Estudo de emulsões de petróleos brasileiros por ressonância magnética nuclear (RMN) de baixo campo bidimensional

• Autor(a) principal: Carneiro, Giovanna da Fraga
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/4679
• topic: RMN de Baixo Campo; Petróleo; Emulsões; Química; Ressonância magnética nuclear; 54

Emulsions are a common issuein crude oil exploration, since water is also found in hydrocarbon reservoirs or can be injected in enhanced recovery projects. Although common, emulsions are a problem in oil industry and low-field 1H Nuclear Magnetic Resonance (NMR) can be a powerful tool for studying them. Longitudinal and transverserelaxation times(T1and T2, respectively)and diffusion coefficient (D) are properties measured through low-field NMR that can help inferring many properties of the fluids involved in the oil production.Two-dimensional NMR, specially, has a high potential for emulsion characterization for combining in one experiment, for example, T2and Dinformation. In this study4 oils were analyzedthrough bidimensional NMR techniques, resulting in T1-T2and D-T2plots. Two of the crude oils studied were water free, so emulsions were prepared by the addition ofMnCl2doped water. The other crudes already presentedemulsions. T2distribuition curves allowed the quantification of water in oil in the cases where water and oil presented different T2values, yielding 23% error for one crude oil and an average of 10% for a set of prepared emulsions.For theemulsions preparedin the laboratory, the separation of the phases was recordedby NMR measurements. For some of these prepared emulsions demulsifiers were added and their speed of action could be evaluated. D-T2plots allowed the visualization of different water behaviors–more or less restricted –due to water in oil emulsion, which can be correlated to droplet size distribution. Quantification of water in oil through Ddistribution curves was not possible.