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

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

Desenvolvimento de sistemas de aditivos químicos para aplicação em cimentações de poços de petróleo

The primary cementing is an important step in the oilwell drilling process, ensuring the mechanical stability of the well and the hydraulic isolation between casing and formation. For slurries to meet the requirements for application in a certain well, some care in the project should be taken into account to obtain a cement paste with the proper composition. In most cases, it is necessary to add chemicals to the cement to modify its properties, according to the operation conditions and thus obtain slurries that can move inside the jacket providing a good displacement to the interest area. New technologies of preparation and use of chemicals and modernization of technological standards in the construction industry have resulted in the development of new chemical additives for optimizing the properties of building materials. Products such as polycarboxylate superplasticizers provide improved fluidity and cohesion of the cement grains, in addition to improving the dispersion with respect to slurries without additives. This study aimed at adapting chemical additives used in civil construction to be used use in oilwell cement slurries systems, using Portland cement CPP-Special Class as the hydraulic binder. The chemical additives classified as defoamer, dispersant, fluid loss controller and retarder were characterized by infrared absorption spectroscopy, thermogravimetric analyses and technological tests set by the API (American Petroleum Institute). These additives showed satisfactory results for its application in cement slurries systems for oil wells. The silicone-based defoamer promoted the reduction of air bubbles incorporated during the stirring of the slurries. The dispersant significantly reduced the rheological parameters of the systems studied. The tests performed with the fluid loss controller and the retarder also resulted in suitable properties for application as chemical additives in cement slurries

Desenvolvimento de pastas cimentantes utilizando cimentos portland compostos para cimentação de poços petrolíferos

The Compound Portland cements are commonly used in construction, among them stand out the CPII-Z, CPII-F and CPIV. These types of cement have limited application on oil well cementing, having its compositional characteristics focused specifically to construction, as cement for use in oil wells has greater complexity and properties covering the specific needs for each well to be coated. For operations of oil wells cementing are used Portland cements designed specifically for this purpose. The American Petroleum Institute (API) classifies cements into classes designated by letters A to J. In the petroleum industry, often it is used Class G cement, which is cement that meets all requirements needed for cement from classes A to E. According to the scenario described above, this paper aims to present a credible alternative to apply the compound cements in the oil industry due to the large availability of this cement in relation to oil well cements. The cements were micro structurally characterized by XRF, XRD and SEM tests, both in its anhydrous and hydrated state. Later technological tests were conducted to determine the limits set by the NBR 9831. Among the compound cements studied, the CPII-Z showed satisfactory properties for use in primary and secondary operations of oil wells up to 1200 meters cementing

Efeito da adição de microfibras de lã de vidro na tenacidade à ruptura de pastas de cimento para poços de petróleo

Although there are a wide variety of additives that act in fresh state, to adjust the properties of cement, there is also a search by additions that improve the tenacity of the cement in the hardened state. This, in turn, can often be increased by inserting fibers, which act on the deflection of microcracks. This study aimed to use a microfiber glass wool (silica-based) as an additive reinforcing the cement matrix, improving the rupture tenacity, in order to prevent the propagation of microcracks in the cement sheath commonly found in oil wells submitted to high temperatures. The fibers were added at different concentrations, 2 to 5% (BWOC) and varied average sizes, grinding for 90 s, 180 s, 300 s, 600 s. The cement slurries were made with a density of 1,90 g/ cm3 (15,6 lb/gal), using Portland cement CPP- Special Class as the hydraulic binder and 40% silica flour. The characterization of the fiber was made by scanning electron microscopy (SEM), particle size by sieving, X-ray fluorescence (XRF), X-ray diffraction (XRD) and thermogravimetry (TG / DTG). Were performed technological tests set by the API (American Petroleum Institute) by rheology, stability, free water, compressive strength, as well as testing rupture energy, elastic modulus and permeability. The characterization results showed good thermal stability of the microfiber glass wool for application in oil wells submitted to steam injection and, also, that from the particle size data, it was possible to suggest that microfibers milled up to 300 s, are ideal to act as reinforcement to the cement slurries. The rheological parameters, there was committal of plastic viscosity when larger lengths were inserted of microfiber (F90). The values obtained by free water and stability were presented according to API. The mechanical properties, the incorporation of microfiber to the cement slurries gave better rupture tenacity, as compared to reference cement slurries. The values of compressive strength, elastic modulus and permeability have been maintained with respect to the reference cement slurries. Thus, cement slurries reinforced with microfiber glass wool can ensure good application for cementing oil wells submitted to steam injection, which requires control of microcracks, due to the thermal gradients

