Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-25T20:37:14Z No. of bitstreams: 1 RosimeireFilgueiraCosta_DISSERT.pdf: 1863855 bytes, checksum: 98da8847b8f23900b5d51e026eebbf2e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-27T00:02:09Z (GMT) No. of bitstreams: 1 RosimeireFilgueiraCosta_DISSERT.pdf: 1863855 bytes, checksum: 98da8847b8f23900b5d51e026eebbf2e (MD5) / Made available in DSpace on 2016-04-27T00:02:09Z (GMT). No. of bitstreams: 1 RosimeireFilgueiraCosta_DISSERT.pdf: 1863855 bytes, checksum: 98da8847b8f23900b5d51e026eebbf2e (MD5) Previous issue date: 2015-07-24 / Neste trabalho, foi investigado o efeito da adi??o de poliacrilamida parcialmente hidrolisada (HPAM) e bentonita nas propriedades f?sico-qu?micas de fluidos de perfura??o aquosos. Duas formula??es foram avaliadas: a formula??o F1, que foi utilizada como refer?ncia, contendo carboximetilcelulose (CMC), ?xido de magn?sio (MgO), calcita (carbonato de c?lcio ? CaCO3 ), goma xantana, cloreto de s?dio (NaCl) e triazina (bactericida); e a formula??o F2, contendo HPAM em substitui??o a CMC e bentonita em substitui??o ? calcita. Os fluidos preparados foram caracterizados quanto ?s propriedades reol?gicas, a lubricidade e o volume de filtrado. A calcita foi caracterizada por granulometria e an?lise termogravim?trica (TGA). A formula??o F2 apresentou controle de filtra??o ? temperatura de 93 ?C 34 mL, enquanto a F1 apresentou filtra??o total. O coeficiente de lubricidade da formula??o F2 foi 0, 1623 e o da F1 0, 2542, acarretando uma redu??o de torque de 25% para F1 e de 52% para F2, comparado ? ?gua. Na temperatura de 49 ?C e taxa de cisalhamento 1022 s ?1 , as viscosidades aparentes foram 25, 5 e 48 cP para as formula??es F1 e F2, respectivamente, evidenciando maior resist?ncia t?rmica para F2. Com a comprova??o da maior estabilidade t?rmica de F2, um planejamento fatorial foi realizado, a fim de determinar as concentra??es de HPAM e de bentonita de melhor desempenho nos fluidos. O planejamento estat?stico gerou superf?cies de resposta indicando as melhores concentra??es de HPAM (4, 3 g/L) e de bentonita (28, 5 g/L) para se alcan?ar propriedades melhoradas dos fluidos (viscosidade aparente, viscosidade pl?stica, limite de escoamento e volume de filtrado) com 95% de confian?a, assim como as correla??es entre esses fatores (concentra??es de HPAM e bentonita). Os testes de envelhecimento t?rmico indicaram que as formula??es contendo HPAM e bentonita podem ser utilizadas ? temperatura m?xima de 150 ?C. A an?lise do reboco formado ap?s filtra??o dos fluidos por Difra??o de Raios X indicou intera??es espec?ficas entre a HPAM e a bentonita, justificando a maior estabilidade t?rmica do fluido F2 comparado ao F1, que suporta temperatura m?xima de 93 ?C. / In this study, we investigated the effect of addition of partially hydrolyzed polyacrylamide (HPAM) and bentonite in the physicochemical properties of acquous drilling fluids. Two formulations were evaluated: F1 formulation, which was used as reference, containing carboxymethylcellulose (CMC), magnesium oxide (MgO), calcite (calcium carbonate - CaCO3 ), xanthan gum, sodium chloride (NaCl) and triazine (bactericidal); and F2, containig HPAM steady of CMC and bentonite in substituition of calcite. The prepared fluids were characterized by rheological properties, lubricity and fluid loss. Calcite was characterized by granulometry and thermal gravimetric analysis (TGA). The formulation F2 presented filtration control at 93?C 34 mL while F1 had total filtration. The lubricity coefficient was 0.1623 for F2 and 0.2542 for F1, causing reduction in torque of 25% for F1 and 52 % for F2, compared to water. In the temperature of 49 ?C and shear rate of 1022 s ?1 , the apparent viscosities were 25, 5 and 48 cP for F1 and F2 formulation, respectively, showing greater thermal resistance to F2. With the confirmation of higher thermal stability of F2, factorial design was conducted in order to determine the HPAM and of bentonite concentrations that resulted in the better performance of the fluids. The statistical design response surfaces indicated the best concentrations of HPAM (4.3g/L) and bentonite (28.5 g/L) to achieve improved properties of the fluids (apparent viscosity, plastic viscosity, yield point and fluid loss) with 95% confidence, as well as the correlations between these factors (HPAM and bentonite concentrations). The thermal aging tests indicated that the formulations containing HPAM and bentonite may be used to the maximum temperature until 150 ?C. The analyze of the filter cake formed after filtration of fluids by X-ray diffraction showed specific interactions between the bentonite and HPAM, explaining the greater thermal stability of F2 compared to the fluid F1, that supports maximum temperature of 93 ?C.

