Prediction of Two-Phase Flow Splitting in Looped Lines Based on Energy Minimization

Abstract

Abstract Looped gas-liquid multiphase flow pipelines are utilized by the oil and gas industry to reduce pressure drop and to increase flow capacity. They can be installed alone as a flow splitter, or they can be combined in series to form a manifold. Application of looped lines is not unique to the petroleum industry, as they are also applied in other industries such as the nuclear and chemical. There has not yet been a comprehensive fundamental investigation of the flow behavior or predictive methods available for such systems because of the huge complexity involved with respect to several process variables such as flow patterns, fluid properties, phase velocities as well as the pipe geometry. Uneven splitting of the gas and liquid phases between the two looped lines can cause malfunction of the downstream processing equipment. In this study, over 65 experiments at different flow conditions are conducted in a looped system utilizing unequal diameter looped line configurations to investigate the pressure drop during the uneven flow splitting. Most of the experiments were carried out with slug flow at the system inlet, while flow patterns such as slug flow, dispersed flow and stratified flow were observed in the looped pipes. A novel computational algorithm is developed for predicting gas-liquid two phase flow splitting in the looped lines, based on energy minimization. The algorithm predicts the uneven splitting of the two phases as well as the corresponding pressure drop along the loop. Good agreements have been achieved between the measured and predicted flow splitting and pressure drop along the looped lines.