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Previous issue date: 2014-04-28 / Reservat?rios que apresentam ?leos muito viscosos necessitam de m?todos que auxiliem a recupera??o dos mesmos at? a superf?cie. A elevada viscosidade do ?leo dificulta o seu fluxo no meio poroso e m?todos convencionais de recupera??o n?o t?m obtido efici?ncia significativa. Com isto, a inje??o de vapor no reservat?rio, atrav?s de um po?o injetor, tem sido o m?todo t?rmico de recupera??o de ?leo mais utilizado, por permitir elevados fatores de recupera??o, pois reduz a viscosidade do ?leo, facilitando sua mobilidade pela rocha e consequente entrada no po?o produtor por onde ser? elevado. Em contrapartida, a inje??o do vapor afeta n?o s? os fluidos contidos nos poros das rochas, mas tamb?m toda a estrutura que comp?e o po?o por onde ? injetado, devido ? alta temperatura empregada no processo. Este incremento de temperatura ? sentido pelo cimento respons?vel pelo isolamento da parede do po?o e revestimento met?lico alocado no mesmo, devido esta alta temperatura atuar na forma??o de novas fases ricas em c?lcio, ocasionando redu??o de sua permeabilidade e consequente fen?meno da retrogress?o de sua resist?ncia mec?nica. Estas altera??es geram falhas no cimento, reduzindo o isolamento hidr?ulico do po?o, propiciando a haver inseguran?a nas opera??es que o po?o venha a ser submetido, bem como redu??o de sua vida econ?mica. Como forma de reduzir o efeito da retrogress?o, este trabalho teve como objetivo avaliar a incorpora??o de cinza da casca de arroz como aditivo mineral substituinte da s?lica four, comercialmente utilizada, como fonte de s?lica para reduzir a raz?o CaO/SiO2 das pastas de cimento submetidas a altas temperaturas na recupera??o t?rmica. Foram formuladas pastas de cimento apresentando teores de cinza de 20 e 30 %, al?m de uma pasta padr?o (?gua + cimento) e uma pasta refer?ncia (?gua + cimento + s?lica flour) como efeito comparativo. As avalia??es foram realizadas atrav?s de ensaios de resist?ncia ? compress?o, t?cnica de difra??o de raios-X (DRX), termogravimetria (TG), microscopia eletr?nica de varredura (MEV) e an?lise qu?mica por fluoresc?ncia de raios-X (EDS) nas pastas submetidas ? cura a baixa temperatura (45 ?C) por 28 dias seguido de cura a 280 ?C e uma press?o de 2.000 PSI por 3 dias, simulando inje??o de vapor. Os resultados obtidos mostraram que a pasta contendo 30 % de cinza da casca de arroz foram satisfat?rios, obtendo resist?ncia mec?nica desej?vel e equivalente ? resist?ncia mec?nica da pasta contendo 40 % de s?lica flour, devido a terem sido obtidos produtos de hidrata??o com baixa rela??o Ca/Si, como as fases Tobermorita e Xonotlita, para a aplica??o em po?os sujeitos ? inje??o de vapor. / Reservoirs that present highly viscous oils require methods to aid in their recovery to
the surface. The elev
ated oil viscosity hinders its flow through porous media and
conventional recovery methods have not obtained significant efficiency. As such, the
injection of steam into the reservoir through an injection well has been the most
widely used method of therma
l recovery, for it allows elevated volumes of recovery
due to the viscosity reduction of the oil, facilitating the oil?s mobility within the rock
formation and consequently into the production well where it will be exploited. On the
other hand, the injecti
on of vapor not only affects the fluids found in the rock pores,
but the entire structure that composes the well where it is injected due to the high
temperatures used in the process. This temperature increment is conducted to the
cement, found in the annu
lus, responsible for the isolation of the well and the well
casing. Temperatures above 110 ?C create new fazes rich in calcium in the cement
matrix, resulting in the reduction of its permeability and the consequential
phenomenon of mechanical resistance ret
rogression. These alterations generate
faults in the cement, reducing the well?s hydraulic isolation, creating insecurity in the
operations in which the well will be submitted as well as the reduction of its economic
life span. As a way of reducing this re
trograde effect, this study has the objective of
evaluating the incorporation of rice husk ash as a mineral additive substitute of
silica
flour
, commercially utilized as a source of silica to reduce the CaO/SiO
2
ratio in the
cement pastes submitted to high
temperatures in thermal recovery.
Cement pastes
were formulated containing 20 and 30% levels of ash, apart from the basic paste
(water + cement) and a reference paste (water + cement + 40% silica flour) for
comparison purposes. The tests were executed th
rough compression resistance
tests, X
-
Ray diffraction (XRD) techniques, thermogravimetry (TG), scanning electron
microscopy (SEM) and chemical anal
ysis BY X
-
ray fluorescence (EDS) on the pastes
submitted to cure at low temperatures (45 ?C) for 28 days following a cure at 280 ?C
and a pressure of 2,000 PSI for 3 days, simulating vapor injection.
The results
obtained show that the paste containing 30% r
ice shell ash is satisfactory, obtaining
mechanical resistance desired and equivalent to that of the paste containing 40%
silica flour,
since the products obtained were hydrated with low
CaO/SiO
2
ratio, like
the Tobermorita and Xonotlita fases, proving its
applicability in well subject to vapor
injection.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/19247 |
| Date | 28 April 2014 |
| Creators | Santiago, Rodrigo Cesar |
| Contributors | 06117988320, http://lattes.cnpq.br/3318871716111536, Garnica, Alfredo Ismael Curbelo, 05227790779, http://lattes.cnpq.br/0257037690238235, Paskocimas, Carlos Alberto, 06296687877, http://lattes.cnpq.br/2365059843175411, Pinto, Erica Natasche De Medeiros Gurgel, 00985100451, http://lattes.cnpq.br/6531020251306710, Freitas, Julio Cezar De Oliveira, 00957245408, http://lattes.cnpq.br/2357217530716519, Melo, Dulce Maria De Araujo |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE MATERIAIS, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/embargoedAccess |
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