[pt] O aumento do fator de recuperação e o uso de métodos de recuperação avançada no atual cenário de novos patamares de preços representam um enorme desafio para a indústria do petróleo. Neste contexto, o uso de emulsões óleo-água como um método de recuperação avançada torna-se bastante atrativo. Diversos trabalhos mostraram um aumento no volume de óleo produzido através da injeção de emulsões óleo-água. Resultados de pesquisas experimentais indicam que a injeção de emulsões pode ser utilizada como agente de controle de mobilidade, bem como reduzindo a saturação residual de óleo. A aplicação do método de injeção alternada água-emulsão-água (WAE) requer o entendimento do escoamento de emulsões no meio poroso e dos mecanismos responsáveis pela melhora na recuperação. Este entendimento tanto na escala de poros como na escala de reservatórios permite incorporação destes mecanismos na modelagem para simulação de fluxo de reservatórios. No presente trabalho foi feita a incorporação dos efeitos gravitacionais no modelo desenvolvido para o escoamento de emulsões em meios porosos através da parametrização das curvas de permeabilidade relativa em função da concentração de gotas e do Número de Capilaridade. O processo WAE foi avaliado através de simulações em duas e três dimensões (2D/3D) utilizando um conjunto de camadas do segundo modelo comparativo do SPE10. Com simulações 2D e 3D foi possível realizar um estudo de sensibilidade do processo em relação ao momento da injeção de emulsão, o tamanho do banco, e as faixas de vazão e respectivos números de capilaridades de atuação da emulsão. / [en] In the current crude oil price scenario, the increase in oil recovery factor and the use of enhanced recovery methods represent a major challenge for the Oil Industry. In this context, the use of oil-water emulsion flooding as an enhanced recovery method becomes very attractive. Several studies have shown a significant potential to increase oil volume recovery by the injection of oil-water emulsions. Experimental results indicate that the emulsions injection can be used as a mobility control agent, resulting in a more uniform fluid displacement in the reservoir and lower residual oil saturation. Based on these experimental results, the most relevant parameters for emulsion injection performance effectiveness are droplet size, the local concentration of the dispersed phase of the emulsion and the local capillary number. The application of water alternating emulsion injection (WAE) method requires understanding of the flow of emulsions in porous media and the mechanisms responsible for the improved recovery. The understanding of this process in both porous scale and reservoir scale is fundamental to model emulsion injection effects in reservoir flow simulation. In this work, the gravitational effects was incorporated in the macroscopic model to represent flow of emulsions in porous media by relative permeability curves parametrization as function of emulsion concentration and of the local capillary number. The WAE process was evaluated in two and three dimensional simulations (2D / 3D) using a set of layers of the second SPE 10 comparative model. With 2D and 3D simulations, it was possible to explore a WAE injection performance sensitivity analysis considering the time at which the emulsion injection is started, the size of emulsion bank, and the injection flow rates and consequently the flow their capillary number.

Hybrid gas/chemical Enhanced Oil Recovery (EOR) methods are such novel techniques to increase oil production and oil recovery efficiency. Gas flooding using carbon dioxide, nitrogen, flue gas, and enriched natural gas produce more oil from the reservoirs by channeling gas into previously by-passed areas. Surfactant flooding can recover trapped oil by reducing the interfacial tension between oil and water phases. Hybrid gas/chemical EOR methods benefit from using both chemical and gas flooding. In hybrid gas/chemical EOR processes, surfactant solution is injected with gas during low-tension-gas or foam flooding. Polymer solution can also be injected alternatively with gas to improve the gas volumetric sweep efficiency. Most fundamentally, wide applications of hybrid gas/chemical processes are limited due to uncertainties in reservoir characterization and heterogeneity, due to the lack of understanding of the process and consequently lack of a predictive reservoir simulator to mechanistically model the process. Without a reliable simulator, built on mechanisms determined in the laboratory, promising field candidates cannot be identified in advance nor can process performance be optimized. In this research, UTCHEM was modified to model four-phase water, oil, microemulsion, and gas phases to simulate and interpret chemical EOR processes including free and/or solution gas. We coupled the black-oil model for water/oil/gas equilibrium with microemulsion phase behavior model through a new approach. Four-phase fluid properties, relative permeability, and capillary pressure were developed and implemented. The mass conservation equation was solved for total volumetric concentration of each component at standard conditions and pressure equation was derived for both saturated and undersaturated PVT conditions. To model foam flow in porous media, comprehensive research was performed comparing capabilities and limitations of implicit texture (IT) and population-balance (PB) foam models. Dimensionless foam bubble density was defined in IT models to derive explicitly the foam-coalescence-rate function in these models. Results showed that each of the IT models examined was equivalent to the LE formulation of a population-balance model with a lamella-destruction function that increased abruptly in the vicinity of the limiting capillary pressure, as in current population-balance models. Foam models were incorporated in UTCHEM to model low-tension-gas and foam flow processes in laboratory and field scales. The modified UTCEM reservoir simulator was used to history match published low-tension-gas and foam coreflood experiments. The simulations were also extended to model and evaluate hybrid gas/chemical EOR methods in field scales. Simulation results indicated a well-designed low-tension-gas flooding has the potential to recover the trapped oil where foam provides mobility control during surfactant and surfactant-alkaline flooding in reservoirs with very low permeability. / text