doctoralThesis
Metodologia para avaliação de cinemática de partículas gasosas em fluidos de viscosidade variável com o tempo e sua aplicação na construção de poços de petróleo
Fecha
2012-12-17Registro en:
PINTO, Gustavo Henrique Vieira Pereira. Metodologia para avaliação de cinemática de partículas gasosas em fluidos de viscosidade variável com o tempo e sua aplicação na construção de poços de petróleo. 2012. 222 f. Tese (Doutorado em Pesquisa e Desenvolvimento em Ciência e Engenharia de Petróleo) - Universidade Federal do Rio Grande do Norte, Natal, 2012.
Autor
Pinto, Gustavo Henrique Vieira Pereira
Resumen
Many challenges have been presented in petroleum industry. One of them is the
preventing of fluids influx during drilling and cementing. Gas migration can occur as
result of pressure imbalance inside the well when well pressure becomes lower than gas
zone pressure and in cementing operation this occurs during cement slurry transition
period (solid to fluid). In this work it was developed a methodology to evaluate gas
migration during drilling and cementing operations. It was considered gel strength
concept and through experimental tests determined gas migration initial time. A
mechanistic model was developed to obtain equation that evaluates bubble displacement
through the fluid while it gels. Being a time-dependant behavior, dynamic rheological
measurements were made to evaluate viscosity along the time. For drilling fluids
analyzed it was verified that it is desirable fast and non-progressive gelation in order to
reduce gas migration without affect operational window (difference between pore and
fracture pressure). For cement slurries analyzed, the most appropriate is that remains
fluid for more time below critical gel strength, maintaining hydrostatic pressure above
gas zone pressure, and after that gels quickly, reducing gas migration. The model
developed simulates previously operational conditions and allow changes in operational
and fluids design to obtain a safer condition for well construction