Doctor of Philosophy (PhD)
The objective of this study is to investigate the characteristics of foam flow behavior in pipes in a wide range of experimental conditions, including two pipe materials (stainless steel and nylon pipes with about 0.36 - 0.38 inch in inner diameter and 12 ft in length), three surfactant formulations (Cedepal FA-406, Stepanform-1050, and Aquet-944), and three surfactant concentrations (0.1, 0.5, and 5 wt%). The concept of “two foam-flow regimes”, consisting of high-quality regime and low-quality regime, is at the heart of interpreting the experimental data. The experimental results in horizontal pipes showed the presence of two distinct high-quality and low-quality foam-flow regimes which could be identified by both pressure responses and direct visual observations. The high-quality regime was characterized by unstable and oscillating pressure responses represented by slug flow, while the low-quality regime was characterized by stable pressure responses represented by either plug flow or segregated flow. These two distinct flow regimes, separated by a locus of fg* in the contour plot, were shown to have different sensitivities to the change in gas and liquid velocities: (1) foam rheology in the high-quality regime was sensitive to both gas and liquid velocities because of the resulting changes in lengths of foam-slug and free-gas sections adjusted to the new flow conditions, and (2) foam rheology in the low-quality regime was sensitive to gas velocity because of finer foam texture at higher shear rates, and was relatively insensitive to liquid velocity because of lubricating effect and drainage effect. The results at different inclination angles showed that foam rheology was not significantly altered by the inclination angle as long as the slug-flow or plug-flow pattern was formed because of a viscous-force dominant environment. However, if flow conditions fell within the segregated-flow pattern, foam rheology was governed by the gravitational force rather than the viscous force, and therefore the flow characteristics were sensitive to inclination angles. These findings were supported by visual observations as well as pressure responses. The implication of these experimental findings is discussed for applications such as foam-assisted underbalanced drilling processes and foam-fracturing treatments in the petroleum industry.
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Gajbhiye, Rahul Narayanrao, "Characterization of foam flow in pipes using two flow regime concept" (2011). LSU Doctoral Dissertations. 2369.