Análise de Argamassas Com Substituição Parcial do Cimento Portland Por Cinza Residual de Lenha de Algaroba

With the increase in cement consumption, it has quickly become one of the inputs most consumed by mankind over the last century. This has caused an increase in CO2 emissions, as cement production releases large quantities of this gas into the atmosphere. Adding this fact to the growing consciousness of environmental preservation, it has led to a search for alternatives to cement to complement its derivatives, in the form of waste materials like the ashes. This research aimed to analyze the properties of mortars in fresh and hardened state with partial replacement of Portland cement by residual algaroba wood ash (CRLA) potteries produced by the state of Rio Grande do Norte. The CRLA was collected and sieved, where part of it was ground and characterized in comparison with that just sifted, being characterized according to its chemical composition, grain size, fineness, density, bulk density and index of pozzolanic activity. It was found that the wood ash does not act as pozzolan, and grinding it has not changed its characteristics compared to those just sifted, not justifying its use. Two traces were adopted for this research: 1:3 (cement: fine sand) and 1:2:8 (cement: hydrated lime: medium sand); both in volume, using as materials the CRLA just sifted, CP II F-32 Portland cement, CH-I hydrated lime, river sand and water from the local utility. For each trace were adopted six percentages of partial replacement of cement for wood ash: 0% (control) 5%, 7%, 10%, 12% and 15%. In the fresh state, the mortars were tested towards their consistency index and mass density. In the hardened state, they were tested towards their tensile strength in bending, compressive strength and tensile adhesion strength, and its mass density in the hardened state. The mortar was also analyzed by scanning electron microscopy and X-ray diffraction. Furthermore, it was classified according to NBR 13281 (2005). The results showed that up to a content of 5% substitution and for both traces, the residual algaroba wood ash can replace Portland cement without compromising the mortars microstructure and its fresh and hardened state

Estudo da viabilidade da utilização de cinza de lodo de esgoto como adição em argamassa de cimento Portland

The use of sewage sludge as a raw material falls within the waste recycling key in the current process model environmental sustainability .Waste recycling has been consolidated as a sustainable environmentally sound technical solution, and. Despite showing very variable composition and characteristics, sewage sludge, can be considered as a residue with a high recycling potential in the building sector. In this paper the feasibility of using sewage sludge ash was studied in addition to Portland cement mortar in 1:3 mass considered the standard dash. This gray additions were studied in proportions of 5%, 10 %, 15 %, 20 %, 25% and 30% by mass of cement. The methodology was focused on the characterization of materials by physical, chemical , mechanical , environmental and morphological followed by the production of mortar tests ,and finalized by the characterization tests of mortar in the fresh state, through the consistency index, content of entrained air, bulk density and water retention, and in the hardened state by bulk density, water absorption by capillarity capillarity coefficient, compressive strength, tensile strength in bending ,tensile bond strength and microstructural analysis for percentages of 0 to 20%. After comparing with the standard mortar mortars with addition of ash, it is concluded that the ash of sewage sludge did not impair the integrity and properties of mortars with addition, including increasing resistance to compression and tension, being 20% more indicated percentage. Thus, it becomes feasible the addition of sewage sludge ash in Portland cement mortar for the trait studied

Desenvolvimento de pastas cimentantes contendo nanossílica como material estendedor para aplicação em fases iniciais, de poços petrolíferos, submetidas à baixa temperatura (5°c ± 3ºc)

