Modern oil/gas well drilling methods in particular in the offshore industry involve deviated drilling in which the production tubing can be inclined at any angle between the vertical and the horizontal. Riser tubes from the seabed to the surface or to floating production vessels (FPSO) will also rarely be exactly vertical. This work describes a study carried out at the University Of Nottingham on the effects of inclination on gas / liquid slug flow. Two advanced tomography techniques were applied simultaneously to the flow of a mixture of air and silicone oil in a 67 mm internal diameter pipe and the pipe was inclined at various angles. A twin plane Electrical Capacitance Tomography (ECT) electrode system driven by Tomoflow electronics was positioned below a Capacitance Wire Mesh Sensor (WMS) developed at Forschungszentrum Rossendorf-Dresden/Germany M. J. Da Silva et al [2]. This enabled an examination of the flow to be carried out at several levels of complexity. Both measuring sensors provide time and cross-sectionally resolved information about the spatial distribution of the phases. Conditions studied were superficial velocities for air ranged from 0.05 to 5.5 m/s and for silicone oil ranged from 0.0 m/s to 0.5 m/s. In present paper, the effect of inclination on the phase distribution in two phase gas liquid slug flow is presented. The liquid hold up within the slug region and in the elongated bubble zone and the averaged liquid hold up were calculated from the output data of the two measurements techniques. Radial gas volume fraction profiles and bubble size distributions were also processed from the wire-mesh sensor data. The shapes of the large bubbles and waves were compared for different inclination angles. The results indicate that the pipe inclination has a significant effect on the slug flow characteristics. Both Taylor bubble and small bubbles in the slug region tend to flow along the upper pipe wall and causing significant variation of Taylor bubble rise velocity with inclination angle.

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