Aditivação de pastas geopoliméricas com tetraborato de sódio e látex não iônico para cimentação de Poços de Petróleo

The development of activities in the oil and gas sector has been promoting the search for materials more adequate to oilwell cementing operation. In the state of Rio Grande do Norte, the cement sheath integrity tend to fail during steam injection operation which is necessary to increase oil recovery in reservoir with heavy oil. Geopolymer is a material that can be used as alternative cement. It has been used in manufacturing of fireproof compounds, construction of structures and for controlling of toxic or radioactive waste. Latex is widely used in Portland cement slurries and its characteristic is the increase of compressive strength of cement slurries. Sodium Tetraborate is used in dental cement as a retarder. The addition of this additive aim to improve the geopolymeric slurries properties for oilwell cementing operation. The slurries studied are constituted of metakaolinite, potassium silicate, potassium hydroxide, non-ionic latex and sodium tetraborate. The properties evaluated were: viscosity, compressive strength, thickening time, density, fluid loss control, at ambient temperature (27 ºC) and at cement specification temperature. The tests were carried out in accordance to the practical recommendations of the norm API RP 10B. The slurries with sodium tetraborate did not change either their rheological properties or their mechanical properties or their density in relation the slurry with no additive. The increase of the concentration of sodium tetraborate increased the water loss at both temperatures studied. The best result obtained with the addition of sodium tetraborate was thickening time, which was tripled. The addition of latex in the slurries studied diminished their rheological properties and their density, however, at ambient temperature, it increased their compressive strength and it functioned as an accelerator. The increase of latex concentration increased the presence of water and then diminished the density of the slurries and increased the water loss. From the results obtained, it was concluded that sodium tetraborate and non-ionic latex are promising additives for geopolymer slurries to be used in oilwell cementing operation

Injeção de vapor e solvente como um método de recuperação avançada em reservatório avançada em reservatórios de óleo pesado

Currently a resource more and more used by the petroleum industry to increase the efficiency of steam flood mechanism is the addition of solvents. The process can be understood as a combination of a thermal method (steam injection) with a miscible method (solvent injection), promoting, thus, the reduction of interfacial tensions and oil viscosity. The use of solvent alone tends to be limited because of its high cost. When co-injected with steam, the vaporized solvent condenses in the cooler regions of the reservoir and mixes with the oil, creating a zone of low viscosity between the steam and the heavy oil. The mobility of the displaced fluid is then improved, resulting in an increase of oil recovery. To better understand this improved oil recovery method, a numerical study of the process was done contemplating the effects of some operational parameters (distance between wells, injection steam rate, kind of solvent and injected solvent volume)on the accumulated production of oil, recovery factor and oil-steam rate. Semisynthetic models were used in this study but reservoir data can be extrapolated for practical applications situations on Potiguar Basin. Simulations were performed in STARS (CMG, 2007.11). It was found that injected solvent volumes increased oil recovery and oil rates. Further the majority of the injected solvent was produced and can be recycled

Estudo paramétrico da recuperação de óleo no processo de drenagem gravitacional com injeção de CO2

The gas injection has become the most important IOR process in the United States. Furthermore, the year 2006 marks the first time the gas injection IOR production has surpassed that of steam injection. In Brazil, the installation of a petrochemical complex in the Northeast of Brazil (Bahia State) offers opportunities for the injection of gases in the fields located in the Recôncavo Basin. Field-scale gas injection applications have almost always been associated with design and operational difficulties. The mobility ratio, which controls the volumetric sweep, between the injected gas and displaced oil bank in gas processes, is typically unfavorable due to the relatively low viscosity of the injected gas. Furthermore, the difference between their densities results in severe gravity segregation of fluids in the reservoirs, consequently leading to poor control in the volumetric sweep. Nowadays, from the above applications of gas injection, the WAG process is most popular. However, in attempting to solve the mobility problems, the WAG process gives rise to other problems associated with increased water saturation in the reservoir including diminished gas injectivity and increased competition to the flow of oil. The low field performance of WAG floods with oil recoveries in the range of 5-10% is a clear indication of these problems. In order to find na effective alternative to WAG, the Gas Assisted Gravity Drainage (GAGD) was developed. This process is designed to take advantage of gravity force to allow vertical segregation between the injected CO2 and reservoir crude oil due to their density difference. This process consists of placing horizontal producers near the bottom of the pay zone and injecting gás through existing vertical wells in field. Homogeneous models were used in this work which can be extrapolated to commercial application for fields located in the Northeast of Brazil. The simulations were performed in a CMG simulator, the STARS 2007.11, where some parameters and their interactions were analyzed. The results have shown that the CO2 injection in GAGD process increased significantly the rate and the final recovery of oil