The improved performance of hydraulic binders, the base of Portland cement, consists in the careful selection and application of materials that promote greater durability and reduced maintenance costs There is a wide variety of chemical additives used in Portland cement slurries for cementing oil wells. These are designed to work in temperatures below 0 ° C (frozen areas of land) to 300 ° C (thermal recovery wells and geothermal); pressure ranges near ambient pressure (in shallow wells) to greater than 200 MPa (in deep wells). Thus, additives make possible the adaptation of the cement slurries for application under various conditions. Among the materials used in Portland cement slurry, for oil wells, the materials with nanometer scale have been applied with good results. The nanossílica, formed by a dispersion of SiO2 particles, in the nanometer scale, when used in cement systems improves the plastic characteristics and mechanical properties of the hardened material. This dispersion is used commercially as filler material, modifier of rheological properties and / or in recovery processes construction. It is also used in many product formulations such as paints, plastics, synthetic rubbers, adhesives, sealants and insulating materials Based on the above, this study aims to evaluate the performance of nanossílica as extender additive and improver of the performance of cement slurries subjected to low temperatures (5 ° C ± 3 ° C) for application to early stages of marine oil wells. Cement slurries were formulated, with densities 11.0;12.0 and 13.0 ppg, and concentrations of 0; 0.5, 1.0 and 1.5%. The cement slurries were subjected to cold temperatures (5 ° C ± 3 ° C), and its evaluation performed by tests rheological stability, free water and compressive strength in accordance with the procedures set by API SPEC 10A. Thermal characterization tests (TG / DTA) and crystallographic (XRD) were also performed. The use of nanossílica promoted reduction of 30% of the volume of free water and increased compression resistance value of 54.2% with respect to the default cement slurry. Therefore, nanossílica presented as a promising material for use in cement slurries used in the early stages of low-temperature oil wells

Avaliação da potencialidade de incorporação de um lodo de uma indústria de produtos de limpeza como adição mineral em concretos de cimento Portland

The generation of industrial wastes has been increased more and more in recent decades, motivating studies about a correct sustainable allocation and that also represents advantages for their generators. In this context, are included two companies of cleaning products niche, located in São José do Mipibu/RN, that produces industrial sludge at a sewage treatment plant, and that is the main approach of this research. Given this, it was studied the incorporation potentiality of this sludge as a mineral addition in cement matrix for concrete production due it high capacity of wastes immobilization inside this material, which are subsequently used in the company for making precast articles. Were added different sludge concentrations (5, 10, 15 and 20%) in a common trait (1: 2: 3), and evaluated their techniques and microstructural implications via workability test in fresh state and compressive strength, full porosity and scanning electron microscopy (SEM) in the hardened state. The results demonstrated the feasibility of the process both from a technical and environmental view as economical. All concretes produced with residue showed an increase of workability given the nature of the waste that had surfactants substances capable of adsorbing tiny particles of air into the batter. However, for all concentrations were obtained lower compressive resistances than standard concrete, with a reduction of 39% for samples with 20% of sludge. This are attributed mainly to an increase of porosity in the transition zone of these material, resulting from increased formation of ettringite at the detriment to the formation of other compounds, but which still allows the use of these for the manufacture of concrete articles with non-structural nature, such as precast floor. In addition, the water absorption and void ratio increased slightly for all samples, except the concrete with 20% of waste that has a reduction for the last parameter. Given this context, the recommended maximum level is 20%, constituting a significant proportion and able to allocate sustainably all waste generated in the industry.

Análise do comportamento reológico de pastas de cimento contendo resíduos de pneu para poços de petróleo

The low tenacity presented by the Portland cement pastes used in the oil wells cementation has been motivating several researches with attention focused on alternative materials. Additives have been developed to generate flexible pastes with mechanical resistance capable to support the expansions and retractions of the metallic covering of the wells that submit to the steam injection, technique very used to increase the recovery factor in oil reservoirs with high viscosity. A fresh paste with inadequate rheological behavior may commit the cementation process seriously, involving flaws that affect the performance of the paste substantially in the hardened state. This work proposes the elaboration and the rheological analysis of Portland cement pastes with addition of residues of rubber tire in several proportions, with the aim of minimizing the damages provoked in the hem cementing of these wells. By thermogravimetric analysis, the particles of eraser that go by the sieve of 0,5mm (35 mesh) opening and treated superficially with NaOH solution of 1 mol/L presented appropriate thermal resistance for wells that submit to thermal cyclic. The evaluation of the study based on the results of the rheological analysis of the pastes, complemented by the mechanical analysis, thickening, stability, tenor of free water and filtrate loss, being used as parameter a paste reference, without rubber addition. The results showed satisfactory rheology, passive of few corrections; considerable loss of mechanical resistance (traction and compression), compensated by earnings of tenacity, however with established limits for its application in oil wells; satisfactory stability, free water and thickening time

