Date

2004

Author

Eren, Tuna

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Foam is one of the most frequently used multiphase fluids in underbalanced drilling operations because of its high carrying capacity of cuttings, compressibility property, formation fluid influx handling, etc. Foam rheology has been studied for many years. Researchers tried to explain foam behaviour by using conventional methods, i.e., determining rheological parameters of pre-defined rheological models like Power law, Bingham Plastic etc., as a function of gas ratio. However, it is known that bubble size and texture of the foam is also effective on foam behaviour. When foam is generated by using different foaming agents, even if the gas ratio is constant, different rheological parameters are observed. Therefore a more general foam characterization method that uses the bubble size and texture of foam is required. Improvements on image analysis, and computer technology allow monitoring the bubble size and texture of foam bubbles. A more comprehensive model of foam rheology definition in which the bubble size, and texture effects of the foam body is developed. Three different analysis methodologies are introduced; i) Generalized volume equalized approach, ii) Generalized volume equalized approach and image processing data, and iii) Image processing data only. The necessary information including the rheological information and image data is acquired from the experimental set-up developed for this study. It has been observed that, the pressure losses could be predicted as a function of bubble size, circularity and general rheological parameters, in ?20 % certainty limit. It is also observed that using only the image information is possible to characterize the foam in an accurate and fast manner.

Subject Keywords

General Science.

URI

http://etd.lib.metu.edu.tr/upload/12605373/index.pdf
https://hdl.handle.net/11511/14505

Collections

Graduate School of Natural and Applied Sciences, Thesis