Influência da adição de gres porcelanato no comportamento mecânico e microestrutural em pastas de cimento portland para cimentação de poços de petróleo

Cementation operation consists in an extremely important work for the phases of perforation and completion of oil wells, causing a great impact on the well productivity. Several problems can occur with the cement during the primary cementation, as well as throughout the productive period. The corrective operations are frequent, but they are expensive and demands production time. Besides the direct cost, prejudices from the interruption of oil and gas production till the implementation of a corrective operation must be also taken into account. The purpose of this work is the development of an alternative cement paste constituted of Portland cement and porcelainized stoneware residue produced by ceramic industry in order to achieve characteristics as low permeability, high tenacity, and high mechanical resistance, capable of supporting various operations as production or oil wells recuperation. Four different concentration measures of hydrated paste were evaluated: a reference paste, and three additional ones with ceramic residue in concentrations of the order of 10%, 20% and 30% in relation to cement dough. High resistance and low permeability were found in high concentration of residues, as well as it was proved the pozolanic reactivity of the residue in relation to Portland cement, which was characterized through x-ray and thermogravimetry assays. It was evident the decrease of calcium hydroxide content, once it was substituted by formation of new hydrated products as it was added ceramic residue

Incorporação de resíduo cerâmico para prevenção da retrogressão da resistência de cimentos de poços de petróleo submetidos à injeção de vapor

Steam injection is the most used thermal recovery method of oil nowadays because of the high degree of development of the technique that allows high recovery factors. However, injection of superheated steam into the reservoir affects the entire structure of the well, including the cemented layer that presents a retrogression of compressive strength and increases the permeability due to formation of more crystalline and denser phases at temperatures above 110 °C. These changes result in failures in the cement that favor the entrance of formation fluids into the annulus space resulting in unsafe operations and restrictions in the economic life of the well. But the strength retrogression can be prevented by partial replacement of cement by silica-based materials that reduce the CaO/SiO2 ratio of cement slurries changing the trajectory of the reactions, converting those deleterious phases in phases with satisfactory mechanical strength and permeability. The aim of this study was to evaluate the behavior of a ceramic waste material rich in silica in partial and total substitution of a mineral additive used to fight the strength retrogression of cement slurries subjected to high temperatures. The evaluation was made by compression, X-ray diffraction (XRD) and thermogravimetry (TG/DTG). The samples were submitted to a cycle of low temperature (38 °C) for 28 days and a cycle of low temperature followed by exposure to 280 ºC and 1000 psi by 3 days. The results showed that slurries with additions of up to 30% of the waste material are not enough to prevent the strength retrogression, while slurries with additions of the waste material combined with silica flour in various proportions produced hydrated products of low Ca/Si ratios that maintained the compressive strength at satisfactory levels

Análise comparativa entre simuladores de linha de fluxo e diferenças finitas para um reservatório de petróleo submetido a injeção de água

Water injection is the most widely used method for supplementary recovery in many oil fields due to various reasons, like the fact that water is an effective displacing agent of low viscosity oils, the water injection projects are relatively simple to establish and the water availability at a relatively low cost. For design of water injection projects is necessary to do reservoir studies in order to define the various parameters needed to increase the effectiveness of the method. For this kind of study can be used several mathematical models classified into two general categories: analytical or numerical. The present work aims to do a comparative analysis between the results presented by flow lines simulator and conventional finite differences simulator; both types of simulators are based on numerical methods designed to model light oil reservoirs subjected to water injection. Therefore, it was defined two reservoir models: the first one was a heterogeneous model whose petrophysical properties vary along the reservoir and the other one was created using average petrophysical properties obtained from the first model. Comparisons were done considering that the results of these two models were always in the same operational conditions. Then some rock and fluid parameters have been changed in both models and again the results were compared. From the factorial design, that was done to study the sensitivity analysis of reservoir parameters, a few cases were chosen to study the role of water injection rate and the vertical position of wells perforations in production forecast. It was observed that the results from the two simulators are quite similar in most of the cases; differences were found only in those cases where there was an increase in gas solubility ratio of the model. Thus, it was concluded that in flow simulation of reservoirs analogous of those now studied, mainly when the gas solubility ratio is low, the conventional finite differences simulator may be replaced by flow lines simulator the production forecast is compatible but the computational processing time is lower.