Estudo de revestimentos inorgânicos com inibidor de corrosão aplicado na superfície do concreto

The corrosive phenomenon on reinforced concrete structures is one of the most founded pathologies on the coastal area. With the objective to prevent the process development, or even, retard its beginning, it was studied the application of inorganic covering over concrete surfaces, after its cure, as well as, evaluate the efficiency of the covering applied on the concrete in reducing its porosity of concrete preventing the entrance of aggressive agents to preserve the integrity of the existing armor inside it, comparing the result obtained with the body-of-proof reference, that didn´t receive covering protection. On the concrete production it was used Portland Cement CP II 32, coarse aggregate, fine aggregate and water from the local distributive. Two types of covering were used, one resin based of silicon and solvent and other white cement based, selected sands and acrylic resin. The concrete mixture adopted was 1:1,5:2,5 (cement, fine aggregate, coarse aggregate) and 0.50 water/cement ratio. With the concrete on fresh state was made the experiment test to determinate the workability. On the hardened state was made the concrete resistance experiment, absorption of water and electrochemical experiments, through polarization curves. Also was held optical microscopy and Scanning Electron Microscopy experiments to analyze the layer of the covering applied to the concrete surface and the interface between the concrete and the layer. The obtained results shows that the covering applied to the concrete surface didn´t affect the resistance towards compression. On the absorption of water occurred a diminution of the percentage absorbed, improving the concrete development by making it more impermeable towards the entrance of aggressive agents. The electrochemical experiment results confirmed the water absorption results; the body-of-proof covered presented larger protection towards the development of corrosives process and retarded the evolution of the corrosive phenomenon

Influência da adição de cálcio nas propriedades de pastas geopoliméricas destinadas a cimentação de poços de petróleo

Nowadays, the search for new technologies that are able to follow the upcoming challenges in oil industry is a constant. Always trying properties improvements of the used materials, looking for the best performance and greater life time. Besides the search for technologies that show an improvement of performance, the search for materials environmentally correct along the whole production process. In Oil well cementing, this search for new technologies passes through the development of slurry systems that support these requests and that are also environmentally friendly. In this context, the use of geopolymer slurries is a great alternative route to cementing oil wells. Besides having good properties, comparable to Portland cement slurries, this alternative material releases much less CO2 gas in the production of their root materials when compared the production of Portland cement, which releases tons of CO2. In order to improve the properties of geopolymer slurries has been added Calcium Oxide, as observed in other studies that slurries where the Calcium is present the values of compressive strength is greater. The addition has been realized based in the CaO/SiO2 molar ratio of 0.05, 0.10 and 0.15. Have been performed compressive strength tests, thickening time, rheology and fliud loss control test of the slurries, following NBR 9831, as well as the physical chemical characterization of XRD, SEM and TG. Has been observed in most of the tests the slurries follow a tendency until the ratio of 0.10, which inverses in the ratio 0.15. This behavior can be explained by two phenomena that occur simultaneously, the first one is the break of the polymer chains and a consequent increase in molucules mobility, which prevails until the ratio of 0.1, and the second is possible approach of the chains due to the capacity of the calcium ions stabilize the charges of two different aluminum. There is only one linearity in the mechanical behavior that can be attributed to the appereance of the C-S-H phase. Based on this, it is concluded that the phenomenon of breaking the polymer chains predominates until the ratio of 0.1, causing an increase of the filtrate volume, lower rheological parameters and increasing thickening time. From the ratio of 0.15 the approach of the chains predominates, and the behavior is reversed

Síntese, aplicação e avaliação do efeito do teor de fósforo da celulose fosfatada em argamassa de alvenaria com aditivo comercial a base de hidroxi-etil-metil celulose (HEMC)

