Estudo do comportamento PVT de misturas de metano e fluidos de perfuração base éster / Study of the PVT behavior of methane and ester based drilling fluids mixtures


IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia




During conventional drilling operations, it is necessary to maintain the wellbore pressure greater than the reservoir pore pressure, otherwise a kick may occur. If the well control procedure is not effective during the circulation of the formation influx out of the well, a blowout could happen, which is a dangerous event concerning safety and environmental issues. Special conditions in deep and ultra deep water, scenarios where large Brazilian oil and gas reserves are located, demand for synthetic based drilling fluids because of technical characteristics such as toxicity, lubricity and shale inhibition. On the other hand, the formation gas will dissolve in the drilling fluid, making the well control operations much more complex. Methane is the major component of natural gas, while ester is an organic compound, used as the base of synthetic drilling fluids. The knowledge of the thermodynamic behavior of such gas-liquid mixtures under wellbore pressure and temperature conditions is very important for drilling operations and scientific purposes. The main objective of the present work is to understand the PVT behavior of methane and ester based drilling emulsions by experimental determination of bubble point, solubility, density and formation volume factor of the saturated and sub-saturated fluid mixture. PVT experiments were conducted on a last generation apparatus, whose main feature is the visualization of the sample fluid, under high pressure and high temperature testing conditions. Experimental tests were run up to 130 °C and up to pressures of 103 MPa. An original gas enrichment procedure was devised to cover temperature, pressure and methane concentration range with a long term, single liquid amount test. Experimental results in the bubble and dew region of the phase envelope were modeled with Peng-Robinson equation and a comprehensive discussion about the thermodynamic behavior of the system was pursued. The present work will enlarge the limited thermodynamic properties database about methane – ester system that is available in the literature and furnish scientific answers to the well control problems encountered when drilling with ester based emulsions.


solubilidade esteres engenharia de petroleo poços de petroleo - fluidos de perfuração solubility esters petroleum engineering oil wells

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