Estudo dos parâmetros operacionais do processo de combustão in situ em reservatório de petróleo pesado

The occurrence of heavy oil reservoirs have increased substantially and, due to the high viscosity characteristic of this type of oil, conventional recovery methods can not be applied. Thermal methods have been studied for the recovery of this type of oil, with a main objective to reduce its viscosity, by increasing the reservoir temperature, favoring the mobility of the oil and allowing an increasing in the productivity rate of the fields. In situ combustion (ISC) is a thermal recovery method in which heat is produced inside the reservoir by the combustion of part of the oil with injected oxygen, contrasting with the injection of fluid that is heated in the surface for subsequent injection, which leads to loss heat during the trajectory to the reservoir. The ISC is a favorable method for recovery of heavy oil, but it is still difficult to be field implemented. This work had as an objective the parametric analysis of ISC process applied to a semi-synthetic reservoir with characteristics of the Brazilian Northeast reservoirs using vertical production and vertical injection wells, as the air flow injection and the wells completions. For the analysis, was used a commercial program for simulation of oil reservoirs using thermal processes, called Steam, Thermal and Advanced Processes Reservoir Simulator (STARS) from Computer Modelling Group (CMG). From the results it was possible to analyze the efficiency of the ISC process in heavy oil reservoirs by increasing the reservoir temperature, providing a large decrease in oil viscosity, increasing its mobility inside the reservoir, as well as the improvement in the quality of this oil and therefore increasing significantly its recovered fraction. Among the analyzed parameters, the flow rate of air injection was the one which had greater influence in ISC, obtaining higher recovery factor the higher is the flow rate of injection, due to the greater amount of oxygen while ensuring the maintenance of the combustion front

Análise paramétrica do método de injeção alternada de água e CO2(WAG) em reservatórios de petróleo

After the decline of production from natural energy of the reservoir, the methods of enhanced oil recovery, which methods result from the application of special processes such as chemical injection, miscible gases, thermal and others can be applied. The advanced recovery method with alternating - CO2 injection WAG uses the injection of water and gas, normally miscible that will come in contact with the stock oil. In Brazil with the discovery of pre-salt layer that gas gained prominence. The amount of CO2 present in the oil produced in the pre-salt layer, as well as some reservoirs is one of the challenges to be overcome in relation to sustainable production once this gas needs to be processed in some way. Many targets for CO2 are proposed by researchers to describe some alternatives to the use of CO2 gas produced such as enhanced recovery, storage depleted fields, salt caverns storage and marketing of CO2 even in plants. The largest oil discoveries in Brazil have recently been made by Petrobras in the pre -salt layer located between the states of Santa Catarina and Espírito Santo, where he met large volumes of light oil with a density of approximately 28 ° API, low acidity and low sulfur content. This oil that has a large amount of dissolved CO2 and thus a pioneering solution for the fate of this gas comes with an advanced recovery. The objective of this research is to analyze which parameters had the greatest influence on the enhanced recovery process. The simulations were performed using the "GEM" module of the Computer Modelling Group, with the aim of studying the advanced recovery method in question. For this work, semi - synthetic models were used with reservoir and fluid data that can be extrapolated to practical situations in the Brazilian Northeast. The results showed the influence of the alternating injection of water and gas on the recovery factor and flow rate of oil production process, when compared to primary recovery and continuous water injection or continuous gas injection

Análise da recuperação em reservatório de gás com baixa permeabilidade (TIGHT GAS) através do fraturamento hidráulico

