Improvement of LedaFlow for churn flow in vertical pipes

An experimental study of vertical two-phase flow was conducted at the SINTEF Multiphase Laboratory using a 51 meter long 4" pipe at system pressures of 45 and 70 bara. This campaign was conducted as part of a project aimed at improving the physical models in LedaFlow for near-vertical pipes, and was divided into several parts. The first part was dedicated to liquid loading in wells, and was published in BHRG 2016 [1]. The current paper describes the second part of the campaign, which was focused on liquid dominated steady-state flows in vertical pipes. In order to extract sufficient information about the flow characteristics in the experiments, the pipe was equipped with ten DPcells, nine static gamma densitometers, one traversing gamma densitometer and one dual wire mesh sensor. The experiments covered all the important flow regimes (bubbly flow, slug flow, churn flow and annular flow), yielding a unique and highly relevant data set with detailed measurements. The new data set, combined with data from previous vertical flow campaigns, was subsequently used to derive improved closure laws for LedaFlow, with particular emphasis on the difficult churn flow regime. The new models were found to improve the overall holdup and pressure drop predictions significantly.