Flow Assurance for Gas-Liquid-Solid Three-Phase Flow at High Void Fraction of Gas Phase for Methane Hydrate Transport

Abstract Methane hydrate and subsea minerals have been found in the deepwater within Japan’s exclusive economic zone. However, their development has not reached the commercialization stage because many technical issues still need to be solved. Gas-lift pumping systems are one of the promising methods for methane hydrate transport from the seafloor to the sea surface. Since the internal flow in pipes becomes a three-phase flow for gas-lift pumping systems, flow assurance for the three-phase flow is essential to design the actual systems. Gas supplied into pipes deep in the sea expands as it returns to the surface. Thus, the void fractions of the gas phase in lines would be larger near sea surface than near seafloor. In addition, there are few studies on flow assurance in the conditions of a high void fraction of the gas phase. We conducted the experiment of gas-lift pumping systems using clear polyvinyl chloride pipes and resin balls as solid particles. As a result, we obtained mass flux data, void fractions, and frictional pressure drops in those conditions. Furthermore, we investigated whether the methods previously proposed clould calculate the void fractions and the frictional pressure drops in three-phase flow by comparing the calculated results with experimental data obtained from the present experiment.