With the increasing of energetic consumption in the worldwile, conventional reservoirs, known by their easy exploration and exploitation, are not being enough to satisfy this demand, what has made necessary exploring unconventional reservoirs. This kind of exploration demands developing more advanced technologies to make possible to exploit those hydrocarbons. Tight gas is an example of this kind of unconventional reservoir. It refers to sandstone fields with low porosity, around 8%, and permeabilities between 0.1 and 0.0001 mD, which accumulates considerable amounts of natural gas. That natural gas can only be extracted by applying hydraulic fracturing, aiming at stimulating the reservoir, by creating a preferential way through the reservoir to the well, changing and making easier the flow of fluids, thus increasing the productivity of those reservoirs. Therefore, the objective of this thesis is analyzing the recovery factor of a reservoir by applying hydraulic fracturing. All the studies were performed through simulations using the IMEX software, by CMG (Computer Modelling Group), in it 2012.10 version

Um modelo matemático baseado em wavelets para análise do método térmico de recuperação de óleo pesado aplicando irradiação eletromagnética

This work proposes a model to investigate the use of a cylindrical antenna used in the thermal method of recovering through electromagnetic radiation of high-viscosity oil. The antenna has a simple geometry, adapted dipole type, and it can be modelled by using Maxwell s equation. The wavelet transforms are used as basis functions and applied in conjunction with the method of moments to obtain the current distribution in the antenna. The electric field, power and temperature distribution are carefully calculated for the analysis of the antenna as electromagnetic heating. The energy performance is analyzed based on thermo-fluid dynamic simulations at field scale, and through the adaptation in the Steam Thermal and Advanced Processes Reservoir Simulator (STARS) by Computer Modelling Group (CMG). The model proposed and the numerical results obtained are stable and presented good agreement with the results reported in the specialized literature

Validação de uma metodologia de ensaio de resistência ao cisalhamento para avaliação da aderência de interfaces revestimento metálico-bainha de cimento aplicada a poços de petróleo

Improving the adherence between oilwell metallic casing and cement sheath potentially decrease the number of corrective actions present/y necessary for Northeastern wells submitted to steam injection. In addition to the direct costs involved in the corrective operations, the economic impact of the failure of the primary cementing aIso includes the loss in the production of the well. The adherence between casing and cement is current/y evaluated by a simple shear tests non standardized by the American Petroleum Institute (API). Therefore, the objective of the present is to propose and evaluate a standardized method to assess the adherence of oilwell metallic casing to cement sheath. To that end, a section of a cemented oilwell was simulated and used to test the effect of different parameters on the shear stress of the system. Surface roughness and different cement compositions submitted or not to thermal cycling were evaluated. The results revealed that the test geometry and parameters proposed yielded different values for the shear stress of the system, corresponding to different adherent conditions between metallic casing and cement sheath

Aplicação de ultrassons no deslocamento de petróleo em meio poroso

The objective of this study was to evaluate the displacement of petroleum/diesel solutions, at different concentrations, observing the effect of ultrasonic vibrations in fluids present in porous media to obtain an increase in oil production. The bubbles produced by ultrasound implode asymmetrically in the rock, generating liquid jets with high speed, displacing the oil present in porous media. The oil/diesel solutions were prepared with concentrations ranging from 20 g/L to 720 g/L in oil in relation to diesel and its viscosities were obtained in a Brookfield Rheometer RS2000, with temperature ranging from 25 to 55 °C. After, calculations were performed to obtain the activation energy data for oil/diesel solutions. For oil recovery experiments, cylindrical samples of porous rock (core samples), with resin around the perimeter and its two circular bases free to allow the passage of fluids, were first saturated with 2% KCl solution and after with oil solutions. The results of oil extraction were satisfactory for all studied solutions, being obtained up to 68% partial displacement with saline solution injection. The ultrasound system was used after saline injection, increasing oil displacement, with oil extractions ranging from 63% to 79%. During the experiments, it was observed the warming of core samples, helping to reduce the viscosity of more concentrated systems, and consequently enhancing the percentage of advanced recovery for all studied solutions

Estudo da recuperação de óleo por drenagem gravitacional assistida por injeção de vapor

