Potencial da jazida de Charqueadas para o armazenamento geológico de CO2 e produção de gás natural utilizando parâmetros petrofísicos e testes de adsorção

• Autor(a) principal: Santarosa, Cristian Sartori
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/3237
• topic: ENGENHARIA DE MATERIAIS; CAPTURA DE CARBONO; CARBONO - ARMAZENAMENTO; GÁS NATURAL; CNPQ::ENGENHARIAS

Coal is one of the most abundant energy resources. The Rio Grande do Sul State has about 90% of all coal in Brazil. This energy source is used in small proportion compared to hydropower plants, for example. But coal is also a strategic resource, it is a complementary source to those used on a larger scale. It is a resource that doesn´t depend on seasonality, and therefore constitutes an important energy security backup. The quest for a greater knowledge and understanding of Brazilian coals situation and its exploitation or in situ use possibilities can contribute to provide an energy resource that today is not considered accessible, especially for the southern region of Brazil. This thesis is focused on the Charqueadas Reservoir, its petrographic characterization, comparison of its theoretical and measured storage capacity for CO2, through sorption tests at the Department of Energy (DOE) laboratories (USA), compared with structural changes in the rock through imaging acquired through computed tomography (CT). These tests will also determine the viability of coalbed production (CBM) and carbon sequestration (CCS). The studied coal has, when taken into account CBM, ECBM and CCS activities, porosities considered normal (in the range of 1 to 5%). As for the permeability for the same activities, it´s considered very low (within the range of hundreds of nanoDarcys). The results of the pre-scans imaging indicate the existence of a high density material in the fractures (cleats), which explains the results of low permeabilities measured on the samples. Imaging using microtomography also showed this feature, indicating high density material filling the microfractures, which consequently reduces the permeability and gas adsorption. The adsorption isotherms indicated a significant amount of CO2 adsorption into the Charqueadas coal micro-structure is possible, but the larger scale results of the core permeability, microtomography, and pre-injection scans (which indicated the existence of a high density material filling fractures) revealed fluid motion within the coal would be difficult. This result was confirmed by the core-scale sorption tests in the coal samples, which indicated that sorption of CO2 in the Charqueadas Deposit would not be easily carried out.