Development of a multi-fluid model for multiphase flows in oil and gas wells A.A. Osiptsova, A.B. Starostina, and B.I. Krasnopolskya,b We present the results of the development of a multi-fluid model for a transient multiphase flow in a pipe with application to cleanup of oil and gas wells after drilling or hydraulic fracturing. The 1D multi-fluid model governs a transient isothermal flow of three compressible fluids in a horizontal, deviated, or vertical pipe. It is able to predict the flow regimes with a single interface between gas and liquid mixture: stratified-smooth, stratified-wavy, and slug-flow regimes. The multi-fluid research code is built in C based on SIMPLE pressure-velocity coupling algorithm. The code is validated on the flow pattern maps. An agreement is found in predicting the transition between the regimes. The code results for the wavy flow regime are also found to be in agreement with linear stability analysis. The model is an extension of the earlier work on multi-fluid models for near-horizontal pipes1,2 to any inclination angle and additional phases. a Dep. Well Testing, Schlumberger Moscow Research, 13 Pudovkina Str., Moscow, Russian Federation. bInstitute of Mechanics, Lomonosov Moscow State University, 1 Michurinsky Ave., Moscow, Russian Federation. 1 Bonizzi and Issa, I.J. Multiphase Flow. 29, 1719 (2003). 2 Bonizzi et al., I.J. Multiphase Flow. 35, 34 (2009). 3 Issa and Kempf, I.J. Multiphase Flow. 29, 69 (2003). 4 Taitel and Dukler, AIChE J., 22, 47 (1976). liquid superficial velocity UL [m/s] 10 Surface stability Waves breaking SLUGS 1 WAVY STRATIFIED 0.1 0.01 0.1 1 10 100 gas superficial velocity UG [m/s] Figure 1: Analytically constructed flow pattern and predictions of the present multi-fluid model for horizontal flow. Background: earlier multi-fluid model3 and flow regime margins4.
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