Design and flow field characteristics analysis of spiral-uniflow coupled gas-liquid separator with wide range of inlet gas volume fractions

During the exploitation of low permeability oilfields, associated gas will be produced with crude oil. The intermittent pumping method leads to a large range of gas-liquid ratio of produced liquid. Although a little separator can meet the separation requirements of oil field, there are problems such as difficult operation or large structure size. Therefore, a spiral-uniflow coupled gas-liquid separator was designed in this study, and the separation mechanism, flow field characteristics and separation performance were analyzed by numerical simulation. The results show that under the action of stabilizing fluids and pre-separation of the primary-separator, the uniformity of the velocity and pressure distribution, the degree of gas-phase aggregation, the stability of the stratification interface and the separation speed of the gas-liquid two-phase of the secondary-separator are significantly improved. With the increase of gas volume fraction, the pressure drop of the separator decreases from 623kPa to 159kPa, and the separation efficiency increases first and then decreases. Under the synergistic effect of the coupling separation mechanism and the progressive gas-liquid separation, the lowest separation efficiency is still as high as 74.6%. The design goal is achieved, which provides a new design for gas-liquid separator with the wide range of inlet gas volume fractions.