Effects of high oil viscosity on oil‐gas downward flow in deviated pipes. Part 1: Experimental setup and flow pattern transitions

Abstract

This work provides new experimental data on high viscosity oil-gas flow. A set of 170 downward flow experiments were carried out using a mixture of air and mineral oil (213 mPa Á s, 50.8 mm internal diameter, 21.5 m long) for five different elevations: −45 , −60 , −70 , −80 , and −85 . Superficial liquid and gas velocities varied from 0.05 m/s to 0.7 m/s and 0.7 m/s to 7 m/s, respectively. Flow pattern transitions were identified and analyzed. The results helped to evaluate the effects of pipe inclination and liquid viscosity on the stratifiedannular transition, as well as the characterization of subclasses of annular flow pattern, named falling film, liquid slip, and wavy annular. Based on the experimental evidence, the study proposes a constant liquid-fraction value as a transition between liquid slip and wavy annular flow patterns. A comparison of the present data with the flow pattern predictions of the available models were made. Results show disagreements, which justifies the need for a detailed study of the effects of viscosity and the inclination of the pipe in liquid-gas downward flow mixtures.

Effects of high oil viscosity on oil‐gas downward flow in deviated pipes. Part 2: Holdup and pressure gradient

“…The experimental study was conducted on a three-phase flow facility. The description of the facility is provided in Soto-Cortes et al [1] The downward flow section consists of a 50.8 mm ID and 22.7 m long pipe with a 7.4 m long test section (Figure 1A). The test section has a 3.6 m long transparent polycarbonate pipe.…”

“…Although downward two-phase flow is found in many engineering process applications, the deep-water oil production is a highlight. [1] The lengths of the downcomers can be quite significant, requiring more accurate pressure drop and liquid holdup prediction models.…”

“…In Part 1 of this work, [1] new experimental data on high viscosity oil-gas flow in inclined downward flow was presented. Flow patterns transitions were identified and analyzed, and the performance of some flow pattern prediction models was validated.…”