[pt] Após uma jazida de petróleo ser encontrada, a produção de óleo ou gás é feita através de um poço produtor que é perfurado até atingir as camadas de rocha onde os hidrocarbonetos estão alojados. Com a constante produção, a pressão de reservatório decresce até atingir um nível que é insuficiente para o aproveitamento econômico. Geralmente, utiliza-se a injeção de água para manter o nível de pressão do reservatório. Nos estudos de um reservatório de petróleo é fundamental o conhecimento de propriedades básicas da rocha e dos fluidos nela contidos. São essas propriedades que determinam as quantidades de fluidos existentes no meio poroso, a sua distribuição, a capacidade desses fluidos se moverem e, mais importante, a quantidade de fluidos que pode ser extraída. Através do método convencional de injeção de água objetiva-se a manutenção da pressão do reservatório e o deslocamento de óleo em direção aos poços produtores. A água (fluido deslocante) tende a ocupar gradualmente o espaço antes ocupado pelo óleo (fluido deslocado), contudo, por efeitos capilares, uma parcela do óleo não é retirada do meio poroso configurando o que chamamos óleo residual. Em função da razão de mobilidade da água e do óleo, a frente de deslocamento não é uniforme, e um grande volume do reservatório não é atingido pela água de injeção. A adição de polímero à água de injeção visa o aumento da viscosidade da água, e assim, melhorar a razão de mobilidade água-óleo, aumentando a eficiência de varrido uma vez que uniformiza a frente de avanço, reduzindo a formação de caminhos preferenciais no reservatório. Além de diminuir a razão de mobilidade, soluções poliméricas podem contribuir para um melhor deslocamento de óleo em escala de poro, a partir de seu efeito elástico, reduzindo, portanto, a saturação de óleo residual. Contudo, tal mecanismo em micro-escala, ou seja, em escala de poro não é totalmente compreendido. O presente trabalho preocupa-se principalmente em analisar o fator de recuperação do óleo e saturação de óleo residual após processo de deslocamento de óleo por água salgada, solução polimérica de poliacrilamida parcialmente hidrolisada (HPAM) e solução de glicerina em testemunhos de Arenito Bentheimer. Um porta-testemunho especial foi utilizado para a realização dos testes de deslocamento, sendo monitoradas a variação de pressão ao longo da amostra, além dos volumes de injeção e produção de fluidos em função do tempo. / [en] After an oil deposit is found, oil or gas is produced through a production well that is drilled until it reaches the rock layers where the hydrocarbons are housed. With constant oil production, the reservoir pressure decreases until it reaches a level that is insufficient for economic use. Water injection is generally used to maintain the reservoir pressure level. It is essential to know the basic rock and fluid properties to study an oil reservoir. These properties determine the volume of fluids in the porous medium, their distribution, the ability of these fluids to move, and most importantly, the volume of fluids that can be extracted. The conventional water injection method aims to maintain the reservoir pressure and the oil displacement towards the producing wells. Water (displacing fluid) tends to gradually occupy the space previously occupied by oil (displaced fluid), however, due to capillary effects, an oil portion is not removed from the porous medium, configuring what we call residual oil. Because of the water-oil mobility ratio, the displacement front is not uniform and a large volume of the reservoir is not reached by the injection water. Polymer addition in the injection water aims at increasing water viscosity, and thus, improving the water-oil mobility ratio, increasing the sweeping efficiency since it unifies the advance front, reducing the formation of preferential paths in the reservoir. Besides reducing the mobility ratio, polymeric solutions can contribute to a better oil displacement in pore-scale, based on its elastic effect, reducing residual oil saturation. However, this mechanism is not fully understood in the micro-scale. The present work is concerned with analyzing oil recovery factor and residual oil saturation after the oil displacement process by saltwater, polymeric solution of partially hydrolyzed polyacrylamide (HPAM), and glycerin solution in sandstone Bentheimer samples. A special core holder was used to displacement tests, the injection differential pressure on the sample was monitored, in addition to the injection volumes and production volume as a function of time.

Technologies such as horizontal wells and multi-stage hydraulic fracturing have made ultra-low permeability shale and tight gas reservoirs productive but the industry is still on the learning curve when it comes to addressing various production issues. Some of the problems encountered while hydraulically fracturing these reservoirs are the absence of frac barriers, thinner shales and the increased presence of geological hazards. Induced vertical fractures sometimes extend to an underlying aquifer and become a conduit to the well. We have developed a low-concentration, low-viscosity and delayed-crosslink polymeric gel system as a water shutoff agent for hydraulically-fractured tight gas and shale reservoirs, where some fractures might connect to water rich zones. The system also is a significant improvement over traditional flowing gels for fracture water shutoff in conventional reservoirs because of these features. The gel uses high molecular weight hydrolyzed polyacrylamide (HPAM) at low polymer concentrations with a delayed organic crosslinker. This crosslinker is more environmentally benign and provides much longer gelation time and stronger final gels than comparable polymer loadings with chromium carboxylate crosslinkers at higher temperatures. The low viscosity system allows low-pressure extrusion of gelant into the narrow-aperture fractures present in unconventional gas reservoirs. The gelant can be pumped at low pressures due to lower polymer concentrations and delayed gelation point. This allows the potential to seal problem zones that are producing excess water even when the fractures conducting water have very narrow apertures. By impeding water production, the gel system developed here can effectively delay water loading thereby avoiding abandonment or installation of expensive equipment with increased operational costs, thus extending life and reserves of unconventional gas wells.