Steam assisted gravity drainage process (SAGD) involves two parallel horizontal wells located in a same vertical plane, where the top well is used as steam injector and the bottom well as producer. The dominant force in this process is gravitational. This improved oil recovery method has been demonstrated to be economically viable in commercial projects of oil recovery for heavy and extra heavy oil, but it is not yet implemented in Brazil. The study of this technology in reservoirs with characteristics of regional basins is necessary in order to analyze if this process can be used, minimizing the steam rate demand and improving the process profitability. In this study, a homogeneous reservoir was modeled with characteristics of Brazilian Northeast reservoirs. Simulations were accomplished with STARS , a commercial software from Computer Modelling Group, which is used to simulate improved oil recovery process in oil reservoirs. In this work, a steam optimization was accomplished in reservoirs with different physical characteristics and in different cases, through a technical-economic analysis. It was also studied a semi-continuous steam injection or with injection stops. Results showed that it is possible to use a simplified equation of the net present value, which incorporates earnings and expenses on oil production and expenses in steam requirement, in order to optimize steam rate and obtaining a higher net present value in the process. It was observed that SAGD process can be or not profitable depending on reservoirs characteristics. It was also obtained that steam demand can still be reduced injecting in a non continuous form, alternating steam injection with stops at several time intervals. The optimization of these intervals allowed to minimize heat losses and to improve oil recovery

Recuperação e purificação de ramnolipídeos produzidos por pseudomonas aeruginosa P029-GVIIA utilizando melaço de cana como substrato

Biosurfactants are molecules produced by microorganisms mainly bacteria as Pseudomonas and Bacillus. Among the biosurfactants, rhamnolipids play an important role due to their tensoactive as well as emulsifying properties. Besides can be produced in a well consolidated way the production costs of biosurfactants are quite expansive mainly if downstream processing is goning to be considered. Actually, attention has been given to identification of biosurfactants as well as optimization of its fermentative processes including downstream ones. This work deals with the development of strategies to recovery and purification of rhamnolipids produced by Pseudomonas aeruginosa P029-GVIIA using sugar-cane molasses as substrate. Broth free of cells was used in order to investigate the best strategies to recovery and purification produced by this system. Between the studied acids (HCl and H2SO4) for the acid precipitation step, HCl was the best one as has been showed by the experimental design 24. Extraction has been carried out using petroleum ether and quantification has been done using the thioglycolic acid method. Adsorption studies were carried out with activated carbon in a batch mode using a 24 experimental design as well as combined with an hydrophobic resin Streamline Phenyl aiming to separate the produced biosurfactant. Biosurfactant partial identification was carried out using High Performance Liquid Chromatography (HPLC). Experiments in batch mode showed that adsorption has been controlled mainly by pH and temperature. It was observed a reduction of 41.4% for the liquid phase and the solid phase it was possible to adsorb up to 15 mg of rhamnolipd/g of activated carbon. The kinetics of adsorption has been well fitted to a pseudo-first order reaction with velocity constant (k1) of 1.93 x 10-2 min-1. Experiments in packed bed ranging concentration on eluent (acetone) has been shown the highest recovery factor of 98% when pure acetone has been used. The combined effect if using activated carbon with an hydrophobic resin Streamline Phenyl has been shown successful for the rhamnolipids purification. It has been possible to purify a fraction of the crude broth with 98% of purity when the eluted of activated carbon packed bed was used with pure acetone

Desenvolvimento de um sistema foto-oxidativo visando aplicação no tratamento de águas produzidas em campos de petróleo

Increasing concern with the environment, in addition to strict laws, has induced the industries to find altenatives to the treatment of their wastes. Actually, the oil industry has sought solutions to overcome a big environmental problem, i.e., oil field produced water being discharged to the sea. These effluents have organic compounds dissolved, such as polycyclic aromatic hydrocarbons, phenols, benzene, toluene, ethylbenzene and xylenes (BTEX). These compounds are difficult to be removed and have high toxicity. The advanced oxidation processes - AOP are effective to degradation of these organic compounds, because they generate hydroxyl radicals with high potential of oxidation. This work includes the reactor photochemical development applied in the photodegradation treatment (by photo-Fenton process) of wastewaters containing organic compounds dissolved, aiming at treatment and recovery the oil field produced water. The studied reactor allowed the evaluation of two ultraviolet radiation sources that is the main factor to describe the feasibility of the photo¬Fenton treatment, i.e., sun and black light fluorescent lamps, and other relevant variables the process: concentration of reagents, irradiated area and also various reactor configurations to maximize the use of radiation. The organic matter degradation was verified with samples collected during the experimental and analyzed with a total organic carbon analyzer (TOC), which expressed the results in terms of mgC/L. The solar radiation was more effective than radiation from the lamps. it's an important factor for the operation costs cutting. Preliminary experiments applied to oil field produced water treatment have showed satisfactory results, reducing up to 76 % of organic matter