Generally, cellulose ethers improves mortar properties such as water retention, workability and setting time, along with adherence to the substrate. However, a major disadvantage of the addition of cellulose ethers in mortars is the delay in hydration of the cement. In this paper a cellulose phosphate (Cp) was synthesized water soluble and has been evaluated the effect of their incorporation into mortar based on Portland cement. Cellulose phosphate obtained was characterized by spectrophotometry Fourier transform infrared (FTIR), X-ray diffraction (XRD), elemental analysis and scanning electron microscopy (SEM). Mortar compositions were formulated with varying phosphorus content in cellulose and cellulose phosphate concentrations, when used in partial or total replacement of the commercial additive based hydroxyethyl methyl cellulose (HEMC). The mortars formulated with additives were prepared and characterized by: testing in the fresh state (consistency index, water retention, bulk density and air content incorporated) and in the hardened state (absorption by capillarity, density, flexural and compression strength). In mixtures the proportion of sand:cement of 1:5 (v / v) and factor a / c = 1.31 and water were held constant. Overall, the results showed that the celluloses phosphates employed in mortars added acted significantly when partially substituting the commercial additive. With regard to consistency index, water retention and bulk density in the fresh state and absorption by capillarity and bulk density apparent in the hardened state, showed no appreciable differences as compared to the commercial additive. The incorporated air content in the fresh state reduced markedly, but did not affect other properties. The mortars with cellulose phosphate, partially replacing the commercial additive showed an improvement of the properties of flexural strength and compressive strength

Efeito da incorporação de diatomita na estabilidade e permeabilidade de compósitos cimentíceos espumados aplicados a poços de petróleo

Lightweight oilwell cement slurries have been recently studied as a mean to improve zonal isolation and sheath-porous formation adherence. Foamed slurries consisting of Portland cement and air-entraining admixtures have become an interesting option for this application. The loss in hydrostatic pressure as a consequence of cement hydration results in the expansion of the air bubbles entrapped in the cement matrix, thus improving the sheath-porous formation contact. Consequently, slurries are able to better retain their water to complete the hydration process. The main objective of the present study was to evaluate the effect of the addition of an air-entraining admixture on the density, stability and permeability of composite slurries containing Portland cement and diatomite as light mineral load. Successful formulations are potential cementing materials for low fracture gradient oilwells. The experimental procedures used for slurry preparation and characterization were based on the American Petroleum Institute and ABNT guidelines Slurries containing a pre-established concentration of the air-entraining admixture and different contents of diatomite were prepared aiming at final densities of 13 to 15 lb/gal. The results revealed that the reduction of 15 to 25% of the density of the slurries did not significantly affect their strength. The addition of both diatomite and the air-entraining admixture increased the viscosity of the slurry providing better air-bubble retention in the volume of the slurry. Stable slurries depicted bottom to top density variation of less than 1.0 lb/gal and length reduction of the stability sample of 5.86 mm. Finally, permeability coefficient values between 0.617 and 0.406 mD were obtained. Therefore, lightweight oilwell cement slurries depicting a satisfactory set of physicochemical and mechanical properties can be formulated using a combination of diatomite and air-entraining admixtures for low fracture gradient oilwells

Compósitos Portland-biopolímeros para cimentação de poços de petróleo

The oil production in mature areas can be improved by advanced recovery techniques. In special, steam injection reduces the viscosity of heavy oils, thus improving its flow to surrounding wells. On the other hand, the usually high temperatures and pressures involved in the process may lead to cement cracking, negatively affecting both the mechanical stability and zonal isolation provided by the cement sheath of the well. The addition of plastic materials to the cement is an alternative to prevent this scenario. Composite slurries consisting of Portland cement and a natural biopolymer were studied. Samples containing different contents of biopolymer dispersed in a Portland cement matrix were prepared and evaluated by mechanical and rheological tests in order to assess their behavior according to API (American Petroleum Institute) guidelines. FEM was also applied to map the stress distribution encountered by the cement at bottom bole. The slurries were prepared according to a factorial experiment plan by varying three parameters, i.e., cement age, contents of biopolymer and water-to-cement ratio. The results revealed that the addition of the biopolymer reduced the volume of free water and the setting time of the slurry. In addition, tensile strength, compressive strength and toughness improved by 30% comparing hardened composites to plain Portland slurries. FEM results suggested that the stresses developed at bottomhole may be 10 to 100 times higher than the strength of the cement as evaluated in the lab by unconfined mechanical testing. An alternative approach is proposed to adapt the testing methodology used to evaluate the mechanical behavior of oilwell cement slurries by simulating the confined conditions encountered at bottornhole