Special Oil & Gas Reservoirs ›› 2024, Vol. 31 ›› Issue (4): 156-162.DOI: 10.3969/j.issn.1006-6535.2024.04.020

• Drilling & Production Engineering • Previous Articles     Next Articles

Experiment and Prediction Method of Liquid Holdup of Gas-liquid Two-phase Slug Flow with Different Viscosity in Inclined Tube

Liu Zilong1,2, Qian Xiao1,2, Liu Chao3, Guan Tong4, Wang Wei5, Liao Ruiquan1   

  1. 1. Hubei Key Laboratory of Drilling and Production Engineering for Oil and Gas, Yangtze University, Wuhan, Hubei 430100, China;
    2. Laboratory of Multiple Phase Pipe Flow Gas Lift Innovation Center, CNPC, Wuhan, Hubei 430100, China;
    3. CNPC Bohai Drilling Engineering Company, Limited, Langfang, Hebei 065000, China;
    4. PetroChina Huabei Oilfield Company, Renqiu, Hebei 062550, China;
    5. PetroChina Tuha Gas Lift Technology Center, Shanshan, Xinjiang 839009, China
  • Received:2023-08-12 Revised:2024-04-29 Online:2024-08-25 Published:2024-09-20

Abstract: Accurate prediction of liquid holdup provides important basis for flow pattern identification and pressure drop calculation in wellbores. Slug flow is the most common flow pattern in heavy oil wellbores. High-viscosity fluids in the wellbore will exacerbate gas-liquid two-phase slippage, resulting in poor prediction accuracy of existing holdup models applied to high-viscosity fluids. Therefore, a new model for liquid holdup in gas-liquid two-phase slug flow in inclined pipes with different viscosities is proposed. This proposal is based on experimental observations and theoretical derivations. The holdup experiments of slug flow are conducted in a multiple phase pipe flow experimental platform, in a test string with an inner diameter of 60 mm. The influence of viscosity on liquid holdup and flow pattern transitions is studied based on the data of slug flow patterns and liquid holdup obtained with different viscosities and different inclinations in the experiments. The study shows that an increase in liquid viscosity will intensify the viscous resistance between the liquid phase and the pipe wall, resulting in a rise in liquid holdup. While the effect of viscosity on liquid holdup will change the transition boundaries between slug flow and other flow patterns. A new model for liquid holdup in gas-liquid two-phase slug flow in inclined pipes is established. This model is based on the Kora liquid holdup relationship formula and uses mixed-phase viscosity instead of liquid-phase viscosity. The model is validated by experimental and literature data, with confirmed higher accuracy. This research can provide technical support for predicting pressure drop in heavy oil wellbores.

Key words: slug flow, liquid holdup, gas-liquid two-phase flow, inclined pipes, heavy oil

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