natural Gas and Biofuels and constitutional limits to the free exercise of patent rights, then confirm or refute our hypothesis that Article 71 on Industrial Property Law is contrary to the existing objectives in Article 3 of the Constitution of the Federative Republic of Brazil. The research aims to examine the relevant aspects of the legal nature attributed to IPGN constitutionally confronting the constitutional limits on the free exercise of patent rights, with the purpose to outline the state of the performance limits in the regulation of the economy, in particular the application of feasibility limitations on the right of property in favor of national interest on the strategic energy industry. The aim is to confront the fundamental rights to property and economic development, against the public interest, limiting these first. As to the objectives, the research will be theoretical and descriptive and harvest of industrial property, respect the possible impact of regulatory standards and limiting the right of ownership in the oil industry. To establish how the state will mitigate the intellectual property right, we discuss, at first, a definition of public interest from the general theory of state and sovereign character in order to establish a new concept of national interest and popular interest, which will in turn the definition of our concept of public interest. In the second phase, will be addressed the issue of industrial property rights and how to will be free exercise thereof, in the constitutional sphere, infra, and demonstrating the use of industrial property rights with examples of market and IPGN . After situating the industrial property rights in the constitution and national legislation, establish their relationship with the national and regional development, will be addressed in this chapter in particular the patent law, as most usual form of intellectual property protection in IPGN. Used a study highlighting the number of patents in the area of the analyzed industry, demonstrating with hard data the importance of a sector for industrial development. The relationship between the social function of intellectual property and the constitutional objective of development was characterized to demonstrate the strategic nature of oil to Brazil in the national and international scene, and put into question the hypothesis of the research which provides that even with large investments the lack of legal certainty in the sector turns out not to have a considerable volume of investment as it could.

Estudo de simulação de reservatórios para o desenvolvimento de um campo do nordeste brasileiro

In the last 16 years emerged in Brazil a segment of independent producers with focus on onshore basins and shallow waters. Among the challenges of these companies is the development of fields with projects with a low net present value (NPV). The objective of this work was to study the technical-economical best option to develop an oil field in the Brazilian Northeast using reservoir simulation. Real geology, reservoir and production data was used to build the geological and simulation model. Due to not having PVT analysis, distillation method test data known as the true boiling points (TBP) were used to create a fluids model generating the PVT data. After execution of the history match, four development scenarios were simulated: the extrapolation of production without new investments, the conversion of a producing well for immiscible gas injection, the drilling of a vertical well and the drilling of a horizontal well. As a result, from the financial point of view, the gas injection is the alternative with lower added value, but it may be viable if there are environmental or regulatory restrictions to flaring or venting the produced gas into the atmosphere from this field or neighboring accumulations. The recovery factor achieved with the drilling of vertical and horizontal wells is similar, but the horizontal well is a project of production acceleration; therefore, the present incremental cumulative production with a minimum rate of company's attractiveness is higher. Depending on the crude oil Brent price and the drilling cost, this option can be technically and financially viable.