Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-22T15:10:01Z No. of bitstreams: 1 DennysSalvinoSergioPereira_DISSERT.pdf: 3075551 bytes, checksum: e6d5511e1a1ab53ec644ffbc4a7e448e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-27T19:21:29Z (GMT) No. of bitstreams: 1 DennysSalvinoSergioPereira_DISSERT.pdf: 3075551 bytes, checksum: e6d5511e1a1ab53ec644ffbc4a7e448e (MD5) / Made available in DSpace on 2016-07-27T19:21:29Z (GMT). No. of bitstreams: 1 DennysSalvinoSergioPereira_DISSERT.pdf: 3075551 bytes, checksum: e6d5511e1a1ab53ec644ffbc4a7e448e (MD5) Previous issue date: 2015-07-10 / Pastas de cimento utilizadas em opera??es de cimenta??o de po?os petrol?feros s?o preparadas conforme as caracter?sticas especificas de cada po?o. As propriedades f?sicas requeridas para cada formula??o de pasta dependem das condi??es de temperatura e press?o do po?o a ser cimentado. As propriedades reol?gicas das pastas s?o par?metros de importante controle para a efici?ncia no deslocamento e posicionamento da pasta durante a opera??o de cimenta??o. Um dos principais tipos de aditivo utilizado para a adequa??o das propriedades reol?gicas das pastas de cimento ? o aditivo dispersante. O presente trabalho tem como objetivo estudar, a influ?ncia da varia??o do tempo de adi??o do policarboxilato (0, 5, 10 e 15 minutos) em pastas de cimento, considerando os per?odos iniciais de hidrata??o das part?culas de cimento como ponto fundamental para uma melhor atua??o do aditivo dispersante. Foram preparadas pastas com densidade fixada em 15,6 lb/gal (1,87 g/cm3) e concentra??es de policarboxilato variando entre 0,01 gpc at? 0,05 gpc, a temperatura de circula??o (BHCT) de 51?C e temperatura est?tica (BHST) de 76? C. As pastas foram caracterizadas a partir de ensaios reol?gicos, volume de filtrado, tempo de espessamento e resist?ncia ? compress?o para formula??es. Foram tamb?m realizados ensaios de Difra??o de raios-X (DRX) e Microscopia Eletr?nica de Varredura (MEV). Os resultados mostraram que a adi??o do policaboxilato ap?s 15 minutos reduziu em 70 % os valores dos par?metros reol?gicos. De acordo com resultados de DRX e MEV, a adi??o do dispersante, ap?s 15 minutos, n?o influenciou as rea??es qu?micas e a consequente forma??o dos produtos de hidrata??o do cimento. / Cement pastes used in cementing oil wells operations are prepared according to the specific characteristics of each well. The physical properties requested for each folder formulation depend on the temperature and pressure of the well to be cemented. The rheological properties of the pulp are important control parameter for efficiency in transportation and positioning the folder during the cementing operation. One of the main types of additive used for the adjustment of rheological properties of cement pastes is the dispersant additive. This work aims to study the influence of variation of the time of addition of the polycarboxylate (0, 5, 10 and 15 minutes) in cement pastes, considering the initial periods of hydration of cement particles as fundamental point for better performance dispersant additive. Pastes were prepared with a density set at 15.6 lb/gal (1.87 g/cm3) and polycarboxylate concentrations ranging from 0.01 gpc to 0.05 gpc circulation temperature (BHCT) of 51?C and static temperature (BHST) of 76 C. The pastes were characterized from a rheological measurements, volume filtered, thickening time and resistance to compression formulations. Also were carried out tests Diffraction X-ray (XRD) and Scanning Electron Microscopy (MEV). The results showed that the addition of policaboxilato after 15 minutes decreased by 70% the values of rheological parameters. According to results of DRX and MEV, the addition of dispersant after 15 minutes did not affect the chemical reactions and subsequent formation of cement hydration products. A study of the economic feasibility to realize the financial benefits of the technique, which can be seen only with the use of the technique in this work to reduce the cost of production of cement paste was carried out, can get up to $ 1015.00 for each folder 100 barrels produced with said formulations.